Expert Commentary

The health effects and costs of air pollution: Research roundup

2015 review of scholarship on impact of air pollution in the United States, including health effects, economic costs and automotive and transportation causes.

Industrial skyline in sunset

If you’d like to start a lively discussion at a politically diverse gathering, a good way is to bring up the potential benefits and costs of environmental regulations. The current political divide in the United States pretty much guarantees that soon you’ll be hearing supporters defending “common-sense laws” on one side while detractors denounce “job-killing taxes” on the other.

It’s hard to remember, but environmental regulations weren’t always an invitation to angry debate and Congressional gridlock. The Clean Air Act of 1970 was signed into law by President Richard Nixon and gave the Environmental Protection Agency (created under the same administration) the authority to regulate emissions of hazardous air pollutants from fixed and mobile sources. Two decades later President George H.W. Bush spearheaded the expansion of the Clean Air Act, giving the EPA authority to tackle ozone depletion and establishing a market-based approach to reduce emissions of sulfur dioxide, a contributor to acid rain. The 1990 amendments also created incentives to promote the use of natural gas and the development of biofuels.

According to the EPA, these laws have produced significant progress across a wide range of pollutants: Between 1990 to 2002, emissions of carbon monoxide, volatile organic compounds, particulate matter, sul­fur dioxide and nitrogen oxides dropped between 17% to 44%; over the same period, mercury emissions dropped 52%. And between 1970 and 2002, lead emissions have been cut by 99%. And across all 188 air toxics, emissions have decreased between 1990 and 2002.

Addressing newer threats such as climate change have been more elusive, however, in part because of increasing partisan polarization and in part because of changes in the environmental movement. The 2007 Climate Security Act, which would have established a carbon cap-and-trade program, never made it out of Congress. But in October 2015, the EPA strengthened the National Ambient Air Quality Standards for ground-level ozone to 70 parts per billion, a change the federal agency considered especially important for children and people with asthma. The EPA also aims to reduce air pollution from passenger cars and trucks by setting new vehicle emissions standards and lowering the sulfur content of gasoline beginning in 2017. Despite significant human costs — a 2013 study calculated that approximately 200,000 early deaths occur every year in the United States because of air pollution — every change is difficult and the fate of such regulations is often decided in the courts.

Below is a selection of studies on a range of issues related to air pollution. It has sections on the health effects, economic costs and automotive causes of air pollution. For journalists who write about pollution regularly, the EPA has compiled a collection of online information, including glossaries, about specific air pollutants, including asbestos, lead and chlorofluorocarbons.


Health effects

The Contribution of Outdoor Air Pollution Sources to Premature Mortality on a Global Scale
Lelieveld, J; Evans, J.S.; Fnais, M.; Giannadaki, D.; Pozzer, A. Nature, September 2015, Vol. 525. doi: 10.1038/nature15371.

Summary: Researchers investigated the link between premature death and seven sources of air pollution in urban and rural environments. They determined, through calculations, that outdoor air pollution led to 3.3 million premature deaths worldwide in 2010, mostly in Asia. Model projections suggest that premature deaths caused by outdoor air pollution could double by 2050. The researchers predict “moderate though significant increases of premature mortality will occur in Europe and the Americas, to a large degree in urban areas.”


“Effect of Air Pollution Control on Life Expectancy in the United States: An Analysis of 545 U.S. Counties for the Period from 2000 to 2007”
Correia, Andrew W.; et al. Epidemiology, January 2013, Vol. 24, Issue 1, 23-31. doi: 10.1097/EDE.0b013e3182770237

Abstract:  “In recent years (2000-2007), ambient levels of fine particulate matter (PM2.5) have continued to decline as a result of interventions, but the decline has been at a slower rate than previous years (1980-2000). Whether these more recent and slower declines of PM2.5 levels continue to improve life expectancy and whether they benefit all populations equally is unknown. Methods: We assembled a data set for 545 U.S. counties consisting of yearly county-specific average PM2.5, yearly county-specific life expectancy, and several potentially confounding variables measuring socioeconomic status, smoking prevalence, and demographic characteristics for the years 2000 and 2007. We used regression models to estimate the association between reductions in PM2.5 and changes in life expectancy for the period from 2000 to 2007. Results: A decrease of 10 μg/m3 in the concentration of PM2.5 was associated with an increase in mean life expectancy of 0.35 years (SD = 0.16 years, P = 0.033). This association was stronger in more urban and densely populated counties. Conclusions: Reductions in PM2.5 were associated with improvements in life expectancy for the period from 2000 to 2007. Air pollution control in the last decade has continued to have a positive impact on public health.”


