Meteorology—Atmospheric Chemistry and Long Range Transport

Abstract. As a part of the IGAC (International Global Atmospheric Chemistry) Mega-cities program, aerosol physical and optical properties were continuously measured from March 2007 to March 2008 at an urban site (37.57° N, 126.94° E) in Seoul, Korea. Spectral optical properties of long-range transported Asian dust and pollution aerosols have been investigated based on the year long measurement data. Optically measured black carbon/thermally measured elemental carbon (BC/EC) ratio showed clear monthly variation with high values in summer and low values in winter mainly due to the enhancement of light attenuation by the internal mixing of EC. Novel approach has been suggested to retrieve the spectral light absorption coefficient (babs) from Aethalometer raw data by using BC/EC ratio. Mass absorption efficiency, σabs (=babs/EC) at 550 nm was determined to be 9.0±1.3, 8.9±1.5, 9.5±2.0, and 10.3±1.7 m2 g−1 in spring, summer, fall, and winter, respectively with an annual mean of 9.4±1.8 m2 g−1. Threshold values to classify severe haze events were suggested in this study. Increasing trend of aerosol single scattering albedo (SSA) with wavelength was observed during Asian dust events while little spectral dependence of SSA was observed during long-range transport pollution (LTP) events. Satellite aerosol optical thickness (AOT) and Hysplit air mass backward trajectory analyses as well as chemical analysis were performed to characterize the dependence of spectral optical properties on aerosol type. Results from this study can provide useful information for studies on regional air quality and aerosol's effects on climate change.

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Atmospheric Chemistry Experiment (ACE) measurements of elevated Southern Hemisphere upper tropospheric CO, C2H6, HCN, and C2H2mixing ratios from biomass burning emissions and long-range transport

Geophysical Research Letters ◽

10.1029/2005gl024214 ◽

2005 ◽

Vol 32 (20) ◽

Cited By ~ 47

Author(s):

Curtis P. Rinsland

Keyword(s):

Southern Hemisphere ◽

Long Range ◽

Biomass Burning ◽

Atmospheric Chemistry ◽

Long Range Transport ◽

Range Transport ◽

Chemistry Experiment

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Impacts of transported background ozone on California air quality during the ARCTAS-CARB period – a multi-scale modeling study

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-10-12079-2010 ◽

2010 ◽

Vol 10 (5) ◽

pp. 12079-12131 ◽

Cited By ~ 1

Author(s):

M. Huang ◽

G. R. Carmichael ◽

B. Adhikary ◽

S. N. Spak ◽

S. Kulkarni ◽

...

Keyword(s):

Air Quality ◽

Long Range ◽

Atmospheric Chemistry ◽

Temporal Variations ◽

Eastern Pacific ◽

Long Range Transport ◽

Northern California ◽

Multi Scale ◽

Background Ozone ◽

Range Transport

Abstract. Multi-scale tracer and full-chemistry simulations with the STEM atmospheric chemistry model are used to analyze the effects of transported background ozone (O3) from the eastern Pacific on California air quality during the ARCTAS-CARB experiment conducted in June 2008. Previous work has focused on the importance of long-range transport of O3 to North America air quality in springtime. However during this summer experiment the long-range transport of O3 is also shown to be important. Simulated and observed O3 transport patterns from the coast to inland northern California are shown to vary based on meteorological conditions and the oceanic O3 profiles, which are strongly episodically affected by Asian inflows. Analysis of the correlations of O3 at various altitudes above the coastal site at Trinidad Head and at a downwind surface site in northern California, show that under long-range transport events, high O3 air-masses (O3>60 ppb) at altitudes between about 2 and 4 km can be transported inland and can significantly influence surface O3 20–30 h later. These results show the importance of characterizing the vertical structure of the lateral boundary conditions (LBC) needed in air quality simulations. The importance of the LBC on O3 prediction during this period is further studied through a series of sensitivity studies using different forms of LBC. It is shown that the use of the LBC downscaled from RAQMS global model that assimilated MLS and OMI data improves the model performance. We also show that the predictions can be further improved through the use of LBC based on NASA DC-8 airborne observations during the ARCTAS-CARB experiment. These results indicate the need to develop observational strategies to improve the representation of the vertical and temporal variations in the air over the eastern Pacific.

