Indoor allergens in school and day care environments

Article Outline

• Abstract
• Exposure to indoor allergens in day care and school environments
  • Study designs and exposure assessment
  • Allergen levels and exposure characteristics
    • Exposure to cat and dog allergens
    • Exposure to dust mite allergens
    • Exposure to cockroach and rodent allergens
    • Exposure to fungal allergens
• Indoor allergen exposures in day care and school environments in relation to allergy and asthma
• Environmental control, remediation, and interventions in school environments
• Summary and conclusions
• Research needs and recommendations
• Acknowledgment
• Table E1. 
• Table E2. 
• Table E3. 
• Table E4. 
• Table E5. 
• References
• References
• Copyright

Most studies that have examined exposure to indoor allergens have focused on home environments. However, allergen exposures can be encountered in environments other than the home. For example, many children spend a large part of their time in schools and day care facilities. Over the past 2 decades, a large number of studies have been conducted in school and day care environments. However, the role of indoor exposures in allergy and asthma development or morbidity in these settings is not well characterized. The purpose of this review is to evaluate the importance of indoor allergen exposures in school and day care settings. We summarize the key findings from recent scientific literature, describe exposure characteristics, discuss the role of these exposures in relation to asthma and allergy symptoms, and provide information on the effectiveness of published interventions.

Key words: Allergen, indoor, exposure, asthma, allergy, school, day care

Abbreviation used: MUP, Mouse urinary protein (mouse allergen)

Exposure and sensitization to indoor allergens are important risk factors for asthma and allergic respiratory diseases.¹ Although the role of indoor allergen exposure in the development of allergic sensitization and asthma remains subject to debate, there is strong evidence that indoor allergens play a key role in triggering and exacerbating allergy and asthma symptoms.²

Most studies of indoor allergens have targeted home environments because homes are often considered the primary sites of exposure. Over the past decades, the importance of nonresidential indoor environments has also been recognized.³ For example, in schools and day care facilities, allergen and other indoor exposures can affect children's health because children spend a large part of their childhood and adolescent years in these environments.

This review focuses on the importance of indoor allergen exposures in day care and school environments. The purpose of this article is to summarize key findings from the scientific literature and to identify future research needs. Studies for this review were searched by using the following databases: PubMed, Embase, Web of Science, Scopus, and Education Resources Information Center. Although inhalation of food allergens might induce allergic reactions in sensitive individuals, food allergens, which can constitute an important part of allergen exposures in day care and school settings, are beyond the scope of this review. Furthermore, the relevance of exposures other than aeroallergens (eg, environmental tobacco smoke, endotoxin, volatile organic compounds, and other irritants) will not be discussed, although these exposures might also affect indoor air quality and occupants' health status.

Back to Article Outline

Exposure to indoor allergens in day care and school environments 

Study designs and exposure assessment 

Indoor allergen exposures in schools and day care centers have been an area of continuing research interest. Studies have been conducted worldwide,⁴, ⁵, ⁶, ⁷, ⁸, ⁹, ¹⁰, ¹¹, ¹², ¹³, ¹⁴, ¹⁵ but the research has been most active in the United States and Scandinavian countries.¹⁶, ¹⁷, ¹⁸, ¹⁹, ²⁰, ²¹, ²², ²³, ²⁴, ²⁵, ²⁶, ²⁷, ²⁸, ²⁹, ³⁰, ³¹, ³², ³³, ³⁴, ³⁵ Although most studies have targeted school environments, the number of studies that have assessed allergen levels in day care centers has increased over the past decade.⁷, ⁹, ¹¹, ¹⁵, ¹⁹, ²², ²⁴, ²⁸ To date, studies have mainly been cross-sectional in design. Some studies, however, have examined seasonal variation in allergen levels.¹⁶, ²⁰

Cat (Fel d 1), dog (Can f 1), dust mite (Der f 1 and Der p 1), cockroach (Bla g 1 and Bla g 2), and mouse (Mus m 1 and mouse urinary protein [MUP]) allergens and molds have been the most frequently studied allergens. Although sampling and analytic procedures used in the studies vary considerably, allergen concentrations are usually quantified by using antibody-based ELISAs.³⁶ However, methodological differences can contribute to the variability of the findings and complicate comparisons between studies. For example, differences in sampling equipments (eg, flow rate, vacuum power, and collection devices), sampling locations, and used metrics can make comparisons difficult.³⁶ In general, correlations between different sampling methods have been poor.³⁷ In most studies allergen levels have been assessed in settled dust samples collected from various indoor sites. Air sampling techniques have been primarily used for pet allergens (eg, Fel d 1), which are carried on aerodynamically smaller-sized particles and remain airborne for longer periods of time. Studies that have assessed allergen levels on the surface of clothing have also used tape sampling.³⁸

Allergen levels and exposure characteristics 

Table E1, Table E2, Table E3, Table E4, Table E5 in this article's Online Repository at www.jacionline.org summarize the main findings on cat, dog, dust mite, cockroach, and mouse allergen levels from published studies that have examined indoor allergen exposures in day care and school environments in the past 2 decades.

Numerous studies have shown that animal allergens can be present in environments in which no animals reside.³, ⁴ In schools and day care centers, cat (Fel d 1) and dog (Can f 1) allergens are frequently detected, but the levels of exposure vary greatly. In general, these common aeroallergens are found at low levels (see Table E1, Table E2) in these settings. Nonetheless, although the magnitude of exposure tends to be low, studies have demonstrated that allergen levels in educational facilities can be higher than in homes where no pets are present.²¹, ²⁹

Cat and dog allergen levels have generally been found in higher levels in carpeted and upholstered areas.⁴, ¹⁰, ¹⁸, ¹⁹, ²³, ²⁶ Levels in carpeting are often significantly lower than levels in upholstered seats.⁴, ²⁷ It is not uncommon that allergen levels in these locations sometimes exceed thresholds that have been associated with allergic sensitization (1.0 μg/g for Fel d 1 and 2.0 μg/g for Can f 1) or asthma symptoms in sensitized individuals (8.0 μg/g for Fel d 1 and 10.0 μg/g for Can f 1).³⁹, ⁴⁰ The highest average concentrations have been found in US and Swedish schools; in samples collected from chairs and desks, geometric means reached as high as 11.3 μg/g for Fel d 1 and 15.0 μg/g for Can f 1.²⁹

There is strong evidence that clothing is the primary transfer mechanism and source of pet allergens.¹⁰, ¹⁷, ⁴¹, ⁴² Among schoolchildren, allergen levels have been found to be significantly higher in dust collected from pet owners' clothing than from clothing of non–pet owners.¹⁰, ³⁸, ⁴¹ Still, allergen levels can be dependent on clothing type and washing frequency.¹⁰, ⁴² A recent study has suggested that in addition to clothing, human hair might be a source for transfer and deposition of pet allergens among schoolchildren.⁴³ Several studies worldwide have demonstrated that levels of cat and dog allergens in day cares and schools correlate with the number of children and staff who have either dogs or cats at home or have frequent contacts with these pets.¹⁰, ¹⁵, ¹⁷, ²⁴, ²⁶, ⁴⁴, ⁴⁵ Increased allergen levels have been detected in both dust and air samples. For example, concentrations of Fel d 1 and Can f 1 in settled dust were significantly lower in Swedish day care centers in which neither children nor staff owned pets compared with centers in which cat and dog ownership was common (median Fel d 1 levels, 0.64 vs 5.45 μg/g; median Can f 1 levels, 0.39 vs 2.51 μg/g).⁴⁵ In another study there was a 5-fold difference in median levels of airborne Fel d 1 between classes with many (>25%) and few (<10%) cat owners.¹⁷

In summary, published data suggest that schools and day care centers can be important sites of exposure to cat and dog allergens, particularly for susceptible individuals (eg, sensitized children who do not have pets at home). However, not all studies link these environments to increased exposure levels. The number of pet owners at school or day care centers is one of the strongest predictors of increased cat and dog allergen levels in these settings.

