Factors influencing the concentration of negative air ions during the year in forests and urban green spaces of the Dapeng Peninsula in Shenzhen, China

Negative air ions(NAIs)benefit the mental and physical health of humans,but rapid urbanization can decrease the abundance of NAIs.Quantifying the spatial and seasonal distribution of NAIs and determining the factors that infl uence the concentration during urbanization is thus essential.In the present study of a typical developing urban district in southern China,negative air ion concentrations(NAICs)in 60 forests sites and 30 urban green spaces were quantifi ed on seven consecutive days in each of the four seasons.Large seasonal variations in NAIC were revealed in forests and urban green spaces with trough values in summer.NAIC progressively decreased from forests to urban green spaces and was infl uenced by local land morphology,vegetation characteristics,and climatic factors.The vast,heavily vegetated northeastern region was the richest area for NAIs,whereas the narrow central region(urbanized area)was the poorest,implying dramatic impacts of urbanization on the spatial distribution of NAIs.The relationship between air temperature and NAIC was better fi tted with a quadratic equation than a linear equation.Moreover,the NAIC was more sensitive to local morphology in urban green spaces than in urban forests,indicating the vulnerability of NAIs in urbanized areas.Therefore,the appropriate design of local urban morphology is critical.

Air Pollution Concentration Approach to Potential Area Selection of the Air Quality Monitoring Station in Nakhon Ratchasima Municipality, Thailand

The purpose of the study is to generate traffic air information system） to determine a proper zone of AQMS （air analyzed were carbon monoxide （CO）, and nitrogen oxides （NOx） pollution map using mathematical model and GIS （geographic quality monitoring station） in municipality area. The pollutants which can be harmful to people living in the area. The three steps of mapping process were performed under the GIS environment using the existing vehicle emission rates and pollutant dispersion model. First, traffic volume, road network, and the emission rates of road segments varying with types of vehicle were collected from existing data. Second, the pollutant concentrations were calculated by use of CALINE4, a tool with Gaussian dispersion model. The model parameters include emission rate, wind directions and speeds, ambient temperature and observed pollutant concentration, and atmospheric stability during all seasons from the January 1, 2010 to May 31,2011 with regardless the rainy season. This resulted in concentrations at many receptor points along links of the road network. Third, distributions of pollution concentrations were generated by means of the spatial interpolation of those from receptors. The results of pollution raster-based maps are used for determining frequency of violence and combined pollution map. The resulting frequency of violence and intensity concentration will be further integrated to determine a potential area of AQMS. Finally, achieving pollution potential area of AQMS can be located as helpful basic data for efficient traffic and transportation planning.

Investigation of air pollution concentration in Kathmandu valley during winter season

The monthly concentrations of NO2, NOx, SO2 and O3 measured by a passive sampler from February 2003 to January 2004 showed that the air pollution during the winter season in Kathmandu valley was higher than the summer season. The O3 level was found the highest during April, May and June due to strong radiation. The hourly concentrations of NO2, NOx, O3 and suspended particulate matter（SPM） were also measured by automatic instruments on December 2003. Temperature at the height of 60 m and 400 m at Raniban Mountain in the northwest of Kathmandu valley was measured on February 2001 in the winter season and the average potential temperature gradient was estimated from observed temperature. Wind speed was also measured at the department of hydrology, airport section, from 18 February to 6 March 2001. It was found that the stable layer and the calm condition in the atmosphere strongly affected the appearance of the maximum concentrations of NO2 and SPM in the morning, and that the unstable layer and the windy condition in the atmosphere was considerably relevant to the decrease of air pollution concentrations at daytime. The emission amounts of NOx, HCs and total suspended particle（TSP） from transport sector in 2003 were estimated from the increasing rate of vehicles on the basis of the emission amounts in 1993 to be 3751 t/a, 30570 t/a and 1317 t/a, respectively. The diurnal concentrations in 2003 calculated by the two-layers box model reproduced the characteristics of air pollution in Kathmandu valley such as the maximum value of O3 and its time, the maximum value of NO in the morning, and the decrease of NO and NO2 at daytime. The comparison with the concentrations in 1993 calculated suggested that the main cause of air pollution was the emission from transport sector.

