According to the Environmental Protection Agency (EPA), the lower threshold for particulates that it implemented in July 1997 but with which few American urban areas at present are able to comply, could reduce by 250,000 the number of severe asthma attacks annually in the U.S. and prevent thousands of yearly deaths attributable to respiratory difficulties. However, many critics protest that the evidence is largely wanting of a direct link between presence of PMs and human health problems. So dubious is the available evidence against particulates to many scientists that Suresh Moolgavkar, at a recent meeting of the Society of Toxicologists in Washington State, referred to the "science" on which the revised standards on particulates were based as a "hypothesis masquerading as a fact." Furthermore, even before the EPA chose to revise the National Ambient Air Quality Standards for Particulates (NAAQS) for PMs last summer, the agency's own scientists that made up the Clean Air Scientific Advisory Committee (CASAC) disagreed over the need to initiate stricter standards. Consequently, the issue over PMs has grown so hazy that the skies of many metropolitan areas such as Washington, DC are described one week by the American Lung Association as so polluted that the ALA was forecasting "a terrible summer of smog" for the nation's capital while the next week the city is billed as "one of the top 10 clean air success stories" by the Foundation for Clean Air Progress, an environmental group.
PMs have always been present, but more than the PMs themselves, it is the reaction toward pollutants that has heated up and risen in recent years. Textbooks as recently as the 1970s discussed particulate matter in reserved, cautious tones, noting a considerable remove between acknowledging the presence of PMs and possessing a certainty of definite health consequences caused by their existence in the atmosphere. Twenty years ago, verifying particulate matter itself was seen as scientifically ambiguous for the very act of measuring particulate matter implies a change in the atmosphere being measured by the agent doing the measuring. However, by the mid-1990s, much of the widely disseminated work on PMs began to take on a far more speculative and strident look and feel. For example, the EPA, in justifying its regulation of the PMs in the atmosphere sees the presence of particulate matter as responsible for numerous morbidity and mortality incidents: premature death; respiratory related hospital admissions and emergency room visits; aggravated asthma; acute respiratory symptoms, including aggravated coughing and difficult or painful breathing; chronic bronchitis; and decreased lung function that can be experienced as shortness of breath.
The writers of a recent textbook on air pollution go even further, arguing that the particulates can not only exacerbate a number of respiratory diseases but can actually initiate illnesses, which they expand beyond the physical to include such psychological manifestations as "emotional upset, anorexia, and mental depression." Some environmentalists, in fact, "see" our air as growing even more polluted with particulates, so much so that one group has asserted on its website that air particulates are responsible for the deaths of over 60,000 Americans annually. In 1996, the EPA's assistant administrator for air and radiation made the astounding estimate in an address to a joint conference of the State and Territorial Air Pollution Program Administrators (STAPPA) and the Association of Local Air Pollution Control Officials (ALAPCO) that the agency's proposed standards for particulate matter would save 58 million lives, a number that certainly tests the boundaries of sound science.
Even the EPA's more moderate recent estimate of 15,000 saved lives a year by virtue of its revised standards is not without its detractors among the scientific community. Many scientists point out, for instance, that asthma, one of the health conditions that the EPA's standards on PMs is designed to combat, seems to be impervious to particulate matter regulations or PMs themselves. While increasingly reported at high rates in the United States, particularly among children, asthma is rarely reported in the metropolitan areas of developing countries which have much higher levels of PMs than do U.S. cities. For example, in a recently completed study of better than 450,000 children aged 13-14 years from 56 countries, researchers found the highest 12-month prevalences of asthma to be from cities in the United Kingdom, Australia, New Zealand, the Republic of Ireland, and the United States, while the lowest prevalences occurred in several Eastern European countries, Indonesia, Greece, China, Taiwan, Uzbekistan, India, and Ethiopia--countries that have far less stringent environmental regulations than do the United States. Comprehensive studies by the European Federation of Asthma and Allergy Associations, in fact, found that sedentary lifestyles in Western developed countries may be the primary culprit in the recent increase in the numbers of individuals diagnosed with asthma, not air particulates. Meanwhile, a July 1996 study by the National Institute of Allergy and Infectious Diseases concluded that far and away the leading cause of asthma stems from an allergic reaction to cockroach presence.
Even more than confusing what may be the cause of the rise in incidences of asthma is the possibility that some scientists have recently put forward which argues that focussing unduly on PMs, because of the potentially devastating economic impact ever more strict air quality regulations could have on personal income, may actually harm human health. The projected costs of complying with the new standards by 2010 (estimated by the EPA to be at $9.7 billion a year and by the President's Council of Economic Advisers at between $11.6 billion to $60 billion annually) could certainly be expected to have, at the very least, a trickle-down effect impacting human morbidity and mortality significantly. Perhaps rather than rushing into the new millenium with decisions taken with incomplete or suspect science, we would be well served to take this advice from Moolgavkar, who termed the EPA's changes in NAAQS "premature": "Pollution is a very complex mixture, and there's simply not enough information to single out any one component and say that's responsible for the health effects."
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