aerosol

摘要： The main transmission routes of Coronavirus Disease 2019(COVID-19)include droplet and contact transmission.Airborne transmission may be possible in specific circumstances and settings in which aerosol-generating procedures are performed^([1]).In2020,more than 83.4 million confirmed cases of COVID-19,including more than 1.8 million deaths.

摘要： 《暖通空调》2021年第10期76页参考文献[6]应改为文中图1所对应的原始文献“[6]LI Y G,QIAN H,HANG J,et al.Evidence for probable aerosol transmission of SARS-CoV-2 in a poorly ventilated restaurant[EB/OL].[2021-09-16].https:∥www.medrxiv.org/content/10.1101/2020.04.16.20067728v1+”。特此更正并向读者致歉。

摘要： Anthropogenic emission inventory for aerosols and reactive gases is crucial to the estimation of aerosol radiative forcing and climate effects.Here,the anthropogenic emission inventory for AerChemMIP,endorsed by CMIP6,is briefly introduced.The CMIP6 inventory is compared with a country-level inventory(i.e.,MEIC)over China from 1986 to 2015.Discrepancies are found in the yearly trends of the two inventories,especially after 2006.The yearly trends of the aerosol burdens simulated by CESM2 using the two inventories follow their emission trends and deviate after the mid-2000s,while the simulated aerosol optical depths(AODs)show similar trends.The difference between the simulated AODs is much smaller than the difference between model and observation.Although the simulated AODs agree with the MODIS satellite retrievals for country-wide average,the good agreement is an offset between the underestimation in eastern China and the overestimation in western China.Low-biased precursor gas of SO_(2),overly strong convergence of the wind field,overly strong dilution and transport by summer monsoon circulation,too much wet scavenging by precipitation,and overly weak aerosol swelling due to low-biased relative humidity are suggested to be responsible for the underestimated AOD in eastern China.This indicates that the influence of the emission inventory uncertainties on simulated aerosol properties can be overwhelmed by model biases of meteorology and aerosol processes.It is necessary for climate models to perform reasonably well in the dynamical,physical,and chemical processes that would influence aerosol simulations.

摘要： This work concerns the 10? North, 20? North African band. Area renowned for having some of the poorest countries in the world. It is also home to the Sahelian strip and part of the Sahara. The countries in this zone have a relatively low electrification rate compared to the enlightened country. To solve this problem, these countries want to turn to renewable energies such as photovoltaics (renewable energy obtained through solar radiation). Therefore, understanding the behavior of irradiation and cloudiness in the 10 - 20 band becomes necessary. The application of the empirical orthogonal functions to the different cloud layers and to the irradiation reveals a seasonality of the latter, in particular compared to the first modes of the empirical orthogonal functions (EOF1). Indeed, by filtering in time and space to isolate solar radiation and cloudiness, the EOF1 expresses respectively 94.3% of the variation of descending solar radiation in clear sky in the 10 - 20 band. Note 65.7% for global radiation, 54.4% for cloudiness at 450 hPa, 69.6% for cloudiness between 800 hPa and 450 hPa, 76.6% for low cloudiness, 61.4% for total cloudiness. These results allow us to say that we have generally good sunshine over several months, with little cloud cover in this band. However, since this zone is considered to be part of the main aerosol emission source zones, it is important in their temporal consideration of the optical depth. By doing the wavelet analysis on the optical depth data from Dakar and Banizoumbou, we note that the average dust presence spectrum over the entire period from 1997 to 2019 in the two stations with a slight shift compared to the peaks and the maximum observed value. A sign that there is a strong presence of dust in this area and that it should be taken into account for any photovoltaic installation in this area.

