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Detection of NO 3 in the polluted troposphere by differential optical absorption
Author(s) -
Platt Ulrich,
Perner Dieter,
Winer Arthur M.,
Harris Geoffrey W.,
Pitts James N.
Publication year - 1980
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl007i001p00089
Subject(s) - differential optical absorption spectroscopy , troposphere , sunset , absorption (acoustics) , nitrate , environmental science , stratosphere , detection limit , absorption spectroscopy , analytical chemistry (journal) , ozone , environmental chemistry , atmospheric sciences , chemistry , meteorology , geology , optics , physics , chromatography , organic chemistry
The nitrate radical, NO 3 , has been identified and measured for the first time in the polluted troposphere using long path (970 and 750 m) differential optical absorption spectroscopy at two sites in the Los Angeles basin. NO 3 concentrations of up to 355 ppt were measured using the strong NO 3 absorption bands at 623 and 662 nm. During pollution episodes from September 11 to September 19, 1979 concentrations increased sharply after sunset and peaked about one hour later at ∼ 20:00 (PDT). In many other cases peak concentrations were much lower and sometimes below the detection limit of several ppt. Possible sinks for the NO 3 radical under polluted conditions are considered, including reaction with NO, reaction with organic species, and the hydrolysis of N 2 O 5 for which a new upper limit rate constant is derived.