SOURCE SPECIFIC FOG DEPOSITION OF BLACK CARBON FROM THE ATMOSPHERE

• Main Author: Dolšak, Petra
• Format: Others
• Language: English
• Published: Högskolan i Halmstad, Miljövetenskap 2016
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-31289

Black carbon (BC) plays an important part in global climate change. In addition, long term exposure to BC is closely related to pulmonary and cardiovascular mortality. BC is formed by the incomplete combustion of carbonaceous compounds. In urban environments the main sources come from the burning of biomass for domestic heating and diesel vehicles. The typical lifespan of airborne BC is about a week and is treated as a short-lived climate pollutant. Wet deposition, which is more significant closer to the source, is the primary deposition mechanism and condensation of water is dependent on the sources of BC. Measurements with aethalometers determine the sources of BC concentrations, particularly fossil fuel combustion from traffic (ff) and wood smoke (bb).   The in-situ measurements in this study reveal that the different source apportionment of BC emissions with different initial properties of BC behaves differently during the fog periods. Foggy periods from the March and January 2015 data set were carefully collected. In January, the fog occurred throughout the entire observation time, while in March the fog occurred for different durations, from 1 to 7 hours. A linear regression between the normalized BC, BCbb, BCff concentrations and 7-hour periods at night was calculated for each individual period. The comparison of slope values (k), standard errors and p-values of different sources of specific BC emissions was then made. Despite there not being a great difference between the slope values of BCbb and BCff in the January data set, the results revealed that BC emissions from biomass burning have fewer non-statistically significant values than the BC emissions from vehicle exhaust. This study corresponds to the different initial properties of fresh aerosols from both sources and indicated an increased fog deposition of BC from biomass burning.