Characteristics of carbonaceous aerosol in Pearl River Delta Region, China during 2001 winter period

Concentrations and distributions of organic carbon (OC) and elemental carbon (EC) in atmospheric particles were measured at 8 sites in four cities (Hong Kong, Guangzhou, Shenzhen and Zhuhai) of Pearl River Delta Region (PRDR), China during two winter months (January and February, 2002). PM_2.5 and PM₁₀ samples were collected on pre-fired quartz filters with mini-volume samplers and analyzed using thermal optical reflectance (TOR) method. Average PM_2.5 and PM₁₀ level were 72.6 and 111.5μgm^-3, respectively, with PM_2.5 constituting 70.4% of the PM₁₀ mass. The average OC and EC concentrations in PM_2.5 were 14.7 and 6.1μgm^-3, respectively, while those in PM₁₀ were 19.7 and 7.8μgm^-3, respectively. The carbonaceous aerosol accounted for 40.2% of the PM_2.5 and 35.9% of the PM₁₀. The average OC/EC ratio was 2.4 for PM_2.5 and 2.5 for PM₁₀, which are comparable with most urban cities in the world. The OC and EC in PRDR were found to be strongly correlated (correlation coefficients >0.7). Secondary organic carbon was found to constitute 42.6% and 38.4% of the total organic carbon in PM_2.5 and PM₁₀, respectively.