Preventing Exposures to Hazardous Air Pollutants

By Robert Amundson, PhD

This essay is in response to: What is the most important achievement we've gained through air pollution management? What remains to be done to safeguard public health from air pollution?

Since implementation of the Clear Air Act of 1970 people across the country breathe healthier air because of much lower concentrations of carbon monoxide, acidic gases of sulfur and nitrogen, lead, particulates, and ozone. Furthermore, ecosystems in the eastern United States are recovering from the effects of acidic precipitation. Why was it so successful?

The Clean Air Act of 1970 allowed for the setting of ambient air standards for the six criteria pollutants: carbon monoxide, lead, particulates, oxides of sulfur and nitrogen, and ozone. By law, areas that did not meet the ambient air quality standards had to control such emissions. Industry was forced to drastically reduce emissions of these gases which resulted in greatly improved public and ecosystem health. Several benefit-cost analyses have shown greater than a 10 to 1 ratio of public health benefits per pollution prevention costs. This is an excellent outcome for public health made possible by the ability of the government to regulate polluters.

The regulation of polluters was not achieved without political push-back, and the biggest impediment to continuing to protect the public from air pollution related disease is the ongoing war between those who see a limited role for government and those depending on the government to protect them from unhealthy air. This war is meticulously documented in Merchants of Doubt (2010) by Naomi Oreskes and Erik M. Conway, and it is worth looking at one of the battles as it illustrates what efforts to improve public health through better air quality are up against.

Oreskes and Conway document government moves to alert the public that cigarette smoking caused cancer. By the 1950s, cigarette smoke was known, in public health circles, to cause cancer. If this fact was accepted by the health community, why would anyone outside the tobacco industry try to dilute this message? Timing explains much of this story. The country was in the grips of the cold war and a few prominent scientists with strong convictions that government regulation of personal choice would lead to communism used their reputations to cast doubt on this fact. Driven by their ideological fervor, these scientists used their political clout to support misinformation from the tobacco industry to effectively delay for years the Surgeon General’s warning on cigarettes.

This same battle has been waged with similar tactics but also with the help of well funded think tanks to stop the regulation of air pollutants such as: acidic gases from power plants (acid rain), refrigerants (ozone hole), and second hand cigarette smoke. This battle continues today with the same mix of anti-regulatory players attempting to cast doubt on the relationships between greenhouse gas emissions and climate change.

Given these powerful forces, how was the Clean Air Act passed? President Nixon pushed for its passage to silence opposition from the environmental movement which helped his re-election in 1972. Regardless of the politics, credit for cleaner air countrywide should go to the Clean Air Act of 1970. The act allowed for the regulation of emissions from all sorts of polluters which has greatly reduced air pollution and simultaneously improved public health. However, the fight to reduce the impacts of air pollution on public health is not over.

A clear scientifically-based message to the global community on how air pollution impacts the short- and long-term livability of the planet is needed. What must the global community hear? Greenhouse gas emissions are causing drastic changes in global climate. Furthermore, emissions of hazardous air pollutants (HAPs) are degrading public health locally and worldwide.

How these two air pollution issues will impact public health differ greatly in magnitude and scale. We must limit emissions of greenhouse gases to slow sea level rise, reduce disruptions in global food production, and secure the availability of potable water worldwide. The potential changes in habitable land, food production, and potable water could set in motion a cascade of human displacement, malnutrition, and disease that will impact all corners of the globe. Effective regulation of greenhouse gases will be difficult because of the global nature of the sources and the enormous costs. Proper decisions can only be made from an informed debate of the issues. Unfortunately, the disinformation war on the relationships between greenhouse gas emissions and climate change is already well engaged and the battle tactics by those in opposition are better funded than ever. If human impacts on climate change aren’t addressed soon, the benefits from control of emissions of HAPs will be inconsequential.

While recognizing this, it is still important to move forward on reducing the public’s exposure to air pollution. People are exposed to air pollutants in many ways. The most direct exposure is breathing contaminated air. Furthermore, air pollutants can be taken into the body by eating foods contaminated by airborne compounds, by drinking contaminated water, by ingesting contaminated soil, or by skin contact with contaminated soil, dust, or water.

The US Environment Protection Agency has designated 188 compounds as HAPs. These compounds have the capacity to cause cancer, birth defects, heart and respiratory disease, and harm to the environment. The sources of HAPs come mainly from human activities and sporadically from natural sources such as forest fires. Emissions from mobile sources (cars, trucks, trains, etc.), stationary sources (large industrial polluters), and area sources (small businesses, cleaning products, paints, small gas engines) contain HAPs. What can be done to protect the public from unhealthy levels of HAPs?   

Public education for self-protection should be part of the solution. Presently, the EPA is working with state, local, and tribal governments to diminish the release of HAPs into the environment. Because of the complexity of setting ambient air quality standards such as was done with the six criteria pollutants, EPA has chosen to reduce emissions of HAPs through rules for specific sources such as: mobile sources (cars and trucks), area sources (household products, small engines, small businesses), and point sources (large industry). The rules limit the amount of HAPs released by a product or process. This form of regulation reduces the amount of HAPs released into the air. However, those using polluting products or living next to a source of HAPs have a greater burden than those using safer products and living further away from polluters. 

Every day we make personal choices that affect our exposure to and generation of HAPs. A good example of this is where we choose to live, work, and recreate. Highly used roads produce unacceptable levels of HAPs such as benzene (cancer) and fine particulates (cancer and respiratory disease). Thus, not only those living near the road but drivers experience unacceptable exposures to HAPs. Clear solutions to this are less driving, cleaner cars and trucks, and alternative forms of transportation.

Regulations calling for higher fuel efficiencies for vehicles and cleaner power generation would do much to protect the public from HAPs. In particular, coal-fired power plants should be compelled to drastically reduce emissions of mercury. Mercury is being distributed worldwide by the burning of coal and it bioaccumulates in certain foods. The EPA has issued warnings on fish consumption as a result of mercury pollution. This issue illustrates the complexity of regulation of HAPs. Coal is a cheap source of power and is found in abundance but its use is contributing to public health problems that are mounting with the real consequences and costs only coming due in the .       

Any and all new regulations on industry or personal choices will be met with strong political opposition of the sort described above. We as a society need to promote a rational dialogue on these issues to create options to mitigate the damage that is taking place now and will accelerate in the future.

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