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Impact of emissions and long-range transport on Air Quality in Delhi

10.5194/egusphere-egu2020-8354 ◽

2020 ◽

Author(s):

Ailish Graham ◽

Richard Pope ◽

Martyn Chipperfield ◽

Ellen Stirling

Keyword(s):

Air Quality ◽

Long Range ◽

Atmospheric Chemistry ◽

Capital City ◽

Long Range Transport ◽

Back Trajectories ◽

Relative Contribution ◽

Range Transport ◽

Regional Emissions ◽

Tract Infections

Delhi is the world&#8217;s most polluted capital city, with annual mean concentrations of PM2.5, O3 and NO2 well above the safe legal limits for Europe. Exposure to these pollutants over short and long-time scales is associated with increases in diseases such as heart disease, stroke and lower respiratory tract infections. Local NO2 concentrations vary by month and season and are controlled by both emissions and meteorology. Locally, vehicle pollution contributes to 67% of the total air pollution load and 48% of NOx. The vehicle population has increased substantially in recent years due to an increase in the number of vehicles travelling into Delhi each day from surrounding areas. High pollution episodes, especially in winter, also contribute to the high annual mean observed. This may be due to the trapping of pollutants in a shallow, stable boundary layer or through the long-range transport of pollutants from surrounding regions to Delhi under favourable wind directions. However, the relative contribution of local vs regional emissions has not been quantified previously. This inhibits the introduction of targeted policies to reduce concentrations in the city.We use observational datasets to quantify the relative contribution of local and regional emissions to local NO2 air quality in Delhi rather than running a computationally expensive atmospheric chemistry transport model (Stirling et al., 2020). We combine satellite data from the TROPOMI instrument on the Sentinel 5 &#8211; Precursor (S5P) platform with back-trajectories, from the Reading Offline Trajectory Model (ROTRAJ). This allows us to investigate how different wind directions affect the relative contributions of local and regional NO2 pollution to Delhi NO2. We will then quantify the contribution of different regions and sectors to NO2 in Delhi by combining the back-trajectories with a high resolution emission inventory for India and Delhi. This method also allows us to consider future emission control scenarios and quantify their impacts on air quality in Delhi.&#160;

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Impacts of transported background ozone on California air quality during the ARCTAS-CARB period – a multi-scale modeling study

Atmospheric Chemistry and Physics ◽

10.5194/acp-10-6947-2010 ◽

2010 ◽

Vol 10 (14) ◽

pp. 6947-6968 ◽

Cited By ~ 55

Author(s):

M. Huang ◽

G. R. Carmichael ◽

B. Adhikary ◽

S. N. Spak ◽

S. Kulkarni ◽

...

Keyword(s):

Air Quality ◽

Long Range ◽

Atmospheric Chemistry ◽

Three Dimensional ◽

Model Performance ◽

Long Range Transport ◽

Northern California ◽

Multi Scale ◽

Background Ozone ◽

Range Transport

Abstract. Multi-scale tracer and full-chemistry simulations with the STEM atmospheric chemistry model are used to analyze the effects of transported background ozone (O3) from the eastern Pacific on California air quality during the ARCTAS-CARB experiment conducted in June, 2008. Previous work has focused on the importance of long-range transport of O3 to North America air quality in springtime. However during this summer experiment the long-range transport of O3 is also shown to be important. Simulated and observed O3 transport patterns from the coast to inland northern California are shown to vary based on meteorological conditions and the O3 profiles over the oceans, which are strongly episodically affected by Asian inflows. Analysis of the correlations of O3 at various altitudes above the coastal site at Trinidad Head and at a downwind surface site in northern California, show that under long-range transport events, high O3 air-masses (O3>60 ppb) at altitudes between about 2 and 4 km can be transported inland and can significantly influence surface O3 20–30 h later. These results show the importance of characterizing the vertical structure of the lateral boundary conditions (LBC) needed in air quality simulations. The importance of the LBC on O3 prediction during this period is further studied through a series of sensitivity studies using different forms of LBC. It is shown that the use of the LBC downscaled from RAQMS global model that assimilated MLS and OMI data improves the model performance. We also show that the predictions can be further improved through the use of LBC based on NASA DC-8 airborne observations during the ARCTAS-CARB experiment. These results indicate the need to develop observational strategies to provide information on the three-dimensional nature of pollutant distributions, in order to improve our capability to predict pollution levels and to better quantify the influence of these Asian inflows on the US west coast air quality.

