Statistical Methods

HEI Research Report 187 was funded as part of HEI’s Accountability research program, aimed at understanding whether actions to improve air quality have resulted in improved health outcomes. Corwin M. Zigler and his colleagues used existing and newly developed statistical methods to assess whether an intervention was causally related to changes in pollutant levels or health outcomes, and applied their methods in two well-developed case studies: effects of air quality interventions to reduce PM₁₀ concentrations in nonattainment areas and the impact of installation of scrubber technologies on emissions from coal-fired power plants.

This newsletter reports on a third study under way in Europe to complete the comprehensive HEI effort to examine the potential health effects of air pollution at low levels; HEI's new research program focusing on the health effects of exposure to traffic-related pollution; and the GBD MAPS team's presentation of preliminary data on coal’s impact on health in China. In addition, it covers the publication of two new research reports covering novel statistical methods for studying pollutant mixtures and a “direct” approach evaluating the impact of air quality interventions through “causal inference” methods, as well as the retirement of HEI's Aaron Cohen, a strategy session held with HEI's sponsors, and HEI in the news.

This report is Part 3 of HEI Research Report 183, Development of Statistical Methods for Multipollutant Research. It describes a study to develop and apply statistical methods to analyze the effects of multipollutant exposures on health, expanding beyond the two-pollutant approaches used in many studies to date. HEI funded three innovative studies in recent years to improve the tools for analyzing complex multipollutant exposures. In this last report from these studies, John Molitor and colleagues describe a Bayesian framework to identify spatial clusters of air pollution exposures — and other covariates such as socioeconomic status — and estimated pregnancy outcomes associated with those clusters, using a data set for Los Angeles county. 

This newsletter reports on the approval of new HEI studies to examine potential health effects of low-level pollution; the completion of a review of diesel exhaust studies (Special Report 19) by an HEI-appointed panel; and WHO's plans to update global air quality guidelines. In addition, it announces the publication of an HEI report taking a closer look at exposure to PM_2.5 and its composition and a report evaluating rapid heart rhythm changes after exposure to PM. HEI also announces the recipient of the 2015 Walter A. Rosenblith New Investigator Award and the appointment of three new HEI Research Committee members.