Asthma
Removing Asthma Triggers From Indoor Environments

Removing Triggers From Indoor Environments Key to Controlling Asthma

Asthma By The Numbers

Asthma - a serious disease that makes breathing difficult - is the most common lung disease associated with indoor air pollutants.[1] During the past two decades, a time when poor indoor air quality (IAQ) has been recognized as a potentially serious health hazard, the number of people with asthma has significantly increased. In the US, for example, the number of people with asthma increased by more than 150 percent from 1980 to 1998, and affects an estimated 17 million Americans, including nearly 5 million children. The number of deaths due to asthma also has increased to almost 5,000 deaths per year. According to the World Health Organization, between 100 and 150 people worldwide - roughly the equivalent of the population of the Russian Federation - have asthma, with deaths reaching more than 180,000 annually.[2]

Asthma occurs in people from all ethnic groups, but is more prevalent in African-Americans (who have asthma rates 15 percent higher than Caucasians [3] and certain Hispanic populations), especially in poor, urban inner cities. Asthma may be more prevalent in these communities because many people may not have health insurance, may have poor access to healthcare and may not have access to preventive care. For example, in the Bronx (a borough of New York City), 8.6 percent of the children have asthma, which is double the rate for urban residents nationally.[4]

The economic cost of asthma worldwide exceeds those of tuberculosis and HIV/AIDs combined. In the US, annual asthma care costs (direct and indirect) exceed $6 billion US. Presently, the United Kingdom spends $1.8 billion US and in Australia, annual direct and indirect medical costs are $460 million US.[2]

Indoor Allergens Among Strongest Risk Factors

Exposure to indoor allergens, especially in infancy, is among the strongest risk factor for developing asthma. These allergens include dust mites in bedding, carpets and upholstered furniture; cats, cockroaches, and environmental tobacco smoke (ETS). Exposure to chemical irritants is an additional risk factor.[2]

Researchers at Curtin University of Technology in Perth, Australia, reported that fumes emitted from home cleaning products and solvents may increase the risk of childhood asthma. They found that the levels of volatile organic compounds (VOCs) were much higher in homes of children with asthma. In particular, they found that the highest risk came from exposure to benzene, ethyl benzene and toluene.[5] These chemicals are commonly found in tobacco products, cleaning products, room air fresheners, polishes, carpets, solvents, paints and floor adhesives.

Other risk factors include a family history of asthma and allergies; taking of certain medications, such as aspirin and other non-steroidal anti-inflammatory drugs; low birth weight; and respiratory infection.[2]

There is some debate among researchers whether children brought up in dusty homes are more likely to develop asthma than those raised in cleaner homes. A recent study challenged the idea that exposure to dust and other indoor allergens such as cats, dust mites and grass pollens directly cause asthma. Researchers from the Imperial College School of Medicine at the National Heart and Lung Institute in London monitored 625 children from birth to age 5.5 years and eventually tested the children for sensitivity to house dust mites, cat allergen and grass pollens. They also interviewed the children's mothers to find out if their children had any wheezing during the previous 12 months. Further, dust samples were taken from the families' living room floors when the children were eight weeks old. The results demonstrated no linear or direct links between levels of allergens measured in dust samples and sensitivity or frequency of wheezing. The results also showed that children whose fathers were susceptible or if the child was first born were more likely to develop asthma. Medical professionals agree that there is a relationship between the environment and asthma symptoms, but that it is very complex and genetic predisposition also is a likely factor.[6]

Allergens and Other Pollutants Can Trigger Asthma Attacks

Not only does exposure to allergens and other pollutants put people at risk for developing asthma, it also can make asthma symptoms worse or cause an asthma attack requiring immediate medical care and sometimes hospitalization. These substances are referred to as asthma triggers and can be found both indoors and outdoors. During the summer months, air pollution alerts will advise people with asthma to stay indoors to avoid exposure to ozone, particulates and other outdoor air pollutants. Indoor air also hosts a number of pollutants that can have an adverse impact on people with asthma. And, since people spend as much as 90 percent of their time inside, recognizing and controlling indoor exposures is a key strategy for managing the asthma symptoms. Examples of common indoor triggers include:

  • Environmental tobacco smoke: Up to an estimated one million children have aggravated asthma symptoms from exposure to environmental tobacco smoke. Among very young children, ETS may be a more important cause of asthma than dust mites.[7]

  • Wood smoke: Some research has shown that a greater proportion of children reporting moderate to severe asthma symptoms were found in homes heated with wood stoves compared with homes with other sources of heating. In addition, infants who were exposed to wood smoke were more likely to develop asthma.[7]

  • Volatile organic compounds: Exposure to chemical emissions from building products, furnishings and furniture also can exacerbate asthma symptoms or cause asthma attack. These products include pressed wood products, indoor paint; hairspray, deodorant and other personal care products, talcum powder; perfume and/or cologne; air cleaners and air fresheners, solvents; and furniture polishes to name a few examples. [1] See also the articles listed in the section on interior furnishings and finishes to learn more about how these and other products can adversely impact the quality of indoor air.

