scholarly journals 785The Effect of Temperature, Humidity, Wind Speed, and UV-Light on the Recovery of Aerosolized Influenza Virus

2014 ◽  
Vol 1 (suppl_1) ◽  
pp. S222-S223
Author(s):  
Werner Bischoff ◽  
Maria Blevins ◽  
Andrea Anderson ◽  
John Stehle
2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Shane Riddell ◽  
Sarah Goldie ◽  
Andrew Hill ◽  
Debbie Eagles ◽  
Trevor W. Drew

Abstract Background The rate at which COVID-19 has spread throughout the globe has been alarming. While the role of fomite transmission is not yet fully understood, precise data on the environmental stability of SARS-CoV-2 is required to determine the risks of fomite transmission from contaminated surfaces. Methods This study measured the survival rates of infectious SARS-CoV-2, suspended in a standard ASTM E2197 matrix, on several common surface types. All experiments were carried out in the dark, to negate any effects of UV light. Inoculated surfaces were incubated at 20 °C, 30 °C and 40 °C and sampled at various time points. Results Survival rates of SARS-CoV-2 were determined at different temperatures and D-values, Z-values and half-life were calculated. We obtained half lives of between 1.7 and 2.7 days at 20 °C, reducing to a few hours when temperature was elevated to 40 °C. With initial viral loads broadly equivalent to the highest titres excreted by infectious patients, viable virus was isolated for up to 28 days at 20 °C from common surfaces such as glass, stainless steel and both paper and polymer banknotes. Conversely, infectious virus survived less than 24 h at 40 °C on some surfaces. Conclusion These findings demonstrate SARS-CoV-2 can remain infectious for significantly longer time periods than generally considered possible. These results could be used to inform improved risk mitigation procedures to prevent the fomite spread of COVID-19.


2020 ◽  
Vol 113 (3) ◽  
pp. 1337-1346 ◽  
Author(s):  
Mark A Hall ◽  
Jeremy Jones ◽  
Maurizio Rocchetti ◽  
Derek Wright ◽  
Romina Rader

Abstract Wild and managed bees provide effective crop pollination services worldwide. Protected cropping conditions are thought to alter the ambient environmental conditions in which pollinators forage for flowers, yet few studies have compared conditions at the edges and center of growing tunnels. We measured environmental variables (temperature, relative humidity, wind speed, white light, and UV light) and surveyed activity of the managed honey bee, Apis mellifera L.; wild stingless bee, Tetragonula carbonaria Smith; and wild sweat bee, Homalictus urbanus Smith, along the length of 32 multiple open-ended polyethylene growing tunnels. These were spaced across 12 blocks at two commercial berry farms, in Coffs Harbour, New South Wales and Walkamin, North Queensland, Australia. Berry yield, fresh weight, and other quality metrics were recorded at discrete increments along the length of the tunnels. We found a higher abundance and greater number of flower visits by stingless bees and honey bees at the end of tunnels, and less frequent visits to flowers toward the middle of tunnels. The center of tunnels experienced higher temperatures and reduced wind speed. In raspberry, fruit shape was improved with greater pollinator abundance and was susceptible to higher temperatures. In blueberry, per plant yield and mean berry weight were positively associated with pollinator abundance and were lower at the center of tunnels than at the edge. Fruit quality (crumbliness) in raspberries was improved with a greater number of visits by sweat bees, who were not as susceptible to climatic conditions within tunnels. Understanding bee foraging behavior and changes to yield under protected cropping conditions is critical to inform the appropriate design of polytunnels, aid pollinator management within them, and increase economic gains in commercial berry crops.


2017 ◽  
Vol 30 (17) ◽  
pp. 6683-6700 ◽  
Author(s):  
Qingyu Guan ◽  
Xiazhong Sun ◽  
Jing Yang ◽  
Baotian Pan ◽  
Shilei Zhao ◽  
...  

Airborne dust derived from desertification in northern China can be transported to East Asia and other regions, impairing human health and affecting the global climate. This study of northern China dust provides an understanding of the mechanism of dust generation and transportation. The authors used dust storm and climatological data from 129 sites and normalized difference vegetation index (NDVI) datasets in northern China to analyze spatiotemporal characteristics and determine the main factors controlling dust storms occurring during 1960–2007. Dust storm–prone areas are consistent with the spatial distribution of northern China deserts where the average wind speed (AWS) is more than 2 m s−1, the mean annual temperature (MAT) ranges from 5° to 10°C, and the mean annual precipitation (MAP) is less than 450 mm. Dust storms commonly occur on spring afternoons in a 3- to 6-h pattern. The three predominant factors that can affect DSF are the maximum wind speed, AWS, and MAT. During 1960–2007, dust storm frequency (DSF) in most regions of northern China fluctuated but had a decreasing trend; this was mainly caused by a gradual reduction in wind speed. The effect of temperature on DSF is complex, as positive and negative correlations exist simultaneously. Temperatures can affect source material (dust, sand, etc.), cyclone activity, and vegetation growth status, which influence the generation of dust storms. NDVI and precipitation are negatively correlated with DSF, but the effect is weak. Vegetation can protect the topsoil environment and prevent dust storm creation but is affected by the primary decisive influence of precipitation.


