Is the reaction between CH3C(O)O2and NO3important in the night-time troposphere?

A discharge-flow system equipped with a laser-induced fluorescence (LIF) cell to detect NO2 and a multi-pass absorption cell to detect NO3 has been used to study the reaction CH3C(O)O2+ NO3→ CH3C(O)O + NO2+ O2(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 k1=(4 ± 1)× 10–12 cm3 molecule–1 s–1. The likely mechanism for the reaction is discussed. The atmospheric implications of reaction (1) are investigated using a range of models and several case studies are presented, comparing model results with actual field measurements. It is concluded that 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.