Air Pollution and Health Recent Findings and Next Steps Antonella Zanobetti

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1 Air Pollution and Health Recent Findings and Next Steps Antonella Zanobetti Principal Research Scientist Department of Environmental Health Harvard T.H. Chan School of Public Health

2 Background Adverse effects of air pollution on health: 3 disasters in which high levels of air pollution associated with high number of deaths Mosa Valley, Belgium 1930 (Firket, 1936) Donora, PA USA 1948 (Shrenk, 1948) London, UK 1952 (Ministry of Health, 1987)

3 Background The association between exposure to particulate matter (PM) and mortality or morbidity is well established Particulate air pollution has been associated with increases in daily deaths and hospital admissions in many studies across the world Air pollution remains a serious, overwhelming problem China: heavy haze in Beijing, January 2013.

4 Recent Air Pollution Facts 10 Top Risk Factors Ranked by Attributable Burden of Disease in 2010 (disability adjusted life years) #3: Household air pollution from solid fuels #9: Ambient particulate matter pollution Lim et al., A comparative risk assessment of burden of disease and injury attributable to 67 risk factors and risk factor clusters in 21 regions, : a systematic analysis for the Global Burden of Disease Study The Lancet (2012)

5 Global Public Health Impact In 2010, globally: Ambient particulate matter pollution accounted for: 3.2 million excess deaths 3.1% of disability adjusted life years (DALYs) Household air pollution from solid fuels accounted for: 3.5 million excess deaths 4.3% of disability adjusted life years (DALYs) Household air pollution is an important contributor to ambient particulate matter pollution Account for 16% of the worldwide burden from ambient particulate matter pollution in 2010 Lim et al. Lancet. 2012

6 Recent Air Pollution Facts Ratio of estimated 2005:1990 PM 2.5 concentrations Between , global ambient PM 2.5 concentrations increased by 2.1% / year Brauer et al., Environ. Sci. Technol. (2012); van Donkelaar et al., EHP (2015)

7 Reducing particle pollution National Research Council (NRC) stated most important research priorities: to set standards for criteria pollutants to understand the relationship between particulate matter and public health Under the Clean Air Act, US Environmental Protection Agency (EPA) set National Ambient Air Quality Standard (NAAQS) for criteria pollutants ozone, lead, sulfur oxides, nitrogen oxides, and particulate matter periodically revised

8 What is Particulate Matter? "Particulate matter," also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets found in the air. Common Sources: Primary particles are emitted directly from a source: dust, fuel combustion, motor vehicles, industrial, fires Secondary particles formed in complicated reactions in the atmosphere of chemicals emitted from power plants, industries and automobiles. These particles make up most of the fine particle pollution in the US.

9 How Big is Particle Pollution? Grouped into size categories: Inhalable particles (PM 10 ) <= 10 mm in diameter. Fine particles (PM 2.5 ) are 2.5 mm in diameter and smaller. Inhalable coarse particles (PM ) >=2.5 mm and <= 10 mm in diameter How small is 2.5 micrometers? The average human hair is about micrometers in diameter making it 30 times larger than the largest fine particle. Robert D. Brook et al. Circulation. 2004;109:

10 How Air Quality Affects Health 1 Enter body through the nose and throat 2 3 Larger particles (PM 10 ) are eliminated 4 PM 2.5 penetrate into the lungs/alveoli

11 Identifying and quantifying the influence of environmental factors on human disease in communities to provide scientific evidence for environmental and health policies. 1. Quantify relationship between air pollution and health 2. Develop mathematical and statistical tools to examine this relationship 3. Identify subpopulations most susceptible to adverse health effects from air pollution exposure 4. Study the physiologic mechanisms by which ambient air pollution mediates adverse health effects 5. Development of models to improve monitoring and exposure methods.

12 Existing literature Many studies around the world found significant associations between particulate matter and health outcomes all-cause and cause-specific mortality cardiovascular & respiratory outcomes lung cancer etc Short-term exposure (few days) Acute health effects Long-term exposure (few years) Chronic health effects

13 Examples studies of short term PM 2.5 effects 1. Fine particles (PM 2.5 ) are more harmful to health than larger particles (PM 10 ) Coarse particles (=PM 10 -PM 2.5 ) are not regulated by U.S. EPA We test the hypothesis that PM 2.5 and PM coarse are associated with mortality 2. Possible mechanisms of mortality/pm 2.5 associations include: oxidative stress systemic inflammation, and cerebrovascular dysfunction These are related to neurovascular dysfunction and neurodegeneration Examine if exposure to PM 2.5 increases the risk of hospitalization for diabetes or neurological disorders

