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Stable carbon isotope ratio of secondary particulate organic matter formed by photooxidation of toluene in indoor smog chamber
Abstract Laboratory studies were conducted for stable carbon isotope ratio for secondary particulate organic matter (POM) formed by photooxidation of toluene. Using an 8m3 indoor YorkU smog chamber, three POM generation experiments were carried out under room temperature, atmospheric pressure, and RH<6%. In this study, the different initial conditions were set from those in the previous flow reactor study for secondary POM formed by photooxidation of toluene: introduction of seed particles, and 40–80 times lower initial toluene mixing ratios (∼1900μgm−3) and ∼60 times higher toluene to NOx ratios (∼7), respectively. The formation of secondary POM was confirmed by the size distribution measurements of particles and the POM was collected on quartz fiber filters for carbon mass and stable carbon isotope ratio analysis. The size distribution measurements showed that the POM mass yields were between 37% and 55% at the end of experiments, while the filter analysis showed that the yields of POM carbon collected then were between 7% and 21%, implying the substantial contribution of heteroatoms. The plot of the POM carbon yields from this study and the previous study indicated that the POM carbon yields were merged into a single profile. The results of isotope measurements demonstrated that the carbon isotope fractionation at the initial reaction step was predominant in the overall carbon isotope fractionations that occur in the sequence of the reactions leading to the formation of secondary POM carbon. Using the results, novel approach for estimation of secondary POM carbon yield with stable carbon isotope ratios is proposed.
Research highlights ► δ13C and carbon yield of secondary POM formed by toluene/OH reaction are presented. ► POM carbon yields were proportional to fraction of toluene consumed. ► The results imply contribution of heteroatoms and/or of inorganic to the PM formed. ► Dependence between isotope ratio and particulate yield is presented.
Stable carbon isotope ratio of secondary particulate organic matter formed by photooxidation of toluene in indoor smog chamber
Abstract Laboratory studies were conducted for stable carbon isotope ratio for secondary particulate organic matter (POM) formed by photooxidation of toluene. Using an 8m3 indoor YorkU smog chamber, three POM generation experiments were carried out under room temperature, atmospheric pressure, and RH<6%. In this study, the different initial conditions were set from those in the previous flow reactor study for secondary POM formed by photooxidation of toluene: introduction of seed particles, and 40–80 times lower initial toluene mixing ratios (∼1900μgm−3) and ∼60 times higher toluene to NOx ratios (∼7), respectively. The formation of secondary POM was confirmed by the size distribution measurements of particles and the POM was collected on quartz fiber filters for carbon mass and stable carbon isotope ratio analysis. The size distribution measurements showed that the POM mass yields were between 37% and 55% at the end of experiments, while the filter analysis showed that the yields of POM carbon collected then were between 7% and 21%, implying the substantial contribution of heteroatoms. The plot of the POM carbon yields from this study and the previous study indicated that the POM carbon yields were merged into a single profile. The results of isotope measurements demonstrated that the carbon isotope fractionation at the initial reaction step was predominant in the overall carbon isotope fractionations that occur in the sequence of the reactions leading to the formation of secondary POM carbon. Using the results, novel approach for estimation of secondary POM carbon yield with stable carbon isotope ratios is proposed.
Research highlights ► δ13C and carbon yield of secondary POM formed by toluene/OH reaction are presented. ► POM carbon yields were proportional to fraction of toluene consumed. ► The results imply contribution of heteroatoms and/or of inorganic to the PM formed. ► Dependence between isotope ratio and particulate yield is presented.
Stable carbon isotope ratio of secondary particulate organic matter formed by photooxidation of toluene in indoor smog chamber
Irei, Satoshi (author) / Rudolph, Jochen (author) / Huang, Lin (author) / Auld, Janeen (author) / Hastie, Donald (author)
Atmospheric Environment ; 45 ; 856-862
2010-11-15
7 pages
Article (Journal)
Electronic Resource
English
Secondary organic aerosol , Stable carbon isotope ratio , Photooxidation of toluene , Kinetic isotope effect , Isotope fractionation , <italic>δ</italic> <sup>13</sup>C<inf>POM</inf> , stable carbon isotope ratio of secondary POM , <italic>δ</italic> <sup>13</sup>C<inf>C7H8</inf> , stable carbon isotope ratio of toluene , <sup>0</sup> <italic>δ</italic> <sup>13</sup>C<inf>C7H8</inf> , initial stable carbon isotope ratio of toluene , <italic>δ</italic> <sup>13</sup>C<inf>AllProd</inf> , stable carbon isotope ratio of sum of all products , <sup>OH</sup>ɛ<inf>C7H8</inf> , carbon kinetic isotope effect for the reaction of toluene with OH radical , <italic>Y</italic> <inf>M</inf> , mass yield of secondary POM , <italic>Y</italic> <inf>C</inf> , carbon mass yield of secondary POM , [M<inf>POM</inf>] , mass concentration of secondary POM , Δ[M<inf>C7H8</inf>] , mass concentration of toluene reacted , <sup>passed</sup>M<inf>C7H8</inf> , mass of toluene passed through sampling filter , <sup>passed</sup>ΔC<inf>C7H8</inf> , reacted carbon mass of toluene passed through sampling filter , <sup>0</sup>[C<inf>C7H8</inf>] , initial carbon mass concentration of toluene , [C<inf>C7H8</inf>] , carbon mass concentration of toluene , Δ[C<inf>C7H8</inf>] , carbon mass concentration of toluene reacted , [C<inf>POM</inf>] , carbon mass concentration of secondary POM , C<inf>POM</inf> , carbon mass of secondary POM collected on filter , <sup>loaded</sup>M<inf>POM</inf> , estimated secondary POM mass loaded on filter
Size distribution of the secondary organic aerosol particles from the photooxidation of toluene
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