Health Studies of Criteria Air Pollutants
Health studies are used to establish guidelines for air quality standards, including those recommended by OEHHA and established by the California Air Resources Board. These include epidemiology studies, which examine real-life exposures in human populations, and how they relate to the incidence or prevalence of disease. Together with controlled human exposure studies and toxicology studies, they form the scientific basis for our air quality standard recommendations.
OEHHA has conducted a number of epidemiological studies on the health effects of particulate matter in California, and are working on a number of studies looking at other widespread air pollutants identified in the Clean Air Act. These studies join other studies done in California, nationally, or internationally that examine the health impacts of air pollution exposure.
Our work at OEHHA has focused on a number of areas based on two legislative mandates: 1) the ascertainment of air pollution constituents most strongly linked to disease, and 2) the identification of subpopulations most vulnerable to the impacts of pollutants (e.g. young children, the elderly, low socioeconomic status individuals).
Criteria Pollutants Studied by OEHHA Staff
PM2.5
Fine particulate matter, or PM2.5, encompasses any airborne liquids or solids less than 2.5um in diameter. Airborne particles of this size are troublesome because they can penetrate deep into the lungs, sometimes entering the bloodstream and causing systemic impacts. These generally form through combustion processes. Main sources of emission include gas- and diesel-fueled vehicles, power plants, fireplaces and other biomass burning sources, and combustion and other process emissions from industrial sources. Health effects of PM2.5 are wide-ranging, with strong links to all-cause mortality, cardiovascular mortality and hospitalizations, and respiratory and asthma hospitalizations. Impacts on health have been observed within hours or days of exposure, but chronic exposure impacts have also been seen for a number of endpoints. Similarly, PM2.5 exposures over pregnancy periods have been associated with birth outcomes, like reduced birth weight and preterm birth.
Coarse Particles
Coarse particles, sized between 2.5 and 10um in diameter, are generated through mechanical, erosive processes, and can deposit in the larger airways in the lungs and cause inflammation. Research points to a relationship between coarse particle exposures and respiratory hospitalizations and ER visits, especially among children, with additional evidence that coarse particles may be related to cardiovascular morbidity and mortality as well.
Nitrogen Dioxide and Ozone
Nitrogen dioxide is produced as a result of emissions from the burning of fuels in vehicles and stationary sources. Ozone is formed through the combination of nitrogen oxides, including nitrogen dioxide, and volatile organic compounds, with help from sunlight and heat. Exposure to either can impact respiratory health, causing respiratory inflammation and asthma exacerbations.
Published Health Studies
2020
Association of Air Pollution and Heat Exposure With Preterm Birth, Low Birth Weight, and Stillbirth in the US (erratum)
- Press release: Adverse Pregnancy Outcomes Linked to Climate Change
- News article: Climate Change Tied to Pregnancy Risks, Affecting Black Mothers Most. Flavelle, C. The New York Times. June 18, 2020.
Changes in US air pollution during the COVID-19 pandemic
2019
Associations between fine particulate matter and changes in lipids/lipoproteins among midlife women
2018
Associations of Source-apportioned Fine Particles with Cause-specific Mortality in California
2017
Association between PM2.5 and PM2.5 constituents and preterm birth in California, 2000-2006
Long- and Short-Term Exposure To Air Pollution and Inflammatory/Hemostatic Markers in Midlife Women
2016
2011-2015
Association of stillbirth with ambient air pollution in a California cohort study
Chronic PM2.5 exposure and inflammation: determining sensitive subgroups in mid-life women
Coarse particles and respiratory emergency department visits in California
2005-2010
Long-term exposure to constituents of fine particulate air pollution and mortality: results from the California Teachers Study (erratum)
Coarse particles and mortality: evidence from a multi-city study in California
The effects of fine particle components on respiratory hospital admissions in children
Fine particulate air pollution and mortality in nine California counties: results from CALFINE