The oxidative potential of the troposphere and its influence by hydrocarbon emissions.
Due to its reactivity, the OH radical is considered to represent the oxidative potential of the troposphere and by a simple photochem. box model, a steady state OH concn. of 1.6 * 106 mol./cm3 for the midday continental troposphere in the absence of hydrocarbons is detd. The concn. of OH depends on a fast photochem. cycle initiated by O3 and water vapor and driven by CO and NO; thus, OH is predicted to be higher by a factor of .apprx.4 in polluted continental air as compared with the clean troposphere. Using CH4 as a model compd., OH in the continental atm. is essentially unaffected for ambient CH4 concns. of 1.5 ppm; for the clean troposphere, OH is decreased by .apprx.25% compared to the CH4-free case. As a consequence of this, a slight shift of the oxidative potential of the troposphere from unpolluted maritime areas to the more polluted continents parallel with the temporal increase of the CH4 concn. is predicted.
Dieser Eintrag ist freigegeben.