Chemical characterization of atmospheric particles

Overview & Synopsis

Atmospheric aerosols are atmospheric pollutants who play an important role in air quality, visibility, climate and human health. They have a complex and changing chemical composition due to their multiple sources and the many reactions that occur in both gas- and particle-phase, which makes understanding their physicochemical properties difficult. This work focused on studying the formation and chemical composition of secondary organic aerosol (SOA) formed from the oxidation of volatile organic compounds (VOC) in an atmospheric simulation chamber. The aerosols were formed from VOCs representative of anthropogenic (naphthalene) and biogenic (α-pinene, β-pinene, limonene) emissions exposed to abundant atmospheric oxidants (O3, OH). The chemical composition of the formed particles was studied using mass spectrometers with extractive electrospray ionization inlets (EESI). The chemical composition of particles was compared to the chemical composition of VOCs oxidation products present in the gas-phase. Those gas-phase oxidation products were studied using mass spectrometers with chemical ionization inlets (CI) or proton-transfer-reaction inlets (PTR). Comparing both gas- and particle-phase allowed the identification of processes responsible for the evolution of the chemical composition of particles during aging.