  • Dust mites: Exposure to mite allergen may trigger attacks in up to an estimated 85 percent of people with asthma.[7]

  • Endotoxins: These substances comprise a group of naturally occurring substances produced by bacteria. In low concentrations, they are not dangerous and may play a role in protecting people from allergies. At higher levels, they can induce serious inflammatory reactions in the respiratory tract. Endotoxins that can cause asthma symptoms to become worse may be found in dust, construction materials and plants. A recent study by researchers at Lund University in Sweden found that very high levels of endotoxins also are associated with environmental tobacco smoke. Their results showed that these levels were 120 times higher in an unventilated room, smoky room than in a smoke-free room.[8]

  • Pollen: Whole pollen grains are too large to enter the tiny airways deep inside the lungs and set off an asthma attack; however, during thunderstorms pollen grains can become broken up into granules that bear allergy-causing proteins just like the pollen grain itself. These granules are small enough to penetrate the narrowest airways where they can provoke asthmatic bronchial spasms in susceptible individuals. This important finding, by researchers at the University of Melbourne in Australia, explains why parts of England experienced an epidemic of asthmatic attacks soon after thunderstorms struck one evening in late June 1994. Emergency rooms became flooded with bewildered people struggling to breathe. The patients were mostly young people who suffered from hay fever but had never had an asthma attack before. The culprit eventually proved to be grass pollen that had been broken up by the storms.[9]

  • Molds and fungi: Between 10 percent and 32 percent of all people with asthma are sensitive to fungal allergens, both indoors and outdoors.[10]

  • Cockroaches: Up to 60 percent of people with asthma in one study tested positive to cockroach allergen.[7]

  • Rodent urine

  • Nitrogen oxides from gas stoves and gas heaters: Nitrogen dioxide is released from the burning of natural gas. Results of a survey of 539 people with asthma demonstrated that those with gas stoves were more likely to report asthma-related emergency room visits, urgent doctor visits, and hospital stays than those with electric stoves.[11] Another study showed that those people who were exposed to home gas heaters as babies were more likely to develop asthma or wheezing later in their childhood.[12]

  • Common cold, influenza, and other respiratory illnesses

  • House dust

  • Odors: In a study of the 55 people with asthma at the Stoneybrook School of Medicine, 51 gave common odor complaints as triggers for their asthma symptoms. The most common of these were: Cigarette smoke (73 percent), insecticides (62 percent); paint (60 percent); cleaners (58 percent); cooking smells (51 percent); auto fumes (45 percent); and perfume (31 percent). Seventy-one percent said they coughed and wheezed within minutes of exposure, 61 percent had gone to an emergency room and 47 percent had been hospitalized after exposure to an offending odor. [3]

  • Other triggers: Strenuous physical exercise; adverse weather conditions such as freezing temperatures, high humidity and thunderstorms; and some foods and food additives can cause an asthma attack. Strong emotional states also can lead to hyperventilation and an asthma attack.[13]

Asthma Symptoms

Asthma can occur at any age but is more common in children than adults. Nearly one out of every 13 school-age children in the US has asthma and that percentage is rising more rapidly in preschool-aged children than in any other group. Asthma is the leading cause of school absenteeism due to chronic illness (10 million school days missed a year). Asthma is the most common chronic childhood disease, affecting 4.8 million children.

One reason may be that their developing bodies may be more susceptible to environmental exposures than those of adults. In a typical day, children may be exposed to a wide array of environmental agents at home, in day care centers, in schools and outdoors. About 20 percent of all pediatric emergency room visits in the US are asthma-related.

Often, asthma develops as an allergic reaction to substances, such as antigens or irritants, which cause changes in lung function. Asthma may develop right away, in a few weeks or several years after initial exposure. The changes in lung function include:

  • Cells in the airways make more mucous than normal. This mucous is very thick and sticky and may clog up the airways.

  • Cells in the airways get inflamed, causing the airway passages to swell.

  • The muscles around the airway passages tighten.

  • These changes cause the air tubes to narrow which makes it hard to breathe.

