Air quality and human health improvements from reduced deforestation in Brazil

Thursday, 17 December 2015: 11:20
3001 (Moscone West)
Carly Reddington, University of Leeds, Leeds, United Kingdom, Edward William Butt, University of Leeds, Institute for Climate and Atmospheric Science, School of Earth and Environment, Leeds, United Kingdom, David A Ridley, Massachusetts Institute of Technology, Cambridge, MA, United States, Paulo Artaxo, USP University of Sao Paulo, São Paulo, Brazil, William Morgan, University of Manchester, Manchester, M13, United Kingdom, Hugh Coe, University of Manchester, School of Earth, Atmospheric and Environmental Sciences, Manchester, United Kingdom and Dominick V Spracklen, University of Leeds, School of Earth and Environment, Leeds, United Kingdom
Significant areas of the Brazilian Amazon have been deforested over the past few decades, with fire being the dominant method through which forests and vegetation are cleared. Fires emit large quantities of particulate matter into the atmosphere, degrading air quality and negatively impacting human health. Since 2004, Brazil has achieved substantial reductions in deforestation rates and associated deforestation fires. Here we assess the impact of this reduction on air quality and human health. We show that dry season (August – October) aerosol optical depth (AOD) retrieved by satellite over southwest Brazil and Bolivia is positively related to Brazil’s annual deforestation rate (r=0.96, P<0.001). Observed dry season AOD is more than a factor two greater in years with high deforestation rates compared to years with low deforestation rates, suggesting regional air quality is degraded substantially by fire emissions associated with deforestation. This link is further demonstrated by the positive relationship between observed AOD and satellite-derived particulate emissions from deforestation fires (r=0.89, P<0.01). Using a global aerosol model with satellite-derived fire emissions, we show that reductions in fires associated with reduced deforestation have reduced regional dry season mean surface particulate matter concentrations by ~30%. Using concentration response functions we estimate that this reduction in particulate matter may be preventing 1060 (388-1721) premature adult mortalities annually across South America. Future increases in Brazil’s deforestation rates and associated fires may threaten the improved air quality reported here.