Mixing ratios and sources of halocarbons in urban, semi-urban and rural sites of the Pearl River Delta, South China

Chan, Cheuk-Yin; Jian, Tang; Li, Y.S.; Чан, Лю

doi:10.1016/j.atmosenv.2006.06.041

Cited by 58 publications

(33 citation statements)

References 29 publications

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“…Higher EFs were found for CH 3 I and CH 3 Br which may be a result of non-biomass-burning sources e.g. oceanic emission in the Pacific Ocean (Chan et al, 2006).…”

Section: Discussionmentioning

confidence: 97%

Pollution events observed during CARIBIC flights in the upper troposphere between South China and the Philippines

et al. 2010

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Abstract.A strong pollution episode in the upper troposphere between South China and the Philippines was observed during CARIBIC flights in April 2007. Five pollution events were observed, where enhancements in aerosol and trace gas concentrations including CO, CO 2 , CH 4 , nonmethane hydrocarbons (NMHCs) and halocarbons were observed along the flight tracks during four sequential flights. The importance of the contribution of biomass/biofuel burning was investigated using chemical tracers, emission factor analysis, back-trajectory analysis and satellite images. The Indochinese peninsula was identified as the probable source region of biomass/biofuel burning. However, enhancements in the urban/industrial tracer C 2 Cl 4 during the events also indicate a substantial contribution from urban anthropogenic emissions. An estimation of the contribution of fossil fuel versus biomass/biofuel to the CO enhancement was made, indicating a biomass/biofuel burning contribution of ∼54 to ∼92% of the observed CO enhancements. Biomass/biofuel burning was found to be the most important source category during the sampling period.

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“…Higher EFs were found for CH 3 I and CH 3 Br which may be a result of non-biomass-burning sources e.g. oceanic emission in the Pacific Ocean (Chan et al, 2006).…”

Section: Discussionmentioning

confidence: 97%

Pollution events observed during CARIBIC flights in the upper troposphere between South China and the Philippines

et al. 2010

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“…Severe air pollution, including high levels of toxic volatile organic compounds (Chan et al , 2006Wang et al 2002), airborne particulate matter (PM; Chan et al 2001;Cao et al 2004), nitrogen dioxide (NO 2 ; Richter et al 2005), and photochemical ozone (O 3 ; Chan et al 1998;Wang et al 2001) have been observed on both urban and regional scales in this region, accompanied by the continuous urbanization, industrial development, and rapid growth in road traffic. This phenomenon has been a central focus of the international scientific community (e.g., Jacob et al 2003;Zhang et al 2008) and the general public.…”

Section: Introductionmentioning

confidence: 99%

Change of air quality and its impact on atmospheric visibility in central-western Pearl River Delta

Wan

Lin

Chan

et al. 2010

Environ Monit Assess

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Ambient air quality data, including atmospheric visibility, of Foshan city, a highly polluted city in the Pearl River Delta (PRD), and data obtained by the On-line Air Pollutant Exhaust Monitoring Network (OAPEMN), recently established by the National Emission Monitoring and Control Network for major industrial enterprises, were analyzed and are reported here for the first time, revealing the change in air pollution patterns and its impact on visibility degradation in the last decade. Reduced visibility of less than 8 km (after elimination of rainy and foggy periods) was found 22% of the time from 1998 to 2008, accompanied by elevated levels of pollutants, especially SO₂ and PM₁₀, in comparison with that of other developed cities. However, PM₁₀ showed a steady decreasing trend (0.004 mg m⁻³) year⁻¹) during 2001-2008, in contrast to the noticeable increase in ambient NO₂ concentrations from ~0.020 mg m⁻³ before 2005 to above 0.050 mg m⁻³ afterward. Multiple regression analysis revealed that the percentage of reduced visibility strongly correlated with PM₁₀ concentration, suggesting that visibility degradation was directly proportional to the loading of particles. Moreover, the fairly significant correlation between reduced visibility and NO₂ concentration also implied that the impact of primary emissions of NO₂ and enhanced secondary pollutants, formed via photochemical processes in the atmosphere, could not be ignored. The decreased PM₁₀levels were obviously the predominant factor for the improvement in visibility (5.0% per 0.01 mg m⁻³) and were likely due to the implementation of stricter air pollution control measures for industrial exhaust, which also resulted in reduced SO₂ pollution levels in the recent 2 years. In particular, the OAPEMN records showed an overall enhanced SO₂ removal by 64% in major industrial sectors. The continuous increase in road traffic and lack of efficient NO(x) control strategies in the PRD region, however, caused an increase in ambient NO₂ concentrations.

