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The changing acidity of air and precipitation over most of Europe and part of U. S. is only part of a larger problem--changes of the chemical climate caused by a variety of emissions into the atmosphere (13, 36). These emissions may create a local, a regional or a global situation depending only on the life-time of the pollutants in the atmosphere. The atmospheric sciences give some answers in this respect, but not all. Soils, vegetation and surface waters act not only as a passive sink for elements in the atmosphere. Several feed-back mechanisms take place including continuous exchange,...

Our ability to simulate atmospheric processes that affect the life cycle of pollution is reviewed. The transport process is considered on three scales (a) the near-source or single-plume dispersion problem, (b) the multiple-source dispersion problem, and (c) the long-range transport. Modeling the first of these is shown to be well within the capability of generally available techniques, although determining the input parameters is often difficult. The second scale has been well studied within the context of urban diffusion and is a very productive area of current research. Finally,...

The mechanisms and rates of conversion of sulfur dioxide to sulfur trioxide, sulfuric acid, and other "sulfate" aerosol precursors are considered in view of current knowledge related to atmospheric reactions and chemical kinetics. Several heterogeneous pathways exist for SO2 oxidation promoted on solid catalyst particles and in aqueous aerosol solutions in ambient air. The rates of these processes are of questionable significance in SO2-containing gases which are well removed from pollutant sources and highly diluted through turbulent diffusion and transport mechanisms. Computer simulations...

In the 1950's a network of stations for observation of the chemical composition of air and precipitation was established in Europe. Analysing these data, Odén in 1968, was able to show that a central area in Europe with highly acid precipitation was expanding from year to year. This was further substantiated by Granat in 1972, and the explanation is the increasing use of fossil fuels in Europe. In 1969, the problem was examined by OECD, and on the initiative of the Scandinavian countries, a joint research programme to study the long range transport of air pollutants was started in 1972....

One of the major problems in interpreting precipitation chemistry data is determining the possible source areas of the materials found in the precipitation. To investigate this problem, the trajectory program developed at Air Resources Laboratories (NOAA) was used to compute five-day backward air trajectories from Ithaca, New York.

Since January 1972, chemical analysis of daily precipitation samples from about 20 background stations in Norway has been carried out on a routine basis. Air monitoring is carried out at six stations. The chemical analysis programme is: sulphate, pH and acidity in precipitation, sulphates and sulphur dioxide in air. In addition, more detailed chemical analysis of aerosol and precipitation has been carried out at selected stations. Some results for the measurement period 1972-1974 are presented. Comparison of air and precipitation concentrations of sulphur compounds show that the precipitati...

Numerous attempts have been made to measure the rate of loss of SO2 in power plant plumes. If SO2 decreases more rapidly than an inert pollutant, the control measures necessary to meet SO2 standards would be eased. More recently, Swedish studies of acid rain, thought to be due to long range transport of sulfuric acid, and U.S. correlations of sulfate loading with health effects, have led to efforts to determine sulfate formation and transport. However, most of the efforts to date indicate very little SO2 conversion and do not support a significant role for power plant SO2 in the production...

In order to evaluate the effect of different types of collectors on the measured chemical constituents of monthly precipitation collections, an array of fourteen precipitation samplers of five different designs has been in operation at Woodbridge, Ontario since March 1974. The collectors are located in an open field near the city of Toronto in an area of approximately 325 square meters, and it is anticipated that the chemical constituents of the precipitation would be uniform across the array for monthly sample collections.

These Proceedings report on the results of The First International Symposium on Acid Precipitation and the Forest Ecosystem which was held at The Ohio State University, Columbus, Ohio, U.S.A., on May 12-15, 1975. The Symposium focused on four related topics: (1) atmospheric chemistry, transport and precipitation; and effects of acidic precipitation on (2) aquatic ecosystems, (3) forest soils, and (4) forest vegetation.

The best white pine growth during a 6-year period in a West Virginia outplanting was obtained with seedlings grown from seed collected in Tennessee, Georgia, and North Carolina. These seed sources are recommended for plantings in West Virginia.