Development of California’s Ambient Air Quality Standards for Particulate Matter Bart Ostro, Chief Air Pollution Epidemiology Unit Office of Environmental Health Hazard Assessment (OEHHA) California EPA Oakland, CA

California PM STANDARDS - 2002 PM10 – Reduced annual average from 30 to 20 g/m3 (USEPA = 50).  – Retained 24-hour standard of 50 g/m3, not to be exceeded (USEPA = 150).  PM2.5 – Added an annual average standard of 12 g/m3 (USEPA = 15).

Studies of Long-term Exposure and Life Expectancy Several studies ( Harvard 6-Cities, American Cancer Society, Adventist Health Study) have examined the effects of long-term exposure to PM10, sulfates and/or PM2.5. These ‘prospective cohort’ studies (gold standard) have followed study subjects for 7 to 16 years. Analyses control for individual-level factors that may influence risk of mortality (e.g., age, gender, weight, tobacco and alcohol use, occupational exposure)

Harvard 6-cities Study (Dockery et al, 1993) 8,111 adults followed up to 16 years Pollution monitors set up specifically for this study Associations reported between both PM2.5 and PM10 and deaths from heart and lung disease 10 g/m3 associated with 8% increase in all-cause mortality

American Cancer Society Study (Pope et al., 1995; 2002) 550,000 individuals in 151 cities followed for 7 and 16 years Associations observed between PM2.5 and sulfate and both cardiopulmonary mortality and lung cancer Results imply significant reduction in life expectancy. Between the most and least polluted cities (25 g/m3 PM2.5), the average decrease in life expectancy was about 1.5 years. In addition, long-term exposure to PM10 or PM2.5 has been significantly associated with mortality due to various adverse health endpoints (like heart attacks, cardiopulmonary disease, and lung cancer). Some of the strongest evidence is from one of the largest U.S. studies--the American Cancer Society or “ACS” study--with roughly half a million individuals in metropolitan areas around the U.S. Validated findings from several studies done on this group if individuals (or “cohort”) have provided strong evidence of death from cardiopulmonary disease and lung cancer. Also, the level of effect is significant as associated deaths from exposure reaching into the thousands per year.

Is the evidence consistent and coherent? Long-term exposure studies supported by results from short-term exposure studies linking PM to: Mortality Cardiovascular and respiratory hospitalization and emergency room visits Worsening of asthma Bronchitis Work loss, school absenteeism Respiratory symptoms Lung function decrements

Long-term Exposure Also Affects Morbidity in Children Increased risk of bronchitis and chronic cough in children related to long-term exposure to PM10 PM exposure during pregnancy may be related to low birth weight, prematurity, and birth defects. Over a 4-year (now 8) period, PM10, PM2.5, coarse particles, acid vapors, and NO2 were associated with reduced lung growth in L.A. Children’s Health Study

Rationale for Standard Based on mortality – robust data. Morbidity effects occur in same range of concentrations as mortality effects, thus protecting children and other susceptibles. Focused on chronic exposures since higher effect estimates than those based on short-term averages. Attaining annual standards will force down short-term averages/peaks. Kept short term PM10 as a “backstop”.

PM10 Range of Long-Term Mean Concentrations Observed in Epidemiologic Studies Chronic Exposure Morbidity: Dockery et al., 1989; McConnell et al., 1999 (LA Children's Health Studies) 21 35 Chronic Exposure Mortality: Dockery et al., 1993 (Six-Cities Study) 18 28 46 Chronic Exposure Mortality: Pope et al., 1995 (ACS), PM10 Equivalent CA Annual Standard Adopted June 2002 18 28 60 Time Series Mortality Studies 15 25 70 10 20 30 40 50 60 70 80 PM10 (mg/m3) ■ = Range of concentrations in a given study  = Study mean concentration  = Range of study mean concentrations among multiple studies o = Lower end of concentrations that may be more relevant to California

PM2.5 Range of Long-term Mean Concentrations Observed In Epidemiologic Studies Chronic Exposure Mortality: Dockery et al., 1993 (Six-Cities Study) 11 18 30 Chronic Exposure Mortality: Pope et al., 1995 (ACS) 9 20 35 Time Series Mortality Studies CA Annual Standard Adopted June 2002 13 18 5 10 12 15 20 25 30 35 40 PM2.5 (mg/m3)   ■ = Range of concentrations in a given study  = Study mean concentration  = Range of study mean concentrations among multiple studies

6,500 (95% C.I. = 3,200 – 9,800) premature deaths/year Significant Benefits are Expected from Attaining the Annual Average Standards Change to proposed annual average PM10 standard estimated to prevent about : 6,500 (95% C.I. = 3,200 – 9,800) premature deaths/year thousands of hospitalizations for cardiopulmonary disease 389,000 lower respiratory symptoms among children aged 7 – 14 Calculations are based on data on population, current ambient concentrations, and exposure-response relationships derived from epidemiological studies.