scholarly journals Elevated Ozone Layers over the Seoul Metropolitan Region in Korea: Evidence for Long-Range Ozone Transport from Eastern China and Its Contribution to Surface Concentrations

2010 ◽  
Vol 49 (2) ◽  
pp. 203-220 ◽  
Author(s):  
In-Bo Oh ◽  
Yoo-Keun Kim ◽  
Mi-Kyung Hwang ◽  
Cheol-Hee Kim ◽  
Soontae Kim ◽  
...  
Keyword(s):  
Long Range ◽  
Transport Process ◽  
Surface Ozone ◽  
Eastern China ◽  
Metropolitan Region ◽  
Long Range Transport ◽  
Pressure System ◽  
Elevated Ozone ◽  
Range Transport ◽  
Seoul Metropolitan Region

Abstract Elevated layers of high ozone concentration were observed over the Seoul metropolitan region (SMR) in Korea by ozonesonde measurements during 6–9 June 2003. An analysis of the synoptic-scale meteorological features and backward trajectories revealed that the layers were associated with the long-range transport of ozone from eastern China. Further examination of the long-range transport process responsible for the development of these layers was performed using the Community Multiscale Air Quality (CMAQ) model. CMAQ demonstrated that the upward mixing of ozone by convective activity in eastern China and subsequent horizontal transport aloft in the periphery of a slow-moving high pressure system led to the development of thick ozone layers over the SMR. Through comparative simulation studies, it was found that the surface ozone levels in the SMR can be significantly enhanced by the vertical down-mixing of ozone from the layer aloft with the growing mixed layer. On average, about 25% of the surface peak concentration in a given area during a high-ozone episode was due to the influence of the ozone layer aloft developed by the long-range transport process.

scholarly journals Seasonal and spatial variability of surface ozone over China: contributions from background and domestic pollution

2011 ◽  
Vol 11 (7) ◽  
pp. 3511-3525 ◽  
Author(s):  
Y. Wang ◽  
Y. Zhang ◽  
J. Hao ◽  
M. Luo
Keyword(s):  
Yangtze River ◽  
Transport Model ◽  
Surface Ozone ◽  
Eastern China ◽  
Long Range Transport ◽  
Anthropogenic Emissions ◽  
Spatial Gradient ◽  
Chemical Transport Model ◽  
Background Ozone ◽  
Range Transport

Abstract. Both observations and a 3-D chemical transport model suggest that surface ozone over populated eastern China features a summertime trough and that the month when surface ozone peaks differs by latitude and region. Source-receptor analysis is used to quantify the contributions of background ozone and Chinese anthropogenic emissions on this variability. Annual mean background ozone over China shows a spatial gradient from 55 ppbv in the northwest to 20 ppbv in the southeast, corresponding with changes in topography and ozone lifetime. Pollution background ozone (annual mean of 12.6 ppbv) shows a minimum in the summer and maximum in the spring. On the monthly-mean basis, Chinese pollution ozone (CPO) has a peak of 20–25 ppbv in June north of the Yangtze River and in October south of it, which explains the peaks of surface ozone in these months. The summertime trough in surface ozone over eastern China can be explained by the decrease of background ozone from spring to summer (by −15 ppbv regionally averaged over eastern China). Tagged simulations suggest that long-range transport of ozone from northern mid-latitude continents (including Europe and North America) reaches a minimum in the summer, whereas ozone from Southeast Asia exhibits a maximum in the summer over eastern China. This contrast in seasonality provides clear evidence that the seasonal switch in monsoonal wind patterns plays a significant role in determining the seasonality of background ozone over China.

scholarly journals Multi-scale modeling study of the source contributions to near-surface ozone and sulfur oxides levels over California during the ARCTAS-CARB period

2010 ◽  
Vol 10 (11) ◽  
pp. 27777-27823 ◽  
Author(s):  
M. Huang ◽  
G. R. Carmichael ◽  
S. N. Spak ◽  
B. Adhikary ◽  
S. Kulkarni ◽  
...  
Keyword(s):  
Long Range ◽  
Surface Ozone ◽  
Long Range Transport ◽  
Sulfur Oxides ◽  
Study Region ◽  
Near Surface ◽  
Fire Emissions ◽  
Multi Scale ◽  
Range Transport ◽  
Local Emissions