Studies show that dust mite allergens (Der f 1 and Der p 1) are found in low levels in many schools and day care facilities (Table E3). Reported levels are often similar or slightly lower than in corresponding local homes.⁵, ⁷ Because ambient relative humidity is a key environmental factor that influences mite populations,⁴⁶ dust mite allergen levels are strongly associated with humidity levels. To survive and thrive, dust mites require that the relative humidity of air is greater than 55% for a sufficient period of time because water vapor in air is their main source of water. Although mite levels tend to exhibit seasonal fluctuations that parallel those in ambient relative humidity, additional factors, including human activities and heating, ventilation, and air conditioning practices, can influence indoor air humidity levels.⁴⁶, ⁴⁷ In the studied facilities the highest average concentrations were detected in Brazil and in some humid regions in the United States (eg, Florida, Texas, Alabama, North Carolina, and Virginia).¹⁶, ²², ²³, ²⁹ In contrast, very low dust mite allergen levels have been found in colder and drier climates (eg, Scandinavia).⁶, ²¹, ²⁴, ²⁵, ²⁶, ²⁹ Levels of Der p 1 were often higher in more humid regions.¹⁶, ²², ³⁴ Although concentrations of Der f 1 and Der p 1 tend to be correlated, they can reflect biologic and ecologic differences between the 2 mite species. Furthermore, the presence of other mite species can also influence concentrations of Der p 1 and Der f 1.¹², ⁴⁶

As in residential environments, dust mite allergen levels in day care centers and schools tend to be significantly higher in carpeted areas.⁷, ¹⁴, ¹⁵, ¹⁶, ¹⁸, ³⁴ Although this is a consistent finding throughout all geographic regions, the highest levels are often detected in humid climates. For example, high average concentrations (geometric mean, 7.0 μg/g) in carpeting were reported in rural schools in North Carolina.²³ Furthermore, study sites in which dust mite allergen concentrations exceeded a provisional threshold level representing increased risk of sensitization (>2 μg/g) were typically located in humid regions.⁴⁸ In Florida, for example, dust mite allergen levels were greater than 2 μg/g in 40% of the studied day care centers,²² and in Texas Der p 1 concentrations exceeded the threshold in all types of schoolrooms, particularly in libraries (68%).¹⁶ However, none of the median or mean concentrations exceeded a threshold (>10 μg/g) that has been associated with asthma symptoms.⁴⁹ In addition to carpeting, upholstered furnishings (eg, mattresses, pillows, seats, stuffed animals, and toys) can also be important reservoirs for dust mite allergens, particularly in day cares and elementary schools.⁷, ¹¹, ¹⁶ Although dust mite allergens can be transferred passively between environments,⁴² it is not known whether the amounts of passively transferred allergen are clinically relevant.

Given that dust mite allergens are primarily associated with large-size particles that settle rapidly, few studies have examined airborne dust mite allergen levels in day care or school environments. A recent study demonstrated that airborne mite allergens were present in the majority of the studied day care centers (80%) in which group 1 mite allergen levels in dust exceeded the clinically relevant threshold (>2 μg/g).²² Airborne dust mite allergen levels were significantly lower during the nighttime, suggesting that mite allergens can become airborne because of reservoir disturbance during daily activities in day care settings. The highest airborne levels were recorded in the day care center with the highest mite allergen level in the carpet (21.8 μg/g).

In summary, dust mite allergen levels in schools and day care centers are associated with climatic, geographic, and building-related factors. Carpeting and upholstered furnishings are important reservoirs and sources of exposure in schools and day care centers, particularly in humid regions.

Most studies that have examined levels of cockroach (Bla g 1 and Bla g 2) and rodent (MUP) allergens in schools and day care centers have been conducted in the United States (Table E4, Table E5). Cockroach and mouse allergens are commonly detected in schools that serve low-income and inner-city populations, as well as in rural schools.¹⁶, ¹⁸, ²⁰, ²³, ²⁸, ³⁰, ³¹, ³⁴, ³⁵ A recent study found detectable levels of cockroach allergen in 71% of the dust samples.²⁰ In another study mouse allergen was found in 100% of the samples.²⁸ Cockroach and mouse allergens have also been present in airborne samples, although the detection frequency has been much lower than in dust samples (21% for Bla g 2 and 5% for MUP).²⁰

Allergen levels show great variability between and within schools.¹⁸, ²⁰, ³⁵ For example, geometric mean concentrations for mouse allergen varied from 0.21 to 133 μg/g in a recent study.²⁰ Although increased cockroach allergen levels (>2 U/g) have been found in many schools,¹⁶, ³⁰, ³¹ low allergen levels are not uncommon in inner-cities.³⁵ Increased cockroach allergen levels have also been reported in rural schools in the United States and some other countries.⁴, ¹¹, ¹², ²³ However, all median or mean concentrations of cockroach allergen were lower than a threshold of 8 U/g, which has been associated with asthma exacerbation.⁵⁰ Some studies have suggested that exposure to cockroach and mouse allergens in schools and day care centers might be similar to that which occurs in homes.²⁰, ²², ³¹ On the other hand, a recent study demonstrated that exposure to mouse allergen can be significantly higher in schools than in homes.³⁵

The highest levels of cockroach and mouse allergens are often found in cafeterias, kitchens, or rooms where food sources are present.¹⁸, ³¹, ³⁵ In an inner-city school kitchen, cockroach allergen concentration was reported to be as high as 591 U/g³¹; correspondingly, the highest mouse allergen concentration was found in a school cafeteria (238 μg/g).³⁵ Visual evidence of cockroach and rodent infestations in schools is another factor that is strongly associated with cockroach and mouse allergen levels.²⁰, ³¹ Therefore indirect exposure to cockroach and rodent allergens in school environments is thought to be less likely.³¹, ³⁵ It is important to note, however, that detectable levels of these allergens can be found without visual evidence of infestations.²⁰ In contrast to pet and dust mite allergens, cockroach and mouse allergen levels have often been higher in noncarpeted areas.¹⁸, ²⁰, ³⁵ Nonetheless, high allergen levels have also been reported in carpeting in rural schools.²³ It is unknown whether this reflects preferences in floor-covering choices in different locations; carpeting appears to be uncommon in inner-city schools.²⁰, ³⁵ Studies have shown that cockroach and mouse allergen levels can also vary by season and region.¹⁶, ²⁰, ³⁰

In summary, recent studies suggest that schools might be important sites for exposure to cockroach and mouse allergens, particularly in locations where roach and rodent infestations are common. However, information on the relative importance of cockroach and mouse allergen exposures in schools and day cares is limited.

Several molds produce allergens that can be risk factors for allergic disease, including asthma.⁵¹ However, a major limitation in assessing exposure to fungal allergens has been the difficulty of the accurate quantification of the exposure. Exposure to fungal allergens has usually been estimated by using indirect methods, considering spores as indicators of the presence of allergens.⁵¹ Nonetheless, spore counts might not accurately reflect allergen exposure because allergen content in spores might vary and fungal allergens can be carried by means other than intact spores (eg, hyphal fragments).⁵² Because the availability of fungal immunoassays has been limited, only a few studies have assessed antigenic and allergenic components of fungi with immunoassays. One study that examined indoor allergen levels in day care facilities in the United States detected Alternaria alternata in 100% of dust samples,¹⁹ whereas in another study in Singapore, Asp f 1 was detected only in 15.4% of the samples.¹⁵

In summary, the complexity of the fungal exposure assessment and the lack of clearly defined threshold levels for fungi and substances derived from fungi (eg, allergens) have limited studies of fungal allergen exposures in day cares and school settings.

