Abstract

In this work, we compare for the first time different anthropogenic NOx emission inventories and examine the associate variation in simulated surface ozone (O₃) in India. Six anthropogenic NOX emission inventories namely Emission Database for Global Atmospheric Research (EDGAR), Intercontinental ... Show moreIn this work, we compare for the first time different anthropogenic NOx emission inventories and examine the associate variation in simulated surface ozone (O₃) in India. Six anthropogenic NOX emission inventories namely Emission Database for Global Atmospheric Research (EDGAR), Intercontinental Chemical Transport Experiment-Phase B (INTEX-B), Regional Emission Inventory in Asia (REAS), MACCity, Indian National Emission Inventory (India_NOx), and Top-Down NOx emission inventory for India (Top-Down) are included in the comparison. We include these emission inventories in regional chemical transport model WRF-Chem to simulate tropospheric column NO₂ and surface O₃ mixing ratios for the month of summer (15-March to 15-April) and winter (December) in 2005. Predicted tropospheric column NO₂ using different NOX emission inventory are evaluated with the OMI satellite observations. All emission inventories show similar spatial features, however uncertainty in NOx emissions distribution is about 20-50% over rural regions and about 60-160% over the major point sources. Compared to OMI, the largest bias in simulated tropospheric NO₂ columns is seen in the REAS (-243.0 ± 338.8 × 1013 molecules cm⁻²) emission inventory, followed by EDGAR (-199.1 ± 272.2 × 1013 molecules cm⁻²), MACCity (-150.5 ± 236.3 × 1013 molecules cm⁻²), INTEX-B (-96.8 ± 199.5 × 1013 molecules cm⁻²), India_NOx (-87.7 ± 159.9 × 10¹³ molecules cm⁻²) and Top-Down (-30.8 ± 69.6 × 10¹³ molecules cm⁻²) inventories during winter. Simulations using different NOx emission inventories produces maximum deviation in daytime 8-h averaged O₃ of the order of 9-17 ppb (15-40%) in summer and 3-12 ppb (5-25%) in winter over most of the land area. The simulation suggests that choice of NOx emission inventories have significant effect on surface O₃ concentration for air quality studies over India. Show less