Ambient Air Pollution in China Poses a Multifaceted Health Threat to Outdoor Physical Activity
Li, Fuzhong; Liu, Yu; Lü, Jiaojiao; Liang, Leichao; Harmer, Peter.  Journal of Epidemiology & Community Health, 2015. doi: 10.1136/jech-2014-203892.

Introduction: “While outdoor physical activity has been shown to promote health and wellbeing, exercising in environments with high levels of air pollution can increase the risk of health problems ranging from asthma attacks to heart or lung pathologies.The interaction of these two phenomena is of specific significance in China, where outdoor physical activity has been a traditional practice but where rapid industrialization has led to major degradation of the environment. This situation raises the specter of an emergent major public health crisis in the most populous country in the world.”


“Prenatal Polycyclic Aromatic Hydrocarbon (PAH) Exposure and Child Behavior at Age 6-7”
Perera, F.P.; Tang, D.; Wang, S; Vishnevetsky, J.; Zhang, B.; Diaz, D.; Camann, D.; Rauh, V. Environmental Health Perspectives, March 2012. doi: 10.1289/ehp.1104315.

Abstract: “Airborne polycyclic aromatic hydrocarbons (PAH) are widespread urban air pollutants from fossil fuel burning and other combustion sources. Methods: Children of nonsmoking African-American and Dominican women in New York City were followed from in utero to 6-7 years. Prenatal PAH exposure was estimated by personal air monitoring of the mothers during pregnancy as well as … in maternal and cord blood…. Results: High prenatal PAH exposure, whether characterized by personal air monitoring (greater than the median of 2.27 ng/m³) or maternal and cord adducts (detectable or higher), was positively associated with symptoms of Anxious/Depressed and Attention Problems.”


“Persistent Environmental Pollutants and Couple Fecundity”
Buck Louis, Germaine M.; et al. Environmental Health Perspectives, November 2012. doi: 10.1289/ehp.1205301.

Abstract: “Evidence suggesting that persistent environmental pollutants may be reproductive toxicants underscores the need for prospective studies of couples for whom exposures are measured.
Methods: A cohort of 501 couples who discontinued contraception to become pregnant was prospectively followed for 12 months of trying to conceive or until a human chorionic gonadotrophin (hCG) test confirmed pregnancy. Couples completed daily journals on lifestyle and provided biospecimens for the quantification of 9 organochlorine pesticides, 1 polybrominated biphenyl, 10 polybrominated diphenyl ethers, 36 polychlorinated biphenyls (PCBs), and 7 perfluorochemicals (PFCs) in serum. Conclusions: We observed that a subset of persistent environmental chemicals were associated with reduced fecundity.”


“Multiple Environmental Chemical Exposures to Lead, Mercury and PCBs Among Childbearing-Aged Women”
Thompson, Marcella Remer; Boekelheide, Kim. Environmental Research, February 2013, doi: 10.1016/j.envres.2012.10.005.

Findings: The researchers based their research on analysis of the National Health and Nutrition Examination Survey (1999-2004). In all, 3,173 women were included in the study. More than 20% of the women examined had levels of lead, mercury, and PCBs at or above average. “Among the 33% of women who had two xenobiotic levels at or above the median, it was as likely to be PCBs-lead (36%), mercury-lead (34%) or mercury-PCBs (29%). Among the 27% of women having only one xenobiotic level at or above the median, it was as likely to be lead (43%), mercury (36%) or PCBs (21%).”



“The Benefits and Costs of the Clean Air Act from 1990 to 2020”
U.S. Environmental Protection Agency, Office of Air and Radiation, March 2011

Findings: “Based on the scenarios analyzed in this study, the costs of public and private efforts to meet 1990 Clean Air Act Amendment requirements rise throughout the 1990 to 2020 period of the study, and are expected to reach an annual value of about $65 billion by 2020…. Though costly, these efforts are projected to yield substantial air quality improvements which lead to significant reductions in air pollution — related premature death and illness, improved economic welfare of Americans, and better environmental conditions. The economic value of these improvements is estimated to reach almost $2 trillion for the year 2020, a value which vastly exceeds the cost of efforts to comply with the requirements of the 1990 Clean Air Act Amendments.”


The Economics of Household Air Pollution
Jeuland, Marc; Pattanayak, Subhrendu K.; Bluffstone, Randall. Annual Review of Resource Economics, October 2015, Vol. 7. doi: 10.1146/annurev-resource-100814-125048.

