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. 2020 Dec 9;31(1):33–37. doi: 10.1093/ppar/praa036

The Importance of Air Quality Policy for Older Adults and Diverse Communities

Jennifer Ailshire 1,✉, Lauren L Brown 2
Editor: Brian Kaskie
PMCID: PMC7799383  PMID: 33462554

Regardless of whether one lives in a rural or urban area, in a city or suburb, pollutants are ubiquitous in the air we breathe. The public health dangers of air pollution exposure are well documented (Sun & Zhu, 2019), and older adults are considered one of the most at-risk populations for adverse health impacts from air pollution (Simoni et al., 2015). Other groups with a disproportionate health burden from air pollution exposure include racial and ethnic minorities and those living in impoverished neighborhoods (Ash & Fetter, 2004). The unequal burden of air pollution may play a key role in racial/ethnic and socioeconomic disparities in the health and aging trajectories of older adults.

In this report, we summarize the research on air pollution and health among older adults, including emerging evidence on the link between air pollution and dementia, and discuss the unequal burden and impact of air pollution within the older population. We also review federal and local policies and approaches to improving air quality, and evaluate the extent to which they address the needs of our diverse, rapidly aging population. We make the case that the adverse impacts of air pollution on older adults specifically should factor more prominently in air quality policy and actions.

The adverse impacts of air pollution on older adults specifically should factor more prominently in air quality policy and actions.

Air Pollution and Older Adult Health

Air pollution is produced through a combination of human activities and natural sources. Pollutants are emitted from a variety of sources, including cars, industrial and agricultural activities, and fires, and can be formed indirectly through complex chemical reactions in the air. The Clean Air Act is a federal law designed to improve air quality through regulatory standards administered by the U.S. Environmental Protection Agency (EPA) and coordinated through state and local policies and actions. The Clean Air Act (CAA) of 1963 established funding for the study of air pollution, but Congress passed a much more comprehensive version of the CAA in 1970, including establishing the Environmental Protection Agency, and further revised and expanded the CAA in 1990 and 1997 (U.S. Environmental Protection Agency, 2007). The EPA has established national air quality standards for six common pollutants—ozone, particulate matter (PM), carbon monoxide, lead, sulfur dioxide, and nitrogen dioxide—and works with state and local governments to reduce emissions of other air toxins (e.g., benzene, toluene, asbestos) and metals (e.g., cadmium, mercury, lead).

Research has found higher levels of air pollution to be associated with increased risks of cardiovascular and respiratory diseases, more hospitalizations from heart and lung problems, and increased mortality among older adults (Simoni et al., 2015). Most studies have found higher risks at older ages. Age-related physiological declines may increase susceptibility to toxin exposure, like exposure to air pollutants. Moreover, chronic conditions that are more prevalent at older ages, such as cardiovascular disease, increase the risk air pollutants pose to health (U.S. Environmental Protection Agency, 2019, 12–9). Age itself may not be the key susceptibility factor in the air pollution–health relationship, but older adults are more likely to have preexisting conditions and greater frailty, which increases their risk from pollutant exposure. In addition, older adults may also have had longer periods of exposure to pollution, leading to an accumulation of pollution-related health damages that puts them at greater risk of the adverse impacts of poor air quality. Although researchers have established both short-term and long-term effects of air pollution on health, a major limitation in research on air pollution and health across the life course is that we do not know what the lifetime exposure has been for current cohorts of older adults. It was only beginning in the 1970s that we started an organized federal and local effort to monitor air quality. Thus, much of what we know about the link between air pollution and health among older adults is based on exposures measured in midlife or later, ignoring exposures accumulated in early life.

