The atmospheric chemistry of hydrogen cyanide (HCN)

摘要: Since 1981, three groups have reported spectroscopic detections and measurements of hydrogen cyanide in the atmosphere. HCN concentrations (volume mixing ratios) (1.5–1.7) × 10−10 appear to characterize stratosphere northern hemisphere's nonurban troposphere. In this paper we explore atmospheric behavior by examining its chemical photochemical properties. Its principal sinks are reactions with OH O(1D); precipitation appears be a negligible sink. stratosphere, vacuum UV photons also attack HCN. Atmospheric model calculations show that should relatively well mixed troposphere concentration decreases slowly altitude stratosphere. residence time about 2.5 years, although 1–5 years is possible range. To maintain observed burden HCN, an annual source 2 10−11 g nitrogen as required; speculate identity these sources. Oxidation OH, while major sink for not simple or direct. Instead, oxidation proceeds from HCN·OH adduct formed + reactions. These pathways their uncertainties outlined here.