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A heterogeneous condensation process facilitates the growth of fine particulate matter, making it more easily removable. The aim of this study was to effectively eliminate pre-existing fine particles in the atmosphere by investigating the growth characteristics of particles in turbulent water vapor environments using experimental and numerical methods. The results reveal that the presence of soluble and hydrophilic particles in atmospheric fine particulate matter enhances their growth compared to coal particles. Increasing temperature differences, reducing particle number concentrations, and elevating the proportion of soluble particle components contribute to particle growth. When the temperature difference is below 10K, particle growth is less effective. The beneficial impact of particle collision and coagulation, partly offsetting water vapor competition, was observed with an increase in particle number concentration. The addition of soluble and hydrophilic components promoted particle activation, further fostering particle growth. The region near the wall exhibited more significant particle growth due to higher supersaturation and lower flow velocity. These findings theoretically support the application of heterogeneous condensation processes in atmospheric purification. [ABSTRACT FROM AUTHOR]

Atmospheric fine particle pollution has an important impact on regional environment, global climate and human health, so it has been one of the key and difficult points of air pollution prevention and control. In recent years, due to the continuous promotion of China's air pollution prevention and control plan, the problem of atmospheric fine particle pollution has been significantly improved, and the relevant measurement technology has also made considerable progress. In this paper, the development and application of atmospheric fine particle measurement technology in recent years are reviewed based on the information of physical and chemical parameters such as atmospheric fine particle number concentration, particle size distribution and chemical composition. For the measurement of fine particle number concentration, it mainly includes diffusion charge counting and condensation particle counting. The former is mainly applicable to the combustion emission scenario, and the latter is applicable to the urban air low concentration scenario. For the measurement of fine particle size, it mainly involves single particle size and overall particle size spectrum analysis. The single particle size is mostly determined by electron microscopy and optical microscopy, and the particle size spectrum analysis is mainly determined by electro migration classification. For the component measurement of fine particles, aerosol mass spectrometry and spectral analysis are mainly used. Finally, in view of the new requirements of research on the evolution mechanism of atmospheric particulates and intelligent monitoring and supervision, this paper discusses the future development of atmospheric fine particulates in multi-parameter comprehensive characterization, rapid measurement of dynamic processes, high-performance micro-nano sensors and other directions.

Ionized field strength is one of the significant parameters of ultrahigh-voltage direct current (UHVDC) power lines, which determines the geometric design of the lines and human exposure in the electromagnetic environment. It is complex to calculate the ionized field distribution accurately due to the ions generated in the processes of corona discharges on the HV lines’ surfaces. Moreover, the existence of atmospheric fine particles with the diameter order of micrometers ($\mu \text{m}$) makes the ionized field calculation problem more difficult because the fine particles surrounding the HV lines will be charged and distributed in the areas between the lines and the ground. In this paper, the impacts of charged atmospheric fine particles on the ±800 kV UHVDC transmission lines’ ionized field distribution at ground level are investigated by the upstream boundary element method. The algorithm is verified by both calculations and measurements. The contribution of charged particles to the charge density in air is also considered and obtained in the algorithm. This paper may provide some valuable reference for the design of UHVDC transmission lines. [ABSTRACT FROM AUTHOR]

12 days with relative steady weather conditions in autumn of 2012 were selected, and the variation of atmospheric fine particle in Xi'an was measured by aerodyne aerosol chemical speciation monitor (ACSM); source apportionment of organics from atmospheric fine particle was analyzed by the means of positive matrix factorization (PMF), and the effect of atmospheric fine particle on visibility was discussed; finally, the scattering coefficient was reconstructed by the means of hygroscopic growth factors from IMPROVE equation and multi-linear regression statistical method. The results show that the correlation between time series of mass concentrations of non-refractory PM1 (except for black carbon and mineral dust) and PM2.5 is significant with a determination coefficient of 0.67 at the observation session; the mass concentration of nonrefractory PM1 is about 60% of PM2.5, and the mass concentration of organic is about 58% of PM1, other components (including SO42-, NO3-, NH4- and Cl-) is about 42%; higher relative humidity increases the mass fraction of primary component, and rainfall significantly improves the wet deposition of primary component; hydrocarbon-like organic aerosol (HOA) and oxygenated organic aerosol (OOA) are resolved from organics by the means of PMF; mass concentration of OOA is about 54% of organics, and that of HOA is about 46%; HOA volatilizes and translates to OOA after a photochemical reaction in the afternoon; nitrate contributes most to light scattering coefficient. [ABSTRACT FROM AUTHOR]