Thick, multilayer elements widen antenna bandwidths : Timothy Holzheimer and T. O. Miles. Microwaves RF 93 (February 1985)

Abstract

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). PM2.5 and PM10 samples were collected on pre-fired quartz filters with mini-volume samplers and analyzed using thermal optical reflectance (TOR) method. Average PM2.5 and PM10 level were 72.6 and 111.5 μg m−3, respectively, with PM2.5 constituting 70.4% of the PM10 mass. The average OC and EC concentrations in PM2.5 were 14.7 and 6.1 μg m−3, respectively, while those in PM10 were 19.7 and 7.8 μg m−3, respectively. The carbonaceous aerosol accounted for 40.2% of the PM2.5 and 35.9% of the PM10. The average OC/EC ratio was 2.4 for PM2.5 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 PM2.5 and PM10, respectively.