Growing population and energy demands cause an increase in emissions of trace gases into the planetary boundary layer. Convective transport lifts the air from the boundary layer into the upper troposphere, where fast horizontal wind patterns transport the locally emitted trace gases on a global scale. These trace gases are dominantly removed by the OH radical, which is created primarily by short wave UV radiation. OH reacts quickly with these trace gases and initiates an oxidation process leading to ozone, particle production, and growth. Depending on the chemical condition, OH can be recycled. Hence this recycling probability is critical for the self-cleaning capacity of the atmosphere. The presentation will highlight the result of three aircraft-based expeditions, studying the impact of convection on the self-cleaning capability in the upper troposphere.