PMID- 32353798
OWN - NLM
STAT- PubMed-not-MEDLINE
DCOM- 20200622
LR  - 20200622
IS  - 1879-1026 (Electronic)
IS  - 0048-9697 (Linking)
VI  - 728
DP  - 2020 Aug 1
TI  - The effects of humidity and ammonia on the chemical composition of secondary 
      aerosols from toluene/NOx photo-oxidation.
PG  - 138671
LID - S0048-9697(20)32188-4 [pii]
LID - 10.1016/j.scitotenv.2020.138671 [doi]
AB  - The secondary aerosol formation mechanism in the presence of ammonia (NH(3)), is 
      poorly understood, especially under high relative humidity (RH) conditions. In 
      this study, a total of seven experiments were conducted from toluene/NOx 
      photo-oxidation in the presence/absence of NH(3) under dry (~7% RH) and wet (>60% 
      RH) conditions in a ~3 m(3) smog chamber. A series of instruments including gas 
      analysers, scanning mobility particle sizer (SMPS), aerosol mass spectrometry 
      (HR-ToF-AMS) etc. were applied to measure the NOx and O(3) concentrations, the 
      mass concentration and chemical composition of secondary aerosol. It was found 
      that NH(3) could enhance the mass loading of secondary aerosol, especially under 
      wet condition. However, the presence of NH(3) or increasing RH did not have a 
      significant influence on SOA yield. The organic aerosol mass spectrum from AMS 
      showed that the most abundant fragment was at m/z = 44, which was mainly from the 
      fragmentation of carboxylic acids. Compared to the absence of NH(3), the fraction 
      of fragment at m/z = 44 and O:C was higher in the presence of NH(3), regardless 
      of dry or wet conditions. The highest O:C value of 0.71-0.75 was observed in the 
      presence of NH(3) under wet condition, suggesting there could be a synergetic 
      effect between the high RH and the presence of NH(3), which jointly contributed 
      to the photochemical aging process of SOA. The N:C increased in the presence of 
      NH(3) under both dry and wet conditions, which might be attributed to the 
      carboxylates and organic nitrates formed from the reaction between NH(3) and 
      carboxylic acids. The results implied that SOA modelling should consider the role 
      of NH(3) and water vapour, which might fill the gap of O:C between laboratory 
      studies and field measurements.
CI  - Copyright (c) 2020 Elsevier B.V. All rights reserved.
FAU - Chen, Linghong
AU  - Chen L
AD  - State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 
      310027, China.
FAU - Bao, Zhier
AU  - Bao Z
AD  - State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 
      310027, China.
FAU - Wu, Xuecheng
AU  - Wu X
AD  - State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 
      310027, China. Electronic address: chenlh@zju.edu.cn.
FAU - Li, Kangwei
AU  - Li K
AD  - State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 
      310027, China.
FAU - Han, Lixia
AU  - Han L
AD  - State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 
      310027, China.
FAU - Zhao, Xingya
AU  - Zhao X
AD  - State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 
      310027, China.
FAU - Zhang, Xin
AU  - Zhang X
AD  - State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 
      310027, China.
FAU - Wang, Zhihua
AU  - Wang Z
AD  - State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 
      310027, China.
FAU - Azzi, Merched
AU  - Azzi M
AD  - CSIRO Energy, PO Box 52, North Ryde, NSW 1670, Australia.
FAU - Cen, Kefa
AU  - Cen K
AD  - State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 
      310027, China.
LA  - eng
PT  - Journal Article
DEP - 20200413
PL  - Netherlands
TA  - Sci Total Environ
JT  - The Science of the total environment
JID - 0330500
SB  - IM
OTO - NOTNLM
OT  - AMS
OT  - Ammonia
OT  - Chemical composition
OT  - Relative humidity
OT  - Smog chamber
COIS- Declaration of competing interest The authors declare that they have no known 
      competing financial interests or personal relationships that could have appeared 
      to influence the work reported in this paper.
EDAT- 2020/05/01 06:00
MHDA- 2020/05/01 06:01
CRDT- 2020/05/01 06:00
PHST- 2020/01/02 00:00 [received]
PHST- 2020/03/30 00:00 [revised]
PHST- 2020/04/11 00:00 [accepted]
PHST- 2020/05/01 06:00 [pubmed]
PHST- 2020/05/01 06:01 [medline]
PHST- 2020/05/01 06:00 [entrez]
AID - S0048-9697(20)32188-4 [pii]
AID - 10.1016/j.scitotenv.2020.138671 [doi]
PST - ppublish
SO  - Sci Total Environ. 2020 Aug 1;728:138671. doi: 10.1016/j.scitotenv.2020.138671. 
      Epub 2020 Apr 13.