AQLI

About

The Air Quality Life Index

The Air Quality Life Index, or AQLI, converts air pollution concentrations into their impact on life expectancy. From this, the public and policymakers alike can determine the benefits of air pollution policies in perhaps the most important measure that exists: longer lives.

 

Produced by the Energy Policy Institute at the University of Chicago (EPIC), the AQLI is based on frontier research by EPIC’s director Michael Greenstone that quantified the causal relationship between human exposure to air pollution and reduced life expectancy. Combining this analysis with highly localized pollution measurements yields unprecedented insight into the true cost of air pollution in communities around the world. Through the interactive platform, users can learn not only how polluted their community is, but also how much longer they could live if their community complied with World Health Organization guidelines or national standards. It makes evident that policies that reduce fossil fuel use can allow people to live longer and healthier lives today, as well as reduce the risks of disruptive climate change.

“By converting air pollution concentrations into tangible terms—its impact on life expectancy—the AQLI establishes particulate air pollution as the single greatest threat to human health globally.” – Michael Greenstone, EPIC


A Unique Approach

For most people, their only insight into particulate air pollution exposure and risk is the popular Air Quality Index, which uses a color-coded system to provide a normative assessment of daily air quality. But these colors do little to convey actual heath risk, and are often accompanied by measurements of units that are unfamiliar to almost everyone (e.g., micrograms of pollution per cubic meter). The AQLI thus represents a completely novel advancement in measuring and communicating the health risks posed by particulate matter air pollution. This is because the AQLI converts particulate air pollution into perhaps the most important metric that exists: its impact on life expectancy.

The AQLI is rooted in peer-reviewed research by an international team of scholars, including Michael Greenstone from the University of Chicago, which for the first time quantified the causal relationship between long-term human exposure to air pollution and life expectancy. The Index combines this research with hyper-localized, global particulate matter measurements. This unique approach makes the AQLI the first pollution index to show what the threat of air pollution means to a person’s life anywhere in the world. It can also illustrate the gains in life expectancy that could be achieved by reducing particulate pollution concentrations to meet the World Health Organization (WHO) guidelines, existing national air quality standards, or user-defined levels.

Specifically, the AQLI stands apart from most work in this space in a few important respects.

  1. The research underlying the AQLI is based on pollution data at the very high concentrations that prevail in many parts of Asia today. Previous work has relied on extrapolations of associational evidence from the low levels in the United States or on extrapolations from cigarette studies.
  2. The causal nature of the AQLI’s underlying research allows it to isolate the effect of air pollution from other factors that impact health. In contrast, previous efforts to summarize the health effects of air pollution have relied on associational studies that are prone to confounding the effects of air pollution with other determinants of human health.
  3. The AQLI delivers estimates of the loss of life expectancy for the average person. Other approaches report the number of people who die prematurely due to air pollution, leaving unanswered how much their life was cut short or if they were more predisposed to be impacted from it (e.g. elderly or sick).
  4. The AQLI uses highly localized satellite data, making it is possible to report life expectancy impacts at the county or similar level around the world, rather than much more aggregated levels reported in previous studies.

Our Funders

The work of the Air Quality Life Index is made possible through the generous support of the following individuals and institutions:

David and Christine Gross-Loh
Eric and Valonia Oei
The Becker Friedman Institute
Donald R. Wilson Jr., University of Chicago, AB ‘88

Look at the studies

New Evidence on the Impact of Sustained Exposure to Air Pollution on Life Expectancy from China’s Huai River Policy

By: Avraham Ebenstein, Maoyong Fan, Michael Greenstone, Guojun He, and Maigeng Zhou Proceedings of the National Academy of Sciences This paper finds that a 10 μg/m3 increase in airborne particulate matter (PM10) reduces life expectancy by 0.64 years (95% CI: 0.21, 1.07). This estimate is derived from quasi-experimental variation in PM10 generated by China’s Huai River Policy, which provides free or heavily subsidized coal for indoor heating during the winter to cities north of the Huai River but not to the south. The findings are derived from a regression discontinuity design based on distance from the Huai River, and are robust to using parametric and non-parametric estimation methods, different kernel types and bandwidth sizes, and adjustment for a rich set of demographic and behavioral covariates. Furthermore, the shorter lifespans are almost entirely due to elevated rates of cardiorespiratory mortality, suggesting that PM10 is the causal factor. The estimates imply that bringing all of China into compliance with its Class I standards for PM10 would save 3.7 billion life years.

Evidence on the Impact of Sustained Exposure to Air Pollution on Life Expectancy from China’s Huai River Policy

This paper's findings suggest that an arbitrary Chinese policy that greatly increases total suspended particulates (TSPs) air pollution is causing the 500 million residents of Northern China to lose more than 2.5 billion life years of life expectancy. The quasi-experimental empirical approach is based on China’s Huai River policy, which provided free winter heating via the provision of coal for boilers in cities north of the Huai River but denied heat to the south. Using a regression discontinuity design based on distance from the Huai River, we find that ambient concentrations of TSPs are about 184 μg/m3 [95% confidence interval (CI): 61, 307] or 55% higher in the north. Further, the results indicate that life expectancies are about 5.5 y (95% CI: 0.8, 10.2) lower in the north owing to an increased incidence of cardiorespiratory mortality. More generally, the analysis suggests that long-term exposure to an additional 100 μg/m3 of TSPs is associated with a reduction in life expectancy at birth of about 3.0 y (95% CI: 0.4, 5.6).

Methodology

Learn more about how the AQLI is calculated

Button / Circle / Small Gray / Internal Link Methodology

Report

A dozen facts about particulate air pollution

Button / Circle / Small Gray / Internal Link Reports