Every person breathes thousands of gallons of air each day, making air the greatest potential source of toxic exposure known to humankind. Occupational exposure to air contaminated with the toxics found in coal or radioactive dust can lead to recognized health conditions such a black lung disease or lung cancer. Many of us assume that avoiding toxics found in poor quality air simply requires avoiding occupational exposure, or at most, refraining from tobacco use, either by not smoking or by not being in a room occupied by smoking individuals.
Unfortunately, we cannot avoid exposure to airborne toxics so easily. It is becoming increasingly clear that the overall quality of the air we breathe has a direct link to our health. Because it would be unethical to purposely expose populations of humans to varying degrees of toxic air, much of this evidence relies on associations between air quality and human diseases.
For example, one natural experiment demonstrating the benefits of improving air quality occurred in North Carolina in 2002, as a result of the passage of the Clean Smokestacks Act — mandating reduction in air pollutants generated by coal-fired power plants. Following the rates of death from respiratory diseases in the decade prior to 2002 and the decade after passage of the Clean Smokestacks Act, we observed a marked reduction in deaths in North Carolina due to asthma, emphysema and pneumonia associated with a reduction in levels of air pollutants.
In fact, follow up studies demonstrated additional improved health outcomes from other diseases associated with air pollution, such as cardiovascular diseases.
In addition to demonstrating improved health benefits with improved air quality, scientists have also found poor health and progression of respiratory and other diseases associated with breathing polluted air.
The magnitude of this effect on our health is not trivial, as polluted air is recognized by many health experts as a source of significant morbidity and mortality in the world. Indeed, the World Health Organization currently estimates that each year 7 million premature deaths around the world are linked to air pollution—indoor and outdoor.
Nonetheless, many individuals feel that air pollution is not a problem to them personally, and must only remain a health problem in developing economic regions or countries, in which air pollution is visible and obvious. Unfortunately, air pollutants such as ozone remain a significant health risk in all parts of the world, even to those unaware of their personal risk.
A recent study of the population of six United States metropolitan areas by Meng Wang and colleagues demonstrated that long-term exposure to ambient air pollutants such as ozone was significantly associated with increasing clinical markers of emphysema.
The magnitude of these changes was similar to changes found in individuals who smoked cigarettes, galvanizing the idea that passive exposure to polluted air is not simply a nuisance or temporary inconvenience, but represents a truly significant personal health hazard, even today in some of most developed and sophisticated regions of the world. Although this study focused on six metropolitan areas, the findings can be generalized to all regions with elevations of ozone, which is commonly associated with fossil fuel combustion.
Over 50 years ago, the United States Surgeon General recognized the detrimental health impact of cigarette smoking in a landmark publication, and this has contributed to an overall decline in cigarette smoking in the U.S. population.
Nonetheless, it took some time to appreciate the effects of passive cigarette smoke on the health of individuals who were exposed to smoke without actually smoking themselves.
This recognition enabled the policies reducing the exposure of individual to passive cigarette smoke. With increasing sophisticated monitoring, we have now been able to ascertain that the population health effects of poor air quality are similar in magnitude to long term cigarette smoking.
Just as second-hand smoke is a recognized health hazard, air pollution is increasingly recognized as being just as harmful to an individual’s health. The time is now to address the health effects of poor air quality, recognize the magnitude of the detrimental effects of our population, and to calculate the true costs of allowing poor air quality to impact the health of our citizens.
Reprinted with modifications from Krauchanka, J., W.H. Schlesinger, and H. K. Lyerly. 2019. Air pollution is as harmful as smoking a pack a day. The Hill, 19 August. 2019. https://thehill.com/opinion/healthcare/457939-air-pollution-is-as-harmful-as-smoking-a-pack-a-day
Kravchenko, J., H.K. Lyerly, and W. Ross. 2018. The health impacts of environmental policy: The North Carolina Clean Smokestacks Act. North Carolina Medical Journal 79: 329-333.
Kravchenko, J., F. Akushevich, A.P. Abemethy, S. Holman, W.G. Ross, and H.K. Lyerly. 2014. Long-term dynamics of death rates of emphysema, asthma, and pneumonia and improving air quality. International Journal of Chronic Obstructive Pulmonary Disease 9: 613-627.
Lelieveld, J., et al. 2015. The contribution of outdoor air pollution sources in premature mortality on a global scale. Nature 525: 367-371.
Wang, M. et al., 2019. Association between long-term exposure to ambient air pollution and change in quantitatively-assessed emphysema and lung function. Journal of the American Medical Association (JAMA) 322: 546-556.