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IAQ Reference Guide
Appendix D - Asthma
IAQ TfS Action Kit
Contents
Asthma has reached epidemic proportions in the United States, affecting millions of people of all ages and races. Asthma is one of the leading causes of school absenteeism, accounting for more than 14 million missed school days in 2001.
Asthma can occur at any age but is more common in children than in adults. According to the Centers for Disease Control and Prevention (CDC), asthma is the third-ranking cause of hospitalization for children 15 years of age and under. Moreover, the asthma rate among children ages 5 to 14 rose 74 percent between 1980 and 1994, making asthma the most common chronic childhood disease.
What is Asthma?
Asthma is a chronic disease typically characterized by inflammation of the airways. During an asthma episode, the airways in the lungs narrow, making breathing difficult. Symptoms usually include wheezing, shortness of breath, tightness in the chest, and coughing. Asthma attacks are often separated by symptom-free periods. The frequency and severity of asthma attacks can be reduced by following a comprehensive asthma management plan that incorporates medical treatment and environmental management of asthma. While scientists do not fully understand the causes of asthma, outdoor air pollution and environmental contaminants commonly found indoors are known to trigger asthma attacks. See www.epa.gov/asthma
Asthma Triggers
Because Americans spend up to 90 percent of their time indoors, exposure to indoor allergens and irritants may play a significant role in triggering asthma episodes. Some of the most common environmental asthma triggers found indoors include:
Other asthma triggers include respiratory infections, pollens (trees, grasses, weeds), outdoor air pollution, food allergies, exercise, and cold air exposure.
Animal Allergens
Any warm-blooded animal -- including gerbils, birds, cats, dogs, mice, and rats -- can cause allergic reactions or trigger asthma attacks. Proteins may act as allergens in the dander, urine, or saliva of warm-blooded animals. The most common source of animal allergens in schools is a pet in the classroom. If an animal is present in the school, direct exposure to the animal’s dander and bodily fluids is possible. It is important to realize that, even after extensive cleaning, pet allergen levels may stay in the indoor environment for several months after the animal is removed.
Schools can minimize exposure to animal allergens by:
- Seating sensitive students away from pets or considering removing pets from the classroom.
- Vacuuming the classroom frequently and thoroughly.
- Cleaning cages and the surrounding area regularly and positioning these cages away from ventilation systems.
Cockroaches
Cockroaches and other pests, such as rats and mice, often exist in the school setting. Allergens from pests may be significant asthma triggers for students and staff in schools. Certain proteins that act as allergens in the waste products and saliva of cockroaches can cause allergic reactions or trigger asthma attacks in some individuals. Pest problems in schools may be caused or worsened by a variety of conditions such as plumbing leaks, moisture problems, and improper food handling and storage practices. It is important to avoid exposure to these allergens through the use of commonsense approaches and integrated pest management (IPM) practices throughout the entire school.
Schools can minimize cockroach exposure by:
- Removing or covering food or garbage found in classrooms or kitchens.
- Storing food in airtight containers.
- Cleaning all food crumbs or spilled liquids immediately.
- Fixing plumbing leaks and other moisture problems.
- Using poison baits, boric acid (for cockroaches), and traps before applying pesticidal sprays.
- If pesticide sprays are used, the school should:
- Notify staff, students, and parents before spraying.
- Limit spraying to the infested area.
- Only spray when rooms are unoccupied.
Ventilate the area well during and after spraying.
Mold and Moisture
Molds can be found almost anywhere; they can grow on virtually any substance when moisture is present. Molds produce tiny spores for reproduction that travel through the air continually. When mold spores land on a damp spot indoors, they may begin growing and digesting whatever they are growing on in order to survive. Molds can grow on wood, paper, carpet, and food. If excessive moisture or water accumulates indoors, extensive mold growth may occur, particularly if the moisture problem remains undiscovered or ignored. Eliminating all mold and mold spores in the indoor environment is impractical -- the way to control indoor mold growth is to control moisture.
When mold growth occurs in buildings, reports of health-related symptoms from some building occupants, particularly those with allergies or respiratory problems, may follow. Potential health effects and symptoms associated with mold exposures include allergic reactions, asthma, and other respiratory complaints.
Schools can minimize mold and moisture exposure by:
- Fixing plumbing leaks and other unwanted sources of water.
- Ensuring that kitchen areas and locker rooms are well ventilated.
- Maintaining low indoor humidity, ideally between 30 and 60 percent. The humidity level can be measured with a hygrometer, available at local hardware stores.