Study on Air Pollutant Concentration inside Railway Tunnels

This paper presents a one-dimensional unsteady flow model and a numerical procedure based on the model. Comparisons between the theory and full scale experiments in a railway tunnel show that the model is capable of produce precise predictions for piston wind and pollutant concentration in railway tunnels.

Histopathological Changes in the Epidermis of the Air Breathing Catfish Heteropneustes fossilis Exposed to Sublethal Concentration of Mercuric Chloride

Histopathological alterations induced by the sublethal concentration of (0.03 ppm) mercuric chloride solution on the epidermis of the fresh-water catfish Heteropneuates fossilis have been studied. It induces slow but significant histopathological changes in the various cellular components of the epidermis. It induces vacuolization, necrosis and pycnosis of the nuclei of the epithelial cells which subsequently shed. Loosening of epithelial cells of the outermost and middle layers following degeneration of the intercellular material and widened intercellular spaces is another important alteration. Prolonged mercury treatment also causes a gradual decrease in staining intensity for sulphated glycosaminoglycans in the outer border of the most superficial layer epithelial cells. The glandular elements (club cells and mucocytes) also get affected, showing cyclic degeneration followed by regeneration.

Transition Periods Between Sea Ice Concentration and Sea Surface Air Temperature in the Arctic Revealed by an Abnormal Running Correlation

This study used the synthetic running correlation coefficient calculation method to calculate the running correlation coefficients between the daily sea ice concentration(SIC) and sea surface air temperature(SSAT) in the Beaufort-Chukchi-East Siberian-Laptev Sea(BCEL Sea), Kara Sea and southern Chukchi Sea, with an aim to understand and measure the seasonally occurring changes in the Arctic climate system. The similarities and differences among these three regions were also discussed. There are periods in spring and autumn when the changes in SIC and SSAT are not synchronized, which is a result of the seasonally occurring variation in the climate system. These periods are referred to as transition periods. Spring transition periods can be found in all three regions, and the start and end dates of these periods have advancing trends. The multiyear average duration of the spring transition periods in the BCEL Sea, Kara Sea and southern Chukchi Sea is 74 days, 57 days and 34 days, respectively. In autumn, transition periods exist in only the southern Chukchi Sea, with a multiyear average duration of only 16 days. Moreover, in the Kara Sea, positive correlation events can be found in some years, which are caused by weather time scale processes.

Measurement of cytoplasmic Ca^(2+) concentration in Saccharomyces cerevisiae induced by air cold plasma

In this study, a novel approach to measure the absolute cytoplasmic Caconcentration([Ca]cyt) using the Caindicator fluo-3 AM was established. The parameters associated with the probe fluo-3 AM were optimized to accurately determine fluorescence intensity from the Ca-bound probe. Using three optimized parameters(final concentration of 6 m M probe,incubation time of 135 min, loading probe before plasma treatment), the maximum fluorescence intensity(F?=?527.8 a.u.) and the minimum fluorescence intensity(F?=?63.8 a.u.) were obtained in a saturated Casolution or a solution of lacking Ca. Correspondingly, the maximum [Ca]cytinduced by cold plasma was 1232.5 n M. Therefore, the Caindicator fluo-3 AM was successfully applied to measure the absolute [Ca]cytin Saccharomyces cerevisiae stimulated by cold plasma at atmospheric air pressure.

Analysis of Air Exchange System Influence on Thermal and Concentration Modes in the Local Working Area under Radiant Heating Conditions

