Review of the Breathability and Filtration Efficiency of Common Household Materials for Face Masks.

The World Health Organization and the United States Centers for Disease Control have recommended universal face masking by the general public to slow the spread of COVID-19. A number of recent studies have evaluated the filtration efficiency and pressure differential (an indicator of breathability) of various, widely available materials that the general public can use to make face masks at home. In this review, we summarize those studies to provide guidance for both the public to select the best materials for face masks and for future researchers to rigorously evaluate and report on mask material testing. Of the tested fabric materials and material combinations with adequate breathability, most single and multilayer combinations had a filtration efficiency of <30%. Most studies evaluating commonly available mask materials did not follow standard methods that would facilitate comparison across studies, and materials were often described with too few details to allow consumers to purchase equivalent materials to make their own masks. To improve the usability of future study results, researchers should use standard methods and report material characteristics in detail.

Heat and Humidity for Bioburden Reduction of N95 Filtering Facepiece Respirators.

Introduction: The coronavirus disease 2019 (COVID-19) pandemic has caused a global shortage of single-use N95 filtering facepiece respirators (FFRs). A combination of heat and humidity is a promising method for N95 FFR decontamination in crisis-capacity conditions; however, an understanding of its effect on viral inactivation and N95 respirator function is crucial to achieving effective decontamination. Objective: We reviewed the scientific literature on heat-based methods for decontamination of N95 FFRs contaminated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and viral analogues. We identified key parameters for SARS-CoV-2 bioburden reduction while preserving N95 fit and filtration, as well as methods that are likely ineffective. Key Findings: Viral inactivation by humid heat is highly sensitive to temperature, humidity, duration of exposure, and the local microenvironment (e.g., dried saliva). A process that achieves temperatures of 70-85°C and relative humidity >50% for at least 30 min is likely to inactivate SARS-CoV-2 (>3-log reduction) on N95 respirators while maintaining fit and filtration efficiency for three to five cycles. Dry heat is significantly less effective. Microwave-generated steam is another promising approach, although less studied, whereas 121°C autoclave treatments may damage some N95 FFRs. Humid heat will not inactivate all microorganisms, so reprocessed N95 respirators should be reused only by the original user. Conclusions: Effective bioburden reduction on N95 FFRs during the COVID-19 pandemic requires inactivation of SARS-CoV-2 and preservation of N95 fit and filtration. The literature suggests that humid heat protocols can achieve effective bioburden reduction. Proper industrial hygiene, biosafety controls, and clear protocols are required to reduce the risks of N95 reprocessing and reuse.

Impact of the COVID-19 pandemic on clean fuel programmes in India and ensuring sustainability for household energy needs.

Clean cooking energy strategies are critical for reducing air pollution, improving health, and achieving related Sustainable Development Goals. The recent COVID-19 lockdowns may impact the transition towards clean cooking fuels. The nationwide lockdown is likely to affect key factors such as energy access, income, transportation, etc., that play a role in decisions influencing household fuel use. The rural population already bears the burden of poverty and may not be able to afford and access clean cooking fuels during the lockdown. They are thus vulnerable to reversion to their traditional cooking methods using solid biomass fuels. The household air pollution caused due to the use of polluting fuels increases their susceptibility to non-communicable diseases, and thus may intensify the risk and severity of COVID-19 infection. Hence, there is an urgent need to expand sustainable energy solutions worldwide. The present study applies the DPSIR modeling framework to establish a set of comprehensive indicators for addressing the transition towards clean cooking fuels during the COVID-19 pandemic. The study also provides insights on various strategies adopted in India in response to the COVID-19 pandemic for maintaining continuity of delivering benefits under a clean cookstove program. The study offers future directions to ensure the transition towards cleaner fuels and sustainability.