Tropospheric Chemistry of Reactive Gases

In this introductory talk, we will describe the importance of understanding the role that key reactive gases play in the chemistry of the atmosphere. These compounds, including surface ozone (O3), carbon monoxide (CO), volatile organic compounds (VOCs), oxidized nitrogen compounds (NOx, NOy), ammonia (NH3) and sulfur dioxide (SO2) are heavily involved in inter-relations between atmospheric chemistry and climate, either through control of ozone and the oxidizing capacity of the atmosphere, or through the formation of aerosols. We will review how changes in atmospheric abundances of these species can affect human health and the ecosystems.

 It is particularly interesting to differentiate the natural variability in the abundances of these gases from the perturbations caused by the various human activities. The biogeochemical cycles in which they are involved need to be understood, as well as their main sources, sinks and production/removal mechanisms. This talk will include advances and limitations in our current understanding of these processes.