One of the effective options for energy saving in terms of heat costs for the formation of routine thermal conditions of working areas of large-sized industrial premises is the replacement of traditional convective(water)heating systems with systems,the main part of which are gas infrared emitters.But the mass introduction of such systems based on emitters was held back until recently by the lack of scientific and technical foundations for ensuring not only the routine thermal conditions of local working areas,but also ensuring acceptable concentrations of carbon dioxide,which is formed during the operation of a gas emitter.Solving the latter problem by the method of experimental selection of heating and air exchange modes is practically impossible due to the multivariate nature of possible solutions to this problem.Therefore,the purpose of the work is to analyze the results of theoretical studies of the possibility of ensuring an acceptable level of carbon dioxide concentrations in local working areas during the operation of gas infrared emitters and an air exchange system.Numerical modeling of heat and mass transfer processes under such conditions was performed in a fairly wide range of the main significant factors:air flow rate in the air exchange system from 0.01 to 0.04 kg/s,the position of the air inlet and outlet channels relative to the radiator and the local workplace(height from 0.3 to 4.1 m).It was found that by varying the numerical values of these factors,it is possible to ensure carbon dioxide concentrations in the local working area within the permissible limits of up to 1400 ppm.

Impact of Spatial Inhomogeneity in Atmospheric CO_(2) Concentration on Surface Air Temperature Variations

Atmospheric CO_(2) concentration is characterized by spatial inhomogeneity and seasonal variability.The response of surface air temperature(SAT)to the inhomogeneity in CO_(2) concentration globally and regionally remains elusive.In this study,the BCC-CSM2-MR climate model was used to investigate the differences in global SAT in response to the spatially inhomogeneous distribution of atmospheric CO_(2) concentration.The analysis was based on three historical experiments(Hist_1dCO_(2),Hist_2dCO_(2),and Hist_3dCO_(2))conducted separately under the forcing of globally homogeneous,zonally homogeneous,and wholly spatially inhomogeneous CO_(2) concentrations from 1850 to 2014,derived from 12 Earth System Models of the Coupled Model Intercomparison Project Phase 6.The simulation results revealed similar trends of evolution in the global mean SATs in the 20th century under the three CO_(2) concentration distributions,and showed that the simulated historical SATs considering the meridional inhomogeneity of CO_(2) concentration in Hist_2dCO_(2) and the wholly spatial inhomogeneity in Hist_3dCO_(2) were more consistent with the observations.Compared with the results of Hist_1dCO_(2),the SATs in Hist_2dCO_(2) were warmer over land in the mid–high latitudes of the Northern Hemisphere(NH)than over other land areas.Further consideration of the zonally inhomogeneous CO_(2) concentration in Hist_3dCO_(2) revealed generally colder SATs over the NH mid–high-latitude ocean than over land at the same latitudes,and even the zonal mean SATs in the NH were slightly colder than those in Hist_2dCO_(2).These differences are ascribed to the uneven distribution of CO_(2) concentration along the same latitude in the NH in Hist_3dCO_(2),which leads to strong large-scale fluctuations in the atmospheric circulation.Eurasia is the region with the highest concentration of atmospheric CO_(2),which leads to remarkable regional SAT warming owing to enhanced downward longwave radiation.Warmer SATs in Eurasia in winter will further strengthen the northwesterly winds over eastern Asia,resulting in an increase in sea ice and strengthened cold SAT anomalies over the northern North Pacific.The simulated varied responses of the atmospheric circulation and SAT to inhomogeneous CO_(2) forcing highlight the imperative need for refined representation of the inhomogeneity of the atmospheric CO_(2) distribution in climate models for more accurate assessment of climate change.

Analysis on Link Between the Macroscopic and Microscopic Air–Water Properties in Self-Aerated Flows

Self-aeration in high-speed free surface flows occurs commonly and is of interest to ocean engineering, hydraulic engineering, and environmental engineering. For two-phase air–water flows, macroscopic air–water flow properties develop gradually, accompanied by the change of microscopic air–water structures. In this article, representational experimental studies on macroscopic and microscopic characteristics of self-aerated open-channel flows are summarized and compared. The isolated effect of the flow Reynolds number and air quantity on the differences in air count rate and chord size are analyzed and discussed. The results show that the characterized flow depth y, affected by the turbulence transfer, is a specific criterion to distinguish the interior air–water structure development. Two distinct linear trends of self-aeration are found, depending on the y/yvariation with a breaking point at Cmean =0.50. The air count rate and size scale in self-aerated flows are affected by the air quantity of self-aerated flows, even with identical flow Reynolds numbers. Thus, a specific parameter is proposed to assess the air–water structures and a series of self-similarity relationships in self-aeration properties are obtained. The link between macroscopic and microscopic air–water properties results in significant scale effect on air–water structures in self-aerated flows.

