Dependence on relative humidity in the formation of reactive oxygen species in water droplets

Proceedings of the National Academy of Sciences, Год журнала: 2024, Номер 121(12)

Опубликована: Март 15, 2024

Water microdroplets (7 to 11 µm average diameter, depending on flow rate) are sprayed in a closed chamber at ambient temperature, whose relative humidity (RH) is controlled. The resulting concentration of ROS (reactive oxygen species) formed the microdroplets, measured by amount hydrogen peroxide (H 2 O ), determined nuclear magnetic resonance (NMR) and spectrofluorimetric assays after droplets collected. results found agree closely with one another. In addition, hydrated hydroxyl radical cations (•OH-H 3 + ) recorded from using mass spectrometry superoxide anions (•O − radicals (•OH) electron paramagnetic spectroscopy. As RH varies 15 95%, H shows marked rise factor about 3.5 going 50%, then levels off. By replacing water deuterium oxide (D O) but keeping gas surrounding O, spectrometric analysis demonstrates that air plays dominant role producing other ROS, which accounts for variation RH. increases, droplet evaporation rate decreases. These two facts help us understand why viruses both survive better low values, as indoor wintertime, disinfected more effectively higher summertime, thus explaining recognized seasonality airborne viral infections.

Язык: Английский

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Associations between indoor relative humidity and global COVID-19 outcomes

Journal of The Royal Society Interface, Год журнала: 2022, Номер 19(196)

Опубликована: Ноя. 1, 2022

Globally, the spread and severity of COVID-19 have been distinctly non-uniform. Seasonality was suggested as a contributor to regional variability, but relationship between weather remains unclear focus attention has on outdoor conditions. Because humans spend most their time indoors because transmission occurs indoors, we here, instead, investigate hypothesis that indoor climate—particularly relative humidity (RH)—may be more relevant modulator outbreaks. To study this association, combined population-based statistics meteorological measurements from 121 countries. We rigorously processed epidemiological data reduce bias, then developed experimentally validated computational workflow estimate conditions based standard comfort Our comprehensive analysis shows robust systematic relationships outbreaks RH. In particular, found intermediate RH (40–60%) robustly associated with better outbreak outcomes (versus < 40% or >60%). Together, these results suggest conditions, particularly RH, modulate

Язык: Английский

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Evaluation of ventilation and indoor air quality inside bedrooms of an elderly care centre

Energy and Buildings, Год журнала: 2024, Номер 313, С. 114245 - 114245

Опубликована: Май 8, 2024

Ventilation and indoor air quality are important factors that affect the health of elderly. The purpose this study was to find effective ventilation design measures for improving in typical two-bed bedrooms elderly care centres (ECCs). Mixing (MV), displacement (DV), zone (ZV) stratum (SV) were analysed with twelve scenarios most solutions including six curtains between beds without beds. Airflow distribution, CO2 concentration, efficiency risk assessment adopted discussion. SV found be an method ECC bedroom while also taking into account needs rights residents, such as privacy. Comparing under same types ventilation, showed a slight (≤8%) decrease concentration pillow area. However, could increase virus transmission compromise privacy, so it is not recommended. Regarding beds, contaminant removal (CRE) using increased by 2.58, 3.22 2.12 times compared MV, DV, ZV respectively. Additionally, ratio (HR) reduced 46.3 %, 53.7 41.7 %. Hence, recommended install apply bedrooms. This can used guide systematically designing systems Furthermore, collaboration among environmental engineers, designers, policymakers, wider community essential develop sustainable environments

Язык: Английский

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Monitoring of indoor air quality at a large sailing cruise ship to assess ventilation performance and disease transmission risk

The Science of The Total Environment, Год журнала: 2025, Номер 962, С. 178286 - 178286

Опубликована: Янв. 1, 2025

Large passenger ships are characterised as enclosed and crowded indoor spaces with frequent interactions between travellers, providing conditions that facilitate disease transmission. This study aims to provide an ship CO

Язык: Английский

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Identifying Key Weather Factors Influencing Human Salmonellosis: A Conditional Incidence Analysis in England, Wales, and the Netherlands.