Back to Article Outline

Indoor allergen exposures in day care and school environments in relation to allergy and asthma 

Indoor air quality in schools and day care environments can affect millions of people, including students and staff. In the United States more than 50 million children are enrolled in public and private schools, and more than half of the children ages 3 to 5 years have attended center-based childcare programs over the past decade.⁵³ Asthma and allergies are important public health concerns, not only in terms of health care costs but also in terms of lost productivity and reduced quality of life. For example, asthma and allergies account for more than 16 million missed school days per year in the United States.⁵⁴, ⁵⁵ Among school-aged children, asthma is the leading cause for absenteeism and can influence a child's academic performance and ability to participate in school-related activities.⁵⁶ Importantly, the burden of asthma in schools extends beyond children; a recent report suggests that asthma within the educational services industry is an occupational health problem, particularly among teachers and teacher's aids.⁵⁷

Although people tend to spend the majority of their time at home,⁵⁸ allergen exposures can be encountered in environments other than the home. Schools and day care centers, where children and teachers spend a large part of their time, can be important sites for indoor allergen exposures. Especially for younger children, the timing of exposure can be critical because IgE-mediated sensitivity to specific aeroallergens develops in early childhood.⁵⁹ In day care and elementary school classrooms, which often have a variety of potential allergen reservoirs (eg, upholstered furniture, pillows, stuffed animals, and toys), exposure levels might be higher than in middle and high school classrooms.¹⁶, ²⁶ Moreover, the disturbance of allergen reservoirs is more likely because children at younger ages are more physically active.

Remarkably few studies to date have evaluated the relationship between asthma- and allergy-related outcomes and indoor allergen exposures in school and day care environments. Most studies that assessed allergen exposures in these environments were primarily designed to determine exposure characteristics. Although some studies reported prevalence rates for atopic outcomes, few studies used multivariate analysis to investigate relationships between health outcomes and exposures. Only a small number of the reviewed studies assessed allergen levels simultaneously in school and home environments (see Table E1, Table E2, Table E3, Table E4, Table E5).

In schools and day cares in which occupant density is high, the magnitude of indirect exposure to pet allergens might be sufficient to induce or maintain symptoms. Indeed, several Swedish studies have suggested that indirect exposure to cat and dog allergens in schools might influence asthma morbidity.²⁵, ⁶⁰, ⁶¹ In a recent study asthmatic children who had diagnosed cat allergy but did not report any direct contact with pets were evaluated after they returned to school after summer break. Those children who attended classrooms in which more than 18% of the students owned 1 or more cats reported significantly decreased peak expiratory flow rates, more asthma symptom days, and increased use of asthma medication than children who attended classes with fewer cat owners (≤18%).⁶⁰

Another study demonstrated that asthmatic children with cat and dog sensitivity had significantly increased bronchial reactivity to inhaled methacholine after 1 school week.⁶¹ In this study concentrations of cat and dog allergens were found higher in school dust than in dust collected from children's homes, suggesting greater exposure in school than in home. Among Swedish schoolchildren, cat allergen levels in dust samples have also been associated with the incidence of asthma diagnosis.³²

Recently, a German study examined whether exposure to cat allergen in the school environment was associated with allergic sensitization rates.⁶² Among school-aged children who did not have regular contact with cats, cat-specific sensitization rates increased in a dose-response fashion, depending on the percentages of students in class or school reporting regular contact with cats.

In the United States only 1 study has examined asthma prevalence in relation to the presence of common indoor allergens in the school environment. This study found a positive correlation between asthma prevalence rates and levels of cockroach allergen in schools.¹⁸

Over the past decades, numerous studies have reported positive associations between respiratory morbidity (eg, asthma) and exposure to fungi in indoor environments,⁶³, ⁶⁴ including schools and day care centers.⁶⁵, ⁶⁶, ⁶⁷, ⁶⁸ However, the underlying mechanisms for the observed health effects are not well characterized. Although fungal allergens can induce IgE-mediated hypersensitivity,⁶⁹ exposure to fungi might also induce non–IgE-mediated inflammatory and immunologic processes; particulates derived from fungi not only contain allergens but also contain a variety of biologically active molecules (eg, β-1,3-glucans).³, ⁷⁰ It has also been suggested that fungal exposure might promote adjuvant effects on allergic immune responses.⁷¹

In summary, although published studies demonstrate the importance of the school environment, the relationship between allergic respiratory diseases and indoor allergen exposures in schools and day cares is not well characterized. Although studies suggest that exposure to pet allergens in schools might influence asthma morbidity, studies provide limited information on whether exposures to indoor allergens in schools and day cares contribute to the development of allergic sensitization and asthma.

Back to Article Outline

Environmental control, remediation, and interventions in school environments 

Most studies designed to evaluate methods for reducing indoor allergen exposures in schools and day care facilities have been conducted in Sweden and have primarily focused on reducing cat and dog allergen exposures. Swedish researchers found that cat allergen levels were significantly reduced in classrooms that required the use of special school clothing compared with control classrooms.³⁸ Intervention measures, however, were rigorous; children with and without pets changed clothes separately, school clothes were worn and laundered only at the school, staff changed their clothes before entering the classroom, a separate entrance was used for allergic children, and no other children were allowed in the area of the school where the special school clothing classrooms were located. The study also showed that similar reductions in cat allergen levels were achieved by implementing a pet ownership ban in which parents agreed not to keep furred pets or birds at home.

Another intervention study examined whether increased cleaning and reduction of potential reservoirs were efficient measures to reduce cat allergen levels in classrooms.⁷² In the intervention classrooms open shelves, upholstery, carpets, curtains, and plants were removed, and cleaning was increased. Children were asked to avoid contact with pets in the mornings before school. The intervention classrooms were compared with control classrooms and allergy-prevention classrooms that had been established before the start of the study. The allergy-prevention classrooms, which were located in a separate school building, had implemented extensive allergen avoidance measures for several years. No differences in cat allergen levels were found in the intervention classrooms before and after the intervention. The allergy-prevention classrooms had a trend toward lower levels of cat allergen than both the intervention and control classrooms.

An earlier Swedish study also evaluated whether extensive renovation, installation of a new ventilation system, ventilated floors, cleaning habits, and pet-avoidance measures (ie, families and personnel avoiding direct and indirect contacts with pets) influence cat and dog allergen levels.⁷³ The intervention measures reduced cat and dog allergen levels substantially (6-fold reduction for Fel d 1 and 10-fold reduction for Can f 1) in a day care facility.

In Australia a “low-allergen” school was designed to reduce exposure to dust and hazardous chemicals.⁷⁴ In the low-allergen school several measures were implemented. These included reducing potential dust reservoirs, improving ventilation, introducing materials with lower emissions of volatile organic compounds and dust particles, and using central vacuuming and radiant heating systems. Allergen concentrations and other environmental end points were measured in the low-allergen school and 3 other schools to evaluate the effectiveness of this intervention. The levels of dust mite and cat allergens tended to be lower in the low-allergen school, but differences between schools did not reach statistical significance.

One US study investigated the effectiveness of measures to reduce cockroach allergen levels.⁷⁵ In an urban dormitory, which was chronically infested with cockroaches, successful abatement was accomplished by using routine extermination and vacuuming.

