气候变化领域集成服务门户

Aerosol black carbon (BC) is the second strongest contributor to global warming, after CO2, and it is linked to many adverse health effects. A sampling campaign of 15 months was carried out in Leon (Spain) in order to evaluate the scavenging of BC with an ensemble aethalometer-disdrometer. The aethalometer provides the concentration of equivalent black carbon (eBC), and the disdrometer, the raindrop size distribution. A total of seventy-five rain events were studied and in 73% of them there was an effective (eBC(initial) > eBC(final)) scavenging, with a mean decrease of 48 +/- 37% in long rain events (>8 h) and 39 +/- 38% in short rain events. The scavenging of BC is strongly related to its source. Thus, the scavenging coefficient (SC) mean value of the BC from fossil fuel (eBC(ff)) for short and long rain events was 5.110(-5) and 1.3 10(-5) s(-1), respectively. For the BC from biomass burning (eBC(bb)), the SC values were 1.6 10(-4) and 2.8 10(-5) s(-1) in short and long events, respectively. There was a significant positive correlation between the SC and the number of drops with diameters between 0375 and 2.5 mm. Rain scavenging of eBC was analyzed depending on the air mass origin obtaining an effective scavenging for air masses from Atlantic, Arctic and Africa. A linear model (R-2 = 0.72) was built to estimate the Delta eBC values with variables from an aethalometer, a disdrometer and a weather station: eBC concentration before rain, swept volume and precipitation accumulated. A Kolmogorov-Smirnov statistical test confirmed the goodness of fit of the model to the measured data. (C) 2018 Elsevier Ltd. All rights reserved.