2017 ◽  
Author(s):  
David S. McLagan ◽  
Carl P. J. Mitchell ◽  
Haiyong Huang ◽  
Batual Abdul Hussain ◽  
Ying Duan Lei ◽  
...  

Abstract. Passive air sampling of gaseous mercury (Hg) requires a high level of accuracy to discriminate small differences in atmospheric concentrations. Meteorological parameters have the potential to decrease this accuracy by impacting the sampling rate (SR), i.e., the volume of air that is effectively stripped of gaseous mercury per unit of time. We measured the SR of a recently calibrated passive air sampler for gaseous Hg in the laboratory under varying wind speeds (wind-still – 6 m s−1), temperatures (−15–35 °C), and relative humidities (44–80 %). While relative humidity has no impact on SR, SR increases slightly with both wind speed (0.003 m3 day−1 increase in SR or 2.5 % of the previously calibrated SR for every m s−1 increase for wind speeds > 1 m s−1, typical of outdoor deployments) and temperature (0.001 m3 day−1 increase in SR or 0.7 % for every 1 °C increase). The temperature dependence can be fully explained by the effect of temperature on the molecular diffusivity of gaseous mercury in air. Although these effects are relatively small, accuracy can be improved by adjusting SRs using measured or estimated temperature and wind speed data at or near sampling sites. We also assessed the possibility of reusing Radiello® diffusive barriers previously used in the passive air samplers. The mean rate of gaseous Hg uptake was not significantly different between new and previously used diffusive barriers in both lab and outdoor deployments, irrespective of the applied cleaning procedure. No memory effect from Radiellos® previously deployed in a high Hg atmosphere was observed. However, a loss in replicate precision for the dirtiest Radiellos® in the indoor experiment suggests that cleaning is advisable prior to reuse.


2021 ◽  
Author(s):  
Valeria Cagno1 ◽  
Chiara Medaglia ◽  
Andreas Cerny ◽  
Thomas Cerny ◽  
Arnaud Zwygart ◽  
...  

Abstract Methylene blue is an FDA (food and drug administration) and EMA (european medicines agency) approved drug with an excellent safety profile. It displays broad-spectrum virucidal activity in the presence of UV light and has been shown to be effective in inactivating various viruses in blood products prior to transfusions. In addition, its use has been validated for methemoglobinemia and malaria treatment. In this study, we first evaluated the virucidal activity of methylene blue against Influenza Virus H1N1 upon different incubation times and in the presence or absence of light activation, and then against SARS-CoV-2. We further assessed the therapeutic activity of methylene blue by administering it to cells previously infected with SARS-CoV-2. Finally, we examined the effect of co-administration of the drug together with immune serum. Our findings reveal that methylene blue displays virucidal preventive or therapeutic activity against Influenza Virus H1N1 and SARS-CoV-2 at low micromolar concentrations and in the absence of UV activation. We also confirm that MB antiviral activity is based on several mechanisms of action as the degradation of genomic RNA is only observed in the presence of light and after long exposure. Our work supports the interest of testing methylene blue in clinical studies to confirm a preventive or therapeutic efficacy against both Influenza Virus H1N1 and SARS-CoV-2 infections.


2021 ◽  
Author(s):  
Kassimou Abdoul Haki Maoude ◽  
Chaffa Odjouwoni Lucien Chaffa ◽  
Idossou Marius Adom

Abstract This paper investigates the effects of climate and governments responses on the spread of the COVID-19. Our strategy is empirical. Our model is based on an accounting equation derived from the SIR model, and estimates the relationship between the growth of the daily COVID-19 confirmed cases on the one hand, and climatic variables (such as the daily average temperature and the wind speed) and governments responses to COVID-19 on the other hand. We also develop a theoretical approach to test the presence of a threshold in the effect of the temperature on the COVID-19 spread. Using a panel data on a sample of 294 territories overs 106 days (from 22 January, 2020 to 06 May, 2020), we find significant negative effect of temperature and temperature variability and significant positive effect of wind speed and precipitation on the growth of the COVID-19 confirmed cases. We also find that governments responses are associated to a lower growth of confirmed cases. But we do not find any universally applicable threshold effect in the relationship between the average temperature and the confirmed cases growth.JEL Classification: C12, C15, C23, C60


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