The influence of Asian dust outflow on particle microphysical and optical properties at Mt. Tai in central east China. (October 2016)

• Record Type: Journal Article
• Authors: Shen, X.J.; Sun, J.Y.; Zhang, Y.M.; Zhang, X.Y.; Wang, T.T.; Wang, Y.Q.; Zhang, L.; Fan, R.X.; Zhao, Y.; Wang, D.Z.
• Is Part Of: Atmospheric environment. Volume 143(2016)
• Page Start: 27
• Page End: 38
• Publication Date: 2016-10
• Subjects: Dust aerosol -- Size distribution -- Scattering and absorption -- Mie model; Air -- Pollution -- Periodicals; Air -- Pollution -- Meteorological aspects -- Periodicals; 551.51
• DOI: 10.1016/j.atmosenv.2016.08.014
• Languages: English
• ISSNs: 1352-2310

Abstract

Abstract: An in-situ measurement of the particle number size distribution and optical properties (scattering and absorption coefficients) of PM2.5 was conducted at Mt. Tai, a mountain top station in central east China in the spring of 2011. It was found that the particle size distribution, mass concentration, as well as the optical properties have been modified during the dust periods. The mean mass concentration of PM2.5 during the dust periods was nearly twice of that during the non-dust period. The number and volume size distribution showed a higher concentration in the size range of 0.5–2.5 μm during the dust period, which were identified as dust particles. The absorption coefficient increased by ∼40%, while the scattering coefficient did not show much difference. The single scattering albedo of 0.85 during dust period was also comparable with the value of 0.89 during non-dust period. The Mie model was applied to simulate the aerosol optical properties and validated through a closure study for an intensive dust event. This study quantitatively demonstrated that dust particles contributed to nearly 63% of the scattering coefficient, while the remainder was mainly due to anthropogenic particles on dust days. The dust particles took a lower portion to the absorption, about 40%, indicating the anthropogenic particles still played a more dominant role in absorbing. This study also indicated that although there were only a few tens of dust particles during dust period, they could influence in particle optical properties significantly. Highlights: Particle number and volume size are modified by the dust particles. Particles with diameter of 0.5–2.5 μm are identified as dust particles. Increase in absorption during the dust period. The dust particles contributed ∼63% to the scattering during dust period. The dust particles contributed ∼40% to the absorption during dust period.