Source-Receptor Relationships for Acid Deposition: Pure and Simple

Abstract

The status of technology for determining the contribution of source emissions to the deposition of acidifying substances at receptors in eastern North America is discussed. Two basic approaches are available for source apportionment. These involve: the interpretation of direct measurement, or the application of theoretically based models accounting for material balance of the acidifiers. The use of direct measurements requires at a minimum either detailed spatial observations or long term historical data taken at sites located in different areas. Analysis of observations to date gives qualitative information about deposition patterns in relation to source regions for sulfur and nitrogen oxides. The analysis of data is enhanced with application of empirical models. Quantitative source apportionment is not possible solely from the measurements; a verified theoretically based model is needed to complete this type of assessment. The current technology of modeling permits estimation of source contribution with unknown reliability. The models themselves are highly parameterized with semiempirical considerations. When the parameters are adjusted to measurements, models yield sometimes acceptable simulations of ambient concentration and deposition distributions of sulfate and nitrate given geographically distributed emissions estimates. Even with models now available, improved quantification of source-receptor relationships will require considerable investment in new field more » experiments, possibly involving passive and reactive atmospheric tracers of emissions. 81 references. « less

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Affiliated Institutions

• Newbury College US

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