No abstract

No abstract

The comparison is represented of the results of surface ozone concentration measurements in two megalopolises, Moscow and Kiev. A temporal course of ozone concentration and temperature in both cities is close by the shape and is typical of medium-polluted plain stations. In both megalopolises, two maxima are observed within the seasonal ozone concentration variability, in spring and summer, and during the day, a usual ozone concentration maximum (approximately in 2-3 hours after the local noon) and the night one being typical of big cities. An average ozone concentration and an average temperature in corresponding periods are higher in Kiev than in Moscow. Evidently, the summer maximum is associated with photochemical ozone generation processes, and the spring one, with dynamic processes of its transport in the atmosphere. In both megalopolises, the episodes are observed in the warm period under meteorological conditions being unfavorable for the pollutant scattering in the atmosphere when the ozone concentration exceeds the threshold limit value and is dangerous for health. The repeatability of such episodes is the highest one in July-August. In Kiev, such episodes are more frequent than in Moscow. An effective statistical model is constructed for both megalopolises in which the observed ozone concentration is represented in the form of regression function of temperature and relative humidity.

No abstract

A modern three-dimensional chemistry transport model is adopted for computation of air pollution with photo-oxidants in the Moscow megalopolis and in the several neighboring regions. Along the vertical, the model covers the entire troposphere and has a two-scale horizontal structure, when the resolution of the "inserted" domain is about 13 km. The model computation results are compared with the satellite tropospheric nitrogen dioxide measurements and ground-based measurements of the surface ozone concentration. The analysis results of one of the episodes of enhanced ozone content is considered as an example of a possible use of the model considered as a diagnostic tool for studying issues connected with the air pollution in the region under consideration.