Application of Space-Based Glyoxal Observation for Estimating Global Nonmethane Volatile Organic Compounds Emissions from Urban Sources and Biomass Burning

Nonmethane volatile organic compound (NMVOC) pollution severely impacts urban atmospheric quality. We propose a top-down method for estimating NMVOC emissions based on glyoxal-an important oxidation product of NMVOCs observed from space. We applied the wind rotation aggregation and exponential modified Gaussian methods to estimate the glyoxal effective lifetime and production rate in the glyoxal plumes downwind. These methods were applied to 60 cities worldwide, and the effective production rate of glyoxal was screened out in 22 cities, ranging from 0.8 +/- 0.3 to 13.7 +/- 3.3 mol/s. The results indicate significant correlation with total NMVOC emission from bottom-up inventory (r = 0.85, p < 0.01). Additionally, we utilized daily satellite results to identify biomass burning emission sources in Australian fire events. Our research offers a novel perspective on monitoring of urban and transient NMVOC emissions and provides a new data source for emission reduction policymaking.