A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Urban-nonurban relationships of halocarbons, SF6, N2O, and other atmospheric trace constituents
Abstract This paper presents the May 1976 northern hemispheric continental United States back-ground concentrations (ppt) of CC12F2 (203.5), CC13F (115.6), CHC12F (14.2), CC12FCC1F2 (19.9), SF6 (0.24), CC14 (113.9), CHC13 (17.1), CH3C1 (713.0), CH3I (9.2), CH3Br (4.7), CH3CC13 (98.8), CC12CC12 (30.7), CHC1CC12 (15.6), COC12 (21.7), and N2O (311.6 × 103). The data also indicate that the ambient burden of CC12F2 and CC13F increased at an average rate of 1.6 ppt per month (11% per year) and 1.3 ppt per month (15% per year), respectively, during the first half of 1976. In addition, the urban-nonurban relationships of these and other pollutants (NO, NO2, TNMHC, O3, CH4 and CO) have been discussed based on a total of six short-term field studies conducted in California at both urban and clean air locations. Significant concentration gradients of CHC13, CH3C1, CH3I and CH3Br between marine and continental air masses suggest a marine source. In the case of CHC13 this gradient has been attributed to coastal water contamination. Seasonal variations of CH3I and probably CH3Br are found to exist in the marine environment. N2O and CCI4 are found to be relatively uniformly distributed with no significant temporal or spatial variation. From our data, the contribution of fluorinated species to the tropospheric chlorine budget (northern hemisphere) in 1976 is found to be about 33% which is comparable to a 28% natural chlorine contribution due solely to CH3C1.
Urban-nonurban relationships of halocarbons, SF6, N2O, and other atmospheric trace constituents
Abstract This paper presents the May 1976 northern hemispheric continental United States back-ground concentrations (ppt) of CC12F2 (203.5), CC13F (115.6), CHC12F (14.2), CC12FCC1F2 (19.9), SF6 (0.24), CC14 (113.9), CHC13 (17.1), CH3C1 (713.0), CH3I (9.2), CH3Br (4.7), CH3CC13 (98.8), CC12CC12 (30.7), CHC1CC12 (15.6), COC12 (21.7), and N2O (311.6 × 103). The data also indicate that the ambient burden of CC12F2 and CC13F increased at an average rate of 1.6 ppt per month (11% per year) and 1.3 ppt per month (15% per year), respectively, during the first half of 1976. In addition, the urban-nonurban relationships of these and other pollutants (NO, NO2, TNMHC, O3, CH4 and CO) have been discussed based on a total of six short-term field studies conducted in California at both urban and clean air locations. Significant concentration gradients of CHC13, CH3C1, CH3I and CH3Br between marine and continental air masses suggest a marine source. In the case of CHC13 this gradient has been attributed to coastal water contamination. Seasonal variations of CH3I and probably CH3Br are found to exist in the marine environment. N2O and CCI4 are found to be relatively uniformly distributed with no significant temporal or spatial variation. From our data, the contribution of fluorinated species to the tropospheric chlorine budget (northern hemisphere) in 1976 is found to be about 33% which is comparable to a 28% natural chlorine contribution due solely to CH3C1.
Urban-nonurban relationships of halocarbons, SF6, N2O, and other atmospheric trace constituents
singh, Hanwant Bir (author) / Salas, L. (author) / Shigeishi, H. (author) / Crawford, A. (author)
Atmospheric Environment ; 11 ; 819-828
1977-01-06
10 pages
Article (Journal)
Electronic Resource
English
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