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2002 Progress Report: Quasi-Experimental Evidence on How Airborne Particulates Affect Human Health
EPA Grant Number: R829402C004Subproject: this is subproject number 004 , established and managed by the Center Director under grant R829402
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: Center for Integrating Statistical and Environmental Science
Center Director: Stein, Michael
Title: Quasi-Experimental Evidence on How Airborne Particulates Affect Human Health
Investigators: Greenstone, Michael , Chay, Kenneth , Neidell, Matthew
Institution: University of Chicago
Current Institution: University of California - Berkeley , University of Chicago
EPA Project Officer: Jones, Brandon
Project Period: March 12, 2002 through March 11, 2007
Project Period Covered by this Report: March 12, 2002 through March 11, 2003
RFA: Environmental Statistics Center (2001)
Research Category: Ecological Indicators/Assessment/Restoration , Environmental Statistics
Description:
Objective:The Center for Integrating Statistical and Environmental Science (CISES) will support research in the development of new statistical methods for addressing environmental problems and for integrating the use of statistics throughout the process of risk assessment. The main objective of this research project is to advance the use of statistical methods to assess the state of the physical environment and its impact on human and ecological health. Specific research problems of the Center's initial projects include investigating the relationship between air pollution and respiratory illnesses, statistical design and analysis for estimating trends in environmental indicators, approaches to combining numerical models and statistical methods, quasi-experimentation to assess the relationship between infant mortality and particulate air pollution, and development of stochastic models and model selection procedures for complex ecological systems. The other objective of this research project is to educate a new generation of environmental statisticians and statistically sophisticated environmental scientists.
Work Status
The Clean Air Act of 1970 and Adult Mortality. Previous research has established an association between air pollution and adult mortality. However, studies utilizing short-term fluctuations in pollution may detect mortality changes among the already ill or dying, while prospective cohort studies, which utilize geographic differences in long-run pollution levels, may suffer from severe omitted variable bias. This study utilizes the long-run reduction in total suspended particulates pollution induced by the Clean Air Act of 1970, which mandated aggressive regulation of local polluters in heavily polluted counties. The Principal Investigators (PIs) for this effort are Kenneth Chay and Michael Greenstone; Carlos Dobkin is a graduate student working on the project.
Airborne Particulate Pollution and Cause-Specific Infant Mortality: Evidence From a Quasi-Experiment and Surveys of Neonatologists and Particulate Researchers. The focus of this paper is to help inform researchers on the potential mechanisms by which particulate matter (PM) exposure affects infant health. First, we designed and administered a survey of leading neonatologists and researchers from PM laboratories on the plausible connections between total suspended particulates (TSPs) and specific causes of infant death. Although no group directly investigates such a link, our objective was to contact a diverse audience whose intersection of responses is potentially informative about pollution and infant health. Second, we use a quasi-experimental research design to estimate the effect of PM on the same specific causes of death identified in the survey. The quasi-experiment consists of exploiting the exogenous changes in pollution induced by the seemingly arbitrary policy rules set forth under the Clean Air Acts. Finally, we document the association between the survey responses and the quasi-experimental statistical results. This exercise aims to increase exchange across disciplines that are fundamentally studying the same issue, but use different approaches. The Pis for this research are Kenneth Chay and Michael Greenstone; Matthew Neidell is a postdoctoral research associate working on this effort.
Air Pollution and Infant Health: What Can We Learn From California's Recent Experience? We examine the impact of air pollution on infant health in California during the 1990s. Our research offers several innovations over the existing literature. First, most previous studies examine populations subject to greater levels of pollution, either because they lived further in the past or in some more heavily polluted area. In contrast, the experience of California in the 1990s is clearly relevant to the current policy debate concerning the regulation of pollution. Second, many studies examine a few routinely monitored pollutants in isolation, generally because of data limitations. We examine four "criterion" pollutants in a common framework. Third, we develop an identification strategy based on ZIP code variation in pollution levels that controls for potentially important unobserved characteristics of high pollution areas. Fourth, we use rich individual-level data to estimate hazard models that investigate whether infant deaths are more affected by pollution exposure before or after the birth. Matthew Neidell, a postdoctoral research associate and Janet Currie from the University of California, Los Angeles, who is not funded by CISES, are working on this effort.
Information and Avoidance Behavior: Do People Respond to Smog Alerts? Avoidance behavior—a protective response by an individual who is exposed to an externality, such as pollution—is a distinguishing feature between willingness-to-pay proposed by economists and cost of illness used by other social scientists. Despite its importance, there is limited evidence on its existence and, furthermore, it is unclear as to how information affects avoidance behavior. The first focus of this paper is to examine the influence of public information on avoidance behavior by examining the impact of air quality episodes, or "smog alerts," on attendance at major outdoor attractions in southern California. Given the evidence that people respond to the alerts, a second focus of this paper is to examine the effect of pollution on health using changes in exposure to pollution rather than changes in actual pollution levels. The final focus is to evaluate the impact from omitting avoidance behavior when estimating the biological effect of pollution on health. Matthew Neidell, a postdoctoral research associate, is working on this research.
Progress Summary:Results to Date
The Clean Air Act of 1970 and Adult Mortality. We find in the first year after the implementation of the Clean Air Act, TSP concentrations significantly declined more in nonattainment counties than in attainment counties. However, there is little systematic association between nonattainment status and changes in adult and elderly mortality rates. The results imply that the regulation-induced reduction in TSPs is not associated with improvements in adult or elderly mortality. Although this design is likely to reduce the mis-specification associated with time series and cross-sectional regressions, we find differences between nonattainment and attainment counties in their preregulation mortality rates and trends that may undermine the designs validity.