- Cleaning mold off hard surfaces with water and detergent, then drying completely.
- Replacing absorbent materials, such as ceiling tiles and carpet, if they are contaminated with mold.
Secondhand Smoke
Secondhand smoke is the smoke from the burning end of a cigarette, pipe, or cigar or the smoke exhaled by a smoker. Secondhand smoke exposure causes a number of serious health effects in young children, such as coughing, wheezing, bronchitis, pneumonia, ear infections, reduced lung function, and more severe asthma attacks. Secondhand smoke is an irritant that may trigger an asthma episode, and increasing evidence suggests that secondhand smoke may cause asthma in pre-school aged children. EPA estimates that between 200,000 and 1,000,000 children with asthma have exacerbated asthma conditions caused by exposure to secondhand smoke. Secondhand smoke can also lead to buildup of fluid in the middle ear -- the most common reason for operations in children.
Most schools in the United States prohibit smoking on school grounds. However, smoking often occurs in school bathrooms, in lounges, and near school entrances. If smoking occurs within the building, secondhand smoke can travel through the ventilation system to the entire school. Even when people smoke outside, secondhand smoke may enter the school through the ventilation system, windows, and doors.
Schools can minimize exposure to secondhand smoke by implementing and enforcing nonsmoking policies, particularly indoors and near school entrances.
Dust Mites
Dust mites are too small to be seen, but they are found in homes, schools, and other buildings throughout the United States. Dust mites live in mattresses, pillows, carpets, fabric-covered furniture, bedcovers, clothes, and stuffed toys. Their primary food source is dead skin flakes. Dust mite allergens may cause an allergic reaction or trigger an asthma episode. In addition, there is evidence that dust mites may cause asthma.
Schools can minimize dust mite exposure by:
- Vacuuming carpet and fabric-covered furniture regularly. Use vacuums with high-efficiency filters or central vacuums, if possible.
- Removing dust from hard surfaces with a damp cloth and sweep floors frequently.
- Purchasing washable stuffed toys, washing them often in hot water, and drying them thoroughly.
Combining steps for reducing environmental triggers with other proactive measures -- relocating areas where vehicles (e.g., buses and delivery trucks) idle away from air intakes, ensuring sufficient ventilation in classrooms and offices, eliminating the use of air fresheners, choosing building materials with minimal formaldehyde content, and purchasing environmentally preferable cleaning products -- can help schools reduce student and staff exposure to asthma triggers.
For additional information on asthma and asthma triggers, refer to Appendix E: "Typical Indoor Air Pollutants" and Appendix L: "Resources."
Outdoor Air Pollution
Exposure to outdoor air pollution, such as diesel exhaust, ozone, and particulate matter, can trigger an asthma episode or exacerbate asthma symptoms. There are simple actions that schools can take to minimize student and staff exposure to outdoor air pollutants.
Diesel Exhaust
Exposure to diesel exhaust from school buses and other diesel vehicles can exacerbate asthma symptoms. Diesel engines emit soot, also known as particulate matter (PM), as well as ozone-forming nitrogen oxides and other toxic air pollutants. PM and ozone (a primary ingredient of smog) are thought to trigger asthma symptoms and lung inflammation, resulting in reduced lung function, greater use of asthma medication, increased school absences, and more frequent visits to the emergency room and hospital. Diesel PM is also associated with more severe allergies and respiratory disease. In recent studies, outdoor ozone, or smog, has been associated with more frequent diagnoses of new asthma cases in children.
Schools can take simple steps to reduce exposure to diesel exhaust pollutants:
- Do not allow school buses or other vehicles such as delivery trucks to idle on school grounds and discourage carousing.
- Encourage your school bus fleet manager to implement district-wide anti-idling policies and practices.
- Work with your school bus fleet manager to replace the oldest buses and to reduce emissions from newer buses by retrofitting them with emission control technology and/or by switching to cleaner fuels.
- For more information, visit www.epa.gov/cleanschoolbus or call 734-214-4780.
Ozone and Particulate Matter
The Air Quality Index (AQI) is a tool to provide the public with clear and timely information on local air quality and whether air pollution levels pose a health concern. The AQI is reported and forecasted every day in many areas throughout the United States on local weather reports and through national media. Asthma episodes are most likely to occur the day after outdoor pollution levels are high.
Schools can take simple steps to ensure the health and comfort of students when the AQI reports unhealthy levels:
- Limit physical exertion outdoors.
- Consider changing the time of day of strenuous outdoor activity to avoid the period when air pollution levels are high or consider postponing sports activities to another time.