The US Environment Protection Agency has launched new air pollution standards for particulate matter. Industry will have to gear up
a plan to regulate the emission of particulate matter smaller than 2.5 micron (micron is one-millionth of metre), technically known as pm 2.5, is on the cards of the us Environmental Protection Agency ( epa ). The debate on implementation continues as critics and researchers battle over the issue. Very little data is available about the effects of pm 2.5 on health. In June 1997, the epa announced a new Clean Air Act standard that envisages regulation of pm2.5 emissions throughout the us . It would cost us $100 million to install the monitors in the country. The project will be fully operational only after four years, as one year is required for designing monitoring networks and three years to install the instruments across the us .
At present, only the states of California, Utah, Texas, Arizona and Alaska have started monitoring pm 2.5 emissions. The monitoring equipment, costing between us $6,000 and us $20,000, would start providing the data in 2002. These monitoring instruments are so advanced that filters retaining the particulate matter are automatically changed after 24 hours. The epa 's new annual standard sets a maximum annual limit of 15 micrograms per cubic metre (g/m 3 ) for pm 2.5 and 24-hour average limit of 65 g/m 3 .
Sources of pm 2.5 vary from region to region, the main source being residential and industrial combustion. pm 2.5 is also formed in the atmosphere from gases like sulphur dioxide, nitrogen oxides, and volatile organic compounds. According to Neil Frank, epa 's air monitoring expert, says that states will have to install monitors, starting with populated areas that reportedly have the highest concentrations. To asses movement of fine particulate matter in the air, they would also be required to install monitors in remote areas. Scientists are of the opinion that these monitors will allow them to understand the correlation between ozone and fine particulate matter.
However, exactly how the tiny particulate matter affect health is not easy to determine. One theory forwarded by Mark J Utel, lung specialist at the medical school of University of Rochester, is that mammalian lungs have evolved defences only against large particles. Smaller particles lodge deeper into the lungs and may affect the immune system and the central nervous system.
According to Carol M Browner, epa 's administrator, 15,000 premature deaths will be prevented if the Act comes into effect. However, affected industry groups doubt the authenticity of the research data. Critics say that air pollution's relation to mortality and morbidity does not show up clearly in all the studies. Supporters of this Act acknowledge that they do not know all the details. But they add that there is enough evidence to act upon. They cite the infamous smog that killed 2,484 in London in one week of 1952.
Douglas W Dockery, epidemiologist at Harvard University, found links between high concentrations of particulate matter and illnesses from data collected by the American Cancer Society. Dockery's team observed 300,000 people from 151 cities. Day-to-day records on deaths and hospital admissions were compared with air pollution levels in the city. Researchers found an association between concentrations of particulate matter and health ailments.
Critics of this theory have a different problem. Industry anticipates that the new standard would cost hundreds of billions of dollars. Epidemiologist Fred Lipfret draws attention to the city-specific aspect of ailments related to particulate matter. For example, people from Ohio are more susceptible to health problems due to a predominantly sedentary lifestyle than people of a state like Wisconsin. Climatic conditions are also crucial. Dockery's team included humidity levels in its study.
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