2005-2016 trends in OMI formaldehyde column over the Indian Subcontinent: changing anthropogenic and biomass burning emissions of volatile organic compounds

Air pollution contributes to the premature death of an estimated 2 million people in India every year, but the underlying emissions and their changes over time are poorly quantified. Major sources of volatile organic compounds (VOCs) contributing to ozone and aerosol formation over India include urban emissions from vehicles and industry, biomass combustion emissions from cooking, heating and crop residue burning, and natural emissions from vegetation. Here we use HCHO column measurements from the OMI satellite sensor to quantify the 2005-2016 trends in HCHO columns over the Indian subcontinent, and interpret those trends in terms of changing VOC emissions. After correcting for the interannual variability associated with biogenic emissions, we find a statistically robust upward trend in HCHO columns over the subcontinent (~0.6 %/year) that is strongest in the pre-monsoon season (~1.4 %/year). The derived HCHO trends exhibit significant variability by region and time of year. Bottom-up anthropogenic VOC emissions from the CEDS inventory likewise predict an increase over this period (~3 %/year), but one that is relatively uniform spatially and throughout the year. This presentation will assess the importance of different anthropogenic and biomass burning VOC emission sources in driving the observed HCHO trends.