Vysoce kvalitní a snadno regenerovatelný osobní filtr

Proper respiratory tract protection is the key factor to limiting the rate of COVID-19 spread and providing a safe environment for health care workers. Traditional N95 (FFP2) respirators are not easy to regenerate and thus create certain financial and ecological burdens; moreover, their quality may vary significantly. A solution that would overcome these disadvantages is desirable. In this study a commercially available knit polyester fleece fabric was selected as the filter material, and a total of 25 filters of different areas and thicknesses were prepared. Then, the size-resolved filtration efficiency (40-400 nm) and pressure drop were evaluated at a volumetric flow rate of 95 L/min. We showed the excellent synergistic effect of expanding the filtration area and increasing the number of filtering layers on the filtration efficiency; a filter cartridge with 8 layers of knit polyester fabric with a surface area of 900 cm(2) and sized 25 x 14 x 8 cm achieved filtration efficiencies of 98% at 95 L/min and 99.5% at 30 L/min. The assembled filter kit consists of a filter cartridge (14 Pa) carried in a small backpack connected to a half mask with a total pressure drop of 84 Pa at 95 L/min. In addition, it is reusable, and the filter material can be regenerated at least ten times by simple methods, such as boiling. We have demonstrated a novel approach for creating high-quality and easy-to-breathe-through respiratory protective equipment that reduces operating costs and is a green solution because it is easy to regenerate.Správná ochrana dýchacích cest je klíčovým faktorem pro omezení rychlosti šíření COVID-19 a zajištění bezpečného prostředí pro zdravotnické pracovníky. Tradiční respirátory N95 (FFP2) se nedají snadno regenerovat a vytvářejí tak určitou finanční a ekologickou zátěž; navíc se jejich kvalita může výrazně lišit. Žádoucí je řešení, které by tyto nevýhody překonalo. V této studii byla jako filtrační materiál vybrána komerčně dostupná pletená polyesterová fleecová tkanina a bylo připraveno celkem 25 filtrů různých ploch a tlouštěk. Poté byla vyhodnocena účinnost filtrace s rozlišením velikosti (40-400 nm) a pokles tlaku při objemovém průtoku 95 l/min. Prokázali jsme vynikající synergický efekt rozšíření filtrační plochy a zvýšení počtu filtračních vrstev na účinnost filtrace; filtrační patrona s 8 vrstvami pletené polyesterové tkaniny o ploše 900 cm(2) a rozměrech 25 x 14 x 8 cm dosáhla účinnosti filtrace 98 % při 95 l/min a 99,5 % při 30 l/min. Sestavená filtrační sada se skládá z filtrační patrony (14 Pa) nesené v malém batohu spojeném s polomaskou s celkovým tlakovým spádem 84 Pa při 95 l/min. Navíc je opakovaně použitelný a filtrační materiál lze jednoduchými metodami, jako je vaření, nejméně desetkrát regenerovat. Prokázali jsme nový přístup k vytvoření vysoce kvalitních a snadno dýchatelných dýchacích ochranných prostředků, které snižují provozní náklady a jsou ekologickým řešením, protože se snadno regenerují

A European aerosol phenomenology - 7: High-time resolution chemical characteristics of submicron particulate matter across Europe

Similarities and differences in the submicron atmospheric aerosol chemical composition are analyzed from a unique set of measurements performed at 21 sites across Europe for at least one year. These sites are located between 35 and 62°N and 10° W – 26°E, and represent various types of settings (remote, coastal, rural, industrial, urban). Measurements were all carried out on-line with a 30-min time resolution using mass spectroscopy based instruments known as Aerosol Chemical Speciation Monitors (ACSM) and Aerosol Mass Spectrometers (AMS) and following common measurement guidelines. Data regarding organics, sulfate, nitrate and ammonium concentrations, as well as the sum of them called non-refractory submicron aerosol mass concentration ([NR-PM1]) are discussed. NR-PM1 concentrations generally increase from remote to urban sites. They are mostly larger in the mid-latitude band than in southern and northern Europe. On average, organics account for the major part (36–64%) of NR-PM1 followed by sulfate (12–44%) and nitrate (6–35%). The annual mean chemical composition of NR-PM1 at rural (or regional background) sites and urban background sites are very similar. Considering rural and regional background sites only, nitrate contribution is higher and sulfate contribution is lower in mid-latitude Europe compared to northern and southern Europe. Large seasonal variations in concentrations (μg/m³) of one or more components of NR-PM1 can be observed at all sites, as well as in the chemical composition of NR-PM1 (%) at most sites. Significant diel cycles in the contribution to [NR-PM1] of organics, sulfate, and nitrate can be observed at a majority of sites both in winter and summer. Early morning minima in organics in concomitance with maxima in nitrate are common features at regional and urban background sites. Daily variations are much smaller at a number of coastal and rural sites. Looking at NR-PM1 chemical composition as a function of NR-PM1 mass concentration reveals that although organics account for the major fraction of NR-PM1 at all concentration levels at most sites, nitrate contribution generally increases with NR-PM1 mass concentration and predominates when NR-PM1 mass concentrations exceed 40 μg/m³ at half of the sites