Articles | Volume 16, issue 4
Atmos. Chem. Phys., 16, 2175–2184, 2016
https://doi.org/10.5194/acp-16-2175-2016
Atmos. Chem. Phys., 16, 2175–2184, 2016
https://doi.org/10.5194/acp-16-2175-2016

Research article 25 Feb 2016

Research article | 25 Feb 2016

Gas–particle partitioning and hydrolysis of organic nitrates formed from the oxidation of α-pinene in environmental chamber experiments

Jeffrey K. Bean and Lea Hildebrandt Ruiz Jeffrey K. Bean and Lea Hildebrandt Ruiz
  • McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas, USA

Abstract. Gas–particle partitioning and hydrolysis of organic nitrates (ON) influences their role as sinks and sources of NOx and their effects on the formation of tropospheric ozone and organic aerosol (OA). In this work, organic nitrates were formed from the photo-oxidation of α-pinene in environmental chamber experiments under different conditions. Particle-phase ON hydrolysis rates, consistent with observed ON decay, exhibited a nonlinear dependence on relative humidity (RH): an ON decay rate of 2 day−1 was observed when the RH ranged between 20 and 60 %, and no significant ON decay was observed at RH lower than 20 %. In experiments when the highest observed RH exceeded the deliquescence RH of the ammonium sulfate seed aerosol, the particle-phase ON decay rate was as high as 7 day−1 and more variable. The ON gas–particle partitioning was dependent on total OA concentration and temperature, consistent with absorptive partitioning theory. In a volatility basis set, the ON partitioning was consistent with mass fractions of [0 0.11 0.03 0.86] at saturation mass concentrations (C*) of [1 10 100 1000] µg m−3.

Download
Short summary
The fate of organic nitrates influences their role as sinks and sources of NOx and their effects on the formation of tropospheric ozone and organic aerosol. Organic nitrates were formed from the photo-oxidation of α-pinene in environmental chamber experiments. Results on partitioning and hydrolysis of organic nitrates from this work could be implemented in chemical transport models to more accurately represent the fate of NOx and the formation of ozone and particulate matter.
Altmetrics
Final-revised paper
Preprint