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

Atmospheric Chemistry and Physics ◽

10.5194/acp-11-3173-2011 ◽

2011 ◽

Vol 11 (7) ◽

pp. 3173-3194 ◽

Cited By ~ 17

Author(s):

M. Huang ◽

G. R. Carmichael ◽

S. N. Spak ◽

B. Adhikary ◽

S. Kulkarni ◽

...

Keyword(s):

Long Range ◽

Atmospheric Chemistry ◽

Surface Ozone ◽

Long Range Transport ◽

Sulfur Oxides ◽

Near Surface ◽

Fire Emissions ◽

Multi Scale ◽

Range Transport ◽

Local Emissions

Abstract. Chronic high surface ozone (O3) levels 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, full-chemistry and adjoint simulations using the STEM atmospheric chemistry model are conducted to assess the contribution of local emission sourcesto SC O3 and to evaluate the impacts of transported sulfur and local emissions on the SC sulfur budgetduring 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. During a long-range transport event from Asia starting from 22 June, high SOx levels (up to ~0.7 ppb of SO2 and ~1.3 ppb of SO4) is observed above ~6 km, but they did not affect CA surface air quality. The elevated SOx observed at 1–4 km is estimated to enhance surface SOx over SC by ~0.25 ppb (upper limit) on ~24 June. The near-surface SOx levels over SC during the flight week are 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 withobservations. 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. Adjoint sensitivity analysis indicated that SO2 levels at 00:00 UTC (17:00 local time) at six SC surface sites were influenced by previous day maritime emissions over the ocean, the terrestrial emissions over nearby urban areas, and by transported SO2 from the north through both terrestrial and maritime areas. Overall maritime emissions contribute 10–70% of SO2 and 20–60% fine SO4 on-shore and over the most terrestrial areas, with contributions decreasing with in-land distance from the coast. Maritime emissions also modify the photochemical environment, shifting O3 production over coastal SC to more VOC-limited conditions. These suggest an important role for shipping emission controls in reducing fine particle and O3 concentrations in SC.

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Spectral optical properties of long-range transport Asian dust and pollution aerosols over Northeast Asia in 2007 and 2008

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-10-2397-2010 ◽

2010 ◽

Vol 10 (2) ◽

pp. 2397-2444 ◽

Cited By ~ 1

Author(s):

J. Jung ◽

Y. J. Kim ◽

K. Y. Lee ◽

M. G. -Cayetano ◽

T. Batmunkh ◽

...

Keyword(s):

Optical Properties ◽

Long Range ◽

Atmospheric Chemistry ◽

Light Attenuation ◽

Measurement Data ◽

Absorption Efficiency ◽

Asian Dust ◽

Urban Site ◽

Long Range Transport ◽

Range Transport

Abstract. As a part of the IGAC (International Global Atmospheric Chemistry) Mega-cities program, aerosol physical and optical properties were continuously measured from March 2007 to March 2008 at an urban site (37.57° N, 126.94° E) in Seoul, Korea. Spectral optical properties of long-range transported Asian dust and pollution aerosols have been investigated based on the year long measurement data. Optically measured black carbon/thermally measured elemental carbon (BC/EC) ratio showed clear monthly variation with high values in summer and low values in winter mainly due to the enhancement of light attenuation by the internal mixing of EC. Novel approach has been suggested to retrieve the spectral light absorption coefficient (babs) from Aethalometer raw data by using BC/EC ratio. Mass absorption efficiency, σabs(=babs/EC) at 550 nm at the measurement site was determined to be 9.0±1.3, 8.9±1.5, 9.5±2.0, and 10.3±1.7 m2 g−1 in spring, summer, fall, and winter, respectively with an annual mean of 9.4±1.8 m2 g−1. Threshold values to classify severe haze events were suggested in this study. Increasing trend of aerosol single scattering albedo (SSA) with wavelength was observed during Asian dust events while little spectral dependence of SSA was observed during long-range transport pollution (LTP) events. Satellite aerosol optical thickness (AOT) and Hysplit air mass backward trajectory analyses as well as chemical analysis were performed to characterize the dependence of spectral optical properties on aerosol type. Results from this study can provide useful information for studies on regional air quality and aerosol's effects on climate change.

Download Full-text