A number of interventions have been conducted to reduce exposure to molds and moisture in schools and day care facilities. Most of the studies have been conducted in Nordic countries.⁷⁶, ⁷⁷, ⁷⁸, ⁷⁹, ⁸⁰ Renovations and repairs of moisture-damaged classrooms and buildings were found to be effective at reducing mold exposure in schools and day care facilities and were associated with improvement in building occupants' symptoms. Improvements in ventilation (eg, increased air-exchange rates) might also affect relative humidity and concentrations of airborne viable molds. In a recent study new ventilation systems improved indoor air quality and reduced asthma symptoms among students in intervened schools.⁸¹ In the United States a small pilot study that combined dehumidification with high-efficiency particulate air filtration reported reductions in airborne fungal spore counts.⁸² Because of the increased concern about indoor mold exposures in school and home environments, a variety of programs and guidelines have been launched over the past decades. For example, in the United States the US Environmental Protection Agency has provided guidance and tools for schools in addressing mold and remediation-related issues.⁸³

In summary, multifaceted approaches might be needed to decrease indoor allergen levels in school and day care settings. Combined allergen-avoidance measures, such as improvements in ventilation systems, control of excess moisture, reductions in potential dust reservoirs, regular and thorough cleaning and maintenance, pest control, and use of special school clothing, might help to decrease exposure to indoor allergens in school and day care environments. However, there is limited information on how to choose and implement the most cost-effective intervention approach and the extent to which reductions in allergen exposures in these environments influence allergy- and asthma-related morbidity.

Back to Article Outline

Summary and conclusions 

We have summarized the key findings of the review in Table I. Exposure to indoor allergens in school and day care environments is common. However, published data show that levels of allergens are highly variable. Allergen levels can vary by time, location, and type of room within the building. This is not surprising because variety of physical (eg, humidity, temperature), structural (eg, age and type of building/room/surface), and behavioral (eg, pet ownership among children and staff, cleaning, and maintenance practices) factors can influence indoor allergen levels. The relative importance of different allergens can vary in different parts of the world depending on a variety of geographic, climatic, and cultural factors. Allergen levels in schools and day care facilities are often lower than levels that have been reported in homes. Nonetheless, it is not unusual that allergen levels in these settings exceed thresholds that have been associated with allergic sensitization and asthma morbidity. It has also been demonstrated that allergen levels in schools can be significantly higher than in the home environment. Carpeting, upholstered furnishings, and clothing are important reservoirs for allergens, particularly for pet and dust mite allergens. Because allergens are also transported passively to school and day care environments, exposure to allergens can occur either directly or indirectly. Schools and day care facilities might be important sources of allergen exposures, but there are limited data available to evaluate to what extent these exposures contribute to allergic sensitization and exacerbation of allergic symptoms. Information on cost-effective intervention strategies is also limited; in published studies the effectiveness of the interventions varied substantially.

Table I. Summary of the key findings

Exposure to indoor allergens in day care and school environments

Exposure to indoor allergens is common in day cares and schools.

Allergen levels can vary by time, location, and type of room within the building.

The relative importance of different allergens can vary in different parts of the world depending on a variety of geographic, climatic, and cultural factors.

Schools and day care facilities might be important sites of allergen exposures. Studies have demonstrated that allergen levels in these environments can sometimes be significantly higher than in the home environment.

Carpeting, upholstered furnishings, and clothing are important reservoirs for allergens.

Exposure to allergens can occur directly or indirectly. For example, clothing is the primary transfer mechanism and source of exposure for pet allergens.

Indoor allergen exposures in relation to allergy and asthma

The relationship between allergic respiratory diseases and indoor allergen exposures in schools and day cares is not well characterized.

Exposure to pet allergens in schools might influence asthma morbidity.

Published data provide limited information on whether exposures to indoor allergens in schools and day cares contribute to the development of allergic sensitization and asthma.

Environmental control, remediation, and interventions

Multifaceted approaches might be needed to decrease indoor allergen levels in schools and day care facilities.

Information on cost-effective intervention strategies is limited.

Little is known about the extent to which reductions in allergen exposures in these environments influence allergy and asthma morbidity.

Back to Article Outline

Research needs and recommendations 

Over the past 2 decades, a considerable amount of research has been conducted on indoor allergen exposures in school and day-care environments. Although several guidelines have been developed and a variety of programs have been initiated to sustain asthma- and allergy-friendly schools in the United States and abroad,⁸⁴, ⁸⁵, ⁸⁶ further research is warranted. Studies are needed to assess the extent to which school and day care environments contribute to allergic sensitization and asthma morbidity. Published data provide limited information on the potential additive effects of school or day care exposures in relation to allergy and asthma outcomes. For instance, few studies have collected information on health outcomes and exposure levels in schools/day cares and homes simultaneously; further studies addressing this issue are needed. Although schools and day care environments might not be primary sites for exposure, sensitization, or both to the dominant local allergen or allergens, it is essential to establish cost-effective approaches to reduce allergen levels in these indoor environments. Allergen exposures in school and day care settings might compromise the effectiveness of allergen avoidance measures used at home. From a public health perspective, it would be important to examine the extent to which various interventions are able to influence exposure levels and building occupants', children's, and staff members' allergy- and asthma-related morbidity. Economic analysis would help to evaluate the cost-effectiveness and clinical benefits of future interventions.

Back to Article Outline

We thank Ms Stephenie Holmgren and Dr Larry Wright for their assistance with the literature search.

Back to Article Outline

Table E1. 

Studies assessing cat allergen (Fel d 1) levels in schools and day care facilities

GSD, Geometric SD; IQR, interquartile range.

Back to Article Outline

Table E2. 

Studies assessing dog allergen (Can f 1) levels in schools and day care facilities

IQR, Interquartile range.

Back to Article Outline

Table E3. 

Studies assessing dust mite allergen levels in schools and day care facilities

GSD, Geometric SD; IQR, interquartile range.

Back to Article Outline

Table E4. 

Studies assessing cockroach allergen levels in schools and day care facilities

Back to Article Outline

Table E5. 