Airborne Particulate Pollution and Cause-Specific Infant Mortality: Evidence From a Quasi-Experiment and Surveys of Neonatologists and Particulate Researchers. Our preliminary quasi-experimental findings indicate that diseases of the respiratory system and complications associated with abnormal pregnancies and deliveries are the primary causes of death that are associated with airborne particulate matter. There also is modest evidence of an association between airborne particulate concentrations and congenital anomalies. When we compare these quasi-experimental estimates with the survey responses, we find a positive association between the two. This finding holds for the survey responses from both neonatologists and PIs of particle research centers. Overall, the correspondence of the findings from the quasi-experimental epidemiology approach and the surveys of medical doctors and PIs suggests that both methods point to similar mechanisms for the observed association between infant mortality and airborne PM. However, the results are not perfectly correlated. The determination of the source of these deviations will help to better focus future research on the relationship between airborne particulates and human health.
Air Pollution and Infant Health: What Can We Learn From California's Recent Experience? Our results suggest that both carbon monoxide (CO) and particulates (PM10) exposure are associated with increased risk of death. We find that the 42 percent reduction in CO that occurred during the 1990s in California resulted in a reduction of 627 deaths (in approximately 3.9 million live births), while reductions in PM10 saved an additional 432 lives. This reduction in deaths was primarily accomplished through reductions in pollution exposure after birth, with no effect from pollution exposure prior to birth.
Information and Avoidance Behavior: Do People Respond to Smog Alerts? This research finds that attendance at the specific locations studied drops by roughly 5-15 percent when smog alerts are announced. The sensitivity analyses conducted point to the robustness of these findings. However, because the most susceptible segments of the populations are theoretically less likely to respond to these alerts, there is only a 1-2 percent drop in respiratory-related hospital admissions. Given that there is little impact on health outcomes, the magnitude of the bias from omitting avoidance behavior in the form of smog alerts is minimal.
Future Activities:The following activities will be completed in the next year:
Clean Air Act of 1970 and Adult Mortality. This research is completed. We will present the results in seminars throughout the year.
Airborne Particulate Pollution and Cause-Specific Infant Mortality: Evidence From a Quasi-Experiment and Surveys of Neonatologists and Particulate Researchers. During the coming year, the analysis will be refined, and a paper will be submitted for publication.
Air Pollution and Infant Health: What Can We Learn From California's Recent Experience? During the coming year, the analysis will be refined, and a paper will be submitted for publication.
Information and Avoidance Behavior: Do People Respond to Smog Alerts? During the coming year, the analysis will be refined, a draft paper will be written, and the paper will be presented at a number of universities.
Journal Articles on this Report: 1 Displayed | Download in RIS Format
| Other subproject views: | All 8 publications | 8 publications in selected types | All 3 journal articles |
| Other center views: | All 102 publications | 59 publications in selected types | All 37 journal articles |
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Chay K, Dobkin C, Greenstone M. The Clean Air Act of 1970 and adult mortality. Journal of Risk and Uncertainty 2003;27(3):279-300. |
R829402C004 (2002) R829402C004 (Final) |
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atmosphere, ozone, water, watersheds, stratospheric ozone, chemical transport, ecological effects, particulates, environmental chemistry, environmental policy, Great Lakes, EPA Region 5, air quality, health effects, regulation, ecosystem sustainability, decision making, exploratory research, environmental biology, air pollution, chemical transport modeling, chemical transport models, ecological effects, ecological health, ecological models, ecological risk, ecosystem health, human health risk, monitoring, policymaking, regulations, risk assessment, risk management, statistical methodology, statistical methods, stochastic models, trend monitoring. , Ecosystem Protection/Environmental Exposure & Risk, Economic, Social, & Behavioral Science Research Program, Air, Geographic Area, Scientific Discipline, Health, RFA, Ecosystem/Assessment/Indicators, Engineering, Chemistry, & Physics, Air Quality, exploratory research environmental biology, Risk Assessments, decision-making, Environmental Statistics, Great Lakes, Health Risk Assessment, Ecological Risk Assessment, Economics & Decision Making, Ecological Indicators, Environmental Engineering, Ecological Effects - Human Health, EPA Region, particulate matter, Ecological Effects - Environmental Exposure & Risk, Ecosystem Protection, Monitoring/Modeling, Environmental Monitoring, risk assessment, trend monitoring, ozone , chemical transport models, particulate, risk management, stochastic models, statistical methodology, ecological risk, ecosystem health, chemical transport, environmental health effects, aersol particles, human health risk, monitoring, policy making, statistical models, air quality models, human health effects, particulates, regulations, statistical methods, Region 5, ambient particle health effects, air pollution, data analysis, ecosystem assessment, environmental risks, water, chemical transport modeling, airborne particulate matter, ecological models, ecological effects, ecological health, human exposure
Relevant Websites:
http://galton.uchicago.edu/~cises/research/tr.html
http://www.nber.org/~confer/2003/si2003/papers/ee/currie.pdf
http://www.stat.uchicago.edu/~cises/index.html
Progress and Final Reports:
Original Abstract
Final Report
Main Center Abstract and Reports:
R829402 Center for Integrating Statistical and Environmental Science
Subprojects under this Center:
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R829402C001 Detection of a Recovery in Stratospheric and Total Ozone
R829402C002 Integrating Numerical Models and Monitoring Data
R829402C003 Air Quality and Reported Asthma Incidence in Illinois
R829402C004 Quasi-Experimental Evidence on How Airborne Particulates Affect Human Health
R829402C005 Model Choice Stochasticity, and Ecological Complexity
R829402C006 Statistical Approaches to Detection and Downscaling of Climate Variability and Change