Abstract. Chronic ozone (O3) problems and the increasing sulfur oxides (SOx=SO2+SO4) ambient concentrations over South Coast (SC) and other areas of California (CA) are affected by both local emissions and long-range transport. In this paper, multi-scale tracer and full-chemistry simulations with the STEM atmospheric chemistry model are used to assess the contribution of local emission sources to SC O3 and evaluate the impacts of transported sulfur and local emissions on the SC sulfur budget during the ARCTAS-CARB experiment period in 2008. Sensitivity simulations quantify contributions of biogenic and fire emissions to SC O3 levels. California biogenic and fire emissions contribute 3–4 ppb to near-surface O3 over SC, with larger contributions to other regions in CA. Long-range transport from Asia is estimated to enhance surface SO4 over SC by ~0.5 μg/sm3, and the higher SOx levels (up to ~0.7 ppb of SO2 and ~6 μg/sm3 of SO4) observed above ~6 km did not affect surface air quality in the study region. Enhanced near-surface SOx levels over SC during the flight week were attributed mostly to local emissions. Two anthropogenic SOx emission inventories (EIs) from the California Air Resources Board (CARB) and the US Environmental Protection Agency (EPA) are compared and applied in 60 km and 12 km chemical transport simulations, and the results are compared with observations. The CARB EI shows improvements over the National Emission Inventory (NEI) by EPA, but generally underestimates surface SC SOx by about a factor of two. Maritime (mostly shipping) emissions contribute to the high SO2 levels over the ocean and on-shore, and fine SO4 over the downwind areas is impacted by maritime sources. Maritime emissions also modify the NOx-VOC limitations over coastal areas. These suggest an important role for shipping emission controls in reducing fine particle and O3 concentrations in SC.

scholarly journals Long-range transport of anthropogenic air pollutants into the marine air: insight into fine particle transport and chloride depletion on sea salts

2021 ◽  
Vol 21 (23) ◽  
pp. 17715-17726
Author(s):  
Liang Xu ◽  
Xiaohuan Liu ◽  
Huiwang Gao ◽  
Xiaohong Yao ◽  
Daizhou Zhang ◽  
...  
Keyword(s):  
East Asia ◽  
Long Range ◽  
Air Pollutants ◽  
Radiative Forcing ◽  
Eastern China ◽  
Long Range Transport ◽  
Anthropogenic Aerosols ◽  
Range Transport ◽  
Anthropogenic Air Pollutants ◽  
Marine Air

Abstract. Long-range transport of anthropogenic air pollutants from East Asia can affect the downwind marine air quality during spring and winter. Long-range transport of continental air pollutants and their interaction with sea salt aerosol (SSA) significantly modify the radiative forcing of marine aerosols and influence ocean biogeochemical cycling. Previous studies poorly characterize variations of aerosol particles along with air mass transport from the continental edge to the remote ocean. Here, the research ship R/V Dongfanghong 2 traveled from the eastern China seas (ECS) to the northwestern Pacific Ocean (NWPO) to understand what and how air pollutants were transported from the highly polluted continental air to clean marine air in spring. A transmission electron microscope (TEM) was used to find the long-range transported anthropogenic particles and the possible Cl-depletion phenomenon of SSA in marine air. Anthropogenic aerosols (e.g., sulfur (S)-rich, S-soot, S-metal/fly ash, organic matter (OM)-S, and OM coating particles) were identified and dramatically declined from 87 % to 8 % by number from the ECS to remote NWPO. For the SSA aging, 87 % of SSA particles in the ECS were identified as fully aged, while the proportion of fully aged SSA particles in the NWPO decreased to 29 %. Our results highlight that anthropogenic acidic gases in the troposphere (e.g., SO2, NOx, and volatile organic compounds) could be transported to remote marine air and exert a significant impact on aging of SSA particles in the NWPO. The study shows that anthropogenic particles and gases from East Asia significantly perturb different aerosol chemistry from coastal to remote marine air. More attention should be given to the modification of SSA particles in remote marine areas due to the influence of anthropogenic gaseous pollutants.

scholarly journals Long-range transport of anthropogenic air pollutants into the marine air: Insight into fine particle transport and chloride depletion on sea salts

