A key consideration in the Covid-19 pandemic is the dominant modes of transmission of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. The objective of this review was to synthesise the evidence...
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A key consideration in the Covid-19 pandemic is the dominant modes of transmission of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. The objective of this review was to synthesise the evidence for the potential airborne transmission of SARS-CoV-2 via aerosols. Systematic literature searches were conducted in PubMed, Embase, Europe PMC and National Health Service UK evidence up to 27 July 2020. A protocol was published and Cochrane guidance for rapid review methodology was adhered to throughout. Twenty-eight studies were identified. Seven out of eight epidemiological studies suggest aerosol transmission may occur, with enclosed environments and poor ventilation noted as possible contextual factors. Ten of the 16 air sampling studies detected SARS-CoV-2 ribonucleic acid;however, only three of these studies attempted to culture the virus with one being successful in a limited number of samples. Two of four virological studies using artificially generated aerosols indicated that SARS-CoV-2 is viable in aerosols. The results of this review indicate there is inconclusive evidence regarding the viability and infectivity of SARS-CoV-2 in aerosols. Epidemiological studies suggest possible transmission, with contextual factors noted. Viral particles have been detected in air sampling studies with some evidence of clinical infectivity, and virological studies indicate these particles may represent live virus, adding further plausibility. However, there is uncertainty as to the nature and impact of aerosol transmission of SARS-CoV-2, and its relative contribution to the Covid-19 pandemic compared with other modes of transmission.
The results on elemental composition of the surface aerosols in Moscow region were studied from the data of the integrated autumn experiment. Elemental composition of aerosol particles in the atmosphere of Moscow city...
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ISBN:
(纸本)9781510639423
The results on elemental composition of the surface aerosols in Moscow region were studied from the data of the integrated autumn experiment. Elemental composition of aerosol particles in the atmosphere of Moscow city and in the suburb in the fall 2019 under unusual weather conditions are presented. The average daily mass concentration and fractional composition are compared with synoptic and meteorological factors, as well as with local aerosol sources. Meteorological conditions and local sources play great roles in forming aerosol elemental composition variability and its mass concentration.
A large-scale episode of biomass burning was observed during the months of August to October 2019. Satellite and in-situ observations reported scores of fires over the regions of central Sumatra and southern Kalimanta...
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ISBN:
(纸本)9781728163741
A large-scale episode of biomass burning was observed during the months of August to October 2019. Satellite and in-situ observations reported scores of fires over the regions of central Sumatra and southern Kalimantan of Indonesia. Prevailing meteorological conditions contributed to long range transport of these aerosol particles and they were observed over several cities in Malaysia, Indonesia and Singapore. In this work, we report in-situ observations at two AERONET sites located in Singapore and Kuching (Sarawak, East Malaysia) complemented by satellite imagery (MODIS) over the above mentioned regions.
The pandemic of coronavirus disease 2019 (COVID-19) has caused major disruption in global health care delivery. In March 2020, based upon guidance from the American Dental Association and the US Centers for Disease Co...
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The pandemic of coronavirus disease 2019 (COVID-19) has caused major disruption in global health care delivery. In March 2020, based upon guidance from the American Dental Association and the US Centers for Disease Control and Prevention, dental procedures in the United States were limited to emergent and urgent care. Establishment of an airborne route of transmission of severe acute respiratory syndrome coronavirus 2, the virus that causes COVID-19, has highlighted the potential risks associated with aerosol-generating dental procedures (AGDPs) during the provision of dental care. It has also served to open the door on novel research avenues that could have a meaningful downstream effect on the practice of dentistry and could enhance current infection control and prevention practices. This commentary seeks to identify gaps in our current knowledge regarding airborne disease transmission in dental practice and to draw attention to potential research questions regarding dental aerosols and their potential to cause disease. Knowledge Transfer Statement: Recent reports on the airborne transmission of respiratory diseases, including COVID-19, have highlighted a need for investigation of dental aerosols and their infectious potential.
Background Legionellosis is caused by the inhalation of aerosolized water contaminated with Legionella bacteria. In this study, we investigated the prevalence of Legionella species in aerosols collected from outdoor s...
