Evaluating Ozone Trends and Attributable Mortality in Urban Areas Worldwide

With over half of the world's population now currently residing in urban areas, there is a need for improved understanding of the impact of urban air pollution on health. Until now, estimates of the burden of disease attributable to ambient ozone exposure have been largely restricted to a national and global scale. This has been due in a part to the limited availability of data at finer spatial resolution. Consequently, estimates of ozone mortality at the city-level are sparsely available, especially for low and middle-income countries. However, the recent availability of air pollution datasets at a finer resolution has created an opportunity to produce such estimates at a city-level. Our approach uses year-specific 6-month average of the 8-hour daily maximum ozone concentration estimates, population, disease rates, and concentration-response relationships from the forthcoming 2019 Global Burden of Disease, to generate ozone-attributable mortality rates in cities worldwide. Results will include the number and rate of ozone-attributable respiratory mortality in hundreds of cities around the world, including temporal trends from 1990 to 2017. Preliminary results for the year 2017 demonstrate that the 6-month average of the 8-hour daily maximum ozone concentration ranges 3.5-fold (25.91 to 91.40 ppb) across the most populated 250 cities worldwide, and we expect greater heterogeneity in ozone-related health impacts since disease rates also vary. By using methods that are consistent across cities, we can compare how urban ozone mortality trends differ for cities that have experienced different patterns of growth and regulation. Our results will provide an improved understanding of the range in ozone concentrations and their associated disease burden in cities worldwide, which can be used to inform air pollution and climate change mitigation actions by individual cities and across cities that are members of urban sustainability networks.