Abstract: “Traditional energy technologies and consumer products contribute to household well-being in diverse ways but also often harm household air quality. We review the problem of household air pollution at a global scale, focusing particularly on the harmful effects of traditional cooking and heating. Drawing on the theory of household production, we illustrate the ambiguous relationship between household well-being and adoption of behaviors and technologies that reduce air pollution. We then review how the theory relates to the seemingly contradictory findings emerging from the literature on developing country household demand for clean fuels and stoves. In conclusion, we describe an economics research agenda to close the knowledge gaps so that policies and programs can be designed and evaluated to solve the global household air pollution problem.”


“Impact of Air Quality on Hospital Spending”
Romley, John A.; Hackbarth, Andrew; Goldman, Dana P. Rand Corporation, 2010.

Findings:  Between 2005 and 2007, nearly 30,000 hospital admissions and emergency-room visits could have been avoided throughout California if federal clean-air standards had been met. These cases led to higher hospital care cost of approximately $193 million. Medicare and Medicaid spent about $132 million on such hospital care while the rest was incurred by private third-party purchasers. Five case studies of individual hospitals in Riverside, Fresno, Lynwood, Stanford and Sacramento show that the costs incurred by the different types of payers vary by region.


“The Impact of Pollution on Worker Productivity”
Graff Zivin, Joshua S.; Neidell, Matthew J. National Bureau of Economic Research, April 2011.

Abstract: “Environmental protection is typically cast as a tax on the labor market and the economy in general. Since a large body of evidence links pollution with poor health, and health is an important part of human capital, efforts to reduce pollution could plausibly be viewed as an investment in human capital and thus a tool for promoting economic growth. While a handful of studies have documented the impacts of pollution on labor supply, this paper is the first to rigorously assess the less visible but likely more pervasive impacts on worker productivity. In particular, we exploit a novel panel dataset of daily farm worker output as recorded under piece rate contracts merged with data on environmental conditions to relate the plausibly exogenous daily variations in ozone with worker productivity. We find robust evidence that ozone levels well below federal air quality standards have a significant impact on productivity: a 10 ppb decrease in ozone concentrations increases worker productivity by 4.2 percent.


The Effect of Pollution on Labor Supply: Evidence From a Natural Experiment in Mexico City
Hanna, Rema; Oliva, Paulina. Journal of Public Economics, February 2015, Vol. 122. doi: 10.1016/j.jpubeco.2014.10.004.

Abstract:  “Moderate effects of pollution on health may exert important influences on work. We exploit exogenous variation in pollution due to the closure of a large refinery in Mexico City to understand how pollution impacts labor supply. The closure led to a 19.7 percent decline in pollution, as measured by SO2, in the surrounding neighborhoods. The closure led to a 1.3 h (or 3.5 percent) increase in work hours per week. The effects do not appear to be driven by differential labor demand shocks nor selective migration.”


“The Effects of Environmental Regulation on the Competitiveness of U.S. Manufacturing”
Greenstone, Michael; List, John A.; Syverson, Chad. MIT Department of Economics, September 2012.

Abstract: “The economic costs of environmental regulations have been widely debated since the U.S. began to restrict pollution emissions more than four decades ago. Using detailed production data from nearly 1.2 million plant observations drawn from the 1972-1993 Annual Survey of Manufactures, we estimate the effects of air quality regulations on manufacturing plants’ total factor productivity (TFP) levels. We find that among surviving polluting plants, stricter air quality regulations are associated with a roughly 2.6 percent decline in TFP. The regulations governing ozone have particularly large negative effects on productivity, though effects are also evident among particulates and sulfur dioxide emitters. Carbon monoxide regulations, on the other hand, appear to increase measured TFP, especially among refineries. The application of corrections for the confounding of price increases and output declines and sample selection on survival produce a 4.8% estimated decline in TFP for polluting plants in regulated areas. This corresponds to an annual economic cost from the regulation of manufacturing plants of roughly $21 billion, which is about 8.8% of manufacturing sector profits in this period.”



“Residential Traffic Exposure and Childhood Leukemia: A Systematic Review and Meta-analysis”
Boothe, Vickie L.; Boehmer, Tegan K.; Wendel, Arthur M.; Yip, Fuyuen Y. American Journal of Preventive Medicine, April 2014, vol. 46, issue 4, 413-422. doi: 10.1016/j.amepre.2013.11.004.

