The nitrate radical, cavity ring-down spectroscopy and atmospheric field measurements

In the field of atmospheric chemistry and especially in hindsight of aerosols and air quality, the interaction between biogenic volatile organic compounds (BVOCs) and anthropogenically emitted nitrogen oxides (NOx = NO+NO2) is an important topic to research. During daytime, reactions involving VOCs and NOx are the main pathway to form toxic ground-level ozone (O3). At night, when photolysis is inhibited, the nitrate radical (NO3) can reach tens of ppt and rapidly oxidizes BVOCs such as isoprene and monoterpenes. This process can indirectly remove NOx, leads to the formation of secondary organic aerosols and results in a reduced production of O3 in the morning. Furthermore, these formed nitrated organic compounds are being studied for their interaction with solar radiation as well as an enhancement of immune responses and allergenicity of proteins. This talk will give an overview about the role of NO3 in the atmosphere, how cavity ring-down spectroscopy (CRDS) is used for quantification and challenges during lab work & field campaigns.