14 The Effect of Fine and Coarse Particulate Air Pollution On Mortality: A National Analysis We conducted a multi-city time series study of the acute effect of PM 2.5 and of PM coarse on the increased risk of death Map of the 112 US cities included in the study. Symbol size: the population Color: PM 2.5 concentrations Health data Counts of mortality from NCHS for years all cause mortality cardiovascular disease myocardial infarction stroke respiratory disease Environmental Data PM 10 PM 2.5 ambient monitors from US EPA s Air Quality System Technology Transfer Network (EPA AQS) Zanobetti A & Schwartz J. Environ Health Perspect, 2009;117(6):

15 Percent increase (95% CI) for 10 mg/m 3 increase in PM 2.5. Combined results across 112 cities of the mortality PM 2.5 association, for the two days mean, sum of 4 days distributed lag and for the two days mean by season

16 Percent increase in mortality for 10 µg/m 3 increase in PM coarse and PM 2.5 for the two days mean, across the 47 cities: two- pollutant model. Increased risk of mortality for all and specific causes associated with PM 2.5 and with PM coarse The risks are higher than what previously observed for PM 10. PM2.5 PM coarse % 95% CI % 95% CI All cause mortality CVD MI STROKE Respiratory

17 A national case-crossover analysis of the short-term effect of PM 2.5 on hospitalizations and mortality in subjects with diabetes and neurological disorders. 1. The association between short-term exposure to PM 2.5 and all-cause mortality is modified by having a previous hospitalization of diabetes or neurological disorders. 2. Exposure to PM 2.5 increases the risk of hospitalization for diabetes or neurological disorders Map of the 121 US cities Zanobetti A, et al. Environ Health 2014;13(1):38. Health Data Medicare data for citizens >65 years Hospitalizations: Dementia (N=717,000) Alzheimer's disease(n=1,335,000) Parkinson s disease (N=714,000) Multiple sclerosis(n=66,000) Diabetes(N=8,245,000) Deaths (N=6,983,000) Environmental Data PM 2.5 from US EPA AQS 2 days average

18 Percent Increase in mortality and admissions for 10 mg/m 3 Increase in the 2 Days Average PM 2.5 % 95% CI 1) Mortality All deaths Deaths without medical conditions Mortality by Previous Cause of Hospitalization Alzheimer's disease Dementia Parkinson's disease Multiple Sclerosis Diabetes ) Cause Specific Hospitalizations Alzheimer's disease Dementia Parkinson's disease Multiple Sclerosis Diabetes

19 Examples studies of long term PM 2.5 effects 1. Increased interest in the effects of air pollution on the central nervous system and neurodegeneration Examined the potential effect of long-term PM 2.5 exposure on first admission for dementia, Alzheimer s or Parkinson s diseases 2. To identify spatial locations and population sub-groups that are more vulnerable to the effects of the exposure We assessed whether community-level variables, including socioeconomic status (SES) indicators, increased urbanicity and temperature modify the association between long term exposure to PM 2.5 and mortality.

20 Long-term PM 2.5 Exposure and Neurological Hospital Admissions in the Northeastern US Assess the potential impact of long-term PM 2.5 exposure on event time, defined as time to the first admission for dementia, Alzheimer s or Parkinson s diseases Health Data Medicare enrollees ( ) 9.8 M subjects > 266K Alzheimer s (AD) > 119 K Parkinson s (PD) 50 cities across 12 Northeastern States Mean age: 76.6 yr (SD: 7.6), 57.3% female, 80.4% white Environmental Data PM 2.5 from US EPA AQS Annual averages Kioumourtzoglou MA et al. EHP 2015

21 Findings City-specific Cox proportional hazard models No confounding across cities, by long-term trends or individual characteristics Per 1 μg/m 3 annual PM 2.5 : Alzheimer s Disease: HR = 1.15 (1.11, 1.19) Parkinson s Disease: HR = 1.08 (1.04, 1.12) One of the first study to examine the relationship between long term exposure to PM 2.5 and time to the first hospitalization for the most common neurodegenerative diseases. Our findings provide the basis for more studies, as the implications to public health can be crucial.

22 Long-term exposure to PM 2.5 and mortality in 207 US cities: Modification by temperature, population characteristics and green space Health Data >35M Medicare enrollees ( ) Observed >11M deaths Environmental Data PM 2.5 from US EPA AQS Annual averages City-level characteristics: Census: median household income % in poverty % of white, black and Asian % of residents with and without high-school degrees and with a college degree Smart Growth America: Urbanicity Behavioral Risk Factor Surveillance System: city-specific smoking ( ) obesity rates ( ) Normalized Difference Vegetation Index (NDVI). Greenness Kioumourtzoglou et al., Epidemiology 2015

23 Effect modification on the PM 2.5 mortality association, HRs per 10 μg/m 3 at the 25 th and 75 th % of each variable HR = 1.19 (1.11, 1.28) per 10 μg/m 3 annual PM 2.5 Largest national study for long-term PM 2.5 and mortality Living in cities with low SES is associated with higher effect estimates.

