(1) During the entire observation period and in seven pollution episodes, SO 4 2−, NO 3 −, and NH 4 + (SNA) accounted for 84.4–93.1% of the total water-soluble ions (TWSIs). All rights reserved.From January 1 to April 22, 2014, an online analyzer for monitoring aerosols and gases (MARGA) was used to measure and analyze water-soluble ions in inhalable particulate matter with a diameter less than 10 μm (PM 10) during winter-spring in Shenyang city, China. On the other hand, a substantial amount of NH 3 reduction (>70%) would be required to lower the aerosol pH, driving more than 50% of the particulate phase NO 3 - to the gas phase, thereby making NH 3 a limiting factor in shifting PM 2.5 composition.Īerosol chemistry Control strategy Gas-particle partition Inorganic salts Light extinction Thermodynamic equilibrium.Ĭopyright © 2022 Elsevier Ltd. Consequently, a reduction of NOx would result in instantaneous cuts of NO 3 -, PM 2.5, and ALWC, and hence improved visibility. As a result, PM 2.5 composition was most sensitive to gas-phase HNO 3, and hence NOx, and relatively insensitive to NH 3. a saturated factor in visibility reduction) and excess NH 4 + amidst a NH 3-rich environment. Simulations from the thermodynamic model depict that the inorganic aerosol system in the study area was characterized by fully neutralized SO 4 2- (i.e. The high relative humidity (RH) at the study area (average 70.7%) was a necessary but not sole factor leading to enhanced NO 3 - formation, which was more directly associated with elevated ALWC and aerosol pH. The diurnal variations of the above parameters indicate that the interaction and likely mutual promotion between NO 3 - and ALWC enhanced the hygroscopicity and aqueous-phase reactions conducive for NO 3 - formation, thus led to severely impaired visibility. In particular, the NO 3 - contribution to PM 2.5 increased, whereas the SO 4 2- contribution decreased, with decreasing visibility. During the entire observation period, PM 2.5 and SNA concentrations, aerosol pH, aerosol liquid water content (ALWC), and sulfur and nitrogen conversion ratios all increased with decreasing visibility. On average, the sulfate (SO 4 2-), nitrate (NO 3 -), and ammonium (NH 4 +) components (SNA) contributed ∼90% of WSI concentrations, which in turn made up about 50% of the PM 2.5 mass. This study investigated the hourly inorganic aerosol chemistry and its impact on atmospheric visibility over an urban area in Central Taiwan, by relying on measurements of aerosol light extinction, inorganic gases, and PM 2.5 water-soluble ions (WSIs), and simulations from a thermodynamic equilibrium model. 7 Institute of Environmental Engineering and Management, National Taipei University of Technology, 1, Sec.

6 NASA Goddard Space Flight Center, Greenbelt, MD, 20771, USA.5 Center for Space and Remote Sensing Research, National Central University, 300, Zhongda Rd., Zhongli Dist., Taoyuan, 320317, Taiwan.1, Jingmao Rd., Beitun Dist., Taichung, 406040, Taiwan. 4 Department of Occupational Safety and Health, China Medical University, 100, Sec.3 Department of Atmospheric Sciences, National Central University, 300, Zhongda Rd., Zhongli Dist., Taoyuan, 320317, Taiwan.Electronic address: 2 Graduate Institute of Environmental Engineering, National Taiwan University, 1, Sec. 1 Department of Occupational Safety and Health, China Medical University, 100, Sec.

Trebs inorganic gases and aerosol