FOSSIL-FUEL-DERIVED CO2 CONTRIBUTION TO THE URBAN ATMOSPHERE IN GUANGZHOU, SOUTH CHINA, ESTIMATED BY (CO2)-C-14 OBSERVATION, 2010-2011

From October 2010 to November 2011, the urban atmospheric CO2 concentration in Guangzhou ranged from 550 to 460 ppm, with mean monthly concentration fluctuating between 530 and 470 ppm. A lower concentration was observed in summer and autumn, while a higher concentration occurred in spring and winter. The urban atmospheric CO2 delta C-13 value varied between -9.00 and -13.10 parts per thousand, with mean monthly value fluctuating between -9.60 and -11.80 parts per thousand. There was no significant relationship between the CO2 concentration and delta C-13 value, reflecting the influence from the fossil-fuel-derived CO2 on the urban atmospheric CO2. The urban atmospheric CO2 Delta C-14 value fluctuated dramatically from 29.1 +/- 2.5 parts per thousand to -85.2 +/- 3.1 parts per thousand, with a mean annual value of -16.4 +/- 3.0 parts per thousand. A similar seasonal variation of Delta C-14 value with the concentrations was observed: the higher Delta C-14 values mainly appeared in summer and autumn (July to September), with a mean value of about -5.2 +/- 2.9 parts per thousand, while lower Delta C-14 values occurred in spring and winter (December to April), about -27.1 +/- 3.2 parts per thousand average. Based on the atmospheric Delta C-14 values, the calculated fossil-fuel-derived CO2 concentrations range between 1 and 58 ppm, with the mean annual concentration around 24 ppm. Similarly, a lower fossil-fuel-derived CO2 concentration appeared in summer and autumn (July to September) with a mean value of similar to 17 ppm, while the higher fossil-fuel-derived CO2 concentration occurred in spring and winter (December to April) with an average value of similar to 29 ppm. A comparison of the CO2 concentrations before and after the Guangzhou Asian Games (in November 2010) and the Spring Festival of 2011 confirmed that human activities can greatly decrease the fossil-fuel-derived CO2 emissions to the urban atmosphere in Guangzhou.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000325752100067&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Geochemistry & GeophysicsSCI(E)0ARTICLE2-3791-8035