Monitoring Ambient Air Quality in the Carpathian Region of Ukraine

Ivano-Frankivsk oblast is located in the south-western part of Ukraine, close to the geographical center of Europe at the junction of the two major geographic units, the East European Plain and the Eastern Carpathians （the Carpathian region of Ukraine）. Between September 2013 and September 2015, the expert group of the Department of Organic and Analytical Chemistry of Vasyl Stefanyk Precarpathian National University conducted the mobile monitoring of air cleanliness in Ivano-Frankivsk region; the authors monitored the level of air contamination with seven gases： carbon monoxide and dioxide, sulfur dioxide, nitrogen dioxide, hydrogen sulfide, ammonia, formaldehyde, beta-particles, and gamma radiation. For this purpose, there were used six automatic analyzers ＂Dozor-C-P＂, the formaldehyde Gas Analyzer ＂MIC-98170＂, and the radiometer ＂TERRA＂. The monitoring resulted in the making of three maps of Ivano-Frankivsk region, on which the average levels of concentration of three particular gases （CO2, SO2, and CH20） throughout all the districts of the oblast were marked. There was registered the excess of CH20 limits--the consequences of the presence of the chipboard and wood-fiber production, for which formaldehyde is used as a raw material. Also there was observed the excess of SO2 in the air caused by gas fumes from vehicles and thermal power stations.

Numerical Simulation and Experimental Research on Indoor Environment Separated with Down-Feed Air Curtain

Indoor environment separated with down-feed air curtain was numerically simulated and experimen-tally researched. Indoor airflow and temperature fields separated with air curtain were numerically simulated. Re-sults show that both polluted airflow and thermal air current can be separated with a down-feed air curtain to pre-vent contaminants from spreading in the room space. In a test chamber, the smoke of burning Tibetan incense served as the source of contaminants, and the probe test shows that 1.0 μm is the prevailing diameter of the smoke particles. During the release of the smoke, the particle concentration of the indoor air was tested with a laser particle counter at the points of three different heights from the floor when the air curtain was running or not. Experimental results show that the higher the test point is located, the lower the particle concentration is, implying that the sepa-rating or isolating effect decreases as the air velocity of the curtain reduces along with the height descends. Accord-ing to both simulation and experimental results, down-feed air curtain can separate indoor environment effectively when the supply air velocity of air curtain is not less than 3 m/s. In order to strengthen separation effect, it is sug-gested that the supply air velocity be speeded up to 5 m/s.

Development of the Program of Monitoring of Composition of Atmospheric Air

To settle the indicators of air pollutions at the industrial enterprises is very important. For this purpose, authors analyzed and developed a program for monitoring atmospheric composition in Borland Delphi 7 for the calculation of the hazard class and the average daily maximum allowable concentration of air. Results of calculations on this program will allow operating composition of air by regulation of operating modes of filtering devices.

The spatial-temporal pattern and influencing factors of negative air ions in urban forests, Shanghai, China

Negative air ions are natural components of the air we breathe Forests are the main continuous natural source of negative air ions （NAI）. The spatio-temporal patterns of negative air ions were explored in Shanghai, based on monthly monitoring in 15 parks from March 2009 to February 2010. In each park, sampling sites were selected in forests and open spaces. The annual variation in negative air ion concentrations （NAIC） showed peak values from June to October and minimum values from December to January. NAIC were highest in summer and autumn, intermediate in spring, and lowest in winter. During spring and summer, NAIC in open spaces were significantly higher in rural areas than those in suburban areas. However, there were no significant differences in NAIC at forest sites among seasons. For open spaces, total suspended particles （TSP） were the dominant determining factor of NAIC in sum- mer, and air temperature and air humidity were the dominant determining factors of NAIC in spring, which were tightly correlated with Shanghai＇s ongoing urbanization and its impacts on the environment. R is suggested that urbanization could induce variation in NAIC along the urban-rural gradient, but that may not change the temporal variation pattern. Fur- thermore, the effects of urbanization on NAIC were limited in non-vegetated or less-vegetated sites, such as open spaces, but not in well-vegetated areas, such as urban forests. Therefore, we suggest that urban greening, especially urban forest, has significant resistance to theeffect of urbanization on NAIC.

