Toxic air pollution and cognitive decline: Untangling particulate matter.

There is increasing evidence indicating air pollution is an important factor influencing the aging brain. However, much of this work measures air pollution using particulate matter (PM). Yet we know that the chemical components of PM are not consistent across space or time. Rather, the possible chemical mixtures of PM vary and are therefore not reliably measuring the same thing across studies. In this study we attempt to disentangle the effects of the components of measured PM by using estimates of concurrent exposures of 415 industrial air toxics, as well as 44 neuro- and developmental toxics. Using bivariate latent curve models, we leverage individual level panel data from the bi-annual Health and Retirement Study to test how these exposures relate to cognitive score trajectories of respondents across the years 2002-2012. We find that more exposure to neurotoxics was associated with faster rate of cognitive decline by 1.09 points (p < 0.05).

Air pollution and respiratory infections: the past, present, and future.

Air pollution levels across the globe continue to rise despite government regulations. The increase in global air pollution levels drives detrimental human health effects, including 7 million premature deaths every year. Many of these deaths are attributable to increased incidence of respiratory infections. Considering the COVID-19 pandemic, an unprecedented public health crisis that has claimed the lives of over 6.5 million people globally, respiratory infections as a driver of human mortality is a pressing concern. Therefore, it is more important than ever to understand the relationship between air pollution and respiratory infections so that public health measures can be implemented to ameliorate further morbidity and mortality. This article aims to review the current epidemiologic and basic science research on interactions between air pollution exposure and respiratory infections. The first section will present epidemiologic studies organized by pathogen, followed by a review of basic science research investigating the mechanisms of infection, and then conclude with a discussion of areas that require future investigation.

Empowering students to confront environmental injustice: Dialogue, theory, empathy, and partnership.

Many students find environmental justice to be emotionally overwhelming and/or politically alienating, and there is currently little work that provides instructors with effective techniques for addressing these types of challenges. In this paper, upon situating the environmental studies classroom and the broader undergraduate experience in sociohistorical context, we identify four sequential strategies for engaging and empowering students on environmental justice issues. First, instructors can facilitate an open and honest dialogue by strategically framing course content for the unique composition of the audience, sharing their own racialized experiences (or working with a guest speaker who would be willing to do so), and using interactive assignments to encourage student participation. Second, social theory can be presented to students as complimentary (rather than competing) ideas which can be used for creative, real-world problem solving. Third, instructors and students can cultivate empathy by acknowledging different standpoints, particularly those that have been historically marginalized. Lastly, by working in partnerships with community-based organizations, instructors and students can think and work beyond hero/savior and perpetrator/victim narratives. These strategies are not intended as a set of silver bullets, but rather as a series of potential starting points that are informed by recent scholarship on these topics.

Concentrated poverty, ambient air pollution, and child cognitive development.

Why does growing up in a poor neighborhood impede cognitive development? Although a large volume of evidence indicates that neighborhood poverty negatively affects child outcomes, little is known about the mechanisms that might explain these effects. In this study, we outline and test a theoretical model of neighborhood effects on cognitive development that highlights the mediating role of early life exposure to neurotoxic air pollution. To evaluate this model, we analyze data from a national sample of American infants matched with information on their exposure to more than 50 different pollutants known or suspected to harm the central nervous system. Integrating methods of causal inference with supervised machine learning, we find that living in a high-poverty neighborhood increases exposure to many different air toxics during infancy, that it reduces cognitive abilities measured later at age 4 by about one-tenth of a standard deviation, and that about one-third of this effect can be attributed to disparities in air quality.

Intersectional inequalities in industrial air toxics exposure in the United States.

Environmental justice and health research demonstrate unequal exposure to environmental hazards at the neighborhood-level. We use an innovative method-eco-intersectional multilevel (EIM) modeling-to assess intersectional inequalities in industrial air toxics exposure across US census tracts in 2014. Results reveal stark inequalities in exposure across analytic strata, with a 45-fold difference in average exposure between most and least exposed. Low SES, multiply marginalized (high % Black, high % female-headed households) urban communities experienced highest risk. These inequalities were not described by additive effects alone, necessitating the use of interaction terms. We advance a critical intersectional approach to evaluating environmental injustices.

Particulate Matter Exposure across Latino Ethnicities.

The Hispanic/Latino health paradox is the well-known health advantage seen across the Hispanic/Latino racial category in the US. However, this racial category collapses several distinct ethnic groups with varying spatial distributions. Certain populations, such as Dominicans and Cubans, are concentrated in specific areas, compared to more dispersed groups such as Mexicans. Historical peculiarities have brought these populations into contact with specific types of environmental exposures. This paper takes a first step towards unraveling these diverse exposure profiles by estimating how exposure to particulate matter varies across demographic groups and narrows down which types of industries and chemicals are contributing the most to air toxins. Exposure to particulate matter is estimated for 72,271 census tracts in the continental US to evaluate how these exposures correlate with the proportion of the population classified within the four largest groups that make up the Hispanic population in the US: Mexican, Puerto Rican, Cuban, and Dominican. Using linear mixed models, with the state nested within US Environmental Protection Agency regulatory region, and controls for population density, we find that the Dominican population is significantly less exposed to PM2.5 and PM10 compared to non-Hispanic Whites. Moreover, those tracts with a higher proportion of Cuban residents are significantly less exposed to PM2.5. However, those tracts with a higher proportion of foreign-born, Mexicans, and Puerto Ricans had significantly higher levels of exposure to all sizes of particulate matter. We discuss the need to consider the chemical components of these particles to better understand the risk of exposure to air pollution.

