Airborne Particulate Matter and Health San Luis Obispo

Airborne Particulate Matter and Health San Luis Obispo County Health Commission September 14, 2009 Melanie Marty, Ph. D. California EPA Office of Environmental Health Hazard Assessment

WHAT IS IN PARTICULATE MATTER? Heavy Metals Nitrates Aerosols Organics Carbon Smoke Soot Soil Sulfates Dust Salts Complex Mixture from Numerous Sources Direct and Indirect

HOW SMALL IS PM? Hair cross section (60 m) Human Hair (60 m diameter) PM 10 (10 m) PM 2. 5 (2. 5 m)

Epidemiological Studies of PM and Daily Mortality –Short-term Exposures • Many time-series studies examine associations between daily concentrations of PM and daily death counts. • Many studies of PM and mortality conducted in hundreds of cities world-wide, over a wide range of climates and seasonal patterns, PM concentrations, co-pollutants, background health conditions, housing stock, etc. • Studies account for weather, seasonal effects, day of week, co-pollutants, and other factors

PM Mortality Epidemiology Studies – Short-term Exposure Results • Consistent associations between daily average PM 10 and PM 2. 5 and mortality. • Linear relationship: no good evidence of a threshold. • Most mortality studies show associations between 0. 5 and 2% increments in daily mortality per 10 g/m 3 PM.

Coherence: Morbidity Effects • Associations also reported between daily PM and multiple measures of illness: – hospitalizations for heart and lung disease – emergency room visits – school absenteeism and work loss – asthma attacks – bronchitis & other respiratory symptoms in children – decreased lung function in children and adults

PM EPIDEMIOLOGY STUDIES -LONG-TERM EXPOSURE • Several prospective cohort studies report associations between mortality and long-term exposure to PM 10 and/or PM 2. 5 including: • Harvard six-cities (Dockery et al. 1993) • ACS studies (Pope et al, 1995; Krewski , 2000, Pope et al, 2002) • Analyses account for relevant individual-level factors (e. g. , smoking, weight, alcohol, occupational exposure, gender, age, and others).

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 PM 2. 5 and PM 10 and risk of deaths from heart and lung disease • Note that larger associations are found in these studies of long-term exposures than in the daily timeseries studies.

Mortality Risks and Long-term PM Exposure in the Harvard Six-Cities Study g/m 3 PM 2. 5 Relative Risk PM 10 g/m 3

American Cancer Society Cohort Study • 550, 000 people from 151 cities followed for 16 years starting in 1982 (Pope et al. , 1995, 2002; reanalyzed by Krewski et al, 2000) • Linked individual risk factors, vital status data, and air pollution measurements • Controlled for age, sex, occupational exposure, obesity, diet (fat, vegies, citrus), alcohol, smoking, socioeconomic status • Association found between risk of mortality (both all cause and cardiopulmonary) and particulates • Findings suggest that a 10 µg/m 3 difference in long-term PM 10 exposure is associated with: 4% increase in all-cause mortality 6% increase in cardiopulmonary mortality 8% increase in lung cancer mortality

Better Exposure Assessment– Higher Risk Estimates • Typically central-site monitor used to estimate exposure in a city or wide area. – Results in measurement error, exposure misclassification, bias towards the null. • Jerrett et al (2005) studied LA subset of ACS (22, 905 people and 5, 856 deaths). • Refined exposure using sophisticated interpolation techniques, 23 monitoring sites. – 17% (95% CI 5, 30) increase in all-cause mortality per 10 µg/m 3 increase in PM 2. 5 (versus 6% in ACS cohort) – Strongest for ischemic heart disease (39%; 95% CI 12 -73)

What about Coarse Particles? • Short-term studies in areas with high PM 10 -2. 5 and low PM 2. 5 find significant association w/coarse PM for : – CV mortality, ↓HRV – Cough in children – Elevated asthma hospitalization in children and adults – Meta-analysis of numerous studies indicates robust association with mortality (Schwartz, 2009) Don’t ignore the coarser particles….

Reduced PM Exposures Linked with Clear Health Improvements • Utah Valley – Steel mill shutdown reduced PM pollution and respiratory hospital admissions (Pope et al, 1989) • Dublin, Ireland – ban on coal sales reduced PM pollution and all-cause, cardiovascular, and respiratory mortality fell by 5. 7, 10. 3, and 15. 5%, respectively. (Clancy et al. Lancet 2002)

Infants and Children - Also Susceptible to PM • Elevated infant mortality associated with PM in several countries including the U. S. – CA Study: Woodruff et al. , 2006; Post-neonatal respiratory mortality ↑ OR 2. 13 (1. 12 -4. 05) per 10 ug/m 3 • Some evidence of adverse birth outcomes (low birth weight; pre-term birth) associated with PM 2. 5 and PM 10. • Evidence of decreased lung function growth in children in Southern CA. • Asthma exacerbation – many studies, both coarse and fine PM.

Air Pollution and Growth of Lung Function • So. Cal Children’s Study found decreased lung function growth associated with NO 2, acid vapors, PM 2. 5 (Gauderman et al. , 2004) • Clinically relevant decreased lung function in 7. 9 percent of 18 year olds at highest PM 2. 5 exposures. • Permanent effect; relevance to respiratory health as older adult. • Children who moved to less polluted areas had improved lung function growth, while those who moved to more polluted areas had decreased growth rates. (Avol et al. AJRCCM 2001)

2002 PM STANDARDS in CA PM 10 – Reduced annual average from 30 to 20 g/m 3 (no Fed std). – Retained 24 -hour standard of 50 g/m 3, not to be exceeded (Fed Std = 150). PM 2. 5 – Added an annual average standard of 12 g/m 3 (Fed Std = 15). Fed 24 -hr std is 35 g/m 3

Questions?

San Luis Obispo County Air Pollution Control District Presents: Particulate Matter and Your Health Tuesday, September 15 from 11: 30 a. m. to 1: 00 p. m. San Luis Obispo Library 995 Palm Street, San Luis Obispo Library Community Room Panel Experts include: Dr. Melanie Marty, Chief of the Air Toxicology and Epidemiology Branch Cal EPA’s Office of the Environmental Health Hazard Assessment Dr. Tracy Thatcher, Assistant Professor of Civil & Environmental Engineering Cal Poly, San Luis Obispo Larry Allen, Director San Luis Obispo County Air Pollution Control District