Research on Health Effects of Air Pollution

CARB has an active research program to investigate the health effects associated with air pollution exposure, particularly in citizens that may be more sensitive to air pollution effects, such as children and the elderly.

Below, you will find information on air pollution health effects research since the year 2000. You can also view all health-related research projects, ongoing and completed, in our Research Projects database. CARB staff provide monthly updates regarding the latest research findings on health and air pollution. Presentations for health updates are provided at https://www.arb.ca.gov/research/health/healthup/healthup.htm.

Children's Health & Exposure

Children's Health Study (Contract 94-331, Completed in 2004) The Children's Health Study was a prospective study of about 6,000 children living in 12 Southern California communities with varying ambient air pollution profiles. The primary purpose of the study was to determine whether air pollution causes chronic adverse respiratory health effects. Results indicated that children's lung function growth was adversely affected by air pollution. New cases of asthma and asthma exacerbations were associated with ambient air pollution levels and school absences from acute respiratory illnesses followed rises in ozone levels.

The Fresno Asthmatic Children's Environment Study (FACES) (Contract 99-322, Completed in 2006) project was focused on the effects of particulate matter air pollution, in combination with other ambient air pollutants and bioaerosols, on asthma in young children in Fresno, California.

Huntington Park Asthma Study (Contract 99-302, Completed in 2002) This study was focused on the effects of air pollution, particularly air toxics, on 26 Hispanic asthmatic school children. The overall goal was to evaluate acute respiratory health effects of volatile organic compounds and other air pollutants in children in a highly industrialized area of Los Angeles flanked by major freeways and trucking routes. The results showed that ambient volatile organic compounds, criteria pollutants and organic and elemental carbon were associated with asthma symptoms.

Traffic and Asthma in Economically Disadvantaged Neighborhoods (Contract 04-323, Completed in 2001) Children who live in economically disadvantaged areas with high traffic density may be particularly susceptible to asthma exacerbation from air pollution exposure. The objective of this study was to examine the associations between traffic and asthma symptoms, provide additional information related to environmental justice issues, and help develop a model for future traffic studies.

Refining Estimates for the East Bay Children's Respiratory Health Study (Contract 03-327, Completed in 2008) The East Bay Children's Respiratory Health Study collected primary data on the concentrations of traffic-related pollutants and on the health of children attending elementary schools in Alameda County, California. The objective of this study was to refine estimates of residential and school exposure to traffic-related pollutants. Its findings elucidated associations between traffic and health, provided methodological guidance for future traffic studies, and addressed issues of environmental justice.

Children's School Bus Study and Follow-Up: Exhaust Intrusion into School Buses (Contract 00-322, Completed in 2003; and Contract 03-343, Completed in 2006) The Children's School Bus Exposure Study characterized the range of children's exposures to diesel vehicle-related pollutants and other vehicle pollutants during their commutes to school. Results indicated that for some buses, significantly higher exposures of vehicle-related pollutants occurred during the bus commutes than roadway pollutant concentrations alone would indicate. The results from this study demonstrated the importance of intrusion of the tailpipe exhaust back into the bus cabin. A follow-up study was conducted to better understand the phenomenon of bus self-pollution and to investigate whether simple measures such as window and door seal replacement or enhancement might provide a cost-effective and simple way to reduce children's exposures to school bus exhaust.

Environmental Health Conditions in California's Portable Classrooms (Contract 00-317, Completed in 2003) CARB and the CA Department of Health Services conducted a comprehensive study of the environmental health conditions in portable and traditional classrooms at several hundred schools throughout California. Numerous problems were found, including inadequate ventilation, high classroom noise levels, poor thermal comfort, high formaldehyde levels, moisture problems, toxic residues in floor dust and inadequate lighting. A Report to the Legislature was also provided in November 2004.

Asthma / Respiratory Health

Inhaled Fine Particle Effects on Lungs (Contract 05-342, Completed in 2010) The objective of this study was to determine how chronic fine particle exposures during the period of rapid lung growth could impact lung development and if any observed deficits become permanent. The investigators used controlled animal exposures (mice) and a mobile exposure system using the Versatile Aerosol Concentration Enrichment System (VACES) particle concentrator.