Studies assessing mouse allergen levels in schools and day care facilities

Back to Article Outline

References 

1. Platts-Mills TA, Vervloet D, Thomas WR, Aalberse RC, Chapman MD. Indoor allergens and asthma: report of the Third International Workshop. J Allergy Clin Immunol. 1997;100(suppl):S2–S24
   • View In Article
   • Full Text
   • Full-Text PDF (2688 KB)
   • CrossRef
2. Langley SJ, Goldthorpe S, Craven M, Morris J, Woodcock A, Custovic A. Exposure and sensitization to indoor allergens: association with lung function, bronchial reactivity, and exhaled nitric oxide measures in asthma. J Allergy Clin Immunol. 2003;112:362–368
   • View In Article
   • Abstract
   • Full Text
   • Full-Text PDF (91 KB)
   • CrossRef
3. Committee on the Assessment of Asthma and Indoor Air, Division of Health Promotion and Disease Prevention, Institute of Medicine. Clearing the air: asthma and indoor exposures. Washington (DC): National Academy Press; 2000;
   • View In Article
4. Custovic A, Green R, Taggart SC, Smith A, Pickering CA, Chapman MD, et al. Domestic allergens in public places. II: Dog (Can f1) and cockroach (Bla g 2) allergens in dust and mite, cat, dog and cockroach allergens in the air in public buildings. Clin Exp Allergy. 1996;26:1246–1252
   • View In Article
   • MEDLINE
   • CrossRef
5. de Andrade AD, Charpin D, Birnbaum J, Lanteaume A, Chapman M, Vervloet D. Indoor allergen levels in day nurseries. J Allergy Clin Immunol. 1995;95:1158–1163
   • View In Article
   • Abstract
   • Full Text
   • Full-Text PDF (473 KB)
   • CrossRef
6. Einarsson R, Munir AK, Dreborg SK. Allergens in school dust: II. Major mite (Der p I, Der f I) allergens in dust from Swedish schools. J Allergy Clin Immunol. 1995;95:1049–1053
   • View In Article
   • Abstract
   • Full Text
   • Full-Text PDF (472 KB)
   • CrossRef
7. Engelhart S, Bieber T, Exner M. House dust mite allergen levels in German day-care centers. Int J Hyg Environ Health. 2002;205:453–457
   • View In Article
   • MEDLINE
   • CrossRef
8. Kim JL, Elfman L, Norbäck D. Respiratory symptoms, asthma and allergen levels in schools—comparison between Korea and Sweden. Indoor Air. 2007;17:122–129
   • View In Article
   • MEDLINE
   • CrossRef
9. Oldfield K, Siebers R, Crane J. Endotoxin and indoor allergen levels in kindergartens and daycare centres in Wellington, New Zealand. N Z Med J. 2007;120:U2400
   • View In Article
10. Patchett K, Lewis S, Crane J, Fitzharris P. Cat allergen (Fel d 1) levels on school children's clothing and in primary school classrooms in Wellington, New Zealand. J Allergy Clin Immunol. 1997;100:755–759
    • View In Article
    • Abstract
    • Full Text
    • Full-Text PDF (450 KB)
    • CrossRef
11. Rullo VE, Rizzo MC, Arruda LK, Solé D, Naspitz CK. Daycare centers and schools as sources of exposure to mites, cockroach, and endotoxin in the city of Sao Paulo, Brazil. J Allergy Clin Immunol. 2002;110:582–588
    • View In Article
    • Abstract
    • Full Text
    • Full-Text PDF (248 KB)
    • CrossRef
12. Zhang L, Chew FT, Soh SY, Yi FC, Law SY, Goh DY, et al. Prevalence and distribution of indoor allergens in Singapore. Clin Exp Allergy. 1997;27:876–885
    • View In Article
    • MEDLINE
    • CrossRef
13. Zhao ZH, Elfman L, Wang ZH, Zhang Z, Norbäck D. A comparative study of asthma, pollen, cat and dog allergy among pupils and allergen levels in schools in Taiyuan city, China, and Uppsala, Sweden. Indoor Air. 2006;16:404–413
    • View In Article
    • MEDLINE
    • CrossRef
14. Zock JP, Brunekreef B. House dust mite allergen levels in dust from schools with smooth and carpeted classroom floors. Clin Exp Allergy. 1995;25:549–553
    • View In Article
    • MEDLINE
    • CrossRef
15. Zuraimi MS, Ong TC, Tham KW, Chew FT. Determinants of indoor allergens in tropical child care centers. Pediatr Allergy Immunol. 2008;19:746–755
    • View In Article
    • CrossRef
16. Abramson SL, Turner-Henson A, Anderson L, Hemstreet MP, Bartholomew LK, Joseph CL, et al. Allergens in school settings: results of environmental assessments in 3 city school systems. J Sch Health. 2006;76:246–249
    • View In Article
    • MEDLINE
    • CrossRef
17. Almqvist C, Larsson PH, Egmar AC, Hedrén M, Malmberg P, Wickman M. School as a risk environment for children allergic to cats and a site for transfer of cat allergen to homes. J Allergy Clin Immunol. 1999;103:1012–1017
    • View In Article
    • Abstract
    • Full Text
    • Full-Text PDF (73 KB)
    • CrossRef
18. Amr S, Bollinger ME, Myers M, Hamilton RG, Weiss SR, Rossman M, et al. Environmental allergens and asthma in urban elementary schools. Ann Allergy Asthma Immunol. 2003;90:34–40
    • View In Article
    • Abstract
    • Full-Text PDF (814 KB)
    • CrossRef
19. Arbes SJ, Sever M, Mehta J, Collette N, Thomas B, Zeldin DC. Exposure to indoor allergens in day-care facilities: results from 2 North Carolina counties. J Allergy Clin Immunol. 2005;116:133–139
    • View In Article
    • Abstract
    • Full Text
    • Full-Text PDF (127 KB)
    • CrossRef
20. Chew GL, Correa JC, Perzanowski MS. Mouse and cockroach allergens in the dust and air in northeastern United States inner-city public high schools. Indoor Air. 2005;15:228–234
    • View In Article
    • MEDLINE
    • CrossRef
21. Dybendal T, Elsayed S. Dust from carpeted and smooth floors. VI. Allergens in homes compared with those in schools in Norway. Allergy. 1994;49:210–216
    • View In Article
    • MEDLINE
    • CrossRef
22. Fernández-Caldas E, Codina R, Ledford DK, Trudeau WL, Lockey RF. House dust mite, cat, and cockroach allergen concentrations in daycare centers in Tampa, Florida. Ann Allergy Asthma Immunol. 2001;87:196–200
    • View In Article
    • Abstract
    • Full-Text PDF (407 KB)
    • CrossRef
23. Foarde K, Berry M. Comparison of biocontaminant levels associated with hard vs. carpet floors in nonproblem schools: results of a year long study. J Expo Anal Environ Epidemiol. 2004;14(suppl 1):S41–S48
    • View In Article
    • CrossRef
24. Instanes C, Hetland G, Berntsen S, Løvik M, Nafstad P. Allergens and endotoxin in settled dust from day-care centers and schools in Oslo, Norway. Indoor Air. 2005;15:356–362
    • View In Article
    • MEDLINE
    • CrossRef
25. Kim JL, Elfman L, Mi Y, Johansson M, Smedje G, Norbäck D. Current asthma and respiratory symptoms among pupils in relation to dietary factors and allergens in the school environment. Indoor Air. 2005;15:170–182
    • View In Article
    • MEDLINE
    • CrossRef
26. Munir AK, Einarsson R, Dreborg SK. Mite (Der p I, Der f I), cat (Fel d I) and dog (Can f I) allergens in dust from Swedish day-care centres. Clin Exp Allergy. 1995;25:119–126
    • View In Article
    • MEDLINE
    • CrossRef
27. Munir AK, Einarsson R, Schou C, Dreborg SK. Allergens in school dust. I. The amount of the major cat (Fel d I) and dog (Can f I) allergens in dust from Swedish schools is high enough to probably cause perennial symptoms in most children with asthma who are sensitized to cat and dog. J Allergy Clin Immunol. 1993;91:1067–1074
