Changes in concentrations of fine and coarse particles under the CO2-induced global warming

Using an aerosol-climate coupled model, we have investigated the climate response to increases in atmospheric carbon dioxide (CO2) levels and the resulting changes in the column concentrations of anthropogenic and natural particulate matters. Special attention has been paid on the fine particulate matters (PM2.5, particulate matters with aerodynamic diameters <= 2.5 mu m) and coarse particles of non-PM2.5 (NPM, particulate matters with aerodynamic diameters > 2.5 mu m). Rising CO2 levels led to significant effects on surface air temperature, large scale circulation, surface water flux, precipitation, etc., which considerably affect the column concentrations of anthropogenic and natural particulate matters, for both fine and coarse modes. Changes in burden of fine particles are major contributions to that of total anthropogenic particulate matters by CO2-induced global warming. The anthropogenic PM2.5 burden was found to decrease in the regions with latitudes > 30 degrees N, whereas in the rest areas increase. The geographical distributions of changes in the column concentrations of fine and coarse natural particles were found in the same order of magnitude in most regions, and the particle size distribution shifted to the coarse mode. The physical mechanisms are analyzed to explain the changes in aerosol local column concentrations due to CO2-induced climate change.