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Effect of climate variability on air quality in East Asia
Rokjin J. Park,Jaein I. Jeong,Seungun Lee,Sang-Wook Yeh,Minjoong J. Kim 한국대기환경학회 2021 한국대기환경학회 학술대회논문집 Vol.2021 No.10
In a warming climate, temperature increases might result in exacerbation of regional air quality driven by increasing precursor emissions from wildfires and vegetations, along with favorable meteorological conditions for fostering chemical reactions and piling up air pollutants in the boundary layer. In addition, natural climate variability, including monsoon, ENSO, and so on, is a key factor for determining year-to-year variability of regional air quality in East Asia, and is also susceptible to future climate change. A complex interaction between air quality and climate is thus very important for us to predict what the future air quality would be in a warming climate and requires a better understanding. Here we use the global chemical transport model, GEOS-Chem, driven by assimilated meteorological data to examine underlying mechanisms for air quality changes in East Asia modulated by climate variability in the past. We also extend our analysis in the future to address a possible climate penalty solely driven by meteorological conditions under global warming with no precursor emission change.
시베리아 산불이 2003년 봄철 동아시아 오존 농도에 끼치는 영향 연구
박록진(Rokjin J. Park),정재인(Jaein I. Jeong),윤대옥(Daeok Youn) 한국기상학회 2009 대기 Vol.19 No.3
Global climate warming induced by long-lived greenhouse gases is expected to cause increases in wildfire frequencies and intensity in boreal forest regions of mid- and high-latitudes in the future. Siberian forest fires are one of important sources for air pollutants such as ozone and aerosols over East Asia. Thus an accurate quantification of forest fire influences on air quality is crucial, in particular considering its higher occurrences expected under the future warming climate conditions. We here use the 3-D global chemical transport model (GEOS-Chem) with the satellite constrained fire emissions to quantify Siberian fire effects on ozone concentrations in East Asia. Our focus is mainly on spring 2003 when the largest fires occurred over Siberia in the past decade. We first evaluated the model by comparing to the EANET observations. The model reproduced observed ozone concentrations in spring 2003 with the high R² of 0.77 but slightly underestimated by 20%. Enhancements in seasonal mean ozone concentrations were estimated from the difference in simulations with and without Siberian fires and amounted up to 24 ppbv over Siberia. Effects of Siberian fires also resulted in 3-10 ppbv incresases in Korea and Japan. These increases account for about 5-15% of the ozone air quality standard of 60 ppbv in Korea, indicating a significant effect of Siberian fires on ozone concentrations. We found however that possible changes in regional meteorology due to Siberian fires may also affect air quality. Further study on the interaction between regional air quality and meteorology is necessary in the future.
Computational fluid dynamics simulation of reactive fine particulate matter in a street canyon
Kim, Minjoong J.,Park, Rokjin J.,Kim, Jae-Jin,Park, Sung Hoon,Chang, Lim-Seok,Lee, Dae-Gyun,Choi, Jin-Young Elsevier 2019 Atmospheric environment Vol.209 No.-
<P><B>Abstract</B></P> <P>We developed a coupled computational fluid dynamics–chemistry model to examine the transport and chemical transformation of reactive aerosols on an urban street. The model was evaluated by comparing the results of simulations with those of observational campaigns in a street canyon in Elche, Spain. The model generally captured the composition of fine particulate matter (PM<SUB>1</SUB>) in the street canyon in summer and winter. However, compared with the observed concentration of PM<SUB>1</SUB> in summer, the simulated concentration of PM<SUB>1</SUB> was overestimated by 40%, indicating that the model predicted a weaker canyon vortex. Although the model has some bias, it reasonably reproduced the observed aerosol concentration. We also investigated the diurnal variations and spatial distribution of PM<SUB>1</SUB> and its composition in the street canyon. The simulated sulfate concentrations were mostly affected by boundary transport, showing weak diurnal variations. The nitrate aerosol concentrations exhibited clear sinusoidal diurnal variations following the precursor gas, HNO<SUB>3</SUB>, which is mainly formed by photochemical reactions. We also found that nitrate aerosol formation was suppressed by low O<SUB>3</SUB> concentrations under extreme volatile organic compound-limited conditions. The concentrations of PM<SUB>1</SUB>, organic carbon, and black carbon followed traffic volume curves, indicating the dominant effect of vehicular emissions on aerosols. Our sensitivity model simulation showed that considering chemical reactions significantly affects the diurnal variations of secondarily produced aerosol concentrations. These results clearly demonstrate that considering chemical production and loss is essential to investigate the diurnal variations of PM<SUB>1</SUB> in street canyons, especially in winter.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We developed a coupled CFD–chemistry model for reactive aerosols. </LI> <LI> PM<SUB>1</SUB> followed the variations of carbonaceous aerosols in a street canyon. </LI> <LI> Low O<SUB>3</SUB> concentrations suppressed nitrate aerosol formation. </LI> <LI> Considering chemical reactions affects the diurnal variations of aerosol. </LI> </UL> </P>
Future ozone and oxidants change under the RCP scenarios
Kim, Minjoong J.,Park, Rokjin J.,Ho, Chang-Hoi,Woo, Jung-Hun,Choi, Ki-Chul,Song, Chang-Keun,Lee, Jae-Bum Elsevier 2015 Atmospheric environment Vol.101 No.-
<P><B>Abstract</B></P> <P>We investigate ozone air quality changes in 2050 caused by global changes in climate and anthropogenic emissions of ozone precursors by using a global chemical transport model driven by meteorological fields from a general circulation model. We use projected emissions based on the Representative Concentration Pathway (RCP) scenarios and conduct model simulations to quantify the effects of climate and emission changes on future air quality, focusing on ozone in surface air. Our model results show that annual mean concentrations of surface ozone will be lower in 2050 relative to 2000 by −3.3, −3.7, and −4.2 ppbv under RCP6.0, RCP4.5, and RCP2.6, respectively. In contrast, the RCP8.5 projection results in a slight increase of 2.1 ppbv caused by a methane increase. The ozone reductions are driven primarily by decreases in NO<SUB>x</SUB> emission, which dominate the climate penalty on ozone driven by temperature increases. We also estimate the effect of 21st century climate change on ozone air quality, assuming no changes in anthropogenic emissions of ozone precursors in the future. We further use a statistical method to analyze the results in order to quantify the effect of each meteorological variable change on ozone concentration in summer. Temperature increase is found to result in ozone increases of up to 2.2 ppbv over land. Ozone over the oceans, however, is largely reduced with specific humidity increase, particularly in the Northern Hemisphere, where the ozone concentration decreases by 0.8 ppbv. We find that future increases in natural NO<SUB>x</SUB> emissions from lightning and soil make an important contribution to the formation of nitric acid and might seriously offset future decreases in nitrogen deposition caused by anthropogenic NO<SUB>x</SUB> emission reduction.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We developed a new linking tool between GEOS-Chem and CESM. </LI> <LI> We investigate ozone air quality changes in 2050 relative to 2000. </LI> <LI> Annual surface ozone changes in 2050 are −4.2–+2.1 ppbv under RCP scenarios. </LI> <LI> Natural NO<SUB>x</SUB> emissions might seriously affect future nitrogen deposition. </LI> </UL> </P>