Further analysis of the ratios of major ions in wet acidic deposition with implications for SO/sub 2/ emissions - wet SO/sub 4//sup 2/- deposition relationships

The molar ratio of SO/sub 4//sup 2 -//NO/sub 3//sup -/(R/sub 1/) wet depositions was found to have a much smaller coefficient of variability(C.V.) over the 10 northeastern state(10NES) subregion and 31 eastern state(31ES) region than in the other 3 regions of North America, and showed some year-to-year variability between 1980 and 1981 in all 5 regions. The mean molar ratio of SO/sub 2//NO/sub 2/ emissions for the 10NES and 31ES regions are close in value to R/sub 1/ for total emissions, but not for the utility source category which contributes about 75% of the total emissions in these two regions. The large C.V. in molar ratios of SO/sub 2//NO/sub 2/ emissions in the 31ES region suggests the similarity in average molar ratios of emissions and depositions may be just an artifact of regional averaging or the inate ability of the atmosphere to rapidly dilute widely different initial molar ratios of emissions. The seasonal and exceptional wet SO/sub 4//sup 2 -/ deposition episode values of R/sub 1/ are significantly higher than the molar ratios of SO/sub 2//NO/sub 2/ emissions for all sources and the annual average values of R/sub 1/ in eastern North America. Since seasonal variations in SO/sub 2/ emissionsmore » from the largest sources and in the molar ratios of SO/sub 2//NO/sub 2/ emissions from all sources appear to be insignificant, preferential scavenging of SO/sub 4//sup 2 -/ in summer or co-pollutant or moisture effects on ion formation appear to be taking place. This result may be the first real evidence of widespread enhanced aqueous phase conversion of SO/sub 2/ to SO/sub 4//sup 2 -/ in the summer season and in exceptional episodes.« less