Asthma symptoms may include:

  • Wheezing

  • A sense of tightness, pressure or pain in the chest

  • Coughing

  • Shortness of breath

These primary symptoms may be accompanied by:

  • Itchy and watery eyes

  • Sneezing

  • Stuffy and runny nose

Removing Triggers From Indoor Environments Key to Controlling Asthma

Asthma cannot be cured, but its symptoms can be controlled by medications and by limiting or eliminating exposure to known triggers. These triggers are not universal for all people with asthma as some people may react to one type of trigger and not to others. Effective management requires knowing which triggers to avoid. Not knowing can lead to taking actions that are not all that helpful and spending extra money unnecessarily.

Results of a recent study demonstrated that efforts of parents of children with asthma to limit exposure to triggers are not always helpful. Of 896 parents, 81 percent took some sort of action to reduce or remove an asthma trigger, but more than one-half (51 percent) tried a measure that did not work. Specifically, the study results found:

  • 216 children (24 percent) lived in a home with a smoker, with only 6 percent of parents who smoked taking action to reduce their child's exposure to ETS despite proven benefits of reducing exposure

  • 224 (25 percent) parents had purchased air filter, even though only 157 (18 percent) reported an environmental trigger that would have needed one

  • Few actions performed by the parents were harmful or not recommended. In all cases, the parents purchased a humidifier, even though dust mites triggered their children's asthma

The results from this study underscore the importance of role of health care providers in educating parents about effective ways to reduce or eliminate triggers and the importance of helping families identify the specific triggers to avoid.[14, 15]

Intervention does work. According to a study appearing in The New England Journal of Medicine, families who take an active role in minimizing or eliminating exposure to asthma triggers such as allergens and ETS had 21 fewer days of asthma symptoms during the one-year study. This study followed 900 children, ages 5 to 11 with moderate to severe asthma, who lived in the Bronx, Boston, Chicago, Dallas, Manhattan, Seattle/Tacoma and Tucson. In each case, investigators designed an individualized environmental intervention carried out by the child's family.[16]

General Guidelines for Avoiding Triggers and Reducing the Number and Severity of Asthma Attacks

In addition to avoiding triggers, the following offers some general guidelines for decreasing the number and severity of attacks:

  • Avoid cooking with natural gas stoves.

  • Lower the amount of moisture in homes to help decrease mold, dust mites, and cockroaches. Ideally, humidity levels should be between 40 percent and 60 percent.

  • Track local air pollution levels and restrict the amount of time spent outside when levels are high. Ozone should not exceed 66 on the pollution standards index (PSI) in local weather reports and particulate matter should not exceed 50 µg/m3 daily. Ozone levels peak from about 3:00 pm to 8:00 pm, so exercise outdoors early in the day.

  • When levels are high, close windows and turn on the air-conditioner, or go to the movies or an air-conditioned mall. Open the windows at night.

  • Avoid plastic building materials and furniture such as vinyl flooring, desktops or shelving. They commonly contain phthalates, which vaporize and bind to dust and other small particles, irritating bronchial passages when inhaled, Norwegian researchers reported in 1997.

  • Reduce exposure to emissions of formaldehyde and VOCs.

  • Eat fresh, oily fish. Researchers carrying out a study in Australia interviewed the parents of 574 children who had had wheezing incidents and reduced breathing within the past year. After statistical adjustments for factors such as parental asthma or smoking, they found that children with current asthma had eaten only about one-fourth as much fresh, oily fish as normal youngsters. They found no such association with other food groups. So increased consumption of fresh, oily fish has the potential to reduce the prevalence of childhood asthma.[17]

  • Keep the house, offices and schools clean. Many asthma triggers can be reduced, although not eliminated, through regular cleaning.

  • Control exposure to pets.

  • Dust masks and respirators can help to control workplace exposure, but special fit testing and training must be given before these are handed out.

General Guidelines for Making Sure Schools Are Asthma Friendly

The following are some guidelines:

  • Make sure the school has alternatives to outdoor activities in place for high pollution days.

  • Ask the school board and the school to work on asthma education, and to allow school nurses to administer asthma medication.

  • Make sure the classroom has working windows or an air-conditioner.

  • Ask that the classroom be damp mopped and wet dusted frequently, and that toxic cleaning products and pesticides not be used.

  • Make sure that the school is tobacco-free, including school-sponsored events.

  • Find out if the school maintains good indoor air quality.

  • Encourage the maintenance staff to reduce or eliminate allergens and irritants that can make asthma symptoms worse, including getting rid of cockroaches and asking staff not to wear perfume or aftershave.

  • Carpeting can harbor high levels of allergens, endotoxins, particles and dust mites. School rooms that do not have carpet are better for children with asthma.

  • Do not forget to see if the school has portable classrooms that may have high levels of pollutants that may trigger asthma attacks. In some parts of Maine, children with severe allergies and asthma are kept out of tightly built portable classrooms.