Disparities in Environmental Exposures to Endocrine-Disrupting Chemicals and Diabetes Risk in Vulnerable Populations.

Burgeoning epidemiological, animal, and cellular data link environmental endocrine-disrupting chemicals (EDCs) to metabolic dysfunction. Disproportionate exposure to diabetes-associated EDCs may be an underappreciated contributor to disparities in metabolic disease risk. The burden of diabetes is not uniformly borne by American society; rather, this disease disproportionately affects certain populations, including African Americans, Latinos, and low-income individuals. The purpose of this study was to review the evidence linking unequal exposures to EDCs with racial, ethnic, and socioeconomic diabetes disparities in the U.S.; discuss social forces promoting these disparities; and explore potential interventions. Articles examining the links between chemical exposures and metabolic disease were extracted from the U.S. National Library of Medicine for the period of 1966 to 3 December 2016. EDCs associated with diabetes in the literature were then searched for evidence of racial, ethnic, and socioeconomic exposure disparities. Among Latinos, African Americans, and low-income individuals, numerous studies have reported significantly higher exposures to diabetogenic EDCs, including polychlorinated biphenyls, organochlorine pesticides, multiple chemical constituents of air pollution, bisphenol A, and phthalates. This review reveals that unequal exposure to EDCs may be a novel contributor to diabetes disparities. Efforts to reduce the individual and societal burden of diabetes should include educating clinicians on environmental exposures that may increase disease risk, strategies to reduce those exposures, and social policies to address environmental inequality as a novel source of diabetes disparities.

Two Mechanisms: The Role of Social Capital and Industrial Pollution Exposure in Explaining Racial Disparities in Self-Rated Health.

This study provides an empirical test of two mechanisms (social capital and exposure to air pollution) that are theorized to mediate the effect of neighborhood on health and contribute to racial disparities in health outcomes. To this end, we utilize the Social Capital Benchmark Study, a national survey of individuals nested within communities in the United States, to estimate how multiple dimensions of social capital and exposure to air pollution, explain racial disparities in self-rated health. Our main findings show that when controlling for individual-confounders, and nesting within communities, our indicator of cognitive bridging, generalized trust, decreases the gap in self-rated health between African Americans and Whites by 84%, and the gap between Hispanics and Whites by 54%. Our other indicator of cognitive social capital, cognitive linking as represented by engagement in politics, decreases the gap in health between Hispanics and Whites by 32%, but has little impact on African Americans. We also assessed whether the gap in health was explained by respondents' estimated exposure to toxicity-weighted air pollutants from large industrial facilities over the previous year. Our results show that accounting for exposure to these toxins has no effect on the racial gap in self-rated health in these data. This paper contributes to the neighborhood effects literature by examining the impact that estimated annual industrial air pollution, and multiple measures of social capital, have on explaining the racial gap in health in a sample of individuals nested within communities across the United States.

Trends in exposure to industrial air toxins for different racial and socioeconomic groups: A spatial and temporal examination of environmental inequality in the U.S. from 1995 to 2004.

In recent decades there have been dramatic declines in industrial air toxins. However, there has yet to be a national study investigating if the drop has mitigated the unequal exposure to industrial toxins by race and social class. This paper addresses this by developing a unique dataset of air pollution exposure estimates, by aggregating the annual fall-out location of 415 air toxins, from 17,604 facilities, for the years 1995 to 2004 up to census block groups (N=216,159/year). These annual estimates of exposure were matched with census data to calculate trends in exposure for different racial and socioeconomic groups. Results show that exposure to air toxins has decreased for everyone, but African-Americans are consistently more exposed than Whites and Hispanics and socioeconomic status is not as protective for African-Americans. These results by race were further explored using spatially specified multilevel models which examine trends over time and across institutional boundaries.

Air pollution around schools is linked to poorer student health and academic performance.

Exposing children to environmental pollutants during important times of physiological development can lead to long-lasting health problems, dysfunction, and disease. The location of children's schools can increase their exposure. We examined the extent of air pollution from industrial sources around public schools in Michigan to find out whether air pollution jeopardizes children's health and academic success. We found that schools located in areas with the highest air pollution levels had the lowest attendance rates-a potential indicator of poor health-and the highest proportions of students who failed to meet state educational testing standards. Michigan and many other states currently do not require officials considering a site for a new school to analyze its environmental quality. Our results show that such requirements are needed. For schools already in existence, we recommend that their environmental quality should be investigated and improved if necessary.