Although several air pollutants are harmful to human health, PM is of growing concern due to accumulating evidence that it can harm the aging brain. Fine particulate matter (PM2.5) consists of small, inhalable particles with diameters 2.5 µm and smaller. To put this in perspective, a grain of fine beach sand is around 90 µm in diameter, or 36 times larger. Once inhaled, fine particles can enter systemic circulation and may even travel from the lungs into other organ systems, such as the brain (Peters et al., 2015), where they can cause damage to the structures and function of the brain that are consistent with cognitive decline and impairment. Living in areas with higher concentrations of PM2.5 has been linked to worse cognitive function and more rapid cognitive declines among older adults (Ailshire & Clarke, 2015; Ailshire & Crimmins, 2014; Gatto et al., 2014; Schikowski et al., 2015; Tonne et al., 2014; Weuve et al., 2012). These findings are consistent with evidence linking air pollution to increased risks of white matter loss, brain inflammation, and the accumulation of beta-amyloid (Calderón-Garcidueñas et al., 2004; Chen et al., 2015; Levesque et al., 2011; Wilker et al., 2015), which are implicated in the pathogenesis of Alzheimer’s disease.

Differential Exposure and Disparate Impacts of Air Pollution

Air quality policy is meant to protect the entire population, but it is clear that some groups are subject to a disproportionate burden of exposure, as well as having greater susceptibility to the adverse impacts of air pollutant exposure. For instance, two recent studies of mortality, one conducted among Medicare beneficiaries (Di et al., 2017) and the other among a cohort of U.S. veterans (Bowe et al., 2019), found that the risks of death were higher among black and Latinx older adults and among those with a lower socioeconomic status, compared to the rest of the population.

There are several reasons why certain groups may suffer a disproportionate health burden from air pollution. Neighborhoods where black, Latinx, and low-income older adults live have historically had higher pollution levels (Ash & Fetter, 2004). One consequence of discriminatory housing practices is that communities where racial/ethnic minorities and low-income individuals live are less likely to be protected by local and federal policies that regulate toxic exposures. Data from 2014 show that among those ages 60 to 64 years, for instance, 25% of Latinx and 13% of black older adults lived in neighborhoods with PM2.5 concentrations above the national standard of 12µm/m3, compared to only 7% of older whites (Figure 1). In addition, hazardous physical and social exposures tend to cooccur, and there may be important synergistic effects between air pollution and other social stressors. Racial/ethnic minorities and economically disadvantaged adults tend to have a higher burden of social and economic stressors (Brown et al., 2020), putting them at higher risk of preexisting health conditions. A greater stress burden and more preexisting health conditions, along with discrimination and segregation in the rental and housing market, may increase susceptibility to the adverse health effects of pollutant exposure for black and Latinx communities (Bravo et al., 2016).

Figure 1.

Figure 1.

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Percentages (and 95% confidence intervals) of non-institutionalized adults ages 60 years and older, by race and age, living in census tracts with particulate matter 2.5 concentrations above 12 µm/m3. All numbers are weighted. Data source: 2014 Health and Retirement Study.

Does Air Quality Policy Need a Greater Focus on Aging and Diverse Populations?

Improvements in air quality over the past several decades, a direct result of federal regulations and local and state actions, may be one of our most successful public health efforts of the 21st century. The EPA established the first standard for PM2.5 in 1997, at 15 µm/m3, based on scientific evidence showing clear, negative population-level health impacts above this threshold. They later revised the regulatory threshold downward in 2006, to 12 µm/m3, again based on the weight of the scientific evidence for negative population-level health impacts. As a result of local and state efforts to improve air quality, from 2000 to 2019 the annual average PM2.5 decreased by 43% nationally. This is undoubtedly a major public health success story. Even short-term reductions in air pollution have shown rapid improvements in population health, particularly in places with high levels of air pollution and for vulnerable populations like older adults (Schraufnagel et al., 2019).

However, recent studies of older adults have observed adverse health impacts at PM2.5 concentrations below the current regulatory threshold (Bishop et al., 2018). Air quality policy is based on an evaluation of the evidence from research conducted across the entire population and at all ages. Much of the scientific evidence that has been used to set standards did not focus on older adult populations specifically; current regulatory thresholds may be too high for the more vulnerable older adult population. Older adults are the fastest growing age demographic in the United States, and so even a modest increase in risk in this group may have disproportionately large impacts on health and health-care spending.

