Fourteen years (1989--2002) of cloud-to-ground (CG) lightning data show a significant enhancement of lightning associated with Lake Charles and Baton Rouge, Louisiana. A peak density value of 7 flashes km-2 yr-1 exists on the western side of the Lake Charles urban area. A comparison of the Louisiana CG flash density distribution with the locations of PM10 (particulate matter less than 10 ¿m in diameter) sources strongly suggests that pollution plays a key role in lightning enhancement. Urban and sea breeze effects can be neglected. The values of median peak negative current show a sharp difference between land and the Gulf of Mexico; inland values are near 24 kA, while over the Gulf waters immediately offshore are over 30 kA. This observation, along with a relative minimum of negative peak current from the mouth of the Mississippi River southeastward seems to support the hypothesis that the underlying surface characteristics influence the calculated negative current distribution.