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Background Legionellosis is caused by the inhalation of aerosolized water contaminated with Legionella bacteria. In this study, we investigated the prevalence of Legionella species in aerosols collected from outdoor sites near asphalt roads, bathrooms in public bath facilities, and other indoor sites, such as buildings and private homes, using amoebic co-culture, quantitative PCR, and 16S rRNA gene amplicon sequencing. Results Legionella species were not detected by amoebic co-culture. However, Legionella DNA was detected in 114/151 (75.5%) air samples collected near roads (geometric mean +/- standard deviation: 1.80 +/- 0.52 log(10) copies/m(3)), which was comparable to the numbers collected from bathrooms [15/21 (71.4%), 1.82 +/- 0.50] but higher than those collected from other indoor sites [11/30 (36.7%), 0.88 +/- 0.56] (P < 0.05). The amount of Legionella DNA was correlated with the monthly total precipitation (r = 0.56, P < 0.01). It was also directly and inversely correlated with the daily total precipitation for seven days (r = 0.21, P = 0.01) and one day (r = - 0.29, P < 0.01) before the sampling day, respectively. 16S rRNA gene amplicon sequencing revealed that Legionella species were detected in 9/30 samples collected near roads (mean proportion of reads, 0.11%). At the species level, L. pneumophila was detected in 2/30 samples collected near roads (the proportion of reads, 0.09 and 0.11% of the total reads number in each positive sample). The three most abundant bacterial genera in the samples collected near roads were Sphingomonas, Streptococcus, and Methylobacterium (mean proportion of reads;21.1%, 14.6%, and 1.6%, respectively). In addition, the bacterial diversity in outdoor environment was comparable to that in indoor environment which contains aerosol-generating features and higher than that in indoor environment without the features. Conclusions DNA from Legionella species was widely present in aerosols collected from outdoor sites near asphalt roa
The Western North Atlantic Ocean (WNAO) and adjoining East Coast of North America are of great importance for atmospheric research and have been extensively studied for several decades. This broad region exhibits comp...
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The Western North Atlantic Ocean (WNAO) and adjoining East Coast of North America are of great importance for atmospheric research and have been extensively studied for several decades. This broad region exhibits complex meteorological features and a wide range of conditions associated with gas and particulate species from many sources regionally and other continents. As Part 1 of a 2-part paper series, this work characterizes quantities associated with atmospheric chemistry, including gases, aerosols, and wet deposition, by analyzing available satellite observations, ground-based data, model simulations, and reanalysis products. Part 2 provides insight into the atmospheric circulation, boundary layer variability, three-dimensional cloud structure, properties, and precipitation over the WNAO domain. Key results include spatial and seasonal differences in composition along the North American East Coast and over the WNAO associated with varying sources of smoke and dust and meteorological drivers such as temperature, moisture, and precipitation. Spatial and seasonal variations of tropospheric carbon monoxide and ozone highlight different pathways toward the accumulation of these species in the troposphere. Spatial distributions of speciated aerosol optical depth and vertical profiles of aerosol mass mixing ratios show a clear seasonal cycle highlighting the influence of different sources in addition to the impact of intercontinental transport. Analysis of long-term climate model simulations of aerosol species and satellite observations of carbon monoxide confirm that there has been a significant decline in recent decades among anthropogenic constituents owing to regulatory activities.
Secondary organic aerosols(SOAs) are an important component of particulates, but whether biogenic SOAs(BSOAs) or anthropogenic SOAs(ASOAs) are the dominant contributors to haze pollution remains poorly characterized. ...
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Secondary organic aerosols(SOAs) are an important component of particulates, but whether biogenic SOAs(BSOAs) or anthropogenic SOAs(ASOAs) are the dominant contributors to haze pollution remains poorly characterized. In this study, particulate samples were collected from September 2014 to August 2015 at an urban site in Jinan, which is the capital of Shandong Province and a typical city in the North China Plain. The PM2.5 samples were analyzed for BSOA(isoprene(SOAI) and monoterpenes(SOAM)) and ASOA(aromatic(SOAA)) tracers. The concentrations of the SOAAtracer(1.1 ± 1.0 ng/m3) were lowest, and those of SOAItracers(41.8 ± 86.2 ng/m3) were highest, with the concentrations of SOAMtracers(19.4 ± 9.9 ng/m3) being intermediate. The SOAItracers were more abundant in the summer and less abundant in the winter. Both SOAIand SOAMincreased with increasing ozone level but decreased with increasing NOx level. Correlation analysis revealed a good correlation between 2,3-dihydroxy-4-oxopentanoic acid and levoglucosan levels in three seasons. These results suggested that biomass burning activities occurring in the NCP can enhance the emissions of aromatics and should be controlled, especially in the autumn and winter. SOA tracers were classified according to pollution degree, and the results showed that as pollution increases, the contributions of SOAAincrease. These results indicate that reducing anthropogenic emissions is necessary to prevent SOA pollution, especially during heavy pollution episodes.
A wide-angle camera-based bistatic imaging lidar is used to profile altitude dependent aerosol extinction at various time of year in the Bahamas. The instrument provides excellent altitude resolution in the near groun...
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We report on measurement results obtained with the first coherent fiber CH4/Doppler lidar, called VEGA. The instrument measure simultaneously range-resolved profiles of methane concentration, wind speed, and relative ...
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Workers performing post-mortem examination and embalming can be exposed to a risk of infection. Based on the hierarchy of preventive measures, ventilation is the most effective solution for reducing worker exposure si...
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