Black carbon aerosols and their radiative properties in the Pearl River Delta region

The climatic and environmental effects of atmospheric aerosols are a hot topic in global science community, and radiative properties of the aerosols are one of the important parameters in assessing climatic change. Here we studied the black carbon concentration and absorption coefficient measured with aethalometers, scattering coefficient measured with nephelometers, and single scattering albedo derived at an atmospheric composition watch station in Guangzhou from 2004 to 2007. Our main results are as follows. The data of black carbon concentration and absorption coefficients measured with instruments cannot be directly used until they are measured in parallel with internationally accepted instruments for comparison, calibration, and reduction. After evaluation of the data, the result shows that the monthly mean of BC concentration varies 3.1–14.8 μg·m−3 and the concentration decreases by about 1 μg·m−3 in average over the four years; It is higher in the dry season with a multi-year mean of 8.9 μg/m3 and lower in the rainy season with a multi-year mean of 8.0 μg·m−3; The extreme maximum of monthly mean concentration occurred in December 2004 and extreme minimum in July 2007, and a 4-year mean is 8.4 μg·m−3. It is also shown that monthly mean scattering coefficient derived varies 129 −565 Mm−1, monthly mean absorption coefficient 32–139 Mm−1, and monthly mean single scattering albedo 0.71–0.91, with annual mean values of 0.80, 0.82, 0.79 and 0.84 for 2004, 2005, 2006 and 2007, respectively. Three instruments were used to take simultaneous measurements of BC in PM10, PM2.5, and PM1 and the results showed that PM2.5 took up about 90% of PM10 and PM1 accounted for about 68% of PM2.5, and BC aerosols are mainly present in fine particulates. The variability of BC concentrations is quite consistent between the Nancun station (141 m above sea level) and the Panyu station (13 m above sea level), which are 8 km apart from each other. The concentration in higher altitude station (Panyu) is consistently lower than the lower altitude station (Nancun), and the difference of annual mean is about 4 μg·m−3.

[1]  Xiangao Xia,et al.  Aerosol optical properties and radiative effects in the Yangtze Delta region of China , 2007, Journal of Geophysical Research.

[2]  Glen Lesins,et al.  Stronger Constraints on the Anthropogenic Indirect Aerosol Effect , 2002, Science.

[3]  Judith C. Chow,et al.  Characteristics of carbonaceous aerosol in Pearl River Delta Region, China during 2001 winter period , 2003 .

[4]  Zhenzhu Wang,et al.  The measurement of aerosol optical properties at a rural site in Northern China , 2007 .

[5]  R. Draxler.  HYSPLIT (HYbrid Single-Particle Lagrangian Integrated Trajectory) Model access via NOAA ARL READY Website , 2010 .

[6]  J. M. Norbeck,et al.  The contribution of elemental carbon to the optical properties of rural atmospheric aerosols , 1986 .

[7]  Y. H. Zhang,et al.  Aerosol optical properties in a rural environment near the mega-city Guangzhou, China: implications for regional air pollution and radiative forcing , 2008 .

[8]  J. Ogren,et al.  Determining Aerosol Radiative Properties Using the TSI 3563 Integrating Nephelometer , 1998 .

[9]  S. Babu,et al.  Anthropogenic impact on aerosol black carbon mass concentration at a tropical coastal station: A case study , 2001 .

[10]  J. Hansen,et al.  Climate Effects of Black Carbon Aerosols in China and India , 2002, Science.

[11]  Wang Meihua,et al.  Observational study of black carbon aerosol in Beijing , 2005 .

[12]  M. Jacobson,et al.  Strong radiative heating due to the mixing state of black carbon in atmospheric aerosols , 2022 .

[13]  Judith C. Chow,et al.  Photoacoustic and filter measurements related to aerosol light absorption during the Northern Front Range Air Quality Study (Colorado 1996/1997) , 1998 .

[14]  Alexis K.H. Lau,et al.  An extremely low visibility event over the Guangzhou region: A case study , 2005 .

[15]  Meinrat O. Andreae,et al.  The dark side of aerosols , 2001, Nature.

[16]  Chandra Venkataraman,et al.  Atmospheric optical and radiative effects of anthropogenic aerosol constituents from India , 2000 .

[17]  E. Kassianov,et al.  Measurements of Black Carbon Specific Absorption in the Mexico City Metropolitan Area during the MCMA 2003 Field Campaign , 2005 .

[18]  Xiangao Xia,et al.  Aerosol optical properties and their radiative effects in northern China , 2007 .

[19]  Joyce E. Penner,et al.  Observational evidence of a change in radiative forcing due to the indirect aerosol effect , 2004, Nature.

[20]  P. Quinn,et al.  Aerosol optical properties measured on board the Ronald H. Brown during ACE-Asia as a function of aerosol chemical composition and source region , 2004 .

[21]  David S. Covert,et al.  Variability of aerosol optical properties derived from in situ aircraft measurements during ACE‐Asia , 2003 .

[22]  Huang Jian,et al.  Effect of Atmospheric Haze on the Deterioration of Visibility over the Pearl River Delta , 2007 .

[23]  Richard Raspet,et al.  Photoacoustic and filter-based ambient aerosol light absorption measurements : Instrument comparisons and the role of relative humidity , 2003 .

[24]  A. G. Clarke,et al.  Characterisation of the carbonate content of atmospheric aerosols , 1992 .

[25]  Paul J. Crutzen,et al.  The Indian Ocean Experiment and the Asian Brown Cloud , 2002 .

[26]  A. Canada.  OBSERVATIONAL STUDY OF BLACK CARBON IN CLEAN AIR AREA OF WESTERN CHINA , 1999 .

[27]  Liu Xiuji.  ADVANCES IN THE STUDY OF ATMOSPHERIC AEROSOL RADIATIVE FORCING AND CLIMATE CHANGE , 1998 .