摘要： This study experimentally investigated two-phase acoustic streaming and droplet properties of aerosols, which were generated by a dental ultrasonic scaler. The velocity field of acoustic streaming was measured using particle image velocimetry with the generated liquid droplets as tracers, and the shadowgraph technique was adopted to measure the droplet diameter. In the PIV measurement of the gas-liquid two-phase flow, the injection of oil smoke substantially suppressed the number of invalid vectors. The acoustic streaming of the ultrasonic scaler showed maximum velocity at a region away from the scaler tip, and the maximum velocity increased with an increase in the liquid flow rate. The droplets of the ultrasonic scaler were generated by capillary waves and had a diameter on the order of tens of micrometers. These droplets effectively enhanced the velocity of the acoustic streaming in the two-phase case compared to the single-phase case without the droplets.

摘要： In this work,the influence of South Asian biomass burning emissions on O_(3) and PM_(2.5)concentrations over the Tibetan Plateau(TP)is investigated by using the regional climate chemistry transport model WRF-Chem.The simulation is validated by comparing meteorological fields and pollutant concentrations against in situ observations and gridded datasets,providing a clear perspective on the spatiotemporal variations of O_(3) and PM_(2.5)concentrations across the Indian subcontinent,including the Tibetan Plateau.Further sensitivity simulations and analyses show that emissions from South Asian biomass burning mainly affect local O_(3) concentrations.For example,contribution ratios were up to 20%in the Indo-Gangetic Plain during the pre-monsoon season but below 1%over the TP throughout the year 2016.In contrast,South Asian biomass burning emissions contributed more than 60%of PM_(2.5)concentration over the TP during the pre-monsoon season via significant contribution of primary PM_(2.5)components(black carbon and organic carbon)in western India that were lofted to the TP by westerly winds.Therefore,it is suggested that cutting emissions from South Asian biomass burning is necessary to alleviate aerosol pollution over the TP,especially during the pre-monsoon season.

摘要： Some of the COVID-19 patients required an intensive care unit admission,additionally an aerosol delivery is an important treatment method in this type of patient.The present mini-review describes the best aerosol delivery method in this type of patients.Additionally,the different delivery methods of aerosol,and the best placement of the aerosol which allows the best delivery was discussed in this paper.

摘要： COVID-19 pandemic has forced to lockdown entire India starting from 24th March 2020 to 14th April 2020(first phase), extended up to 3rd May 2020(second phase), and further extended up to 17th May 2020(third phase) with limited relaxation in non-hotspot areas. This strict lockdown has severely curtailed human activity across India. Here, aerosol concentrations of particular matters(PM) i.e., PM,PM, carbon monoxide(CO), nitrogen dioxide(NO), sulphur dioxide(SO), ammonia(NH) and ozone(O), and associated temperature fluctuation in four megacities(Delhi, Mumbai, Kolkata, and Chennai)from different regions of India were investigated. In this pandemic period, air temperature of Delhi,Kolkata, Mumbai and Chennai has decreased about 3 °C, 2.5 °C, 2 °C and 2 °C respectively. Compared to previous years and pre-lockdown period, air pollutants level and aerosol concentration(-41.91%,-37.13%,-54.94% and-46.79% respectively for Delhi, Mumbai, Kolkata and Chennai) in these four megacities has improved drastically during this lockdown period. Emission of PMhas experienced the highest decrease in these megacities, which directly shows the positive impact of restricted vehicular movement. Restricted emissions produce encouraging results in terms of urban air quality and temperature, which may encourage policymakers to consider it in terms of environmental sustainability.

摘要： There has been significant research in recent decades on Land use Land cover (LULC) changes and their influence on biodiversity but little to no research on its impact on air quality. This research seeks to demonstrate how geospatial technologies such as geographic information system (GIS) and remote sensing can be used to assess the effects of LULC changes on particulate matter emissions and their impact on air quality in the East Baton Rouge area. In pursuit of these objectives, this study uses LANDSAT imageries from the past 30 years specifically Landsat Thematic Mapper (TM C2L2) and Landsat 8 Operational Land Imager/Thermal Infrared (OLI/TIRS C2L2) covering 1991, 2001, 2011 and 2021 were collected, processed, and analyzed for the LULC change analysis using QGIS software. Additionally, Sentinel 5P and the Air quality index from the U.S. Environmental Protection Agency (EPA) were used to assess the air quality trend over the years to establish the correlation between LULC and air quality. Results showed an increasing trend in air quality over the past 3 decades with concentrations of CO, NO2, and PM2.5 abruptly falling however, urbanization and the population expanded throughout the time. The paper concludes by outlining a policy recommendation in the form of encouraging Louisiana residents to use alternative renewable energies rather than the over-dependence on coal-fired electric generating plants that have an impact on the environment.

