title: Heterogeneous reactions of particulate benzo[b]fluoranthene and benzo[k]fluoranthene with NO(3) radicals.
abstract: Benzo[b]fluoranthene (B[b]F) and benzo[k]fluoranthene (B[k]F) are widespread priority pollutants of polycyclic aromatic hydrocarbons (PAHs), which can react with atmospheric oxidants during transport in the troposphere and lead to the formation of more toxic compounds. At present, the rates of heterogeneous reactions of B[b]F and B[k]F aerosols with NO3 radicals, an important atmospheric oxidant, are not fully understood. Thus, this study investigated the products and kinetics of heterogeneous reactions of suspended B[b]F and B[k]F particles with NO3 radicals in an aerosol reaction chamber at room temperature (293±2K) under atmospheric pressure. The reactions are monitored online using a vacuum ultraviolet photoionization aerosol time-of-flight mass spectrometer (VUV-ATOFMS) and an atmospheric gas analysis mass spectrometer. The mono-nitro-, di-nitro-, tri-nitro-products, and those products containing both nitro and ketone groups are observed with VUV-ATOFMS. The effective rate constants for heterogeneous reactions of particulate B[b]F and B[k]F with NO3 radicals under the experimental conditions are respectively estimated to (1.2±0.1)×10(-12)cm(3)molecule(-1)s(-1) and (5.8±0.3)×10(-13)cm(3)molecule(-1)s(-1) using a mixed-phase relative rate method, and the corresponding effective uptake coefficients are respectively estimated to 0.22 and 0.65. The lifetimes of particulate B[b]F and B[k]F at a typical concentration of NO3 radicals (5×10(8)moleculecm(-3)) in the lower troposphere during the night are estimated to 3.0 and 3.9h, respectively. The experimental results of these heterogeneous reactions in the aerosol state provide supplementary knowledge for kinetic behaviors of airborne PAHs particles.
authors.affiliation: Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Zhang
authors.affiliation: Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
authors.forename: Youfeng
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. Electronic address: boyang@rcees.ac.cn.
authors.forename: Bo
authors.initials: B
authors.lastname: Yang
authors.affiliation: Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
authors.forename: Changgeng
authors.initials: C
authors.lastname: Liu
authors.affiliation: Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
authors.forename: Jinian
authors.initials: J
authors.lastname: Shu
mesh_terms: D000336:Aerosols / Q000737:chemistry; D000393:Air Pollutants / Q000737:chemistry*; D005449:Fluorenes / Q000737:chemistry*; D007700:Kinetics; D008956:Models, Chemical; D009566:Nitrates / Q000737:chemistry*; D052638:Particulate Matter / Q000737:chemistry*; D011084:Polycyclic Aromatic Hydrocarbons / Q000737:chemistry*
chemical_list: D000336:Aerosols; D000393:Air Pollutants; D005449:Fluorenes; D009566:Nitrates; D052638:Particulate Matter; D011084:Polycyclic Aromatic Hydrocarbons; C006703:benzo(b)fluoranthene; C022921:benzo(k)fluoranthene
keywords: Aerosol mass spectrometry; Heterogeneous reactions; NO(3) radicals; Polycyclic aromatic hydrocarbons