Size-dependent influence of NO _x on the growth rates of organic aerosol particles

Abstract

Atmospheric new-particle formation (NPF) affects climate by contributing to a large fraction of the cloud condensation nuclei (CCN). Highly oxygenated organic molecules (HOMs) drive the early particle growth and therefore substantially influence the survival of newly formed particles to CCN. Nitrogen oxide (NOx) is known to suppress the NPF driven by HOMs, but the underlying mechanism remains largely unclear. Here, we examine the response of particle growth to the changes of HOM formation caused by NOx. We show that NOx suppresses particle growth in general, but the suppression is rather nonuniform and size dependent, which can be quantitatively explained by the shifted HOM volatility after adding NOx. By illustrating how NOx affects the early growth of new particles, a critical step of CCN formation, our results help provide a refined assessment of the potential climatic effects caused by the diverse changes of NOx level in forest regions around the globe.

Multifunctional Products of Isoprene Oxidation in Polluted Atmosphere and Their Contribution to SOA

“…It should be noted that the difference of volatility cannot reflect the real situation of bulk volatility estimation, since the contribution of different isomers is unknown. The uncertainty of the volatility of individual IPOOM as well as the overall volatility distribution is hard to get, the current estimation is based on our best knowledge and established methods (Mohr et al., 2019; Simon et al., 2020; Stolzenburg et al., 2018; Yan et al., 2020). An additional 33% uncertainty is also introduced from the determination of the calibration factor of IPOOMs (Kürten et al., 2012).…”

“…The uncertainty of the volatility of individual IPOOM as well as the overall volatility distribution is hard to get, the current estimation is based on our best knowledge and established methods (Stolzenburg et al, 2018;Mohr et al,2019;Simon et al,2020;Yan et al, 2020). An additional 33% uncertainty is also introduced from the determination of the calibration factor of IPOOMs…”

The Effect of Meteorological Conditions and Atmospheric Composition in the Occurrence and Development of New Particle Formation (NPF) Events in Europe

“…Growth rate had weaker correlations with NOx and different trends between the sites, either being positive or negative. The variable effect of NOX on particle growth, shifting HOMs' volatility, was previously discussed by Yan et al (2020). While variability was found for the background sites, all roadsides regardless of the strength of the relation had positive relation between NOx and the growth rate.…”

Enhancement of nanoparticle formation and growth during the COVID-19 lockdown period in urban Beijing

“…3). The previous study indicated that NOx suppresses NPF events by influencing the formation of highly oxygenated organic molecules (HOMs), which participated in nucleation and initial particle growth (Lehtipalo et al, 185 2018, Yan et al, 2020, suggesting that the reduction of NO2 during LCD provided favorable conditions for particle growth.…”

“…The non-linear dependence of J2,tot, and GR on the condensing vapors indicates a complex mechanism in the multi-component nucleation and growth system. When the 205 particles overcame the criteria size of 10 nm, sulfuric acid-which plays an important role in smaller growth processes from 2-10 nm-could not explain condensational growth (Stolzenburg et al, 2020). For particles larger than 10 nm, low volatile https://doi.org/10.5194/acp-2020-1064 Preprint.…”