<mark>America – mostly driven by changes in population sizes, shifting age structures, and pre-existing disease prevalence. They estimate that 1.8 million premature deaths in urban areas can be attributed to PM2.5 exposure in 2019. These numbers suggest that meaningful reductions in air pollution deaths can only be</mark> achieved through rapid pollution reduction and improved access to affordable high-quality health care.

<mark>Besides mortality and morbidity effects, air pollution also reduces cognitive ability and productivity of affected populations. Empirical evidence from brain-training experiments shows that PM2.5 exposure impairs cognitive abilities of adults, while these effects are largest for those in prime working age and those with low ability (La Nauze and Severini, 2021). There is even evidence that short-term exposure to air pollution negatively affects the performance of highly skilled workers – professional baseball umpires have been documented to make more incorrect calls when exposed to high levels of carbon monoxide (Archsmith et al 2018). Such evidence on the relationship between air quality and brain health explains how air pollution can negatively impact productivity and exacerbate inequalities (Peeples 2020).</mark>

# **Poor people tend to be more exposed and more vulnerable to air pollution.**

While global estimates of air pollution deaths differ somewhat from study to study, the evidence is in strong agreement that air pollution is one of the leading causes of deaths (Lelieveld et al. 2020). Several factors are compounding so that this burden is disproportionately borne by low- and middle-income countries. Especially in the developing countries of South and East Asia, large populations are located in densely populated urban areas. Less stringent air quality regulations, the prevalence of older polluting machinery and vehicles, subsidized fossil fuels, congested urban transport systems, rapidly developing industrial sectors, and cut-and-burn practices in agriculture are all contributing to heightened concentration levels. In addition, high proportions of physical and outdoor labor mean that more people are faced with heightened exposure. Constraints in terms of the accessibility, availability and quality of health care provision further increase air pollution related mortality in developing countries (Lelieveld, et al. 2020). Evidence on air pollution in India suggests that a one GW increase in coal-fired capacity corresponds to a 14 percent increase in infant mortality rates in districts near versus far from the plant site (Barrows et al 2019). This effect is 2-3 times larger than estimates from the developed world.

The burden of air pollution not only falls disproportionately on poorer countries; within countries poorer and more marginalized communities also tend to be exposed to higher pollution levels (Jbaily et al. 2022; Bell et al 2013). This inequality in exposure is well documented in the United States, where data on socioeconomic characteristics is available with high spatial disaggregation (Fann et al, 2018; Bell et al, 2013; Colmer et al, 2020; Kioumourtzoglou et al 2016; Bell & Ebisu, 2012; Mikati et al. 2018).

Patel et al. (2021) show that in the US, industrial planning policies have disproportionately placed polluting industries in areas with large Black, Hispanic and Asian populations. As a result, these minority groups face systematically higher pollution levels. Tessum et al. (2021) show that the disproportionate exposure to high PM2.5 exposure by racial-ethnic minorities in the US is not limited to industrial emitters. The study documents that the disproportionate pollution exposure is consistent across all major emission categories, across states, urban and rural areas, income levels, and exposure levels. Studying the period from 2004 to 2016, Jbaily et al (2022) show that in addition to ethnic minorities, low-income populations also face systematically higher PM2.5 pollution levels – and these exposure disparities have been increasing over time. Air quality is also documented to influence real estate prices, so that lower-income households tend to locate into cheaper, more polluted neighborhoods (Chay & Greenstone, 2005).

Outside the US, evidence on the inequality in air pollution exposure is more limited – often due to a lack of socio-economic data with high spatial disaggregation. Hajat et al. (2015) offer a systematic review of the literature on socio-economic disparities and air pollution exposure, compiling country- and city-level evidence from all regions. They confirm the strong evidence of unequal exposure in the US, but find mixed 4