Although the air quality improvements have been remarkable, two caveats should be kept in mind. First, air pollutant concentrations tend to be higher in places where the population includes larger proportions of racial and ethnic minorities and low-income individuals (U.S. Environmental Protection Agency, 2011, 2–60). One concern is that air quality improvements are not occurring evenly across the United States, but even if pollution declines uniformly across places, certain groups may still have an increased burden of exposure if they live in areas that have always had more pollution. Consider the following comparison of the 50th and 90th percentiles of PM2.5 for older white, black, and Latinx adults from 2002 to 2014 (Figure 2). PM2.5 declined during this time for all groups, falling below the 12µm/m3 standard by 2010, but older black adults consistently lived in neighborhoods with higher PM2.5 concentrations than white and Latinx older adults. However, it is important to consider differences not just at the median, but at other points in the distribution, particularly for populations with significant within-group heterogeneity, such as the Latinx population. The top 90th percentile of PM2.5 exposure was higher for older Latinx adults than for either white or black older adults at the same percentile. Considering only average improvements in air quality over time may obscure important subgroup differences in exposure to high concentrations of pollutants.

Figure 2.

Figure 2.

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Particulate matter 2.5 (PM2.5) concentrations at the 50th (median) and 90th percentiles, by race/ethnicity, of non-institutionalized adults ages 60 years and older. All numbers are weighted. Data source: 2014 Health and Retirement Study (Ailshire & Kang, 2020; Health and Retirement Study, 2019).

Finally, recent data suggest that PM2.5 levels have increased in the last several years. After observing year-over-year declines of PM2.5 from 2009 to 2016, annual average PM2.5 levels in counties with monitors actually increased in 2017, and again in 2018 (Clay & Muller, 2019). Plausible explanations for these increases include increased economic activity, less enforcement of EPA standards under the Clean Air Act, and recent increases in wildfires. Importantly, this study evaluated the broader impacts of the recent increases in PM2.5, concluding that an additional 9,700 premature deaths occurred from 2016 to 2018, representing $89 billion in damages. Furthermore, the authors determined that 80% of the burden was born by older adults, particularly among those who had 5–10 years of remaining life. This study underscores the reality that success in air quality policy can be reversed, whether as a result of lack of enforcement or increases in the duration and intensity of the wildfire season. For the sake of the nation’s health, and older adults in particular, we need to remain vigilant and maintain efforts to improve air quality both nationally and locally.

For the sake of the nation’s health, and older adults in particular, we need to remain vigilant and maintain efforts to improve air quality both nationally and locally.

Conclusion

As we were writing this report, “mega fires” were stretching across our state of California. The governor, who noted that we have already had thousands more known fires as of early August 2020 than were counted in the entire prior year, has declared a state of emergency. We can see the impacts of these fires, which are largely in the northern part of the state, hundreds of miles south in our air quality in Los Angeles. In a city with such a large and diverse population of older adults, haze is always worrisome, but even more so when it is worsened as a result of the growing number of fires that blaze through the state each year.

Research on the impacts of air pollution on older adults underscores the importance of considering aging and older adults more centrally in our air quality policies and enforcement actions. With a rapidly growing older adult population, even modest reductions in risk could have substantial positive impacts on population health (Di et al., 2017). The flip side of this, of course, is that small increases in air pollution risk could have outsized impacts on exacerbating racial/ethnic and socioeconomic inequalities in health. Thus, it is critical that the air quality standards review process, which is responsible for assessing the adequacy of current air quality standards for protecting population health, incorporate more input from stakeholders in aging (e.g., researchers, practitioners, policymakers). Gerontologists could participate in the scientific advisory process, for instance, by joining the Scientific Advisory Board to the EPA’s Clean Air Scientific Advisory Committee (https://yosemite.epa.gov/sab/sabpeople.nsf/WebCommittees/CASAC), where they could provide key insights on, and establish priorities for, the nation’s aging population. We have made remarkable progress toward cleaner air, but we may get even better results from greater attention—from both researchers and policymakers—to the collective actions needed to ensure we protect the health of the nation’s older adults.

Acknowledgments

The views expressed in this paper are attributable to the authors and do not necessarily reflect the official policies or positions of the funders.

Funding

This work was supported by the National Institute on Aging Network on Life Course Health Dynamics and Disparities (grant number R24 AG045061).

Conflicts of Interest

None reported.

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