Response to comments on 'Impact of California's air pollution laws on black carbon and their implications for direct radiative forcing' by R. Bahadur et al

摘要

We address possible sampling biases reported in an earlier work (Bahadur et al., 2011) relating decreases in black carbon (BC) measurements from the IMPROVE monitoring network to diesel emissions in California. A decrease in average BC concentration of between 40 and 60% is found at each site between 1988 and 2007, consistent with the statewide average of 50%. No significant regional biases are found to drive these trends, which are independent of latitude as well as mean BC concentration. We find no reason to revise the conclusions of Bahadur et al, in response to the methodological issues raised by Schichtel et al.