OH-initiated heterogeneous oxidation of tris-2-butoxyethyl phosphate: implications for its fate in the atmosphere
TLDR
In this paper, a particle-phase relative rates technique is used to investigate the heterogeneous reaction between OH radicals and tris-2-butoxyethyl phosphate (TBEP) at 298 K by combining aerosol time-of-flight mass spectrometry (C-ToF-MS) data and positive matrix factor (PMF) analysis.Abstract:
. A particle-phase relative rates technique is used to investigate the heterogeneous reaction between OH radicals and tris-2-butoxyethyl phosphate (TBEP) at 298 K by combining aerosol time-of-flight mass spectrometry (C-ToF-MS) data and positive matrix factor (PMF) analysis. The derived second-order rate constants (k2) for the heterogeneous loss of TBEP is (4.44 ± 0.45) × 10−12 cm3 molecule−1 s−1, from which an approximate particle-phase lifetime was estimated to be 2.6 (2.3–2.9) days. However, large differences in the rate constants for TBEP relative to a reference compound were observed when comparing internally and externally mixed TBEP/organic particles, and upon changes in the RH. The heterogeneous degradation of TBEP was found to be depressed or enhanced depending upon the particle mixing state and phase, highlighting the complexity of heterogeneous oxidation in the atmosphere. The effect of gas-particle partitioning on the estimated overall lifetime (gas + particle) for several organophosphate esters (OPEs) was also examined through the explicit modeling of this process. The overall atmospheric lifetimes of TBEP, tris-2-ethylhexyl phosphate (TEHP) and tris-1,3-dichloro-2-propyl phosphate (TDCPP) were estimated to be 1.9, 1.9 and 2.4 days respectively, and are highly dependent upon particle size. These results demonstrate that modeling the atmospheric fate of particle-phase toxic compounds for the purpose of risk assessment must include the gas-particle partitioning process, and in the future include the effect of other particulate components on the evaporation kinetics and/or the heterogeneous loss rates.read more
Citations
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On the Evaporation Kinetics and Phase of Laboratory and Ambient Secondary Organic Aerosol
TL;DR: It is found that even when gas phase organics are removed, it takes ∼24 h for pure α-pinene SOA particles to evaporate 75% of their mass, which is in sharp contrast to the ∼10 min time scale predicted by current kinetic models.
Journal ArticleDOI
Heterogeneous chemistry and reaction dynamics of the atmospheric oxidants, O3, NO3, and OH, on organic surfaces
TL;DR: Experimental and computational studies have begun to reveal the detailed reaction mechanisms and kinetics for gas-phase O3, NO3, and OH when they impinge on organic surfaces, which will help others more accurately predict the properties of aerosols, the environmental impact of interfacial oxidation, and the concentrations of tropospheric gases.
Journal ArticleDOI
Effects of Atmospheric Water on ·OH-initiated Oxidation of Organophosphate Flame Retardants: A DFT Investigation on TCPP
Chao Li,Chao Li,Jingwen Chen,Hong-Bin Xie,Yuanhui Zhao,Deming Xia,Tong Xu,Xuehua Li,Xianliang Qiao +8 more
TL;DR: It is revealed for the first time that water has a negative role in the ·OH-initiated degradation of TCPP by modifying the stabilities of prereactive complexes and transition states via forming hydrogen bonds, which unveils one underlying mechanism for the observed persistence ofTCP in the atmosphere.
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Flame retardants in urban air: A case study in Toronto targeting distinct source sectors.
Amandeep Saini,Jenna Clarke,Narumol Jariyasopit,Cassandra Rauert,Jasmin K. Schuster,Sabina Halappanavar,Greg J. Evans,Yushan Su,Tom Harner +8 more
TL;DR: It is recommended that long-term monitoring programs targeting flame retardants (FRs) include urban sites, which provide an early indicator of effectiveness of control measures of targeted FRs, while at the same time providing information on emission sources and trends of replacement FR chemicals.
Images reveal that atmospheric particles can undergo liquid-liquid phase separations
Allan K. Bertram,Yuan You,Lindsay Renbaum-Wolff,Marc Carreras-Sospedra,Naruki Hiranuma,M. L. Smith,Xiaolu Zhang,Rodney J. Weber,John E. Shilling,Donald Dabdub,Scot T. Martin +10 more
TL;DR: Using optical and fluorescence microscopy, images are presented that show the coexistence of two noncrystalline phases for real-world samples collected on multiple days in Atlanta, GA as well as for laboratory-generated samples under simulated atmospheric conditions that reveal that atmospheric particles can undergo liquid–liquid phase separations.
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