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Extramural Research

PM Centers

PM Centers
In 1997, with evidence of particulate matter (PM) air pollution linked to increases in respiratory and cardiac health problems, resulting in loss of school and work time, hospitalization, and even premature death, EPA established new air quality standards for PM smaller that 2.5m in aerodynamic diameter. Scientific uncertainties in the PM health evidence prompted Congress to increase funding for PM research at EPA and call for the establishment of up to five university-based PM research centers. EPA's STAR Program issued a request for applications (RFA) for the centers structured around the recommendations from the National Research Council report, Research Priorities for Airborne Particulate Matter: 1) Immediate Priorities and Long-Range Research Portfolio. The five centers established in June 1999 have been a central component of EPA's on-going integrated research program for PM, which also includes ORD's intramural research program, interagency and public/private partnerships, and other STAR Program RFAs for individual research grants. Selected from 22 applicants after a merit review by a panel of external scientific experts, these centers were funded between 1999 and 2005. The research areas of focus related to the health effects of PM included: exposure, dosimetry and modeling, toxicology, and epidemiology. The PM Research Centers program has advanced the understanding of PM health effects, how they occur, and populations that are susceptible to health effects from exposure.

Integrated report from the original Particulate Matter Research Centers:

A second competition was held in 2004 reflecting areas emphasized in the final National Research Council Report, Research Priorities for Airborne Particulate Matter: 4) Continuing Research Progress. The cross cutting theme of the RFA was to conduct research linking health effects of the PM mixture with its components and emission sources. The five Centers funded in 2005 focus on the following key research issues: health effects of specific PM characteristics and constituents at various exposure levels, important factors affecting susceptibility to these effects, plausible mechanistic hypotheses to describe how PM may exert effects, and ultimately, the major theme of linking the effects with specific components and sources. Collectively, the research can help identify those sources and attributes of PM contributing to the most hazardous exposures.

Descriptions of all the Centers, as well as links to their reports, publications, and web sites, can be found below.


Harvard Particulate Center (1999 present)
Between 1999 and 2005, the Harvard Particulate Center produced over 140 publications addressing key scientific issues regarding the health effects of ambient particles, with a focus on three research themes: exposure, susceptibility, and biological mechanisms/dosimetry. The Center collected data on personal exposures and indoor and outdoor concentrations of PM. Researchers found increased susceptibility among those with congestive heart failure, diabetes, and chronic obstructive pulmonary disease (COPD), and proposed several biological mechanisms and intermediate processes for these health effects. Toxic components found in PM included trace metals, elemental carbon, sulfates, and silicon, and greater toxicity was found for PM from traffic and power plants than for soil dust. In addition, statistical and epidemiological methods were developed to improve data gathering and analysis.

With its new grant, the Center has focused on how specific PM characteristics and sources impact inflammation, autonomic responses, and vascular dysfunction all related to cardiopulmonary health. One project involves examining the association between PM exposures and intermediate markers of health endpoints in an ongoing prospective cohort study of aging veterans in eastern Massachusetts. The second will examine the cardiovascular effects of fine, coarse, and ultrafine concentrated ambient particles (CAPs) in 50 healthy adults in Toronto. A third project will investigate the relationship between PM composition and vascular response in normal and hypersensitive rats, comparing responses from PM exposures that were locally emitted or transported through the atmosphere. The last project will investigate the effects of primary and secondary vehicular emissions from a Big Dig tunnel in Boston, using the same animal models and biological measurements as in the third project.

Reports and Publications (1999-2005)
Reports and Publications (2006-2010)
Harvards web site: Harvard Particulate Center exit EPA

Johns Hopkins Particulate Matter Research Center (2005 present)
The Johns Hopkins Particulate Matter Research Center maps health risks of PM across the United States, based on analyses of national databases on air pollution, mortality, and hospitalization. These maps are then used to guide detailed monitoring and collection of PM samples for physical, chemical, and biological characterization in assays relevant to pulmonary and cardiovascular outcomes. To map health risks from PM, the Center is linking its National Morbidity, Mortality and Air Pollution Study (NMMAPS) and its nationwide cohort of Medicare participants with air pollution monitoring data (including data on specific PM species) and meteorology from the National Weather Service. This is the Centers guiding matrix for assessing health risks from PM components and sources. The maps will be used to select locations for particle collection and monitoring. The collected particles will be analyzed for physical and chemical characterization to better understand PM composition. The samples will be tested in cellular assays and animal studies to provide information on comparative toxicity, resulting in further insights into cardiopulmonary toxicity and mechanisms.

Reports and Publications (2006-2010)
Website: Johns Hopkins Particulate Matter Research Center exit EPA

New York University Particulate Matter Health Effects Research Center (1999 2005)
The overall objective of the NYU-EPA Particulate Matter (PM) Health Research Center was to develop and conduct a comprehensive research program focused on the identification and characterization of the physical and chemical properties of PM that adversely impact human health. The Center produced over 80 publications that identified PM components with a disproportionate impact on health, found correlations between components, sources, and health effects, and tested for increased susceptibility to these effects among several populations.

The most notable accomplishments of the NYU PM Center included its demonstration that when mice susceptible to atherosclerosis were subchronically exposed to northeastern U.S. regional ambient fine particles, they exhibited acute and chronic changes in cardiac function. The investigators reported an increase in aortic plaque and its invasiveness, genetic marker changes, and a reduction of cells in the substantia nigra region of the brain. In a second, 6-month study at lower dose levels, the investigators reported altered vasomotor tone, induced vascular inflammation, and potentiated atherosclerosis. During this follow-up study, the Center researchers were able to identify a remote point source of nickel, a PM component, which was responsible for significant acute changes in cardiac function.