Inflammatory Response to Short-Term Particle Exposure (Contract 05-341, Completed in 2010) The goal of this project is to determine how airway and cardiovascular function in healthy and asthmatic humans is altered by short-term exposure to concentrated ambient particulate matter (PM) in controlled exposures. The results from this study indicated how sensitive individuals respond to short-term exposures to levels of PM encountered in situations such as highly polluted days or in areas of very high traffic.

Genotype Effect on Ozone-induced Airway Inflammation (Contract 03-315, Completed in 2012) Genotypes of the GSTM1 gene may explain the wide range of responsiveness to ozone exposure observed among both healthy and asthmatic people. This study investigated whether GSTM1 genotype influences airway inflammatory responses of asthmatic subjects exposed to ozone. The results of the study are critical to development of adequately protective ambient air quality standards.

Effects of Smoke on Airway Function and Inflammation (Contract 97-322, Completed in 2003) The results of this project suggest that short exposures to very high concentrations of smoke from rice field burning is capable of inducing airway inflammation in healthy individuals and in individuals with asthma or allergic rhinitis.

Nitrogen Dioxide Effects in Asthmatics (Contract 00-337, Completed in 2004) The results from this study suggest that most asthmatics do not have a late phase response to inhaled allergen following three-hour exposure to 0.4 ppm nitrogen dioxide (NO₂), although some may experience an early phase response. In addition, NO₂ exposure did not alter lung function or induce non-allergic airway inflammation.

Nitric Oxide Effects on Lung Function (Contract 97-329, Completed in 2001) This literature review concluded that nitric oxide (NO) can be both beneficial and injurious and suggests that ambient concentrations of NO could affect cardiopulmonary regulation, pulmonary inflammation, asthma and other inflammatory lung diseases, host defense, immune responses and platelet function.

Cardiovascular Health

Cardiovascular Health Effects of In-Vehicle Particle Exposure (Contract 04-324, Completed in 2010) The purpose of this study was to investigate possible links between exposures to freeway-related ultrafine and fine particles and cardiovascular effects through controlled, on-road exposures of human volunteer subjects. The results will aid CARB in evaluating the importance of motor vehicle related ultrafine particles on cardiovascular health.

Cardiovascular Effects of Ozone Exposure (Contract 04-322, Completed in 2011) This study investigated the effect of ozone exposure on heart rate variability, inflammation and coagulability. The results provided a biological basis for epidemiological findings that this pollutant can induce adverse cardiovascular effects.

Effects of Inhaled Particles on Cardiovascular Disease (Contract 04-320, Completed in 2010) Exposure to levels of particulate matter (PM) found in California has been linked to an increased risk of cellular inflammation and heart disease. This study examined the link between particle-induced inflammation and the development of atherosclerosis in normal and atherosclerosis-prone mice, using both fine and ultrafine PM exposures.

Air Pollution Exposure Effects and Cardiovascular Disease in Teachers (Contract 06-336, Completed in 2011) This study investigated the effects of long-term exposure to particulate air pollution and various gaseous pollutants on cardiovascular and cardiopulmonary disease incidence and mortality in a study group of California teachers and whether these effects are related to exposure to traffic emissions. This study provided additional evidence that long-term exposure to air pollution is associated with mortality from heart disease, and also demonstrated that exposure to particulate matter is associated with the incidence of new cases of stroke.

Indoor Health and Exposure

Indoor Exposures in Child Care Facilities and Follow-up: Possible Health Risks (Contract 08-305, Completed in 2012; and Contract 12-330, Completed in 2015) These studies examined environmental characteristics and contaminant levels in air and dust of 40 California early childhood education (ECE) facilities. The initial study detected over 40 volatile organic compounds (VOC) in the air of these child care facilities. The follow-up study involved detailed analyses of many of the VOCs and their potential health risks.

