IS THE REACTION BETWEEN CH3C(O)O-2 AND NO3 IMPORTANT IN THE NIGHTTIMETROPOSPHERE

A discharge-flow system equipped with a laser-induced fluorescence (LI F) cell to detect NO2 and a multi-pass absorption cell to detect NO3 h as been used to study the reaction CH3C(O)O-2+NO3-->CH3C(O)O+NO2+O-2 ( 1) at T = 403-443 K and P = 2-2.4 Torr. The rate constant was found to be independent of temperature with a value of k(1) = (4+/-1) x 10(-12 ) cm(3) molecule(-1) s(-1). The likely mechanism for the reaction is d iscussed. The atmospheric implications of reaction (1) are investigate d using a range of models and several case studies are presented, comp aring model results with actual held measurements. It is concluded tha t reaction (1) participates in a cycle which can generate OH at night. This reaction cycle (see text) can operate throughout the continental boundary layer, but may even occur in remote regions.