Global tropospheric ozone dynamics - Part I: Tropospheric ozone precursors - Part II: Numerical modelling of tropospheric ozone variability

(Part I). An overview of the tropospheric ozone changes is presented focussing mainly on the tropospheric ozone precursors. The complexity of the problem is shown through the consideration of a great number of relevant substances, like nitrogen compounds, volatile organic compounds, peroxyacetyl nitrate, hydroxyl radical, carbon monoxide, alkyl nitrates. The up-to-date knowledge on the relevant numerical modelling is presented in Part II. (Part II). Various causes of tropospheric changes have been considered in Part I in connection with the analysis of observation data. It is clear however, that the principal instrument for understanding numerous and often interacting causes of ozone changes is numerical modelling. A review of the current status of the numerical modelling has been made for the variability of the ozone concentration in the troposphere. Observation data on tropospheric ozone and relevant numerical modelling results show that a necessity exists to get more adequate global observational data.