Concentrations of some minor gas components were measured in Moscow in the winter-spring period of 1996. The dynamics of peroxy radical concentrations was evaluated on the basis of a one-dimensional photochemical model, taking into account the variable insolation, which depends on the cloud cover and the level of urban atmosphere pollution. Diurnal and weekly periods were found in the concentration behavior. They are associated with the city's industrial rhythm. The total concentration of peroxy radicals can serve as an air purity indicator.
$^1$Atmospheric Physics Institute, Russian Academy of Sciences
$^2$Faculty of Physics, Moscow State University, Leninskie Gory, Moscow, 119992, Russia