Observations of atmospheric oxidation and ozone production in South Korea

South Korea routinely experiences poor air quality with ozone and small particles exceeding standards. To build a better understanding of this problem, in 2016, the KORea-United States cooperative Air Quality (KORUS-AQ) study collected surface airborne measurements many chemical species, including reactive gases hydroxyl (OH) hydroperpoxyl (HO2). Several different results are reported here. First, OH HO2 measured on NASA DC-8 agree to within uncertainties values calculated by two box models, both statistical comparisons as function altitude from 8 km. These show substantial scatter, likely due variability instrument performance difficulty interpolating made frequencies those model time step. Second, uptake aerosol mechanism inconsistent observations. Third, planetary boundary layer over ocean land, model-calculated reactivity sometimes different, missing reactivity, which is much ∼4 s−1, increased April June originated primarily Korean peninsula. Fourth, repeated missed approaches at Seoul Base during several days that changes sum nitrogen dioxide consistent production rates either observed or modeled Langley Research Center model.