A New Method of Removing Fine Particulates Using an Electrostatic Force.

Many studies have found that the concentration of fine particulates in the atmosphere has increased. In particular, when using the bus, the situation in which people are exposed to relatively high concentrations of fine particulates is increasing. The purpose of this study is to reduce exposure to these potentially harmful particulates by introducing open shelters at outdoor bus stops. In order to use it as an outdoor fine particulates reduction device, a brush filter using electrostatic force (EF) was used on an experimental scale and the generation of electrostatic force, according to the material, was examined. As electrostatic force was generated, the fine particulates collection performance was about 90% efficiency. In addition, it was confirmed that the efficiency of each particle size was improved by 57% through structural improvement. Finally, through experimentation, it was confirmed that the brush module can be used for about 70 days.

Solid Oxygen-Purifying (SOP) Filters: A Self-Disinfecting Filters to Inactivate Aerosolized Viruses.

Normal heating, ventilation, and air conditioning (HVAC) systems typically use high-efficiency particulate air (HEPA) filters, which can filter dust, various pollutants, and even bacteria and viruses from indoor air. However, since HEPA filters cannot not clean themselves and due to the nature of these microbes which can survive for long periods of time, changing these filters improperly could transmit pathogenic bacteria or viruses, and could even lead to new infections. This study indicated that these manufactured Solid Oxygen-purifying (SOP) filters have the potential to self-disinfect, filter, and inactivate aerosolized viruses. MS2 bacteriophage was used as a model virus in two different experiments. The first experiment involved aerosolization of the virus, while the second were a higher viral load using a soaking method. The SOP filters inactivated up to 99.8% of the virus particles in both experiments, provided that the density of the SOP filter was high. Thus, SOP filters could self-clean, which led to protection against airborne and aerosolized viruses by inactivating them on contact. Furthermore, SOP filters could be potentially use or addition in HVAC systems and face masks to prevent the transmission of airborne and aerosolized viruses.

Reduction of Escherichia Coli Using Metal Plates with the Influenced of Applied Low Current and Physical Barrier of Filter Layers.

Although metal contact is known to reduce bacterial growth, the effects of physical barriers and electricity need further investigation. This study examined the bacteria-reducing properties of copper and stainless-steel metal plates with an added electrical current and up to three filter layers on the growth of Escherichia coli (bacteria) and MS2 bacteriophages (virus). When used with a stainless-steel plate, electricity increased bacteria reduction by 39.5 ± 2.30% in comparison with no electricity added, whereas a three-layer physical barrier decreased its efficiency. Copper also reduced the growth of bacteria, by 58.2 ± 8.23%, and the addition of electricity reduced it further (79.5 ± 2.34%). Bacteriophages were also affected by the metal contact. Further experiments showed that MS2 was also reduced by copper, to 82.9 ± 4.5% after 24 h at 37 °C.

Emission Characteristics of Particulate Matter, Volatile Organic Compounds, and Trace Elements from the Combustion of Coals in Mongolia.

This study characterized emissions of particulate matter (PM), volatile organic compounds (VOCs), heavy metals, and anions from Mongolian bituminous coals in a controlled heating experiment. Three coal samples from Alag Tolgoi (coal 1), Baganuur (coal 2), and Nalaikh (coal 3) were combusted at a constant heat flux of 50 kW/m² using a dual-cone calorimeter. The coal samples were commonly used in ger district of Ulaanbaatar, Mongolia. PM10 emission factors were 1122.9 ± 526.2, 958.1 ± 584.0, and 472.0 ± 57.1 mg/kg for coal samples 1, 2, and 3, respectively. PM with a diameter of 0.35⁻0.45 µm was dominant and accounted for 41, 34, and 48% of the total PM for coal samples 1, 2, and 3, respectively. The emissions of PM and VOC from coals commonly used in Ulaanbaatar, Mongolia were significant enough to cause extremely high levels of indoor and outdoor air pollution.

Characteristics of Particulate Matter and Volatile Organic Compound Emissions from the Combustion of Waste Vinyl.

Vinyl samples were burned in a controlled environment to determine the characteristics of particulate matter (PM) and volatile organic compound (VOC) emissions during the combustion process. Open burning of plastic or vinyl products poses several environmental and health risks in developed and developing countries, due to the release of high concentrations of harmful pollutants. The production of fine and ultrafine particles was significant. At a heat flux of 25 kW/m², the production of PM of 0.35 µm in size was highest at 63.0 µg/m³. In comparison, at fluxes of 35 and 50 kW/m², the production of PM of 0.45 µm in size was highest with values of 67.8 and 87.7 µg/m³, respectively. Benzene, acetone, and other toxic compounds were also identified in the analyses.

Inactivation of filter bound aerosolized MS2 bacteriophages using a non-conductive ultrasound transducer.

The inactivation of viruses that retain their infectivity when transmitted through the air is challenging. To address this issue, this study used a non-contact ultrasound transducer (NCUT) to generate shock waves in the air at specific distances, input voltages, and exposure durations, targeting bacteriophage virus aerosols captured on to H14 HEPA filters. Initially, a frequency of 27.56 kHz (50V) at 25-mm distance was used, which yielded an inactivation efficiency of up to 32.69 ±â€¯12.10%. Other frequencies at shorter distances were investigated, where 29.10 kHz had the highest inactivation efficiency (up to 81.95 ±â€¯9.79% at 8.5-mm distance and 100 V). Longer exposure times also influenced virus inactivation, but the results were inconclusive because the NCUT overheated with time. Overall, NCUT appears to be a promising method for inactivating virus aerosols that may be safer than other forms of inactivation, which can cause genetic mutations or produce dangerous by-products.