  • Find out if there is a nurse at school all day, every day. If not, is a nurse regularly available to the school to help write plans and give guidance for students with asthma about medicines, physical education, and field trips.

  • Find out if children take medicines at school as recommended by their doctor and parents as many children carry their own asthma medicines.

  • Find out about the school's emergency plan for taking care of a child with a severe asthma attack. Find out what they do and whom they call.

  • Ask the school to have someone teach school staff about asthma, asthma management plans and asthma medicines. In addition, it would help if there were somebody available to teach all students about asthma and how to help a classmate who has it.

Additional Resources

American Lung Association
A national, non-for-profit organization, the American Lung Association® is the oldest voluntary health organization in the United States. Founded in 1904 to fight tuberculosis, the American Lung Association® today fights lung disease in all its forms, with special emphasis on asthma, tobacco control and environmental health. For more information, visit the America Lung Associate website at www.lungusa.org.

US Environmental Protection Agency Tools for Schools Program
Since 2000, the Indoor Air Quality Tools for Schools Program has recognized more than 100 schools and school districts for their accomplishments in creating a safe and healthy learning environment and maintaining good IAQ in their facilities. To learn more, visit the EPA's Tools for Schools website at www.epa.gov/iaq/schools/.

Allergy and Asthma Network/Mothers of Asthmatics, Inc. (AAN/MA)
A national, not-for-profit organization, AAN/MA provides asthma and allergy outreach to improve public and patient awareness and management of asthma. They serve as a valuable communication link among families, medical professionals, caregivers, the pharmaceutical and medical supply industries, and the government. For more information, visit AANIMA website at www.aanma.org.

Asthma and Allergy Foundation of America (AAFA)
This not-for-profit patient advocacy organization is dedicated to finding a cure for and controlling asthma and allergic diseases. Education and support services are available to asthma and allergy patients and their families through AAFA's local education support groups and chapters nationwide. To find out more, visit the AAFA website at www.aafa.org.

Air Quality Sciences Advanced School Test Kit
This easy-to-use kit allows school nurses, faculty and staff to easily evaluate school facilities for the presence of indoor chemicals and allergens most likely to provoke asthma attacks. For more information, visit the AQS website at www.aqs.com.

References

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  2. Bronchial Asthma. Fact Sheet No. 206. World Health Organization. Brussels, Belgium. January 2000.

  3. King W. Research stepped up as asthma rates rise. New Orleans Times-Picayune. May 28, 1995.

  4. Haney DQ. Roaches top cause of asthma among the poor. Palm Beach Post. June 9, 1996.

  5. Rumchev K, Spickett J, Bulsara M, et al. Association of domestic exposure to volatile organic compounds with asthma in young children. Thorax. 2004: 59:746-751.

  6. Cullinan P, MacNeill SJ, Harris JM, et al. Early allergen exposure, skin prick responses and atopic wheeze at age 5 in English children: A cohort study. Thoras. 2004: 59:855-861.

  7. Jones AP. Asthma and domestic air quality. Soc. Sci. Med. 1998;47(6):755-764.

  8. Larsson L, Szponar B, Pehrson C. Tobacco smoking increases dramatically air concentrations of endotoxin. Indoor Air. Online publication date: 20 July 2004.

  9. Vines G. Asthma is blowing in the wind; what do hay fever, global warming and crops have in common? Pollen?and many of us are feeling the effects. The Independent (London). August 20, 1999.

  10. Trudeau WL, Fernández-Caldas E. Identifying and measuring indoor biologic agents. J Allergy Clin Immunol. 1994;2(2):393-400.

  11. Gas stoves risky for asthma sufferers. The Montreal Gazette. November 16, 1999.

  12. Ponsonby A, Couper D, Duyer T, Carmichael A, Kemp A, Cochrane J. The relation between infant indoor environment and subsequent asthma. Epidemiology. 2000;11(2):128-135.

  13. Basic Facts About Asthma. Centers for Disease Control and Prevention. Atlanta, Georgia. October 2003.

  14. Cabana MD, Slish KK, Lewis TC, et al. Parental management of asthma triggers within a child's environment. J Allergy Clin Immunol. 114 (2). August 2004.

  15. Cabana MD, Slish KK, Brown RW, et al. Factors that predict which parents will address environmental asthma triggers. J Allergy Clin Immunol. 113 (5) Suppl. February 2004.

  16. Morgan WJ, Crain EF, Gruchalla RS, et al. Results of a home-base environmental intervention among urban children with asthma. N Eng J Med. 351 (11): 1068-1080. September 9, 2004.

  17. Hodge L, Salome CM, Peat JK, Haby MM, Xuan W, Woolcock AJ. Consumption of oily fish and childhood asthma risk. Med J Aust. 1996;164(3):137-40