In an ongoing effort to understand the health implications of air quality, Constantinos Sioutas, professor of civil and environmental engineering in the USC Viterbi School’s Sonny Astani Department, has begun a new $1.12 million study to examine coarse particle pollution in rural, coastal and heavily populated inner city areas of the Los Angeles Basin.

The three-and-one-half year investigation, funded by the U.S. Environmental Protection Agency, will allow Sioutas to set up mobile air pollution monitors in a wide range of environmental niches around Los Angeles and neighboring counties, all of which are impacted differently by coarse particle pollution.

Coarse particulate matter is larger in diameter than the ultrafine particle matter that Sioutas has been studying recently. Such coarse matter is classified by the EPA as having diameters of between 2.5 and 10 micrometers, the larger of that range being roughly one-sixth the diameter of a human hair.

“We are seeing a lot of new epidemiological and toxicological evidence, especially among children, suggesting that coarse particulate matter, as well as ultrafine particulate matter – which is smaller than 0.1 micrometers in diameter – is contributing to respiratory ailments such as coughing, asthma, decreased lung function and chronic bronchitis,” said Sioutas, holder of the Fred Champion Professorship in Civil and Environmental Engineering and co-director of the Southern California Particle Center, a leading center in the nation for the study of the nature and health effects of airborne particulate pollution.

“The goal of this study will be to assess the toxicity of coarse particle pollution in areas of the Los Angeles Basin that haven’t been studied before and compare those measurements to other urban and rural areas of the basin that have been overlooked,” he said.

Coarse particulate matter comes from both direct, or primary, and indirect, or secondary, sources. Primary sources include dust from paved and unpaved roads, industrial materials, brake linings, tire residues, trace metals and bioaerosols, such as pollen.

Secondary particulate matter can be formed through complex reactions in the atmosphere when, for example, gas-phase byproducts of combustion, such as hydrocarbons, ammonia, sulfur dioxide and nitrogen oxides from automobiles, power plants and industries mix together with sunlight.

“Many adverse health effects of coarse particle pollution seem to be induced by oxidative damage in cells, which weakens the body’s ability to produce antioxidants and maintain a healthy metabolism,” Sioutas said. “The effects still aren’t completely understood, but some of the newest studies suggest that these larger, coarser particles of pollution can cause inflammation in the nose, lungs and cardiovascular system.”

Studies have shown that reduced lung function makes it harder for people to fight off infections and cope with allergens, as well as to extract needed oxygen from each breath.

The Environmental Protection Agency-funded study utilizes state-of-the-art facilities at the USC Aerosol Lab, which features the latest instrumentation and sampling equipment for sample collection.

Colleagues at the Keck School of Medicine of USC and at the UCLA Geffen School of Medicine will assist with some of the sample analysis under the direction of professor Andre Nel, UCLA immunologist and co-director of the Southern California Particle Center.

Scientists under the direction of Jamie Schauer at the University of Wisconsin, Madison, also will collaborate. As the study progresses, exposure and toxicology data from the multi-institutional study will be combined with other major efforts currently under way in Southern California at the Particle Center and in the Multi-Ethnic Study of Atherosclerosis Air Pollution Study (MESA Air Study).

Ten locations were chosen for the study to represent areas of the Los Angeles Basin affected by different particulate matter sources. Seven of the 10 sites currently are used by the MESA Air Study investigators, who are cooperating with the study.

The sites are varied and include two schools with large enrollments of Hispanic children in heavily polluted areas of South Central and eastern Los Angeles; a classic desert site in Lancaster; and several “near-freeway” sites in West Los Angeles, metropolitan/greater Los Angeles and parts of rural Riverside County.

Sioutas and his co-investigators will use USC personal cascade impactors and coarse particle concentrators, developed through Sioutas’ Southern California Supersite Program, to collect the air samples.

The impactors and the coarse particle concentrators are small, compact and inexpensive, and are being combined into a single, easily transportable package for the study.

Over an 18-month period, samples will be collected during one 24-hour cycle each week from each of the sites, thus allowing researchers to sample coarse particulate matter concurrently from midnight to midnight on specific days. These measurements will be coordinated with the regulatory sampling performed by both the South Coast Air Quality Management District and the Antelope Valley Air Quality Management District to take advantage of their particulate data collection.

The researchers also will conduct intensive winter (January) and summer (August) campaigns in three of the sites – L.A., Rubidoux (in Riverside County) and Lancaster – with multiple samples collected over the 24-hour period in order to determine the role of different sources in each region.

In addition to the outdoor samples, researchers will measure particle pollution inside the classrooms of school sites in Long Beach and East Los Angeles to investigate what fraction of particles is entering the buildings.

Sioutas, who is interested in the impact of particulate matter on health, said the new data will augment recent findings from the Particle Center that children living near major interstate highways, including the 110, 710 and 405 freeways, are at high risk of developing asthma and other respiratory ailments due to the toxicity of airborne particulate matter.