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The standard method to evaluate human exposure to volatile organic compounds (VOCs) is in general performed by sampling the air on sorbents followed by liquid extraction and detection using laboratory gas chromatograph (GC). The conventional method is time and labor intensive and employs a toxic solvent which adds a risk factor as well as waste. Hence, there have been increasing demands for portable GC instruments which allow near real-time, in-situ analysis. In this study, the potential use of a prototype, dual column portable GC (protoGC) with flame ionization detector (FID) was examined by comparing its performance with a conventional GC laboratory method. Four target concentration levels (1x, 2x, 4x, and 8x; x = 1.12 ± 0.01 ppm) of toluene, ethylbenzene, and o-, m-, and p-xylene were generated in an exposure chamber (24 ± 1 °C and 50 ± 5% RH). The challenge atmosphere was directly sampled and analyzed with protoGC while for the conventional method it was sampled on a sorbent tube and analyzed with a laboratory GC/FID. The results of protoGC correlated well with the conventional method (r = 0.991–0.999), indicating that protoGC has comparable performance with the conventional method within the test conditions. Although two-way ANOVA showed significant differences in mean concentrations between the methods, the differences were small. protoGC would be useful to monitor VOCs in air with high temporal resolution or to quickly determine the safety of the environment of interest due to the substantial time savings in sampling and analysis. Further examinations at various environmental conditions and other analytes will be necessary to thoroughly evaluate its performance. [ABSTRACT FROM AUTHOR]

The pandemic created by SARS-CoV-2 has caused a shortage in the supplies of N95 filtering facepiece respirators (FFRs), disposable respirators with at least 95% efficiency to remove non-oily airborne particles, due to increasing cases all over the world. The current article reviewed various possible decontamination methods for FFR reuse including ultraviolet germicidal irradiation (UVGI), hydrogen peroxide vapor (HPV), microwave-generated steam (MGS), hydrogen peroxide gas plasma (HPGP), and 70% or higher ethanol solution. HPV decontamination was effective against bacterial spores (6 log10 reduction of Geobacillus stearothermophilus spores) on FFRs and viruses (> 4 log10 reduction of various types of viruses) on inanimate surfaces, and no degradation of respirator materials and fit has been reported. 70% or higher ethanol decontamination showed high efficacy in inactivation of coronaviruses on inanimate surfaces (> 3.9 log10 reduction) but it was lower on FFRs which filtration efficiency was also decreased. UVGI method had good biocidal efficacy on FFRs (> 3 log10 reduction of H1N1 virus) combined with inexpensive, readily available equipment; however, it was more time-consuming to ensure sufficient reduction in SARS-CoV-2. MGS treatment also provided good viral decontamination on FFRs (> 4 log10 reduction of H1N1 virus) along with less time-intensive process and readily available equipment while inconsistent disinfection on the treated surfaces and deterioration of nose cushion of FFRs were observed. HPGP was a good virucidal system (> 6 log10 reduction of Vesicular stomatitis virus) but filtration efficiency after decontamination was inconsistent. Overall, HPV appeared to be one of the most promising methods based on the high biocidal efficacy on FFRs, preservation of respirator performance after multiple cycles, and no residual chemical toxicity. Nonetheless, equipment cost and time of the HPV process and a suitable operating room need to be considered. [ABSTRACT FROM AUTHOR]