24 Issues in existing studies Long-term and short-term exposure to fine particulate matter has been consistently associated with adverse health Previous studies have generally focused on: Either long-term or short-term exposures Exposure across the entire range of PM2.5 concentrations Use monitored data

25 Issues in existing studies Rural areas are not generally represented Spatial variability in PM 2.5 concentrations within cities not taken into account, which can introduce exposure measurement error No simultaneous estimate of long-term and short term effects Relevant to future assessments of current U.S. EPA standards Health effects when air quality concentrations are at or below the existing NAAQS levels

26 Moving forward 1. Improve exposure assessment 2. Estimate health effects when air quality concentrations are at or below the existing or alternative NAAQS levels U.S. EPA review NAAQS every 5 years Idea is that if significant effects are seen at lower level of the existing NAAQS, there is support for the NAAQS not being adequate to protect public health

27 Improving Exposure assessment Monitoring stations: Usually average across available monitoring stations in a county Represent the average exposure concentration for all population Temporal variation Land Use Regression models Uses spatial patterns of land use, such as population density, distance to roads, etc. to predict PM measurements at monitoring stations and apply the predictions elsewhere To assess long term exposure Provide good estimates of spatially resolved long-term exposures, but are poor at capturing short term exposures Spatial variation Spatio-temporally resolved predictions

28 Spatio-temporally resolved predictions Novel spatio-temporally resolved predictions PM 2.5 concentrations at the grid level (1km x 1km) Daily predictions (short and long term exposure) Include both spatial and temporal variables ground PM 2.5 measurements land use regression variables meteorological variables Satellite-based remote sensing data on aerosol optical depth (AOD). Kloog I, et al. Atmospheric Environment, 2011, 45, 35, p

29 Low-Concentration PM 2.5 and Mortality: Estimating Acute and Chronic Effects in a Population-Based Study The present study aimed to: 1. Simultaneously estimate acute and chronic health effects of PM 2.5 in a population-based cohort ( 65 years of age) in New England region 2. PM 2.5 satellite based predictions 3. Estimate the effects of low-concentration PM 2.5 on mortality Shi L, et al. Environ Health Perspect 124:46 52, 2016

30 Mean PM 2.5 concentrations in 2004 at a high resolution (1 km x 1 km) across New England predicted by the AOD models Data Health Data Medicare enrollees ( ) Daily count of death for each ZIP code Environmental Data PM 2.5 : Spatio-temporally resolved predictions Short term exposure (2-day average, lag01) Long term exposure (365-day moving avera ge) Restricted to annual concentrations below 10 µg/m 3 or daily concentrations below 30 µg/m 3

31 Percent increase in mortality for a 10 µg/m 3 increase for PM 2.5 PM 2.5 exposure type Model Percent increase p-value Short-term PM 2.5 exposure Low daily exposure a 2.14 (1.34,2.95) <.001 Full cohort 2.14 (1.38,2.89) <.001 Long-term PM 2.5 exposure Low chronic exposure b 9.28 (0.76,18.52) Full cohort 7.52 (1.95,13.40) a Restricted only to person time with daily PM 2.5 less than 30 µg/m 3. b Restricted only to person time with chronic PM 2.5 less than 10 µg/m 3. Using a mutually adjusted model, we found that short- and long-term exposure to PM 2.5 were associated with all-cause mortality, even for exposure levels not exceeding the newly revised U.S. EPA standards Shi et al., EHP,2015

32 Dose-response relationship for lowconcentration PM 2.5 and mortality Adverse health effects occur at low levels of fine particles Improving air quality below the current PM 2.5 NAAQS can still yield health benefits Below daily PM 2.5 NAAQS (35 µg/m 3 ) Below annual PM 2.5 NAAQS (12 µg/m 3 )

33 Conclusion Based on the literature there is a causal effect of short-term exposures to PM 2.5 and mortality Strong evidence for other outcomes and for chronic exposure Moving Forward Changes in the standards require additional studies to elucidate whether health effects occur at levels below the current annual and daily U.S. EPA NAAQS of 12 and 35 μg/m 3 More studies estimating acute and chronic effects of cardiovascular morbidity outcomes associated with short and long-term exposure to PM 2.5, in both rural and urban areas, and at low concentrations.

34 Acknowledgments Clean Air Research Center (CLARC) RD Harvard-NIEHS Center for Environmental Health P30ES R21 ES024012, R01 ES Joel Schwartz, Diane Gold, Petros Koutrakis Francesca Dominici, Brent Coull Marianthi-Anna Kioumourtzoglou, Itai Kloog Marc G. Weisskopf, Liuhua Shi

35 THANK YOU!