The U.S. Environmental Protection Agency has awarded $22 million in federal grants to study the components and sources of tiny particles (soot, dust, dirt, smoke) that pollute the air.

Fine particle pollution is primarily a by-product of combustion from diesel engines, power plants, industry boilers, and incinerators, EPA says. The fine particles can penetrate deeply into the lungs and may cause a number of health problems, including respiratory disease and impaired lung function.
EPA has for some time contended that diesel exhaust is a major health threat. Last year the Clean Air Science Advisory Committee, part of EPA's Science Advisory Board, rejected the agency's claims that it's a major cancer threat, mainly because the conclusions lacked scientific support.
This latest research program is part of the "Supersites" monitoring program intended to generate more useful information about air quality samples. The data, EPA said, will help develop techniques for pinpointing the sources, formation and travel of fine particulate matter. The program also aims to identify the components of particulate pollution that are most important to health.
Grant recipients are the University of California Los Angeles; Washington University, St. Louis; University of Texas, Houston; UCCSN/Desert Research Institute, Fresno, CA; State University of New York; Carnegie Mellon University, Pittsburgh; and the University of Maryland, Baltimore.