Temporal variations of black carbon in Guangzhou, China, in summer 2006

Verma, R. L.; Sahu, L. K.; Kondo, Yutaka; Takegawa, N.; Han, Sung‐Hee; Jung, Jinsang; Kim, Y. J.; Fan, SJ; Sugimoto, Naoki; Shammaa, M. Haitham; Zhang, Y. H.; Zhao, Yibing

doi:10.5194/acp-10-6471-2010

Cited by 66 publications

(62 citation statements)

References 66 publications

(63 reference statements)

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“…This ratio is consistent with a fossil-fuel-dominated carbonaceous aerosol, as is typically observed at urban sites, e.g. 5.7 ± 0.9 (Tokyo; Kondo et al, 2006), 5.4 ± 0.4 (Guangzhou;Verma et al, 2010), 5.8 ± 1.0 (Houston, Dallas; Spackman et al, 2008), and 3.5-5.8 (Beijing; Han et al, 2009), and somewhat lower than values found for periods when urban air masses are polluted by diesel traffic emissions: 7.9 ± 0.2 (Guangzhou; Andreae et al, 2008b), 7.7 ± 0.2 (Beijing, fall; Wang et al, 2011), and 8.4 ± 0.4 (North China Plain; Wang et al, 2011) (Table 3).…”

Section: Polluted Winter Airsupporting

confidence: 86%

Long-term measurements (2010–2014) of carbonaceous aerosol and carbon monoxide at the Zotino Tall Tower Observatory (ZOTTO) in central Siberia

et al. 2017

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Abstract. We present long-term (5-year) measurements of particulate matter with an upper diameter limit of ∼ 10 µm (PM 10 ), elemental carbon (EC), organic carbon (OC), and water-soluble organic carbon (WSOC) in aerosol filter samples collected at the Zotino Tall Tower Observatory in the middle-taiga subzone (Siberia). The data are complemented with carbon monoxide (CO) measurements. Air mass back trajectory analysis and satellite image analysis were used to characterise potential source regions and the transport pathway of haze plumes. Polluted and background periods were selected using a non-parametric statistical approach and analysed separately. In addition, near-pristine air masses were selected based on their EC concentrations being below the detection limit of our thermal-optical instrument. Over the entire sampling campaign, 75 and 48 % of air masses in winter and in summer, respectively, and 42 % in spring and fall are classified as polluted. The observed background concentrations of CO and EC showed a sine-like behaviour with a period of 365 ± 4 days, mostly due to different degrees of dilution and the removal of polluted air masses arriving at the Zotino Tall Tower Observatory (ZOTTO) from remote sources. Our analysis of the near-pristine conditions shows that the longest periods with clean air masses were observed in summer, with a frequency of 17 %, while in wintertime only 1 % can be classified as a clean. Against a background of low concentrations of CO, EC, and OC in the near-pristine summertime, it was possible to identify pollution plumes that most likely came from crude-oil production sites located in the oil-rich regions of Western Siberia. Overall, our analysis indicates that most of the time the Siberian region is impacted by atmospheric pollution arising from biomass burning and anthropogenic emissions. A relatively clean atmosphere can be observed mainly in summer, when polluted species are removed by precipitation and the aerosol burden returns to near-pristine conditions.

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Section: Polluted Winter Airsupporting

confidence: 86%

Long-term measurements (2010–2014) of carbonaceous aerosol and carbon monoxide at the Zotino Tall Tower Observatory (ZOTTO) in central Siberia

et al. 2017

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“…However, the lower BC/ CO ratio obtained over megacities such as Beijing and Shanghai is due to the higher number of gasoline and diesel vehicles (Zhou et al, 2009). The ratios obtained at Lumbini are within the range of emission ratios from diesel used in transport sector (0.0013-0.055), coal (0.0019-0.0572) and biofuels (0.0087-0.0266) for domestic activities (Verma et al, 2010, and references therein), implying that BC and CO observed are from mixed sources.…”

Section: Meteorologysupporting

confidence: 61%

Pre-monsoon air quality over Lumbini, a world heritage site along the Himalayan foothills