摘要： There are many theoretical explanations for the mitigation of tornados, storms, and hurricanes and one or two known simulation models that address the reduction of the intensities of these forces. We introduce an innovative methodology that releases environmentally friendly aerosol particles responsible for cloud condensation and weakens the intensities of these forces. For the past nine years, we did several experiments and analyzed the results. Experimental results give evidence to this methodology is practical, environment-friendly, cost-effective, and consistent. In this paper, we described our experiments along with results in three different scenarios such as tornado (March 2021, Georgia USA), storm Claudette (June 2021, Georgia USA), and hurricane Elsa (July 2021, Florida USA). Our experimental outcome and subsequent relevant meteorology data support the reason for mitigating the intensity of these destructive forces in and around the experiment locations.

摘要： The seasonal variations in background aerosol optical depth (AOD) and aerosol type are investigated over various ecosystems in China based upon three years’ worth of meteorological data and data collected by the Chinese Sun Hazemeter Network. In most parts of China, AODs are at a maximum in spring or summer and at a minimum in autumn or winter. Minimum values (0.10～0.20) of annual mean AOD at 500 nm are found in the Qinghai-Tibetan Plateau, the remote northeast corner of China, the northern forest ecosystems and Hainan Island. Annual mean AOD ranges from 0.25 to 0.30 over desert and oasis areas as well as the desertification grasslands in northern China; the annual mean AOD over the Loess Plateau is moderately high at 0.36. Regions where the highest density of agricultural and industrial activities are located and where anthropogenic sulphate aerosol and soil aerosol emissions are consistently high throughout the whole year (e.g. the central-eastern, southern and eastern coastal regions of China) experience annual mean AODs ranging from 0.50～0.80. Remarkable seasonal changes in the main types of aerosol over northern China (characterized by the Angstrom exponent, α) are seen. Due to biomass and fossil fuel burning from extensive agricultural practices in northern rural areas, concentrations of smoke and soot aerosols rise dramatically during autumn and winter (high α), while the main types of aerosol during spring and summer are dust and soil aerosols (low α). Over southeast Asia, biomass burning during the spring leads to increases in smoke and soot emissions. Over the Tibetan Plateau and Hainan Island where the atmosphere is pristine, the main types of aerosol are dust and sea salt, respectively.

摘要： This article describes the design and performance of a cavity ring-down spectroscopic (CRDS)instrument for measuring extinction coefficients of laboratory and ambient atmospheric aerosols. Throughaveraging 1000 individual waveforms, a minimum detectable aerosol extinction coefficient of 6.1×10-7m-1isachieved. Tests with polystyrene spheres (PSS), we suggested this CRDS agrees well with visibilityobservations from Shanghai Meteorological Bureau. Combined with the TSI integrating nephelometer andNOxanalyzer, CRDS was used to monitor the optical properties of ambient aerosols in the heavy pollutionepisode. The uncertainty for using the CRDS and TSI nephelometer to measure single scattering albedo (SSA)in an ambient measurement is estimated to be＜12%.

摘要： 用于在物体，具体是太阳能电池上的触点和母线敷金属线上沉积多根线的方法和装置。该接触线的宽度优选小于100微米，并且所有的接触线优选在沉积头的单程中沉积。在沉积头上可以存在多行喷嘴。多种材料可以沉积在彼此的上面，从而在所述物体上形成层状结构。每一个层均可以的厚度小于5微米。这些层的对齐优选在不必沉积超尺寸的对齐结构的情况下实现。可以使用多个雾化器来沉积多种材料。母线装置优选具有多个喷嘴，每一个喷嘴对于在单程中沉积母线是足够宽的。