When developing neutralization systems for harmful agents, it is necessary to understand the mechanisms of the formation and evolution of an aerosol cloud in a closed or open space. Effective decontamination with aerosol clouds is provided by a rather high particle concentration and dispersion in an open space or on contaminated surfaces. This paper considers neutralization systems based on pulsed powder aerosol generators. It is shown that an aerosol cloud consisting of micron- and submicron-sized particles appears for several seconds after spraying. A further evolution of the aerosol cloud in a room is associated with the gravitational settling, diffusion, and coagulation of particles and their settling on the walls and ceiling. In the case of an open space or a ventilation system in a room, the evolution of the aerosol cloud is affected by the airflow. The main purpose of this paper is to determine the most important parameters and critical conditions of pulsed aerosol generation. A mathematical model is, thus, proposed for pulsed aerosol generation, and its parametric study is conducted in the most typical conditions. The purpose performance predicted by the model is the mass concentration of aerosol particles in the air and on surfaces, depending on the time of particle spraying and dispersion.
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http://dx.doi.org/10.3390/ma16165701 | DOI Listing |
Environ Sci Technol
January 2025
School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
Fenton-like reactions between organic peroxides and transition-metal ions in the atmospheric aqueous phase have profound impacts on the chemistry, composition, and health effects of aerosols. However, the kinetics, mechanisms, and key influencing factors of such reactions remain poorly understood. In this study, we synthesized a series of monoterpene-derived α-acyloxyalkyl hydroperoxides (AAHPs), an important class of organic peroxides formed from Criegee intermediates during the ozonolysis of alkenes, and investigated their Fenton-like reactions with iron ions in the aqueous phase.
View Article and Find Full Text PDFACS EST Air
January 2025
Lyles School of Civil & Construction Engineering, Purdue University, West Lafayette, Indiana 47907, United States.
Commercial HVAC systems intended to mitigate indoor air pollution are operated based on standards that exclude aerosols with smaller diameters, such as ultrafine particles (UFPs, D ≤ 100 nm), which dominate a large proportion of indoor and outdoor number-based particle size distributions. UFPs generated from occupant activities or infiltrating from the outdoors can be recirculated and accumulate indoors when they are not successfully filtered by an air handling unit. Monitoring UFPs in real occupied environments is vital to understanding these source and mitigation dynamics, but capturing their rapid transience across multiple locations can be challenging due to high-cost instrumentation.
View Article and Find Full Text PDFSci Total Environ
January 2025
Université Paris Cité and Univ Paris Est Creteil, CNRS, LISA, F-75013 Paris, France.
Understanding the solubility dynamics of elements during wet deposition is crucial for assessing their environmental impacts. In this study, we investigated the solubility behaviour of various elements originating from natural and anthropogenic sources using a dataset of 106 samples describing the sequential collections of 8 rainfall events. Our results reveal distinct solubility patterns depending on the type of event, with mineral-dust events exhibiting lower solubility and anthropogenic events displaying higher solubility, in relation with dust content and pH.
View Article and Find Full Text PDFEnviron Pollut
January 2025
Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, Los Angeles, CA, 90095, USA.
With the continuous intensification of global warming, the reduction and ultimate phase-out of coal combustion is an inevitable trend in the future global energy transformation. This study comprehensively analyzed the impact of phasing out coal combustion on global emissions and concentrations of air pollutants, radiative fluxes, meteorology and climate using Community Earth System Model 2 (CESM2). The results indicate that after the global phase-out of coal combustion, there is a marked decrease in the concentrations of sulfur dioxide (SO), nitrogen oxides (NO) and fine particulate matter (PM), with some regions experiencing a reduction of exceeding 50%.
View Article and Find Full Text PDFNatl Sci Rev
January 2025
College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China.
China's pursuit of carbon neutrality targets hinges on a profound shift towards low-carbon energy, primarily reliant on intermittent and variable, yet crucial, solar and wind power sources. In particular, low-solar-low-wind (LSLW) compound extremes present a critical yet largely ignored threat to the reliability of renewable electricity generation. While existing studies have largely evaluated the impacts of average climate-induced changes in renewable energy resources, comprehensive analyses of the compound extremes and, particularly, the underpinning dynamic mechanisms remain scarce.
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