et al. 2017

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Abstract. Lumbini, in southern Nepal, is a UNESCO world heritage site of universal value as the birthplace of Buddha. Poor air quality in Lumbini and surrounding regions is a great concern for public health as well as for preservation, protection and promotion of Buddhist heritage and culture. We present here results from measurements of ambient concentrations of key air pollutants (PM, BC, CO, O 3 ) in Lumbini, first of its kind for Lumbini, conducted during an intensive measurement period of 3 months (April-June 2013) in the pre-monsoon season. The measurements were carried out as a part of the international air pollution measurement campaign; SusKat-ABC (Sustainable Atmosphere for the Kathmandu Valley -Atmospheric Brown Clouds). The main objective of this work is to understand and document the level of air pollution, diurnal characteristics and influence of open burning on air quality in Lumbini. The hourly average concentrations during the entire measurement campaign ranged as follows: BC was 0.3-30.0 µg m −3 , PM 1 was 3.6-197.6 µg m −3 , PM 2.5 was 6.1-272.2 µg m −3 , PM 10 was 10.5-604.0 µg m −3 , O 3 was 1.0-118.1 ppbv and CO was 125.0-1430.0 ppbv. These levels are comparable to other very heavily polluted sites in South Asia. Higher fraction of coarsemode PM was found as compared to other nearby sites in the Indo-Gangetic Plain region. The BC / CO ratio obtained in Lumbini indicated considerable contributions of emissions from both residential and transportation sectors. The 24 h average PM 2.5 and PM 10 concentrations exceeded the WHO guideline very frequently (94 and 85 % of the sampled period, respectively), which implies significant health risks for the residents and visitors in the region. These air pollutants exhibited clear diurnal cycles with high values in the morning and evening. During the study period, the worst air pollution episodes were mainly due to agro-residue burning and regional forest fires combined with meteorological conditions conducive of pollution transport to Lumbini. Fossil fuel combustion also contributed significantly, accounting for more than half of the ambient BC concentration according to aerosol spectral light absorption coefficients obtained in Lumbini. WRF-STEM, a regional chemical transport model, was used to simulate the meteorology and the concentrations of pollutants to understand the pollutant transport pathways. The model estimated values were ∼ 1.5 to 5 times lower than the observed concentrations for CO and PM 10 , respectively. Model-simulated regionally tagged CO tracers showed that the majority of CO came from the upwind region of Ganges Valley. Model performance needs significant improvement Published by Copernicus Publications on behalf of the European Geosciences Union.

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“…Much research has focused on these experimental results (Verma et al, 2010;Fan et al, 2011). In this study, the observations at Guangzhou site ( Fig.…”

Section: Data Descriptionmentioning

confidence: 96%

Accessing the Impact of Sea-Salt Emissions on Aerosol Chemical Formation and Deposition over Pearl River Delta, China

Liu

Zhang

Fan

et al. 2015

Aerosol Air Qual. Res.

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Sea-salt aerosol (SSA) emissions have a significant impact on aerosol pollution and haze formation in the coastal areas. In this study, the Models-3/CMAQ modeling system was utilized to access the impact of SSA emissions on aerosol chemical formation and deposition over Pearl River Delta (PRD), China in July 2006. More SSAs were transported inland from the open-ocean under the southeast wind in summertime. Two experiments (with and without SSA emissions in the CMAQ model) were set up to compare the modeling results with each other. The results showed that the increase of sulfate concentrations was more attributable to the primary emissions of coarse SO 4 2-particles in SSA, while the increase of nitrate concentrations were more attributable to secondary chemical formations, known as the mechanisms of chloride depletion in SSA. In the coastal areas, 17.6 % of SO 4 2-, 26.6% of NO 3 -and 38.2% of PM 10 concentrations were attributed to SSA emissions, while those portions were less than 1% in the inland areas. The increases of PM 10 and its components due to SSA emissions resulted in higher deposition fluxes over PRD, particularly in the coastal areas, except for the wet deposition of nitrate. Nitrate was more sensitive to SSA emissions in chemical formations than sulfate and dry deposition of aerosol was also more sensitive than that for wet deposition. Process analysis of sulfate and nitrate was applied to find out the difference of physical and chemical mechanisms between Guangzhou (the inland areas) and Zhuhai (the coastal areas). The negative contributions of dry deposition process to both sulfate and nitrate concentrations increased if SSA emissions were taken into account in the model, especially in Zhuhai. The negative contributions of cloud process also increased due to cloud scavenging and wet deposition process. In the coastal area, the gas-to-particle conversions became more active with high contributions of aerosol process to nitrate concentrations.

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Temporal variations of black carbon in Guangzhou, China, in summer 2006

Cited by 66 publications

References 66 publications

Long-term measurements (2010–2014) of carbonaceous aerosol and carbon monoxide at the Zotino Tall Tower Observatory (ZOTTO) in central Siberia

Long-term measurements (2010–2014) of carbonaceous aerosol and carbon monoxide at the Zotino Tall Tower Observatory (ZOTTO) in central Siberia

Pre-monsoon air quality over Lumbini, a world heritage site along the Himalayan foothills

Accessing the Impact of Sea-Salt Emissions on Aerosol Chemical Formation and Deposition over Pearl River Delta, China

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