2021 ◽  
Author(s):  
Liang Xu ◽  
Xiaohuan Liu ◽  
Huiwang Gao ◽  
Xiaohong Yao ◽  
Daizhou Zhang ◽  
...  
Keyword(s):  
East Asia ◽  
Long Range ◽  
Air Pollutants ◽  
Eastern China ◽  
Long Range Transport ◽  
Marine Aerosols ◽  
Anthropogenic Aerosols ◽  
Range Transport ◽  
Anthropogenic Air Pollutants ◽  
Marine Air

Abstract. Long-range transport of anthropogenic air pollutants from East Asia can affect the downwind marine air quality during spring and winter. Long-range transport of continental air pollutants and their interaction with sea salt aerosols (SSA) significantly modify the radiative forcing of marine aerosols and influence ocean biogeochemical cycling. Previous studies poorly characterize variations of aerosol particles along with air mass transport from the continental edge to the remote ocean. Here, the research ship R/V Dongfanghong 2 traveled from the eastern China seas (ECS) to the northwestern Pacific Ocean (NWPO) to understand what and how air pollutants were transported from the highly polluted continental air to clean marine air in spring. A transmission electron microscope (TEM) was used to find the long-range transported anthropogenic particles and the possible Cl-depletion phenomenon of SSA in marine air. Primary and secondary anthropogenic aerosols were identified and dramatically declined from 87 % to 8 % by number from the ECS to remote NWPO. For the SSA aging, 86 % of SSA particles in the ECS were identified as fully aged, while the proportion of fully aged SSA particles in the NWPO decreased to 31 %. The result highlights that anthropogenic acidic gases in the troposphere (e.g., SO2, NOx, and volatile organic compounds) were transported longer distances compared to the anthropogenic aerosol and could exert a significant impact on marine aerosols in the NWPO. These results show that anthropogenic particles and gases from East Asia significantly perturb aerosol chemistry in marine air. The optical properties and cloud condensation nucleation of the modified SSA particles should be incorporated into the more accurately modeling of clouds in the ECS and NWPO in spring and winter.

scholarly journals Simulation of long-range transport aerosols from the Asian Continent to Taiwan by a Southward Asian high-pressure system

2008 ◽  
Vol 406 (1-2) ◽  
pp. 168-179 ◽  
Author(s):  
Ming-Tung Chuang ◽  
Joshua S. Fu ◽  
Carey J. Jang ◽  
Chang-Chuan Chan ◽  
Pei-Cheng Ni ◽  
...  
Keyword(s):  
High Pressure ◽  
Long Range ◽  
Long Range Transport ◽  
Asian Continent ◽  
Pressure System ◽  
High Pressure System ◽  
Range Transport

scholarly journals Attribution of future US ozone pollution to regional emissions, climate change, long-range transport, and model deficiency

2014 ◽  
Vol 14 (19) ◽  
pp. 26231-26256 ◽  
Author(s):  
H. He ◽  
X.-Z. Liang ◽  
H. Lei ◽  
D. J. Wuebbles
Keyword(s):  
Climate Change ◽  
Long Range ◽  
Transport Model ◽  
Surface Ozone ◽  
Long Range Transport ◽  
Ozone Pollution ◽  
Model Biases ◽  
Range Transport ◽  
Regional Emissions ◽  
Model Deficiency

Abstract. A regional chemical transport model (CTM) is used to quantify the relative contributions of future US ozone pollution from regional emissions, climate change, long-range transport (LRT) of pollutants, and model deficiency. After incorporating dynamic lateral boundary conditions (LBCs) from a global CTM, the representation of present-day US ozone pollution is notably improved. This nested system projects substantial surface ozone trends for 2050's: 6–10 ppbv decreases under the "clean" A1B scenario and ~15 ppbv increases under the "dirty" A1Fi scenario. Among the total trends, regional emissions changes dominate, contributing negative 20–50% in A1B and positive 20–40% in A1Fi, while LRT effects through chemical LBCs and climate changes account for respectively 15–50% and 10–30% in both scenarios. The projection uncertainty due to model biases is region dependent, ranging from −10 to 50%. It is shown that model biases of present-day simulations can propagate into future projections systematically but nonlinearly, and the accurate specification of LBCs is essential for US ozone projections.

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