Ultrafine Particles in Schoolrooms and Homes (Contract 05-305, Completed in 2010) This study identified and improved our understanding of the factors that influence ultrafine particle levels in schoolrooms and homes by characterizing the generation of ultrafines from indoor sources and measuring infiltration from outdoors (heavily traveled roadways).

Health Impacts of Indoor Particulate Matter (Contract 05-302, Completed in 2010) Few studies had examined health impacts from particulate matter (PM) from indoor sources. This study identified and quantified the relative toxicities of particulate matter from indoor sources, including cooking, fireplace wood burning, candle and incense burning, and vacuuming.

Field Study of Ventilation and Indoor Air Quality in New Homes (Contract 04-310, Completed in 2009) The overall objective of this study was to obtain information on ventilation practices and indoor air quality in new single-family detached homes in California. Results will help determine the adequacy of ventilation in new homes for possible revisions to the state energy efficiency standards, and provide current indoor pollutant concentration data for California residences.

Cleaning Agents and Indoor Air Chemistry (Contract 01-336, Completed in 2006) The investigators measured toxic emissions from cleaning products and indoor reactions between emissions and ozone. Some cleaning products emitted measurable indoor concentrations of ethylene-based glycol ethers and terpenes. When the cleaning products were used in the presence of ozone, a number of pollutants were formed, including formaldehyde.

Particulate Matter (PM) Health Effects

Ultrafine Particulate Matter and Cardiorespiratory Health in the Elderly (Contract 03-329, Completed in 2009) The National Institute of Environmental Health Sciences funded a major health study that includes collection of health outcome data from elderly people who live in Southern California. The objective of this study was to enhance indoor and outdoor air monitoring of ultrafine and fine particles in several Southern California communities and to evaluate oxidative stress in elderly residents of retirement homes.

Particulate Toxicity: Effects in Susceptible Humans (Contract 99-314, Completed in 2004) This study showed that in asthmatics, particulate carbon and ammonium nitrate exposures caused significant decreases in spirometric pulmonary function (SPF), some changes in airway cell distribution and heart rate variability (HRV) and no changes in gene expression. However, combined exposure to particles and ozone, in addition to decreases in SPF, produced increases in several inflammatory associated cells, increases in protein and gene expression, and multiple changes in HRV.

Particulate Toxicity: Respiratory Effects (Contract 96-310, Completed in 2000) This study's findings in both an animal model of allergic airways disease and human asthmatics suggest the airway epithelium is an important target of particle-induced effects associated with inflammation and the perturbation of proinflammatory cytokines present in the lungs.

Particulate Toxicity: Respiratory Effects in an Animal Model (Contract 99-315, Completed in 2004) This study demonstrated changes in blood pressure and heart rate variability consistent with an adverse effect of particulate matter on the heart. Significant changes were seen in an animal model, the senescent (geriatric) rat. Macrophage changes were seen in human subjects.

Immune Effects

Nitrogen Dioxide Effects on Macrophage Responses (Contract 95-311, Completed in 1998) Results showed that multi-day exposures to nitrogen dioxide (NO₂) do not affect the body's production of macrophage cells nor the cells' ability to recognize invading pathogens and recruit other infection-fighting cells. However, following NO₂ exposure, macrophages released more potentially toxic inflammatory chemicals that could cause lung damage.

Community Health

Air Pollution and Environmental Justice (Contract 04-308, Completed in 2010) This project sought to develop diverse methodological approaches to address environmental justice (EJ) concerns of relevance to air pollution regulation in California. The project consisted of several interlocking research projects, including: 1) a landscape analysis of environmental hazard and air pollution burden disparities in the Bay Area; 2) development of an Environmental Justice Screening Method (EJSM) to identify areas of environmental justice concern with regard to the cumulative impacts of hazard proximity, air pollution, exposure and estimated health risk, and social vulnerability; 3) the implementation of the EJSM to evaluate a hypothetical siting of a power plant facility; 4) a statewide analysis of the association between ambient pollution exposures and adverse perinatal outcomes; 5) the implementation of a community-based participatory ground truthing research project to evaluate the coverage of emissions inventory databases of localized emission sources and sensitive receptors and to build community confidence in the research and regulatory process.