Research emphasis is placed on environmental chemistry and soil physical chemistry. Recent projects dealing with environmental chemistry include emissions of ammonia from swine lagoons; temporal and spatial patterns in ambient ammonia and ammonium aerosol concentrations across eastern North Carolina; a nitrogen budget for the Coastal Plain river basins of North Carolina using a Geographical Information System (GIS); dry deposition of ammonia and ammonium aerosols to crop and woodland canopies; the trace metal content of fertilizer source materials produced in North America; and the issue of whether perchlorate is present in fertilizer source materials and fertilizer blends produced and marketed in North America.