Three aspects of tropospheric chemical processes imposed by manmade emission of source gases will be discussed. First, the implications for the OH distribution and thereby for the lifetime of source gases which are controlled by reactions with OH in the troposphere (e.g., CH4 and HCFC) are investigated. This is of importance for stratosphere ozone and climate. Second, we will study the impact of source gas emission on tropospheric ozone and discuss the possibility to estimate indirect climate effects from the changes in ozone and other climate gases. Finally, the degradation of HFC and HCFC's is discussed. Isaksen, Ivar S. A. and Fuglestvedt, J. A. and Lee, Yuan-Pern and Johnson, Colin and Atkinson, Roger and Lelieveld, Joseph and Sidebottom, Howard and Thompson, Anne and Brune, William H. and Oppenheimer, Michael Goddard Space Flight Center ...