Reports and Publications (1999-2005)
Website: New York University Particulate Matter Health Effects Research Center exit EPA

Northwest Research Center for Particulate Air Pollution and Health (1999 2005)
The Northwest Research Center for Particulate Air Pollution and Health conducted epidemiological, exposure, and toxicological studies of the effects of PM. The Center produced over 80 publications addressing a variety of topics, including investigation of PM exposure and cardiac effects in Seattle, identification of a relationship between cardiac outcomes and chronic PM exposure in the national Womens Health Initiative cohort, characterization of aerosols and woodsmoke contributions to ambient PM, models of personal PM exposure and health effects, use of exhaled nitric oxide as an indicator for health outcomes, and new developments in statistical methods.

Reports and Publications (1999-2005)
Website: Northwest Center for Particulate Matter and Health exit EPA

Rochester Particulate Matter Research Center (1999 present)
Between 1999 and 2005, in research that produced over 80 publications, the University of Rochester PM Center focused on understanding the health effects of ultrafine particles (size less than 100nm), particularly in susceptible populations. Studies showed that ambient particles can have significant oxidative capacity, and that ultrafine particle exposure can lead to significant effects not only in the respiratory tract but also in the vascular and cardiac system. Studies in humans and animals indicated that age and underlying disease are susceptibility factors that can exacerbate the effects of PM exposure. Additionally, results from rodent studies showed that inhaled ultrafine PM can be transported to locations beyond the respiratory tract, including the heart and central nervous system.

Since 2006, the Rochester Center has worked to identify health hazards of source-specific physicochemical components of fine PM (e.g., ultrafine particles; organics) in epidemiological, controlled clinical, animal, and in vitro studies. A multidisciplinary team of experienced investigators are testing the hypothesis that ultrafine particles occurring in the urban atmosphere cause adverse health effects. A main focus is on sources and pathophysiological mechanisms by which ambient ultrafine and fine PM trigger cardiovascular adverse health effects, with specific emphasis on events leading to endothelial dysfunction. These include vascular events involving activation of endothelial cells and blood platelets and pathophysiological mechanisms of neurodegenerative effects.

The center has released a summary report integrating results of many of their studies titled Assessment of Ambient UFP Health Effects: Linking Sources to Exposure and Responses in Extrapulmonary Organs (PDF) (35 pp, 213 K)
Reports and Publications (1999-2005)
Reports and Publications (2006-2010)
Website: Rochester Particulate Matter Research Center exit EPA

San Joaquin Valley Aerosol Health Effects Research Center (2005 present)
The San Joaquin Valley Aerosol Health Effects Research Center at the University of California Davis seeks to establish a causal link between the physical and chemical characteristics of particulate matter and their resulting health effects. The Center is conducting particle characterization and animal toxicology studies in the San Joaquin Valley an area with one of the worst particulate air pollution problems in the U.S. Complementing these field studies, Center researchers at UC Davis are conducting animal laboratory studies to investigate the effects of both ambient and laboratory-generated particles with carefully controlled properties. The San Joaquin Valley Health Effects Research Center focuses on five complementary projects addressing the mechanisms of pulmonary and cardiac responses, whole animal effects of exposure, transport of particles from the airways to other tissues, and the effects of particles and gases on lung development in very young animals.

Reports and Publications (2006-2010)
Website: San Joaquin Valley Aerosol Health Effects Research Center exit EPA

Southern California Particle Center (1999 present)
Between 1999 and 2005, the Southern California Particle Center (SCPC) used an integrated approach to address the areas of exposure, dosimetry, toxicology, and epidemiology. In research that resulted in over 120 publications, SCPC studied biological mechanisms of PM as they related to its physical and chemical characteristics. The Center also studied the relationship between sources of PM emission and adverse health effects, with a focus on traffic sources, as well as spatial and temporal patterns of ambient PM and co-pollutant concentrations in the Los Angeles basin.

Among the Centers significant accomplishments were its development and application of chemical assays that were then used to assess activity associated with PM toxicity. This work related well to toxicological studies showing that cell biological effects of PM related to oxidative stress and mitochondrial damage were most highly related to ultrafine PM exposures. In its many freeway and traffic studies, the Center reported that wind speed and direction, temperature, and relative humidity were important factors in determining the local concentration of ultrafine particles near freeways. Maximum concentrations of ultrafine particles observed near freeways were about 25 times greater than background. A key finding showed these levels decaying exponentially, becoming indistinguishable from upwind background concentrations at 300 meters downwind from the freeway. Through its involvement with the Childrens Health Study, Center researchers found that exposure to vehicular pollutants is associated with the respiratory health of children, including effects on lung function, lung function growth, asthma incidence and exacerbation, and school absences.

SCPCs work since 2006 elaborates upon the hypothesis that chemical composition and physical characteristics related to PM sources determine the toxicity and exposure-response of PM. It includes extensive characterization of chemical composition, activity, and toxicological potential of a wide variety of ambient PM collected from several sources, including secondary formation of particles, under varying climate conditions. Researchers will consider how PM exposures vary within and across communities, considering complex, unstudied sources such as airports and shipping ports. Results from the toxicological studies provide a basis for identifying the characteristics of PM sources that raise the greatest concern for public health, in terms of potential to induce oxidative stress and related health effects. This work will lead to a greater understanding of causal pathways along the continuum from particulate source through exposure to response. The Centers study of elderly residents will advance knowledge on the importance of particle size and composition in inducing oxidative stress and inflammatory responses that may be responsible for adverse cardiovascular effects.

Reports and Publications (1999-2005)
Reports and Publications (2006-2010)
Website: Southern California Particle Center exit EPA

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