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PSAPCA’s mission "to protect our air resources for the health of current and future generations by fostering individual responsibility and regulatory accountability" says it all. To this end, we turn to scientists and health care professionals to help us understand the relationship between air quality and our health.
Under the Federal Clean Air Act, the U.S. Environmental Protection Agency is responsible for establishing the National Ambient Air Quality Standards to protect public health. These standards are based on the results from numerous scientific studies. It is the job of the scientist to look for a causal relationship or evidence within a population (epidemiological) to show that exposure to a specific pollutant causes adverse effects on our health. Researchers use scientific methods and statistical tests to "reduce the uncertainty" about a relationship between a specific pollutant exposure and identifiable effects.
Health studies are designed a number of ways to explore relationships between exposure to pollutants and adverse impacts on our health. Most studies focus on children, people with respiratory illnesses and the elderly, as they are at the greatest risk. Children spend a great deal of time outside and are therefore potentially exposed to a greater proportion of outdoor pollutants. Children also breathe in more air relative to their size and weight than adults. In addition, residential pollution is more likely to cause harm than industrial pollution to children, people with respiratory illnesses and the elderly, because they spend a greater percentage of time at home.
The pollutant with the greatest evidence of adverse health effects and the pollutant most people in our area are exposed to is fine particulate matter. In response to the concern for widespread exposure to this pollutant, a panel of experts has been meeting made up of representatives from PSAPCA, the Washington State Department of Health - Office of Toxic Substances, Washington Thoracic Society, Washington State Department of Ecology, University of Washington Departments of Environmental Health and Civil Engineering, the American Lung Association and the Northwest Asthma and Allergy Center.
The panel performed an extensive literature search and interpreted the results of local and national health studies in order to propose that PSAPCA set a regional goal for fine particulate matter or PM2.5. In July 1996, the panel made recommendations to the PSAPCA Board of Directors concerning a goal for PM2.5 which would protect public health. This goal is significantly more stringent than EPA’s proposal to revise the National Ambient Air Quality Standards for PM. At the September 1996 meeting, the board decided to respond to the PM panel’s recommendation through a process that provides time to educate stakeholders on the underlying scientific evidence and the ramifications of formally adopting such a goal.
Local studies in particular are used by PSAPCA to provide more meaningful information as the agency works to raise awareness of the pollutants and their health impacts. Local studies have helped us understand the impact our air mix has on our children. In fact, studies done in the Puget Sound region have contributed to an improvement in our air quality by supporting the case for the legislature to authorize indoor and outdoor burn bans. Studies have shown a decrease in health effects right in our own backyard since 1988.
The following studies were conducted in the Puget Sound Region in the past ten years. Following the title and authors of each study is place
"Pulmonary Function Changes in Children Associated with Fine Particle Matter"
J. Koenig, T. Larson, Q. Hanley, V. Rebolledo, K. Dumlar, H. Checkoway, S. Wang, D. Lin and W. Pierson. Environmental Research. 63:26-38; 1993. Status of Study: Peer Reviewed and Published
During winter months, neighborhoods in the Seattle metropolitan area are affected by particulate matter from residential wood burning. A study was conducted to investigate the relationship between fine particulate matter and pulmonary function in young children. Data were gathered before, during and after the 1988-89 and 1989-90 winter heating seasons. The subjects were 326 elementary school children, including 24 asthmatics. Analysis of the relationship between particulate matter and lung function indicated that an increase in particulate air pollution was associated with a decline in asthmatic children’s pulmonary function.
Koenig et al. presented preliminary results from the study discussed above to provide information to the Washington State Legislature for wood stove regulation. This information was summarized in the Northwest Environmental Journal (4:41-54; 1988)
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"A Questionnaire Study of Respiratory Health in Areas of High and Low Ambient Wood Smoke Pollution"
K. Browning, J. Koenig, H. Checkoway, T. Larson, and W. Pierson. 1990. Status of Study: Peer Reviewed
A questionnaire was distributed to two target areas in Shoreline, Washington, one area on a ridge fairly free from smoke and the other area in the Lake Forest Park valley, which is known as a woodsmoke "hot spot." Six hundred questionnaires were sent to residents in each area. The questionnaire was designed to gather information about respiratory symptoms. Response rate was high in both areas (more than 50% of questionnaires returned). Results showed a trend toward more symptoms in children aged 1-5 in high wood smoke areas supporting other research that suggests that wood smoke air pollution aggravates symptoms of respiratory disease in preschool children.
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"Particulate Air Pollution and Hospital Emergency Room Visits for Asthma in Seattle"
J. Schwartz, D. Slater, T. Larson, W. Pierson, J. Koenig. Am. Rev. Respir. Dis. 147:826-831; 1993. Status of Study: Peer Reviewed and Published
To confirm whether PM10 exposure is associated with increased symptoms of asthma, daily records of asthma emergency room visits from eight hospitals in the Seattle area were compiled. Controlling for weather, season, time trends, age, hospital and day of the week, the daily counts of emergency room visits for persons under the age of 65 were significantly associated with PM10 exposure on the previous day. Even at PM10 levels significantly lower than EPA standards, there are still associated health risks. For every increase in PM equal to 20% of the standard, the health risk increases by 12%.
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"A Panel Study of Children with Asthma Exposed to Wood Smoke"
D. Booth, J. Koenig, T. Larsen, C. Betchley, T. McRorie. Department of Environmental Health, Civil Engineering, and Pharmacy, University of Washington, Seattle, WA 1995-96. Status of Study: Peer Review in Progress
Two Puget Sound communities affected by wood smoke were selected for this 1995-96 study, Puyallup and Shoreline. Children with asthma were studied to identify risk factors which predict an adverse respiratory response to inhalation of wood smoke. Twenty children aged 6-12 with asthma were recruited for the study. The children kept daily symptom and medication diaries for three to four months from October through March. Also the children wore NO2 badges for a three-to-four day period once during the pre-heating season and once during the heating season to measure exposure to nitrogen dioxide. During the same period, fine particulate matter was measured inside and outside the child’s home. The child was given a peak flow meter and asked to record morning and evening values during the three-to-four day periods. No direct relationship between the levels of pollutants and respiratory health was seen. However, there were significant increases in symptoms of upper and lower respiratory disease during the heating season compared to the pre-season. Other causes such as respiratory infections and other indoor air pollutants can not be entirely ruled out. Children who were taking daily asthma medication had fewer symptoms than those not taking daily medication.
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"A Study of Pulmonary Function in Elementary School Children Living in Shoreline."
Jane Q. Koenig, Department of Environmental Health, University of Washington, Seattle, WA. Status of Study: Study in Progress
During the 1995-96 school year, lung function was studied in 36 elementary school children in the Shoreline, Washington, school district. The objective was to evaluate whether there was an association between depressed lung function and wood burning (as measured by concentrations of PM10). The study tested whether current levels of PM10, which are dramatically lower than levels in 1988-90, are associated with changes in pulmonary function in children. Study results do not support this hypothesis. While there was no significant decrease in either children with or without asthma, there is a pattern of decreased lung function in the healthy children.
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For more information on these or other studies, contact Naydene Maykut, Senior Air Quality Scientist at (206) 689-4062 or via electronic mail: eng@psapca.org.
Updated June 1997
