A Double-spot Methodology with Different Aerosol Loading Rates to Adjust Filter-based Optical Black Carbon Data for Measurement Artifacts

摘要

Black carbon (BC) aerosols are produced by the incomplete combustion of carbonaceous fuels and are important atmospheric components because of their potentially negative effects on climate and health. Hence, measurement of BC has become increasing important in the past decade in urban, rural and background areas worldwide. The most common method used to measure BC involves collecting aerosols on a filter and measuring the reduction in light transmission through the filter. The Aethalometer (AE; Magee Scientific) is one of the currently available devices used for measuring BC by this kind of filter-based optical technique. In the Aethalometer, sample air is drawn through a filter and aerosols are collected on it. Then, the decrease of light transmission through the aerosols on the filter is measured. Decreasing transmission leads to increasing attenuation, ATN. It is assumed that the ATN increase is only due to light absorption by BC aerosols accumulating on the filter, and BC concentrations is therefore calculated from the rate of ATN change.