Identification of acetylene (C₂H₂) in infrared atmospheric absorbtion spectra

Infrared atmospheric absorption spectra at ∼0.02 cm −1 resolution obtained during a balloon flight made on March 23, 1981, show absorption features attributable to C 2 H 2 . These features are used to derive a preliminary mixing ratio of ∼25 pptv near 9 km. This mixing ratio falls into the range of values we calculate for upper tropospheric C 2 H 2 in a photochemical/transport model but well below values measured previously in samples collected by other researchers.