    • View In Article
    • MEDLINE
    • CrossRef
28. Perry TT, Vargas PA, Bufford J, Feild C, Flick M, Simpson PM, et al. Classroom aeroallergen exposure in Arkansas head start centers. Ann Allergy Asthma Immunol. 2008;100:358–363
    • View In Article
    • Abstract
    • Full Text
    • Full-Text PDF (127 KB)
    • CrossRef
29. Perzanowski MS, Rönmark E, Nold B, Lundbäck B, Platts-Mills TA. Relevance of allergens from cats and dogs to asthma in the northernmost province of Sweden: schools as a major site of exposure. J Allergy Clin Immunol. 1999;103:1018–1024
    • View In Article
    • Abstract
    • Full Text
    • Full-Text PDF (85 KB)
    • CrossRef
30. Ramachandran G, Adgate JL, Banerjee S, Church TR, Jones D, Fredrickson A, et al. Indoor air quality in two urban elementary schools–measurements of airborne fungi, carpet allergens, CO2, temperature, and relative humidity. J Occup Environ Hyg. 2005;2:553–566
    • View In Article
    • MEDLINE
    • CrossRef
31. Sarpong SB, Wood RA, Karrison T, Eggleston PA. Cockroach allergen (Bla g 1) in school dust. J Allergy Clin Immunol. 1997;99:486–492
    • View In Article
    • Abstract
    • Full Text
    • Full-Text PDF (671 KB)
    • CrossRef
32. Smedje G, Norbäck D. Incidence of asthma diagnosis and self-reported allergy in relation to the school environment—a four-year follow-up study in schoolchildren. Int J Tuberc Lung Dis. 2001;5:1059–1066
    • View In Article
    • MEDLINE
33. Smedje G, Norbäck D, Edling C. Asthma among secondary schoolchildren in relation to the school environment. Clin Exp Allergy. 1997;27:1270–1278
    • View In Article
    • MEDLINE
    • CrossRef
34. Tortolero SR, Bartholomew LK, Tyrrell S, Abramson SL, Sockrider MM, Markham CM, et al. Environmental allergens and irritants in schools: a focus on asthma. J Sch Health. 2002;72:33–38
    • View In Article
    • MEDLINE
    • CrossRef
35. Sheehan WJ, Rangsithienchai PA, Muilenberg ML, Rogers CA, Lane JP, Ghaemghami J, et al. Mouse allergens in urban elementary schools and homes of children with asthma. Ann Allergy Asthma Immunol. 2009;102:125–130
    • View In Article
    • Abstract
    • Full Text
    • Full-Text PDF (160 KB)
    • CrossRef
36. Tranter DC. Indoor allergens in settled school dust: a review of findings and significant factors. Clin Exp Allergy. 2005;35:126–136
    • View In Article
    • MEDLINE
    • CrossRef
37. Karlsson AS, Renström A, Hedrén M, Larsson K. Comparison of four allergen-sampling methods in conventional and allergy prevention classrooms. Clin Exp Allergy. 2002;32:1776–1781
    • View In Article
    • MEDLINE
    • CrossRef
38. Karlsson AS, Andersson B, Renström A, Svedmyr J, Larsson K, Borres MP. Airborne cat allergen reduction in classrooms that use special school clothing or ban pet ownership. J Allergy Clin Immunol. 2004;113:1172–1177
    • View In Article
    • Abstract
    • Full Text
    • Full-Text PDF (190 KB)
    • CrossRef
39. Custovic A, Fletcher A, Pickering CA, Francis HC, Green R, Smith A, et al. Domestic allergens in public places III: house dust mite, cat, dog and cockroach allergens in British hospitals. Clin Exp Allergy. 1998;28:53–59
    • View In Article
    • MEDLINE
    • CrossRef
40. Ingram JM, Sporik R, Rose G, Honsinger R, Chapman MD, Platts-Mills TA. Quantitative assessment of exposure to dog (Can f 1) and cat (Fel d 1) allergens: relation to sensitization and asthma among children living in Los Alamos, New Mexico. J Allergy Clin Immunol. 1995;96:449–456
    • View In Article
    • Abstract
    • Full Text
    • Full-Text PDF (749 KB)
    • CrossRef
41. Berge M, Munir AK, Dreborg S. Concentrations of cat (Fel d1), dog (Can f1) and mite (Der f1 and Der p1) allergens in the clothing and school environment of Swedish schoolchildren with and without pets at home. Pediatr Allergy Immunol. 1998;9:25–30
    • View In Article
    • MEDLINE
    • CrossRef
42. De Lucca SD, O'Meara TJ, Tovey ER. Exposure to mite and cat allergens on a range of clothing items at home and the transfer of cat allergen in the workplace. J Allergy Clin Immunol. 2000;106:874–879
    • View In Article
    • Abstract
    • Full Text
    • Full-Text PDF (91 KB)
    • CrossRef
43. Karlsson AS, Renström A. Human hair is a potential source of cat allergen contamination of ambient air. Allergy. 2005;60:961–964
    • View In Article
    • MEDLINE
    • CrossRef
44. Kim JL, Elfman L, Mi Y, Wieslander G, Smedje G, Norbäck D. Indoor molds, bacteria, microbial volatile organic compounds and plasticizers in schools—associations with asthma and respiratory symptoms in pupils. Indoor Air. 2007;17:153–163
    • View In Article
    • MEDLINE
    • CrossRef
45. Wickman M, Egmar A, Emenius G, Almqvist C, Berglind N, Larsson P, et al. Fel d 1 and Can f 1 in settled dust and airborne Fel d 1 in allergen avoidance day-care centres for atopic children in relation to number of pet-owners, ventilation and general cleaning. Clin Exp Allergy. 1999;29:626–632
    • View In Article
    • MEDLINE
    • CrossRef
46. Arlian LG, Morgan MS, Neal JS. Dust mite allergens: ecology and distribution. Curr Allergy Asthma Rep. 2002;2:401–411
    • View In Article
    • MEDLINE
    • CrossRef
47. The house-dust mite: its biology and role in allergy. Proceedings of an international scientific workshop. Oslo, Norway, 4-7 September 1997. Allergy. 1998;53:1–135
    • View In Article
    • MEDLINE
    • CrossRef
48. Sporik R, Holgate ST, Platts-Mills TA, Cogswell JJ. Exposure to house-dust mite allergen (Der p I) and the development of asthma in childhood. A prospective study. N Engl J Med. 1990;323:502–507
    • View In Article
    • MEDLINE
    • CrossRef
49. Dust mite allergens and asthma—a worldwide problem. J Allergy Clin Immunol. 1989;83:416–427
    • View In Article
    • MEDLINE
    • CrossRef
50. Rosenstreich DL, Eggleston P, Kattan M, Baker D, Slavin RG, Gergen P, et al. The role of cockroach allergy and exposure to cockroach allergen in causing morbidity among inner-city children with asthma. N Engl J Med. 1997;336:1356–1363
    • View In Article
    • MEDLINE
    • CrossRef
51. Burge HA, Rogers CA. Outdoor allergens. Environ Health Perspect. 2000;108(suppl 4):653–659
    • View In Article
    • CrossRef
52. Green BJ, Mitakakis TZ, Tovey ER. Allergen detection from 11 fungal species before and after germination. J Allergy Clin Immunol. 2003;111:285–289
    • View In Article
    • Abstract
    • Full Text
    • Full-Text PDF (192 KB)
    • CrossRef
53. The condition of education. Jessup (MD): National Center for Education Statistics (NCES); 2007;Available at: http://nces.ed.gov/pubs2007/2007064_1.pdfAccessed February 14, 2009
    • View In Article
54. Mannino DM, Homa DM, Akinbami LJ, Moorman JE, Gwynn C, Redd SC. Surveillance for asthma—United States, 1980-1999. MMWR Surveill Summ. 2002;51:1–13
    • View In Article
    • MEDLINE
55. Nathan RA. The burden of allergic rhinitis. Allergy Asthma Proc. 2007;28:3–9
    • View In Article
    • MEDLINE
    • CrossRef
56. Moonie SA, Sterling DA, Figgs L, Castro M. Asthma status and severity affects missed school days. J Sch Health. 2006;76:18–24
