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 are popular air quality index systems, which many countries and other organizations use. They are color-coded systems that provide a normative assessment of daily air quality. But these colors do little to convey long-term 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 the world 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.