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A theoretical analysis of the contribution to rainwater sulfate concentration by precipitation scavenging of gaseous SO2 and sulfate containing aerosols is presented. Aspects, such as the proper choice of mean raindrop diameter, are discussed in detail, and guidelines for their use are explored. Sample calculations are provided in which emissions from a hypothetical stack are considered as the source of the gaseous SO2 and sulfate aerosol. The basic assumption of irreversible sorption behavior is discussed and utilized to obtain an upper limit to the resulting sulfate concentration. The...

Episodical long-range transport is the quasi-instantaneous peak event. It does not express the total dosage of pollutant carried over from the source area to some distant place. The purpose of the present paper is to obtain an average material balance of a pollutant leaving a given area. Available information from the OECD "Long Range Transport of Air Pollutants" is being used for this purpose. The IRCHA is one of the laboratories participating in this project. Our main sampling station is 37 km from the center of the Paris district. This position allows us to compute, based on emission...

Studies were undertaken to determine factors affecting composition of acidic precipitation formation in the Austin area of Central Texas. The study was initiated to determine background levels of acid and alkalinity producing constituents in an area with elevated natural dust levels from nearby limestone rock formations. Results showed normal rainfall pH values of 6.5 to 6.6 in the area, with extreme variations from 5.8 to 7.3. Significant calcium levels of 1 to 4 mg per liter were observed from probably natural origin which appeared to have a buffering effect on acidity. Significant...

Rain and snow were collected in plastic beakers either manually or with a Wong sampler during 58 precipitation events in 1974 at Yonkers, New York approximately 24 km north of the center of New York City. Determinations were made of total dissolved ionic species, free hydrogen ions, total hydrogen ions, sulfate, nitrate, chloride, and fluoride. Conductivity measurements ranged from 618 to 162 umhos, pH from 3.4 to 4.9, total acidity from 36 to 557 ueg/l sulfate from less than 1 to 20 mg/l, nitrate from less than 1 to 14 mg/l, and chloride from less than 1 to 7 mg/l. All fluoride concentrati...

Bulk precipitation samples were collected from ten sites in south-central Maine during the period 18 June to 30 September 1974. Data from the chemical analyses of the precipitation were used to determine regional deposition patterns of the ionic constituents. Acidic pH values ranging from 3.8 to 5.0 are characteristic of the region, but relatively alkaline pH values of 5.5 to 7.0 were observed in the precipitation from one collection site. Systematic increases in sulphate and sodium deposition in the samples from this site suggest a local source. The observations of the bulk precipitation...

Nutrient content and pH of precipitation samples collected at six sites during 1971-1973 were studied to determine the reaction of rainfall and snowmelt and the amounts of N, S, and P added by precipitation over Iowa. The amount of NH4-N added by precipitation per hectare annually at each site was about equal to that added as NO3-N. The amounts of inorganic N added per hectare per year ranged from 10 kg in north-central to 14 kg in west-central Iowa, and the annual amounts of SO4-S added per hectare ranged from 13 kg in northeastern to 17 kg in north-central Iowa. It is estimated that, on...

Personnel from the Monongahela National Forest and the Northeastern Forest Experiment Station are collaborating in forest-wide monitoring of precipitation chemistry. Present monitoring facilities consist of one continuous precipitation collector/pH recorder and 12 precipitation collectors. Samples collected in these facilities are picked up and analyzed biweekly for specific conductance, pH, acidity, alkalinity, calcium, magnesium, sodium, potassium, nitrate-nitrogen, sulfate, and iron. Precipitation monitored at six (6) ranger districts is analyzed for pH and specific conductivity only....

Satellite imagery provides a convenient and inexpensive means for monitoring smoke plumes and evaluating inadvertant weather modification. Visual examination of LANDSAT-1 imagery for two sites in east-central Ohio indicates that, at times, a plume may extend nearly 48 km downwind and reach a width of six km. Density slicing techniques provide clues as to the particulate loading in a plume. The areal extent of plumes can be mapped and could be studied for adequate siting of ground stations in order to monitor the chemical quality of precipitation and evaluate the effects on the ecosystem....

Precipitation is currently collected by several methods, including several different designs of collection apparatus. We are investigating these differing methods and designs to determine which gives the most representative sample of precipitation for the analysis of some 25 chemical parameters. The experimental site, located in Ithaca, New York, has 22 collectors of 10 different designs. The designs include bulk (wet and dry deposition collected together), wet only (only rain and snow) and wet/dry (collects wet and dry deposition separately). In every sampling period, which varies from...

The main indicator for acidic substances in the atmosphere is, now as before, the pH of rainwater. Factors influencing the acidity of precipitation are discussed, using results of air monitoring stations in Germany.