    • View In Article
    • MEDLINE
    • CrossRef
57. Mazurek JM, Filios M, Willis R, Rosenman KD, Reilly MJ, McGreevy K, et al. Work-related asthma in the educational services industry: California, Massachusetts, Michigan, and New Jersey, 1993-2000. Am J Ind Med. 2008;51:47–59
    • View In Article
    • CrossRef
58. Leech JA, Nelson WC, Burnett RT, Aaron S, Raizenne ME. It's about time: a comparison of Canadian and American time-activity patterns. J Expo Anal Environ Epidemiol. 2002;12:427–432
    • View In Article
    • MEDLINE
    • CrossRef
59. Guilbert TW, Morgan WJ, Zeiger RS, Bacharier LB, Boehmer SJ, Krawiec M, et al. Atopic characteristics of children with recurrent wheezing at high risk for the development of childhood asthma. J Allergy Clin Immunol. 2004;114:1282–1287
    • View In Article
    • Abstract
    • Full Text
    • Full-Text PDF (158 KB)
    • CrossRef
60. Almqvist C, Wickman M, Perfetti L, Berglind N, Renström A, Hedrén M, et al. Worsening of asthma in children allergic to cats, after indirect exposure to cat at school. Am J Respir Crit Care Med. 2001;163:694–698
    • View In Article
    • MEDLINE
61. Lönnkvist K, Halldén G, Dahlén SE, Enander I, van Hage-Hamsten M, Kumlin M, et al. Markers of inflammation and bronchial reactivity in children with asthma, exposed to animal dander in school dust. Pediatr Allergy Immunol. 1999;10:45–52
    • View In Article
    • MEDLINE
62. Ritz BR, Hoelscher B, Frye C, Meyer I, Heinrich J. Allergic sensitization owing to “second-hand” cat exposure in schools. Allergy. 2002;57:357–361
    • View In Article
    • MEDLINE
    • CrossRef
63. Peat JK, Dickerson J, Li J. Effects of damp and mould in the home on respiratory health: a review of the literature. Allergy. 1998;53:120–128
    • View In Article
    • MEDLINE
    • CrossRef
64. Verhoeff AP, Burge HA. Health risk assessment of fungi in home environments. Ann Allergy Asthma Immunol. 1997;78:544–556
    • View In Article
    • Abstract
    • Full-Text PDF (209 KB)
    • CrossRef
65. Daisey JM, Angell WJ, Apte MG. Indoor air quality, ventilation and health symptoms in schools: an analysis of existing information. Indoor Air. 2003;13:53–64
    • View In Article
    • MEDLINE
    • CrossRef
66. Haverinen U, Husman T, Toivola M, Suonketo J, Pentti M, Lindberg R, et al. An approach to management of critical indoor air problems in school buildings. Environ Health Perspect. 1999;107(suppl 3):509–514
    • View In Article
    • CrossRef
67. Meklin T, Husman T, Vepsäläinen A, Vahteristo M, Koivisto J, Halla-Aho J, et al. Indoor air microbes and respiratory symptoms of children in moisture damaged and reference schools. Indoor Air. 2002;12:175–183
    • View In Article
    • MEDLINE
    • CrossRef
68. Santilli J, Rockwell W. Fungal contamination of elementary schools: a new environmental hazard. Ann Allergy Asthma Immunol. 2003;90:203–208
    • View In Article
    • Abstract
    • Full-Text PDF (673 KB)
    • CrossRef
69. Beezhold DH, Green BJ, Blachere FM, Schmechel D, Weissman DN, Velickoff D, et al. Prevalence of allergic sensitization to indoor fungi in West Virginia. Allergy Asthma Proc. 2008;29:29–34
    • View In Article
    • CrossRef
70. Portnoy JM, Kwak K, Dowling P, VanOsdol T, Barnes C. Health effects of indoor fungi. Ann Allergy Asthma Immunol. 2005;94:313–32290
    • View In Article
    • Abstract
    • Full-Text PDF (83 KB)
    • CrossRef
71. Instanes C, Ormstad H, Rydjord B, Wiker HG, Hetland G. Mould extracts increase the allergic response to ovalbumin in mice. Clin Exp Allergy. 2004;34:1634–1641
    • View In Article
    • MEDLINE
    • CrossRef
72. Karlsson AS, Renström A, Hedrén M, Larsson K. Allergen avoidance does not alter airborne cat allergen levels in classrooms. Allergy. 2004;59:661–667
    • View In Article
    • MEDLINE
    • CrossRef
73. Munir AK, Einarsson R, Dreborg S. Allergen avoidance in a day-care center. Allergy. 1996;51:36–41
    • View In Article
    • MEDLINE
    • CrossRef
74. Zhang G, Spickett J, Rumchev K, Lee AH, Stick S. Indoor environmental quality in a “low allergen” school and three standard primary schools in Western Australia. Indoor Air. 2006;16:74–80
    • View In Article
    • MEDLINE
    • CrossRef
75. Sarpong SB, Wood RA, Eggleston PA. Short-term effects of extermination and cleaning on cockroach allergen Bla g 2 in settled dust. Ann Allergy Asthma Immunol. 1996;76:257–260
    • View In Article
    • Abstract
    • Full-Text PDF (146 KB)
    • CrossRef
76. Lignell U, Meklin T, Putus T, Rintala H, Vepsäläinen A, Kalliokoski P, et al. Effects of moisture damage and renovation on microbial conditions and pupils' health in two schools—a longitudinal analysis of five years. J Environ Monit. 2007;9:225–233
    • View In Article
    • MEDLINE
    • CrossRef
77. Meklin T, Potus T, Pekkanen J, Hyvärinen A, Hirvonen MR, Nevalainen A. Effects of moisture-damage repairs on microbial exposure and symptoms in schoolchildren. Indoor Air. 2005;15(suppl 10):40–47
    • View In Article
    • CrossRef
78. Patovirta RL, Husman T, Haverinen U, Vahteristo M, Uitti JA, Tukiainen H, et al. The remediation of mold damaged school—a three-year follow-up study on teachers' health. Cent Eur J Public Health. 2004;12:36–42
    • View In Article
    • MEDLINE
79. Rylander R. Airborne (1→3)-beta-D-glucan and airway disease in a day-care center before and after renovation. Arch Environ Health. 1997;52:281–285
    • View In Article
    • MEDLINE
    • CrossRef
80. Savilahti R, Uitti J, Laippala P, Husman T, Roto P. Respiratory morbidity among children following renovation of a water-damaged school. Arch Environ Health. 2000;55:405–410
    • View In Article
    • MEDLINE
    • CrossRef
81. Smedje G, Norbäck D. New ventilation systems at select schools in Sweden—effects on asthma and exposure. Arch Environ Health. 2000;55:18–25
    • View In Article
    • MEDLINE
    • CrossRef
82. Bernstein JA, Levin L, Crandall MS, Perez A, Lanphear B. A pilot study to investigate the effects of combined dehumidification and HEPA filtration on dew point and airborne mold spore counts in day care centers. Indoor Air. 2005;15:402–407
    • View In Article
    • MEDLINE
    • CrossRef
83. US Environmental Protection Agency, Office of Air and Radiation, Indoor Environments Division. Mold remediation in schools and commercial buildings. Washington (DC): Environmental Protection Agency; 2001;EPA publication no. 402-K-01-001
    • View In Article
84. IAQ tools for schools: managing asthma in the school environment. Available at: http://www.epa.gov/iaq. Accessed February 16, 2009.
    • View In Article
85. Borres MP, Abrahamsson G, Andersson B, Andersson B, Bråkenhielm G, Fabricius T, et al. Asthma and allergies at school—a Swedish national position paper. Allergy. 2002;57:454–457
    • View In Article
    • MEDLINE
    • CrossRef
86. Merkle SL, Wheeler LS, Gerald LB, Taggart VS. Introduction: learning from each other about managing asthma in schools. J Sch Health. 2006;76:202–204
    • View In Article
    • MEDLINE
    • CrossRef

