Global concentrations of three chloroflurocarbons, 1984-1988

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1991

OSTI ID:7015322

Gilpin, T M

During a five-year period, 1984 to 1988, the temporal, seasonal and spatial variations in the background tropospheric concentrations (1 pptv range) of CCl[sub 2]F[sub 2], CCl[sub 3]F and CCl[sub 2]FCC1F[sub 2] were measured. From 35 to 75 grab samples of tropospheric air were collected four times a year from remote locations in the Pacific, ranging between 72 degrees north to 47 degrees south (occasional 90 degrees south), using stainless steel canisters fitted with high-vacuum valves. The samples were analyzed in the laboratory using a high-vacuum preconcentration line coupled to an electron capture gas chromatograph. Standards in the pptv range for accurate calibration of background concentrations were prepared by two entirely different methods. One technique involved a four-step dilution starting with pure starting materials on an all-glass vacuum line. The second method was a one-step dilution starting with pure starting materials on an all metal vacuum line. The final results give the December 1988 global mixing ratios for CFC-12, CFC-11 and CFC-113 to be 465 pptv, 242 pptv and 64 pptv respectively. The global mixing ratio growth rates for 1984 through 1988 are 21.3 for CFC-12, 11.9 for CFC-11 and 6.3 for CFC-113. Growth rates were determined by using first order linear regression fits to the data with one standard deviation given in parenthesis.

• Research Organization: California Univ., Irvine, CA (United States)
• OSTI ID: 7015322
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540120* -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (1990-)
AIR POLLUTION MONITORING
CAPTURE
CHROMATOGRAPHY
DISTRIBUTION
ECOLOGICAL CONCENTRATION
ELECTRON CAPTURE
FREONS
GAS CHROMATOGRAPHY
GLOBAL ASPECTS
HALOGENATED ALIPHATIC HYDROCARBONS
MATHEMATICS
MONITORING
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
REGRESSION ANALYSIS
SEASONAL VARIATIONS
SEPARATION PROCESSES
SPATIAL DISTRIBUTION
STATISTICS
VARIATIONS