Abstract: Exposure to elevated concentrations of traffic-related air pollutants in the near-road environment is associated with numerous adverse human health effects, including childhood cancer, which has been increasing since 1975. Results of individual epidemiologic studies have been inconsistent. Therefore, a meta-analysis was performed to examine the association between residential traffic exposure and childhood cancer…. Current evidence suggests that childhood leukemia is associated with residential traffic exposure during the postnatal period, but not during the prenatal period. Additional well-designed epidemiologic studies that use complete residential history to estimate traffic exposure, examine leukemia subtypes, and control for potential confounding factors are needed to confinn these findings.”


“Measurement of Airborne Concentrations of Tire and Road Wear Particles in Urban and Rural areas of France, Japan and the United States”
Panko, Julie M.; Chu, Jennifer; Kreider, Marisa L.; Unice, Ken M. Atmospheric Environment, June 2013, Vol. 72.

Abstract: “Exhaust and non-exhaust vehicle emissions are an important source of ambient air respirable particulate matter (PM10). Non-exhaust vehicle emissions are formed from wear particles of vehicle components such as brakes, clutches, chassis and tires…. In this study, a global sampling program was conducted to quantify tire and road wear particles (TRWP) in the ambient air in order to understand potential human exposures and the overall contribution of these particles to the PM10. The sampling was conducted in Europe, the United States and Japan and the sampling locations were selected to represent a variety of settings including both rural and urban core; and within each residential, commercial and recreational receptors…. Results indicated that TRWP concentrations in the PM10 fraction were low with averages ranging from 0.05 to 0.70 μg m−3, representing an average PM10 contribution of 0.84%.”


The Effect of Beijing’s Driving Restrictions on Pollution and Economic Activity
Viarda, V. Brian; Fub, Shihe. Journal of Public Economics, May 2015. Vol. 125. doi:10.1016/j.jpubeco.2015.02.003.

Abstract: “We evaluate the pollution and labor supply reductions from Beijing’s driving restrictions. Causal effects are identified from both time-series and spatial variation in air quality and intra-day variation in television viewership. Based on daily data from multiple monitoring stations, air pollution falls 21 percent during one-day-per-week restrictions. Based on hourly television viewership data, viewership during the restrictions increases by 9 to 17 percent for workers with discretionary work time but is unaffected for workers without, consistent with the restrictions’ higher per-day commute costs reducing daily labor supply. We provide possible reasons for the policy’s success, including evidence of high compliance based on parking garage entrance records.”


“Traffic-Related Air Pollution, Particulate Matter and Autism”
Volk, Heather E.; Lurmann, Fred; Penfold, Bryan; Hertz-Picciotto, Irva; McConnell, Rob. JAMA Psychiatry. January 2013. doi:10.1001/jamapsychiatry.2013.266.

Abstract: “This population-based case-control study includes data obtained from children with autism and control children with typical development who were enrolled in the Childhood Autism Risks from Genetics and the Environment study in California. [The study found that] children with autism were more likely to live at residences that had the highest quartile of exposure to traffic-related air pollution, during gestation and during the first year of life, compared with control children. Regional exposure measures of nitrogen dioxide and particulate matter less than 2.5 and 10 μm in diameter (PM2.5 and PM10) were also associated with autism during gestation and during the first year of life.”


“Filtration Effectiveness of HVAC Systems at Near-roadway Schools”
McCarthy, M.C.; Ludwig, J.F.; Brown, S.G.; Vaughn, D.L.; Roberts, P.T. Indoor Air, January 2013, doi: 10.1111/ina.12015.

Abstract: “Concern for the exposure of children attending schools located near busy roadways to toxic, traffic-related air pollutants has raised questions regarding the environmental benefits of advanced heating, ventilation, and air-conditioning (HVAC) filtration systems for near-road pollution. Levels of black carbon and gaseous pollutants were measured at three indoor classroom sites and at seven outdoor monitoring sites at Las Vegas schools. Initial HVAC filtration systems effected a 31% to 66% reduction in black carbon particle concentrations inside three schools compared with ambient air concentrations. After improved filtration systems were installed, black carbon particle concentrations were reduced by 74% to 97% inside three classrooms relative to ambient air concentrations. Average black carbon particle concentrations inside the schools with improved filtration systems were lower than typical ambient Las Vegas concentrations by 49% to 96%. Gaseous pollutants were higher indoors than outdoors. The higher indoor concentrations most likely originated at least partially from indoor sources, which were not targeted as part of this intervention.”


Keywords: pollution, cars, cancer, coal, fossil fuels, research roundup, driving, China, premature death

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