WASHINGTON -- As the Environmental Protection Agency (EPA) tightens standards for airborne particulates, it should redirect some research and maintain an integrated study program ensuring that the most serious public health risks posed by the particles are addressed, says a new report by a committee of the National Research Council. To that end, EPA should devote more funds to studying the types of particles most likely to be harmful to human health, the ways the particles cause damage, and the levels of exposure people actually receive.
"Recent studies have consistently shown that airborne particles are somehow associated with adverse health effects, especially for people with heart and lung ailments," said committee chair Jonathan Samet, professor and chair, department of epidemiology, Johns Hopkins University School of Hygiene and Public Health, Baltimore. "But as the new standards begin to take effect, further research must be done to determine precisely which particles pose the greatest health risks, and how. Gathering this information should be of the highest priority. The results will greatly increase the likelihood that money spent on regulating and controlling particulates will fully protect public health."
EPA recently set stricter standards for particulate matter -- a broad class of materials that originate from industrial manufacturing processes, forest fires, automobile exhaust, fossil fuel combustion, wind erosion, and a variety of other sources. The standards were changed after several epidemiological studies found associations between exposure to the particles and serious health consequences, including the exacerbation of asthma and other respiratory tract diseases -- which in some cases were leading to premature deaths. The new standards, set last July, for the first time target particulates smaller than 2.5 microns in diameter. When inhaled, these tiny particles are more likely than larger ones to reach deeply into the lungs. EPA must review the standards and the scientific data on which they are based every five years to determine whether revisions are warranted. In the meantime, the agency is beginning a national outdoor air monitoring program to determine which geographic areas are not in compliance. States with areas not meeting the standards will have to develop plans to control particulates.
EPA estimates that compliance could prevent 15,000 premature deaths each year. However, because of scientific uncertainties surrounding the standards, and limited data on the health risks from exposure, Congress directed EPA to conduct a major research program to improve understanding of these risks. In addition, Congress asked the Research Council to provide independent guidance to EPA on the program. The committee's report, Research Priorities for Airborne Particulate Matter, examines EPA's plans for research and identifies the 10 most critical needs for strengthening the scientific data. The report, the first of four, lays out a comprehensive 13-year national program for the study of particulate matter, with emphasis on critical information needed before the next scheduled review of the standards in 2002.
EPA is directing nearly one-third of its particulate matter research budget toward developing improved monitoring techniques and characterizing the sources of emissions and their movement through the atmosphere. While some funding should continue to be devoted to these efforts, the agency could defer much of this work for three or four years until researchers develop a better understanding of how particulates affect health, the committee said. Moreover, the agency should re-evaluate its plans for developing a national monitoring network. If these efforts are planned and implemented without some of the key data and guidance from the scientific community, then monitoring might not measure the most hazardous air particles or the most serious exposures.
Setting Priorities
The committee's 13-year proposed research program would cost about $440 million and extend through the year 2010. To carry out the research, funding would need to remain roughly consistent with current levels for several more years. The plan incorporates 10 areas of research that should be the highest priority, based on the scientific value of the information that would result, how useful the data would be in decision-making, and schedule considerations. Some of the priorities are:
- identifying the most harmful particulates, assessing personal exposure
levels, and examining biological mechanisms through which the particles act;
- assessing exposure levels for people who are thought to be most vulnerable,
such as children, the elderly, and those with chronic heart or lung ailments;
- studying how particulates might combine with other pollutants to cause
short- and long-term health problems; and
- developing modeling tools to link the sources of particulate matter with people who have been exposed.
Copies of Research Priorities for Airborne Particulate Matter: 1. Immediate Priorities and a Long-Range Research Portfolio will be available in May from the National Academy Press; tel. (202) 334-3313 or 1-800-624-6242. The cost of the report is $35.00 (estimated) plus shipping charges of $4.00 for the first copy and $.50 for each additional copy. Reporters may obtain pre-publication copies from the Office of News and Public Information (contacts listed above).