Particle‐Phase Uptake and Chemistry of Highly Oxygenated Organic Molecules (HOMs) From α‐Pinene OH Oxidation

Abstract

A substantial fraction of sub-micron tropospheric aerosol particles (20%-90%) consists of organic matter (Jimenez et al., 2009;Q. Zhang et al., 2007). Its formation can be attributed to either direct emission of primary organic aerosol or to reactions of organic compounds in the gas phase followed by condensation and chemical processing leading to secondary organic aerosol (SOA;Ervens et al., 2011). Currently, the total global SOA burden is modeled to range from 0.3 to 2.3 Tg (

Secondary Organic Aerosol (SOA) through Uptake of Isoprene Hydroxy Hydroperoxides (ISOPOOH) and its Oxidation Products

“…While the initial drop of the concentration of monomeric compounds varied a lot, the dimeric compounds showed only small variability. Interestingly, the initial uptake coefficients of the α-pinene monomers measured by Poulain et al also cover a comparable range from 0.01 to 0.2. Although monomeric compounds of α-pinene already have as many carbon atoms in the molecular structure as isoprene dimers, the uptake coefficients are more comparable to monomeric compounds of ISOPOOH oxidation than to dimeric compounds.…”

“…The chamber was flushed with 200 L min –1 of purified air for at least 18 h before switching to batch mode operation for the experiment. A detailed description of the chamber can be found in previous publications. , Both ISOPOOH and OH radical oxidation products were quantified by using a chemical ionization atmospheric pressure interface time-of-flight mass spectrometer (CI-APi-ToFMS) with nitric acid (NO 3 – -CIMS) and n -butylamine ( n BA-CIMS) utilized as primary ion sources. A calibration with in situ-produced gaseous sulfuric acid was performed to quantify oxidation products following the procedure of Kürten et al with a slight modification .…”

The fate of organic peroxides indoors: quantifying humidity-dependent uptake on naturally soiled indoor window glass

“…In this work, 1,2-ISOPOOH was used as a model indoor ROOH to represent the dynamics of this class of indoor pollutants with real indoor surfaces. Like outdoors, 56,93,141–144 there is likely a plethora of ROOH compounds present indoors, due particularly to oxidation of indoor terpenes ( e.g. , from air fresheners, cleaning products, wood materials) 145,146 but also from polycyclic aromatic hydrocarbons ( e.g.…”

“…30,58 Aerosol water and acidity have been shown to promote reactive uptake of ISOPOOH. 53,55,56,95 A major fate of 1,2-ISOPOOH in acidied sulfate aerosols is acidic cleavage of the O-O bond leading to gas-phase decomposition products (hydroxy acetone and acetaldehyde). 95 These products were not detected in the gases leaving the reactor in the current study, either because they were not produced or, more likely, because the I-HR-TOF-CIMS is not very sensitive to these small carbonyl compounds.…”

“…50,51 Reactive uptake of ROOHs is already known to play an important role in the chemistry of outdoor aqueous aerosols and clouds. 37,[52][53][54][55][56] For example, humidity, and presumably aerosol liquid water, was shown to facilitate the reactive uptake to aerosols of ROOHs derived from terpene ozonolysis. 53,55 Certainly differences between ROOH multiphase chemistry on surfaces in damp homes and on outdoor aerosols are expected, because differences in pH, hygroscopicity, phase separation and other critical properties are likely, although not adequately characterized.…”