Air Bubble Frequency Distribution in the Cavity Zone

In this paper, a series of experiments were carried out on the air concentration distribution. In the cavity zone, the air bubble frequency distribution was similar to the air concentration distribution. The air bubble frequency increased from the bottom and then decreased near the tmaerated black water region. The position of the maximum air bubble frequencyfmax moved downwards. At the air-water cross section, the relationship between the air bubble frequency and the air concentration was self-similar, the position of the maximum air bubble frequency caused by the air-water discontinuity gradually approached C = 0.50 with the development of aeration. Meanwhile, the dimensionless air bubble frequency in the cavity zone followed a parabolic function.

Practice and analysis of recycling non-drinking water from air-condition and reverse-osmosis system into rainwater collection system

This paper is based on the rainwater collection project in the retrofit of the Dongyi teaching block in Zhejiang University Xixi Campus.The analysis incorporates the local meteorological data, recycling water utilization, and precipitation adjustment.The rainwater collection system in this program also adds the condensation water from the heating, ventilation and air conditioning （ HVAC） system and the concentration from the reverse-osmosis system used for watering greens and supplying waterscapes.By calculating, the quantity of the HVAC condensation water in summer is 3.48 m3/d, and the quantity of the reverse-osmosis concentrated water is 198 to 396 L/d.This method solves the water shortage caused by high evaporation in summer and low precipitation in winter.Supported by empirical monitoring data, the proposed method significantly increases the economic efficiency of the system during the summer period.

Application of land use regression for estimating concentrations of major outdoor air pollutants in Jinan, China

SO2, NO2, and PM10 are the major outdoor air pollutants in China, and most of the cities in China have regulatory monitoring sites for these three air pollutants. In this study, we developed a land use regression (LUR) model using regulatory monitoring data to predict the spatial distribution of air pollutant concentrations in Jinan, China. Traffic, land use and census data, and meteorological and physical conditions were included as candidate independent variables, and were tabulated for buffers of varying radii. SO2, NO2, and PM10 concentrations were most highly correlated with the area of industrial land within a buffer of 0.5 km (R2=0.34), the distance from an expressway (R2=0.45), and the area of residential land within a buffer of 1.5 km (R2=0.25), respectively. Three multiple linear regression (MLR) equations were established based on the most significant variables (p<0.05) for SO2, NO2, and PM10, and R2 values obtained were 0.617, 0.640, and 0.600, respectively. An LUR model can be applied to an area with complex terrain. The buffer radii of independent variables for SO2, NO2, and PM10 were chosen to be 0.5, 2, and 1.5 km, respectively based on univariate models. Intercepts of MLR equations can reflect the background concentrations in a certain area, but in this study the intercept values seemed to be higher than background concentrations. Most of the cities in China have a network of regulatory monitoring sites. However, the number of sites has been limited by the level of financial support available. The results of this study could be helpful in promoting the application of LUR models for monitoring pollutants in Chinese cities.

INFLUENCE OF FILLING WATER ON AIR CONCENTRATION

The filling water inside the cavity below an aerator occurs for the flow of low Froude number or the small bottom slope of a spillway. The aerator may cease to protect against cavitation damages, and may even act as a generator of cavitation if it is fully filled by water. The experiments were conducted to investigate the influences of the geometric parameters, and then the filling water on the air concentration. The results show that the filling water, or the net cavity length, is closely related to the plunging jet length for a given aerator, and the air concentration at some section is proportional to the ratio Ln/Lj at a fixed Lj for different geometric parameters of aerators. Secondly, at the same ratio of Ln / Lj, the aerator with a larger height or a larger angle of ramp, or a larger bottom slope, would have a larger plunging jet length, and then a larger net cavity length based on the ratio of Ln / Lj. As a result, the large space of cavity, or the high air concentration of the flow could be obtained although the filling water increases also based on the fact that Lf = Lj - Ln. It is the space of the cavity that is the dominant factor to affect the air concentration of the flow.