| Popis: |
A 14 day study was carried out at an isolated oil-burning power plant in the northeastern United States during July 1977 to determine the impact of the direct emissions of sulfate on the ambient air environment in the vicinity of the source. An air monitoring network was used to obtain measurements of 24-h average suspended paniculate matter within a 6-km radius of the source emission, which was located in the Hudson River Valley. Ambient paniculate was analyzed for sulfate, nitrate, bromide, and several metals. Meteorological data were recorded at a site adjacent to the source as well as at an airport U.S. National Weather Service — about 18 km north-northwest of the power plant. At the airport, hourly observations of visual range were noted. These measurements were correlated with the total suspended paniculate levels and their chemical composition for each daily sampling interval. In particular, visual range was found to be inversely related to the sulfate fraction of the suspended paniculate matter ( r = 0.94) over an average daily sulfate concentration ranging from 5 to 25/gmm −3 . Measured visibility at the airport was found to be strongly influenced by wind direction with southeasterly winds corresponding to periods of low visibility. Under these conditions the average sulfate content of the suspended paniculate was 35%. Higher visibility levels occurred with northwest winds and sulfate comprised only 15% of the ambient paniculate matter. The sulfate to particulate matter ratio in the boilers was found to be 0.35, which has been identified as being a general characteristic of emissions from residual oil combustion. Although a twofold increase in ambient sulfate was noted in particulate samples taken downwind of the source, the upwind (incoming background) samples also exhibited a sulfate to particulate matter ratio of 0.35–0.40 with southeasterly winds, suggesting the possibility of transport of combustion-generated sulfate from the heavily populated Mid-Atlantic coastal region where residual oil is used as the principal fuel for both electrical energy production and to a large extent, domestic space heating. |
