1975•OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information)Requires access
Ambient concentrations of phytopathogenic air pollutants in Voyageurs National Park, Minnesota
J. A. Laurence, Maxi Schreiber, S.V. Krupa
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Abstract
Ambient concentrations of ozone (O/sub 3/), nitrogen oxides (NO/sub x/) and sulfur dioxide (SO/sub 2/) were monitored in Voyageurs National Park, near the US-Canadian border, to determine baseline concentrations of these pollutants. O/sub 3/ and NO/sub x/ concentrations were collected using chemiluminescent monitors; SO/sub 2/ concentrations were recorded using a coulometric monitor. SO/sub 2/ was not detected in 824 hr of monitoring. O/sub 3/ concentrations recorded during 676 hr of monitoring varied between 14.7 ..mu..g/m/sup 3/ (0.0075 ppm) and 156.8 ..mu..g/m/sup 3/ (0.08 ppm). The latter concentration occurred once during the summer for 20 minutes. Mean hourly concentrations were lowest from 4 AM to 7 AM (48.8 ..mu..g/m/sup 3/ = 0.0249 ppm at 6 AM) and reached a maximum between 2 PM and 8 PM (68.0 ..mu..g/m/sup 3/ = 0.0347 ppm at 6 PM). Total nitrogen oxides were monitored for 491 hr. Mean hourly concentrations ranged from 0.32 ppm near 5 AM to 0.397 ppm at 5 PM. Concentrations varied widely from day to day, the minimum concentration observed being 0.0 ppm and the maximum, 0.60 ppm. Pollutant concentrations were not correlated with area weather conditions. These data suggest ozone concentrations observed are not the result of man-related activities ormore » transport from distant urban areas.« less