The oxidation of NO_2 to nitrate day and night

In a recent article Richards (1983) has suggested a chemical reaction mechanism, given in Table 1, for night-time NO_2 oxidation. Richards makes several qualitative statements concerning the ability of this mechanism to represent measured night-time NO_x, concentrations but does not present simulated results based on this mechanism. In order to assess the validity of Richards' suggested mechanism, we have integrated the rate equations corresponding to the reactions in Table 1 under the following conditions: (1) There is a constant source of NO, S_(NO) (ppm min^(-1)) during the night, (2) At t = 0 (1800 PDT) the initial concentrations are those reported by Platt et al. (1980) from the Los Angeles area.