Back to Article Outline

References 

1. Platts-Mills TA, Vervloet D, Thomas WR, Aalberse RC, Chapman MD. Indoor allergens and asthma: report of the Third International Workshop. J Allergy Clin Immunol. 1997;100(suppl):S2–S24
2. Langley SJ, Goldthorpe S, Craven M, Morris J, Woodcock A, Custovic A. Exposure and sensitization to indoor allergens: association with lung function, bronchial reactivity, and exhaled nitric oxide measures in asthma. J Allergy Clin Immunol. 2003;112:362–368
3. Committee on the Assessment of Asthma and Indoor Air, Division of Health Promotion and Disease Prevention, Institute of Medicine. Clearing the air: asthma and indoor exposures. Washington (DC): National Academy Press; 2000;
4. Custovic A, Green R, Taggart SC, Smith A, Pickering CA, Chapman MD, et al. Domestic allergens in public places. II: Dog (Can f1) and cockroach (Bla g 2) allergens in dust and mite, cat, dog and cockroach allergens in the air in public buildings. Clin Exp Allergy. 1996;26:1246–1252
5. de Andrade AD, Charpin D, Birnbaum J, Lanteaume A, Chapman M, Vervloet D. Indoor allergen levels in day nurseries. J Allergy Clin Immunol. 1995;95:1158–1163
6. Einarsson R, Munir AK, Dreborg SK. Allergens in school dust: II. Major mite (Der p I, Der f I) allergens in dust from Swedish schools. J Allergy Clin Immunol. 1995;95:1049–1053
7. Engelhart S, Bieber T, Exner M. House dust mite allergen levels in German day-care centers. Int J Hyg Environ Health. 2002;205:453–457
8. Kim JL, Elfman L, Norbäck D. Respiratory symptoms, asthma and allergen levels in schools—comparison between Korea and Sweden. Indoor Air. 2007;17:122–129
9. Oldfield K, Siebers R, Crane J. Endotoxin and indoor allergen levels in kindergartens and daycare centres in Wellington, New Zealand. N Z Med J. 2007;120:U2400
10. Patchett K, Lewis S, Crane J, Fitzharris P. Cat allergen (Fel d 1) levels on school children's clothing and in primary school classrooms in Wellington, New Zealand. J Allergy Clin Immunol. 1997;100:755–759
11. Rullo VE, Rizzo MC, Arruda LK, Solé D, Naspitz CK. Daycare centers and schools as sources of exposure to mites, cockroach, and endotoxin in the city of Sao Paulo, Brazil. J Allergy Clin Immunol. 2002;110:582–588
12. Zhang L, Chew FT, Soh SY, Yi FC, Law SY, Goh DY, et al. Prevalence and distribution of indoor allergens in Singapore. Clin Exp Allergy. 1997;27:876–885
13. Zhao ZH, Elfman L, Wang ZH, Zhang Z, Norbäck D. A comparative study of asthma, pollen, cat and dog allergy among pupils and allergen levels in schools in Taiyuan city, China, and Uppsala, Sweden. Indoor Air. 2006;16:404–413
14. Zock JP, Brunekreef B. House dust mite allergen levels in dust from schools with smooth and carpeted classroom floors. Clin Exp Allergy. 1995;25:549–553
15. Zuraimi MS, Ong TC, Tham KW, Chew FT. Determinants of indoor allergens in tropical child care centers. Pediatr Allergy Immunol. 2008;19:746–755
16. Abramson SL, Turner-Henson A, Anderson L, Hemstreet MP, Bartholomew LK, Joseph CL, et al. Allergens in school settings: results of environmental assessments in 3 city school systems. J Sch Health. 2006;76:246–249
17. Almqvist C, Larsson PH, Egmar AC, Hedrén M, Malmberg P, Wickman M. School as a risk environment for children allergic to cats and a site for transfer of cat allergen to homes. J Allergy Clin Immunol. 1999;103:1012–1017
18. Amr S, Bollinger ME, Myers M, Hamilton RG, Weiss SR, Rossman M, et al. Environmental allergens and asthma in urban elementary schools. Ann Allergy Asthma Immunol. 2003;90:34–40
19. Arbes SJ, Sever M, Mehta J, Collette N, Thomas B, Zeldin DC. Exposure to indoor allergens in day-care facilities: results from 2 North Carolina counties. J Allergy Clin Immunol. 2005;116:133–139
20. Chew GL, Correa JC, Perzanowski MS. Mouse and cockroach allergens in the dust and air in northeastern United States inner-city public high schools. Indoor Air. 2005;15:228–234
21. Dybendal T, Elsayed S. Dust from carpeted and smooth floors. VI. Allergens in homes compared with those in schools in Norway. Allergy. 1994;49:210–216
22. Fernández-Caldas E, Codina R, Ledford DK, Trudeau WL, Lockey RF. House dust mite, cat, and cockroach allergen concentrations in daycare centers in Tampa, Florida. Ann Allergy Asthma Immunol. 2001;87:196–200
23. Foarde K, Berry M. Comparison of biocontaminant levels associated with hard vs. carpet floors in nonproblem schools: results of a year long study. J Expo Anal Environ Epidemiol. 2004;14(suppl 1):S41–S48
24. Instanes C, Hetland G, Berntsen S, Løvik M, Nafstad P. Allergens and endotoxin in settled dust from day-care centers and schools in Oslo, Norway. Indoor Air. 2005;15:356–362
25. Kim JL, Elfman L, Mi Y, Johansson M, Smedje G, Norbäck D. Current asthma and respiratory symptoms among pupils in relation to dietary factors and allergens in the school environment. Indoor Air. 2005;15:170–182
26. Munir AK, Einarsson R, Dreborg SK. Mite (Der p I, Der f I), cat (Fel d I) and dog (Can f I) allergens in dust from Swedish day-care centres. Clin Exp Allergy. 1995;25:119–126
27. Munir AK, Einarsson R, Schou C, Dreborg SK. Allergens in school dust. I. The amount of the major cat (Fel d I) and dog (Can f I) allergens in dust from Swedish schools is high enough to probably cause perennial symptoms in most children with asthma who are sensitized to cat and dog. J Allergy Clin Immunol. 1993;91:1067–1074
28. Perry TT, Vargas PA, Bufford J, Feild C, Flick M, Simpson PM, et al. Classroom aeroallergen exposure in Arkansas head start centers. Ann Allergy Asthma Immunol. 2008;100:358–363
29. Perzanowski MS, Rönmark E, Nold B, Lundbäck B, Platts-Mills TA. Relevance of allergens from cats and dogs to asthma in the northernmost province of Sweden: schools as a major site of exposure. J Allergy Clin Immunol. 1999;103:1018–1024
30. Ramachandran G, Adgate JL, Banerjee S, Church TR, Jones D, Fredrickson A, et al. Indoor air quality in two urban elementary schools–measurements of airborne fungi, carpet allergens, CO2, temperature, and relative humidity. J Occup Environ Hyg. 2005;2:553–566
31. Sarpong SB, Wood RA, Karrison T, Eggleston PA. Cockroach allergen (Bla g 1) in school dust. J Allergy Clin Immunol. 1997;99:486–492
32. Smedje G, Norbäck D. Incidence of asthma diagnosis and self-reported allergy in relation to the school environment—a four-year follow-up study in schoolchildren. Int J Tuberc Lung Dis. 2001;5:1059–1066
33. Smedje G, Norbäck D, Edling C. Asthma among secondary schoolchildren in relation to the school environment. Clin Exp Allergy. 1997;27:1270–1278
34. Tortolero SR, Bartholomew LK, Tyrrell S, Abramson SL, Sockrider MM, Markham CM, et al. Environmental allergens and irritants in schools: a focus on asthma. J Sch Health. 2002;72:33–38
35. Sheehan WJ, Rangsithienchai PA, Muilenberg ML, Rogers CA, Lane JP, Ghaemghami J, et al. Mouse allergens in urban elementary schools and homes of children with asthma. Ann Allergy Asthma Immunol. 2009;102:125–130