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“…Many observational and model studies have focused on pollution in the Yangtze River delta Fu et al, 2008;Yin et al, 2009;Gao et al, 2009Gao et al, , 2011Kang et al, 2013) and Pearl River delta regions around the time of their initial, rapid economic development (Zheng et al, 2000;Lee et al, 2001;Cao et al, 2004;Wu et al, 2006;Chan et al, 2006;Chak et al, 2008;Huang et al, 2008a;Tan et al, 2009Tan et al, , 2011. However, the 3JNS region has recently become the most polluted area of the three regions, and is now attracting serious concern (Wang et al, , 2014aChen et al, 2007;Wu et al, 2008;Wei et al, 2010;Duan et al, 2012;Che et al, 2014).…”

Section: H Wang Et Al: Study Of the Interactions Between Aerosols Amentioning

confidence: 99%

Mesoscale modeling study of the interactions between aerosols and PBL meteorology during a haze episode in Jing–Jin–Ji (China) and its nearby surrounding region – Part 1: Aerosol distributions and meteorological features

et al. 2015

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Abstract. The urbanized region ofJing(Beijing)-Jin(Tianjin)-Ji (alias of Hebei province) and its nearby surrounding region (3JNS) is becoming China's most polluted area by haze, exceeding even the Yangtze and Pearl river deltas. Aside from pollutant emission, the meteorology of the planetary boundary layer (PBL) is the most important factor affecting haze pollution. Focusing on July 2008, the aerosol optical properties and PBL meteorology features closely related to haze formation were simulated in the 3JNS region using an online atmospheric chemical transport model. The relationship between regional PBL meteorology, PM 2.5 , and haze is discussed. Model results accurately simulated the aerosol optical depth (AOD), single scattering albedo (SSA) and asymmetry parameter (ASY), validated by comparison with observations from the MODerate Resolution Imaging Spectroradiometer (MODIS), the China Aerosol Remote Sensing NETwork (CARSNET) and the Aerosol Robotic NETwork (AERONET). Modeled PBL wind speeds showed reasonable agreement with those from the National Centers for Environmental Prediction (NCEP) Reanalysis 2. A monthly mean AOD value as high as 1.2 was found from both model and observations, with a daily mean larger than 2.0 during haze episodes in the 3JNS region. Modeled and observed SSA values of 0.90-0.96 and ASY values of 0.72-0.74 demonstrated the high scattering characteristic of summer aerosols in this region. PBL wind speeds from modeled and NCEP data both showed a reversing trend of PM 2.5 variation, illustrating the importance of the "PBL window shadow" in haze formation. Turbulence diffusion and PBL height had opposite phases to surface PM 2.5 , indicating that lower PBL height and weaker PBL turbulence diffusion are essential to haze formation. It is noted that homogeneous air pressure does not occur at the surface, but at an 850-950 hPa height during the haze episode. The momentum transmitting downward of the cold air from above the PBL to the low PBL and surface lead to an increase in surface wind speeds and haze dispersal.

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Mixing ratios and sources of halocarbons in urban, semi-urban and rural sites of the Pearl River Delta, South China

Cited by 58 publications

References 29 publications

Pollution events observed during CARIBIC flights in the upper troposphere between South China and the Philippines

Pollution events observed during CARIBIC flights in the upper troposphere between South China and the Philippines

Change of air quality and its impact on atmospheric visibility in central-western Pearl River Delta

Mesoscale modeling study of the interactions between aerosols and PBL meteorology during a haze episode in Jing–Jin–Ji (China) and its nearby surrounding region – Part 1: Aerosol distributions and meteorological features

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