OH Reactivity Observations during the MAPS-Seoul Campaign: Contrasts between Urban and Suburban Environments

Abstract:

Direct total OH reactivity was observed in the urban and suburban environments of Seoul, South Korea using a comparative reactivity method (CRM) during the MAPS-Seoul field campaign. In addition, CO, NO_x, SO₂, ozone, VOCs, aerosol, physical, and chemical parameters were also deployed. By comparing the observed total OH reactivity results with calculated OH reactivity from the trace gas observational datasets, we will evaluate our current status in constraining reactive gases in the urban and suburban environments in the East Asian megacity. Observed urban OH reactivity will be presented in the context of the ability to constrain anthropogenic reactive trace gas emissions. It will then be compared to the observed suburban results from Taehwa Research Forest (located ~ 50 km from the Seoul City Center). Our understanding of reactive trace gases in an environment of high BVOC emissions in a mildly aged anthropogenic influences will be evaluated. Using an observational constrained box model with detailed VOC oxidation schemes (e.g. MCM), we will discuss: 1) what is the amount of missing OH reactivity 2) what are the potential sources of the missing OH reactivity, and 3) what are the implications on regional air quality?