TY - JOUR
T1 - Atmospheric fate of peroxyacetyl nitrate in suburban Hong Kong and its impact on local ozone pollution
AU - Zeng, Lewei
AU - Fan, Gang-Jie
AU - Lyu, Xiaopu
AU - Guo, Hai
AU - Wang, Jia-Lin
AU - Yao, Dawen
N1 - Funding Information:
This study was supported by the Research Grants Council of the Hong Kong Special Administrative Region via Grants PolyU5154/13E , PolyU152052 / 14E, PolyU152052/16E , CRF/C5004-15E , and CRF/C5022-14G and by the Research Institute for Sustainable Urban Development, Hong Kong Polytechnic University ( 1-BBW4 & 1-BBW9 ). This study was partially supported by Hong Kong PolyU internal grants ( G-YBUQ , 1-ZVJT , and 4-BCF6 ) and the National Key R&D Program of China supported by Ministry of Science and Technology of the People's Republic of China ( 2017YFC0212001 ).
Publisher Copyright:
© 2019 Elsevier Ltd
PY - 2019/9
Y1 - 2019/9
N2 - Peroxyacetyl nitrate (PAN) is an important reservoir ofatmospheric nitrogen, modulating reactive nitrogen cycle and ozone (O3)formation. To understand the origins of PAN, a field measurement was conductedat Tung Chung site (TC) in suburban Hong Kong from October to November 2016.The average level of PAN was 0.63 ± 0.05 ppbv, with a maximum of 7.30 ppbv.Higher PAN/O3 ratio (0.043–0.058) was captured on episodes, i.e. when hourly maximum O3exceeded 80 ppbv, than on non-episodes (0.01), since O3 productionwas less efficient than PAN when there was an elevation of precursors (i.e. volatile organic compounds(VOCs) and nitrogen oxide (NOx)). Model simulations revealed thatoxidations of acetaldehyde (65.3 ± 2.3%), methylglyoxal (MGLY, 12.7 ± 1.2%) andother oxygenated VOCs (OVOCs) (8.0 ± 0.6%), and radical cycling (12.2 ± 0.8%)were the major production pathways of peroxyacetyl (PA) radical, while localPAN formation was controlled by both VOCs and nitrogen dioxide (NO2).Among all VOC species, carbonyls made the highest contribution (59%) to PANformation, followed by aromatics (26%) and biogenic VOCs (BVOCs) (10%) throughdirect oxidation/decomposition. Besides, active VOCs (i.e. carbonyls, aromatics, BVOCsand alkenes/alkynes) could stimulate hydroxyl (OH) production, thus indirectlyfacilitating the PAN formation. Apart from primary emissions, carbonyls werealso generated from oxidation of first-generation precursors, i.e., hydrocarbons, of whichxylenes contributed the most to PAN production. Furthermore, PAN formationsuppressed local O3 formation at a rate of 2.84 ppbv/ppbv, when NO2,OH and hydroperoxy (HO2) levels decreased and nitrogen monoxide (NO)value enhanced. Namely, O3 was reduced by 2.84 ppbv per ppbv PANformation. Net O3 production rate was weakened (∼36%)due to PAN photochemistry, so as each individual production and loss pathway.The findings advanced our knowledge of atmospheric PAN and its impact on O3production.
AB - Peroxyacetyl nitrate (PAN) is an important reservoir ofatmospheric nitrogen, modulating reactive nitrogen cycle and ozone (O3)formation. To understand the origins of PAN, a field measurement was conductedat Tung Chung site (TC) in suburban Hong Kong from October to November 2016.The average level of PAN was 0.63 ± 0.05 ppbv, with a maximum of 7.30 ppbv.Higher PAN/O3 ratio (0.043–0.058) was captured on episodes, i.e. when hourly maximum O3exceeded 80 ppbv, than on non-episodes (0.01), since O3 productionwas less efficient than PAN when there was an elevation of precursors (i.e. volatile organic compounds(VOCs) and nitrogen oxide (NOx)). Model simulations revealed thatoxidations of acetaldehyde (65.3 ± 2.3%), methylglyoxal (MGLY, 12.7 ± 1.2%) andother oxygenated VOCs (OVOCs) (8.0 ± 0.6%), and radical cycling (12.2 ± 0.8%)were the major production pathways of peroxyacetyl (PA) radical, while localPAN formation was controlled by both VOCs and nitrogen dioxide (NO2).Among all VOC species, carbonyls made the highest contribution (59%) to PANformation, followed by aromatics (26%) and biogenic VOCs (BVOCs) (10%) throughdirect oxidation/decomposition. Besides, active VOCs (i.e. carbonyls, aromatics, BVOCsand alkenes/alkynes) could stimulate hydroxyl (OH) production, thus indirectlyfacilitating the PAN formation. Apart from primary emissions, carbonyls werealso generated from oxidation of first-generation precursors, i.e., hydrocarbons, of whichxylenes contributed the most to PAN production. Furthermore, PAN formationsuppressed local O3 formation at a rate of 2.84 ppbv/ppbv, when NO2,OH and hydroperoxy (HO2) levels decreased and nitrogen monoxide (NO)value enhanced. Namely, O3 was reduced by 2.84 ppbv per ppbv PANformation. Net O3 production rate was weakened (∼36%)due to PAN photochemistry, so as each individual production and loss pathway.The findings advanced our knowledge of atmospheric PAN and its impact on O3production.
KW - Formation pathways
KW - Master chemical mechanism (MCM)
KW - O formation
KW - Photochemical smog
KW - Precursors
UR - http://www.scopus.com/inward/record.url?scp=85070494854&partnerID=8YFLogxK
U2 - 10.1016/j.envpol.2019.06.004
DO - 10.1016/j.envpol.2019.06.004
M3 - Journal article
C2 - 31227349
AN - SCOPUS:85070494854
SN - 0269-7491
VL - 252, Part B
SP - 1910
EP - 1919
JO - Environmental Pollution
JF - Environmental Pollution
ER -
