THE AIR QUALITY INDEX: IMPLICATIONS FOR PHYSICAL THERAPY. Michael J. Fillyaw* Physical Therapy, University of New England, Portland, ME UNIQUE: A growing body of epidemiological and experimental evidence shows the association between high levels of air pollutants and cardiovascular and pulmonary diseases. Increases in all-cause, cardiopulmonary, and lung cancer mortality, symptoms (dyspnea, wheezing, cough, chest tightness, perceived exertion), and hospital and healthcare visits have been linked to air pollution, particularly ground-level ozone (O3) and particles less than 2.5 micrometers in diameter [PM2.5]. The Environmental Protection Agency (EPA) developed the Air Quality Index (AQI) to help citizens understand what local air quality means to health. The AQI focuses on health effects that can happen within a few hours or days after breathing polluted air. PURPOSE: The purposes of this report are to: 1) illustrate the use of the AQI with O3 and PM2.5 data from Maine during 1999 - 2004; 2) provide an evidence-based review of the harmful effects of O3 and PM2.5; 3) promote awareness about the potential to reduce cardiovascular morbidity and mortality by improving air quality; 4) suggest ways physical therapists can educate clients about air quality and how to modify their activity. FOUNDATION: A network of EPA stations records the concentrations of ground level O3, particulate matter, and other air pollutants at more than 1000 locations across the country. The raw data are converted into separate AQI values using formulas developed by the EPA. The AQI ranges from 0 - 500 with higher values indicating greater air pollution and greater health concern. To make the AQI easy to understand, the scale is divided into standard, color-coded categories: For AQI 0 - 50, the air quality is Good (green). For AQI 51 - 100, air quality is Moderate (yellow). For AQI 101 - 150, air quality is Unhealthy for Sensitive Groups (orange). For AQI 151 - 200, air is Unhealthy (red). For AQI values 201 - 300, air is Very Unhealthy (purple). AQI values over 300 are Hazardous (maroon). Air quality information is published in most newspapers and broadcast on some television and radio news, as well as being available on the EPA web site. DESCRIPTION: The Maine Department of Environmental Protection reports the maximum concentrations of O3 and PM2.5 measured daily in Maine from May through September. The O3 concentration reports from 16 monitoring sites since 1999 and PM2.5 concentration reports from 3 sites since 2002 were analyzed to determine the percentage of days the air quality was reported to be Good, Moderate, Unhealthy for Sensitive Groups, Unhealthy, Very Unhealthy, and Hazardous. OBSERVATIONS: From 1999 to 2004, there were 13324 possible site-days (# monitoring sites # days) for O3 and 1236 possible site-days for PM2.5. For O3: 90.6% were Good, 5.7% were Moderate, 1.2% was Unhealthy for Sensitive Groups, 0.2% was Unhealthy, and 2.4% were not reported. For PM2.5: 84% were Good, 13% were Moderate, 0.9% was Unhealthy for Sensitive Groups, and 1.8% were not reported. 2002 had the poorest air quality. July had the greatest number of site-days rated less than Good for O3 and PM2.5 each year. When air quality is Good, no health impacts are expected and no precautions are necessary. When air quality is Moderate, unusually sensitive people should consider limiting prolonged or heavy exertion outdoors. Air quality rated Unhealthy for Sensitive Groups corresponds to a Health Notice and active children and adults, and people with heart or lung disease should reduce prolonged or heavy exertion outdoors. An air quality rating of Unhealthy corresponds to a Health Advisory and active children and adults and people with heart or lung disease should avoid prolonged or heavy exertion; everyone else should reduce prolonged or heavy exertion outdoors. Very Unhealthy air quality corresponds to a Health Alert. Active children and adults and people with heart or lung disease should avoid all outdoor exertion; everyone else, especially children, should avoid prolonged or heavy exertion outdoors. Hazardous air quality triggers a Health Warning and it is recommended that everyone avoid all activity outdoors. CONCLUSIONS: Physical therapists concerned with health promotion and primary and secondary prevention of cardiovascular and pulmonary diseases should be aware of the harmful effects of air pollution. In particular, therapists working in cardiac or pulmonary rehabilitation programs should know how air quality affects exercise capacity and health. Strategies to reduce the effects of air pollution include: 1) check the AQI forecasts and reports and heed warnings; 2) stay indoors as much as possible during peak ozone hours, usually sunny, summer afternoons; 3) in lieu of outdoor exercise, consider walking in an inside shopping mall or gym or using an exercise machine; 4) schedule outdoor exercise, including children's activities and school sports, before 11 AM or after 8 PM; 5) individuals who are particularly sensitive to O3, or who have asthma or other respiratory problems, should stay in air-conditioned areas, if possible; 6) take prescribed medication before exercise and carry inhaler. Although exposure to air pollution poses smaller relative risks for cardiovascular disease than other factors, because exposure is ubiquitous and occurs over a lifetime, everyone is affected. Therapists can educate their clients and raise public awareness about air quality and health by posting daily AQI reports in their clinics, by speaking to patient support groups, by writing an editorial or letter to the editor for the newspaper, and through continuing education. APTA can promote public health by supporting regulations to expedite attaining the National Ambient Air Quality Standards. FUNDING SOURCE: None. KEYWORDS: health promotion, air quality, cardiopulmonary disease Copyright 2009 by the American Physical Therapy Association. Requests for reprints should be directed to the corresponding author of the article. Educators, students, and other academic customers may receive permission to reprint copyrighted material from Physical Therapy (ISSN 1538-6724) by contacting the Copyright Clearance Center Inc, 222 Rosewood Dr, Danvers, MA 01923. Other types of customers who want permission to reprint should contact the APTA Editorial Office, Attn: Physical Therapy.