Intra-Annual Deposition of Atmospheric ^(210)Pb, ^(210)Po and the Residence Times of Aerosol in Xiamen, China

Zhou Wang ； Weifeng Yang ； Min Chen ； Peng Lin ； Yusheng Qiu

《Aerosol and Air Quality Research》 14卷5期 (2014/08) Pp. 1402-1410

https://doi.org/10.4209/aaqr.2013.05.0170

並列摘要

Atmospheric deposition of ^(210)Pb and ^(210)Po from Nov. 2010 to Jan. 2012 were analyzed to reveal their temporal variations, as well as applications in constraining the residence times of aerosol. The monthly depositional fluxes varied from 2.42 to 29.31 Bq/m^2/mon and from 0.160 to 3.388 Bq/m^2/mon for ^(210)Pb and ^(210)Po, respectively. High fluxes of ^(210)Pb and ^(210)Po were observed in the southwest monsoon prevailing months, while low fluxes corresponded to the northeast monsoon seasons, revealing the monsoon control over ^(210)Pb and ^(210)Po deposition on seasonal timescales. There were significant positive linear correlations between the daily depositional fluxes and precipitation, supporting the predominant removal passage of ^(210)Pb and ^(210)Po through rainfall. The inverse relations between specific activities and precipitation indicated that the removal efficiencies were much higher at the beginning of rainfall. In contrast, the dry deposition only accounted for 22% and 29% of the bulk depositional fluxes of ^(210)Pb and ^(210)Po, respectively. The depositional flux ratios of ^(210)Po to ^(210)Pb varied between 0.015 and 0.223 with a mean of 0.091 ± 0.012, corresponding to the residence times of 3.1-57.5 d with an average of 20.8 ± 3.0 d. Investigations on size-fractionated ^(210)Po and ^(210)Pb could provide better understanding of the resident timescales of aerosol.

並列關鍵字

Aerosol ； Residence time ； ^(210)Pb, ^(210)Po ； Monsoon