Measurement report: Atmospheric new particle formation in a coastal agricultural site explained with binPMF analysis of nitrate CI-APi-TOF spectra

Abstract

Abstract. The occurrence of new particle formation (NPF) events detected in a coastal agricultural site, at Qvidja, in Southwestern Finland, was investigated using the data measured with a nitrate ion-based chemical-ionization mass spectrometer (CI-APi-TOF). The binned positive matrix factorization method (binPMF) was applied to the measured spectra. It resulted in eight factors describing the time series of ambient gas and cluster composition at Qvidja during spring 2019. The most interesting factors related to the observed NPF events were the two factors with the highest mass-to-charge ratios, numbered 7 and 8, both having profiles with patterns of highly oxygenated organic molecules. It was observed that the factor 7 had elevated intensities during the NPF events. A variable with an even better connection to the observed NPF events is fF7, which denotes the fraction of the total spectra within the studied mass-to-charge ratio range between 169 and 450 Th being in a form of the factor 7. Values of fF7 higher than 0.5 were typically observed during the NPF events, of which durations also correlated with the duration of fF7 exceeding the critical value of 0.5. It was also observed that the factor 8 acts as a precursor of the factor 7 with high solar irradiance levels.

What chemical species are responsible for new particle formation and growth in the Netherlands? A hybrid positive matrix factorization (PMF) analysis using aerosol composition (ACSM) and size (SMPS)

“…We performed the analysis using the PMF Evaluation Tool (PET) v3.08 in Igor Pro 8. The details of applying positive matrix factorization (PMF) to aerosol mass spectrometry datasets have been discussed elsewhere (Paatero and Tapper, 1994;Paatero, 1999;. Prior to analysis before the PMF input matrix preparation, the variable values and errors of species mass concentrations and particle number concentrations were downweighted in reference to the highest average peak of the original organic mass spectrum, m/z 44 (f 44 ).…”

“…Sulfuric acid (H 2 SO 4 ) is typically understood to be the most prevalent nucleation-inducing agent in NPF events, together with other airborne chemical species, including nitric acid (HNO 3 ), bases (e.g., amines), and organic acids (Zhang et al, 2012(Zhang et al, , 2015Kulmala et al, 2013;Wagner et al, 2017;Lehtipalo et al, 2018;Kürten, 2019;Lee et al, 2019;Brean et al, 2021;Olin et al, 2022). Numerous studies have also reported low-volatility organic species, such as terpene oxidation products and organic nitrates, participating in the formation of new particles (Berkemeier et al, 2016;Tröstl et al, 2016;Barsanti et al, 2017;Dall'Osto et al, 2018;Kerminen et al, 2018;Lee et al, 2019;Heinritzi et al, 2020).…”