Regional climate feedbacks in Central Chile and their effect on air quality episodes and meteorology

• Recent trends in air quality and emissions in Santiago, Chile are described.
• Current and future air quality episodes are compared using a forecasting model.
• WRF-Chem is used to estimate regional warming due to black carbon aerosol feedbacks.
• Black carbon is shown to warm the Andes mountain range up to 0.4 °C in temperature.
• Regional emissions of SO2 are shown to generate coastal cooling of up to 1 °C.

Santiago, an emerging megacity of 7 million plus inhabitants has shown great improvement in its air quality reducing PM2.5 concentrations from 69 μg/m3 in 1989 to 24 μg/m3 in 2013 with a comprehensive air quality management strategy. An operational air quality forecasting model that has shown great potential in predicting air quality episodes is used to establish how the climate A1B scenario can impact the frequency of bad air days. In comparison to 2011, in 2050 extreme air quality episodes will be reduced in 20%. WRF-Chem is used to evaluate the effect of anthropogenic emissions on the regional climate including aerosol radiative feedbacks for October–November 2008. Anthropogenic emissions of sulfur and black carbon show different geographical patterns which result in local cooling (0.2–1 °C) in coastal Chile, due to large sources of SO2. Central Chile, where most of the population of the country lives, shows transportation of black carbon emissions into the Andes mountain range, resulting in local warming of 0.4 °C. While global forcings may cause regional heating for 2050, reducing current black carbon emissions in Central Chile can reduce anthropogenic warming with immediate benefits to the regional climate, and simultaneously reducing local air pollution.