Atmospheric Chemistry and Physics Discussions

Interactive comment on “Source-receptor relationships between East Asian sulfur dioxide emissions and Northern Hemisphere sulfate concentrations ” by J. Liu et al. J. Liu et al. Received and published: 3 April 2008 One motivation for this study was to quantitatively describe the spatial extent of the linearity (and non-linearity) of the conversion of emitted SO2 to sulfate. Our con-clusion that "sulfate concentrations over downwind regions respond nearly linearly to changes in SO2 emissions, but sulfate concentrations over the source region increase more slowly than SO2 emissions " allows Liu and Mauzerall (2007) to derive an inter-continental Influence Potential (IP) metric. The IP quantifies the human exposure that occurs in a receptor region as a result of a unit of SO2 emissions from a source region. With the S-R curves for SO2/SO4 from this work, Liu and Mauzerall (2007) calculate IP ratios (IPR) between foreign and domestic SO2 emissions over ten continental regions. Due to the non-linearity of SO2 to sulfate conversion over source regions, the IPR pro