Tropospheric NO vertical column densities (VCDs) from ozone monitoring instrument(OMI) were analyzed to evaluate the decrease in NO emissions during two special events, 70th anniversary of the end of World War Ⅱ in 2015 and the G20 summit in 2016. Results showed a positive correlation between NO VCDs and near ground NO emissions and verified that the NO emission control policy during "12 five-year plan" were remarkably effective, with a 24.98% drop in VCDs in five years. At the early stage of "13 five-year plan", in 2016, NO VCDs decreased by 3.18% year-on-year, showing a consistent drop in NO.
