Quantification of the role of stabilized Criegee intermediates in the formation of aerosols in limonene ozonolysis

Abstract

Abstract. Stabilized Criegee intermediates (SCIs) have the potential to oxidize trace species and to produce secondary organic aerosols (SOAs), making them important factors in tropospheric chemistry. This study quantitatively investigates the performance of SCIs in SOA formation at different relative humidity (RH) levels, and the first- and second-generation oxidations of endo- and exocyclic double bonds ozonated in limonene ozonolysis are studied separately. Through regulating SCI scavengers, the yields and rate constants of SCIs in a reaction system were derived, and the quantities of SCIs were calculated. The quantity of SOAs decreased by more than 20 % under low-humidity conditions (10 % RH–50 % RH), compared to that under dry conditions, due to the reactions of SCIs with water, while the inhibitory effect of water on SOA formation was not observed under high-humidity conditions (60 % RH–90 % RH). When using excessive SCI scavengers to exclude SCI reactions, it was found that the effect of water on SOA formation with the presence of SCIs was different from that without the presence of SCIs, suggesting that SCI reactions were relevant to the non-monotonic impact of water. The fractions of the SCI contribution to SOAs were similar between dry and high-humidity conditions, where the SCI reactions accounted for ∼ 63 % and ∼ 73 % in SOA formation in the first- and second-generation oxidation; however, marked differences in SOA formation mechanisms were observed. SOA formation showed a positive correlation with the quantity of SCIs, and the SOA formation potential of SCIs under high-humidity conditions was more significant than that under dry and low-humidity conditions. It was estimated that 20 %–30 % of SCIs could be converted into SOAs under high-humidity conditions, while this value decreased by nearly half under dry and low-humidity conditions. The typical contribution of limonene-derived SCIs to SOA formation is calculated to be (8.21 ± 0.15) × 10−2 µg m−3 h−1 in forest, (4.26 ± 0.46) × 10−2 µg m−3 h−1 in urban areas, and (2.52 ± 0.28) × 10−1 µg m−3 h−1 in indoor areas. Water is an uncertainty in the role SCIs play in SOA formation, and the contribution of SCIs to SOA formation needs consideration even under high RH in the atmosphere.

Temperature-dependent kinetics of the atmospheric reaction between CH2OO and acetone

“…Criegee intermediates 1 (carbonyl oxides) are formed in the ozonolysis of unsaturated compounds in the atmosphere, [2][3][4][5][6][7][8][9][10][11] and they are very important in the atmosphere because they contribute to the formation of OH radicals [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] and secondary organic aerosols. [28][29][30][31][32][33][34][35][36][37] Criegee intermediates act as oxidants, and their kinetics provide key parameters [38][39][40][41][42] for estimating the oxidative capacity of the atmosphere. 5,38,[40][41][42][43] However, information about their kinetics is still limited.…”

Atmospheric Kinetics: Bimolecular Reactions of Carbonyl Oxide by a Triple-Level Strategy

“…Criegee intermediates (carbonyl oxides) are of particular importance in the atmosphere because they lead to the formation of OH − and secondary organic aerosols (SOAs) − andby oxidizing SO 2 to SO 3 to the formation of sulfuric acid. − OH radical is an important oxidant, and SOAs are important for absorbing and scattering solar radiation and for cloud formation. As a consequence, understanding the reactions of Criegee intermediates is critical to climate modeling.…”

Quantitative kinetics for the atmospheric reactions of Criegee intermediates with acetonitrile

“…Criegee intermediates play significant roles in the atmosphere because they control the atmospheric oxidation capacity and lead to the formation of secondary organic aerosols. [2][3][4][5][6][7][8] Therefore, it is necessary to obtain the kinetics of reactions involving Criegee intermediates for atmospheric modeling and understanding their atmospheric effects. However, elucidating the atmospheric oxidation capacity of Criegee intermediates is still a challenge because knowledge of the kinetics of reactions involving Criegee intermediates is still limited.…”