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Air inequality: Global Divergence in Urban Fine Particulate Matter
JOSHUA S. APTE, Sarah Seraj, Sarah Chambliss, Melanie Hammer, Veronica Southerland, Susan Anenberg, Aaron van Donkelaar, Randall Martin, Michael Brauer, University of California, Berkeley
Abstract Number: 553
Working Group: Urban Aerosols
Abstract
Fine particle air pollution (PM2.5) is the largest global environmental risk factor for ill-health and is implicated in 7-12% of all human deaths. Improved air quality is a key policy goal for cities around the world, yet in-situ PM2.5 measurements are missing for > 50% of the urban population. Here, we use satellite remote sensing of aerosol optical depth constrained by a geophysical model and in-situ observations to develop a 20-year time series of PM2.5 for nearly all urban areas in the world with year-2010 population exceeding 100,000 people, encompassing 2.9 billion people in 4231 cities. Over this period, we find a growing divide in urban air quality between lower-income and higher-income world regions, with the PM2.5 disparity increasing by > 50% between the highest- and lowest income quartiles of world cities. Within Asia, a sharp divergence is underway, with sustained increases in urban PM2.5 in South Asia (+48%) contrasted against dramatic improvements in Chinese cities (-40% since 2011). While 85% of the world's urban population experiences PM2.5 higher than World Health Organization guidelines, urban PM2.5 concentrations are tightly linked to regional conditions, suggesting that city-level efforts alone may be insufficient to address this major health threat.