Nevertheless, organic nitrate, for example, measured by this novel The new VIA– NO 3-CIMS system used in this work will require moreĭetailed characterization to better understand how the thermal desorptionĪnd wall effects may modify the measured particle-phase HOM distributions. Particle-phase processes within 1 h after HOM condensation. Our results indicate that these C 17 compounds might be related to

C 17H 26O z compounds, which have often been reported by previous offline measurements, dominate the particle-phase HOM mass spectra in α-pinene ozonolysis experiments. In addition to the generally shorter carbon skeletons of the particle-phase dimers (i.e., C 16– C 19) compared to the gas phase ( C 19– C 20), average O / C ratios of the HOMs (especially in the dimer range) also decreased slightly in the particle phase. In particular, gas-phase dimer formation was considerably suppressed in experiments with the addition of CO or NO, but dimers still made up a considerable fraction of the observed SOA. Within the 50 min residence time of our Teflon chamber, we observed enhancement of C 16– C 19 HOM dimers in particles compared to the HOMs that were condensing.

Here, combining a novel particle evaporation inlet, the VIA (Vaporization Inlet for Aerosols), with a nitrate chemical ionization mass spectrometer ( NO 3-CIMS), gas- and particle-phase HOM products of α-pinene ozonolysis were studied under different conditions. However, the speciation of particle-phase HOMs and its relationship with gas-phase HOM formation has been limited by the lack of suitable analytical techniques.

Highly oxygenated organic molecules (HOMs) are important for the formation of secondary organic aerosol (SOA), which poses serious health risks and exerts great influence on Earth's climate.

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