Journal of Infection, Год журнала: 2025, Номер 90(2), С. 106410 - 106410

Опубликована: Янв. 16, 2025

Язык: Английский

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A Review of Air-side Economizers in Human-centered Commercial Buildings: control logic, energy savings, IAQ potential, faults, and performance enhancement

Energy and Buildings, Год журнала: 2025, Номер unknown, С. 115389 - 115389

Опубликована: Янв. 1, 2025

Язык: Английский

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Investigation on the source of VOCs emission from indoor construction materials using electronic sensors and TD-GC-MS

Environmental Pollution, Год журнала: 2024, Номер 348, С. 123765 - 123765

Опубликована: Март 17, 2024

Язык: Английский

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Urban moisture and dry islands: spatiotemporal variation patterns and mechanisms of urban air humidity changes across the globe

Environmental Research Letters, Год журнала: 2023, Номер 18(10), С. 103003 - 103003

Опубликована: Сен. 8, 2023

Abstract Urbanization-induced atmospheric moisture changes, embodied as urban island (UMI) and dry (UDI) effects, are not thoroughly understood the heat (UHI) despite their significant influence on human comfort well-being. This paper offers first systematic review quantitative meta-analysis of global urban–rural humidity contrasts, aiming to advance our comprehension mechanisms, intensity, patterns, implications changes. The compiles observational data from 34 studies across 33 cities. It reveals that mid-latitude cities predominantly exhibit moderate UMI UDI with low mean annual precipitation distinct dry/wet seasons, however, extreme effects. diurnal cycle analysis presents more pronounced effects at night, largely due increased evapotranspiration delayed dewfall linked UHI. On a seasonal scale, dominate in spring, while peak winter for summer low-latitude In addition, city characteristics such topography, morphology, size significantly shape contrasts. Coastal subject sea-breeze circulation, importing sea land, whereas mountainous can accumulate geographical barriers vertical airflow. High-density areas generally experience heightened restricted airflow ventilation. Larger higher populations contribute particularly winter, stronger anthropogenic sources. also discusses multi-dimensional impacts strategies humidity-sensitive planning context climate change. identifies critical gaps current research, paving way future exploration into

Язык: Английский

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The influence of meteorological factors on COVID-19 spread in Italy during the first and second wave

Environmental Research, Год журнала: 2023, Номер 228, С. 115796 - 115796

Опубликована: Апрель 3, 2023

The relation between meteorological factors and COVID-19 spread remains uncertain, particularly with regard to the role of temperature, relative humidity solar ultraviolet (UV) radiation. To assess this relation, we investigated disease within Italy during 2020. pandemic had a large early impact in Italy, 2020 effects vaccination viral variants not yet complicated dynamics. We used non-linear, spline-based Poisson regression modeled UV humidity, adjusting for mobility patterns additional confounders, estimate daily rates new cases, hospital intensive care unit admissions, deaths two waves found little association endpoints both waves, whereas radiation above 40 kJ/m2 showed weak inverse ICU admissions first wave, stronger all second wave. Temperature 283 K (10 °C/50 °F) strong non-linear negative endpoints, inconsistent relations below cutpoint waves. Given biological plausibility temperature COVID-19, these data add support proposition that K, possibly high levels radiation, reduced spread.

Язык: Английский

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Indoor air humidity revisited: Impact on acute symptoms, work productivity, and risk of influenza and COVID-19 infection

International Journal of Hygiene and Environmental Health, Год журнала: 2023, Номер 256, С. 114313 - 114313

Опубликована: Дек. 27, 2023

Recent epidemiological and experimental findings reconfirm that low indoor air humidity (dry air) increases the prevalence of acute eye airway symptoms in offices, result lower mucociliary clearance airways, less efficient immune defense, deteriorate work productivity. New research also support environmental conditions for risk infection influenza COVID-19 virus is lowest Goldilocks zone 40–60% relative (RH) by decrease airways' susceptibility, which can be elevated particle exposure. Furthermore, RH generation infectious laden aerosols exhaled from infected people. In general, elevation dry health airways concomitantly with viability virus. Thus, negative effects ventilation outdoor (low absolute humidity) should assessed according to 1) weakened functionality 2) increased possible transmissibility virus, 3) evaporation containing droplets out droplet nuclei (also at high room temperature), their floating time air. The removal acid-containing ambient filtration pH, viruses, infection, synergistically may further increase dilution pollutants compared beneficial control center RH, an essential factor optimal additional positive impact on symptoms, productivity, reduced infection.

Язык: Английский

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