California Air Resources Board

Project Summary

The impact of air pollution, particularly PM2.5, is linked to a number of adverse health outcomes, such as cardiovascular and respiratory hospitalizations and emergency room visits and mortality.  However, the relationship between PM2.5 and milder adverse health events that can lead to work loss due to illness can also cause disruption, loss of income or other consequences such as impacts on job security and has been understudied.  One nationwide study conducted in the 1980s, using limited exposure information, reported that PM was associated with increased days of work loss.  The effect estimate has been adapted in the U.S. EPA’s Environmental Benefits Mapping and Analysis Program (BenMAP) for estimating health and economic effects.  Given that work loss due to air pollution-related illness could have a major economic impact for both companies and communities in California, CARB funded work to investigate how PM2.5 exposure impacts illness-related work absences in California.  In addition, the study considered how wildfire smoke can affect the relationship between exposures to PM2.5 and work absences.

The study linked data from the California Health Interview Survey from 2015-2018, which provides representative statewide health data, to PM2.5 exposure data using the survey respondents’ residential addresses.  Ambient and wildfire-specific PM2.5 concentrations were modeled using advanced techniques, and the health impacts of PM2.5 exposure were estimated by an array of statistical analysis methods.  Lastly, the statewide health and cost burdens of work loss associated with PM2.5 exposure were calculated.  The results indicate that PM2.5 exposure is associated with increases in risk for illness-related work absences, and exposure to wildfire smoke amplifies this impact.  According to the findings in the study, every one unit increase in PM2.5 exposure could result in more than 1 million days of work loss due to sickness and a quarter-billion dollars of economic loss annually in California.  This study updates the health and economic impact estimates for work loss days and PM2.5 exposure and provides an important metric that could be used to update CARB’s health benefits analysis and inform policy development.

Background

Currently, CARB is expanding health endpoints for our quantitative health analysis of air quality rules and programs from four outcomes (i.e., mortality, cardiovascular and respiratory hospitalizations and emergency room visits) to twelve, including work loss days.  The acute health impacts of short-term exposure on more minor conditions such as coughs, headaches, colds, flu etc., that do not require hospital visits but that do result in the use of sick leave have not been extensively studied.  The loss of work due to sick leave represents a serious burden to Californians and therefore, understanding the effects of short-term PM2.5 exposure in work loss days is important.  The key study used for this health endpoint is over thirty years old, and updated research is needed to better inform analysis of CARB’s regulations and programs.  Given the more intense and more frequent wildfires in California, this study also investigates whether wildfire exposure alters the impact of PM2.5 exposure on work loss due to sickness. 

Biography

The principal investigator of this study, Ying-Ying Meng, DrPH, is the director of research at the UCLA Center for Health Policy Research.  She has extensive publications using CHIS data and has conducted numerous epidemiologic studies on the health effects of air pollution.  Dr. Meng’s research focuses on the causes of and solutions to inequalities in health and health care delivery from a holistic perspective, as well as analysis of population-based data to understand the complex relationship between physical and social environments and chronic disease morbidity.

The co-PI, Michael Jerrett, PhD, is professor and chair of the Department of Environmental Health Sciences in the Fielding School of Public Health at UCLA.  Dr. Michael Jerrett is an internationally recognized expert in Geographic Information Science for Exposure Assessment and Spatial Epidemiology.  For the past decades, Dr. Jerrett has researched how to characterize population exposures to air pollution and built environmental variables, how to understand the social distribution of these exposures among different groups, and how to assess the health effects from environmental exposures.  Over the last decade, Dr. Jerrett has also studied the contribution of the built and natural environment to physical activity, obesity, and several health outcomes.

Contact

For further information regarding the content of the seminar agenda, please contact Feng-Chiao Su, Air Pollution Specialist.