scholarly journals The Innovative Method of Purifying Polluted Air in the Region of an Inversion Layer

2021 ◽  
Vol 9 ◽  
Author(s):  
F. Jędrzejek ◽  
D. Gryboś ◽  
J. Zyśk ◽  
J. Leszczyński ◽  
K. Szarłowicz ◽  
...  
Keyword(s):  
Air Pollution ◽  
Natural Convection ◽  
Shock Waves ◽  
Inversion Layer ◽  
Ground Level ◽  
Temperature Inversion ◽  
Vertical Movement ◽  
Vertical Movements ◽  
Innovative Method ◽  
High Concentrations

Formation of the inversion layer causes a lack of vertical movement of the atmosphere and the occurrence of long-lasting high concentrations of pollution. The new invention makes use of shock waves, created by explosions of a mixture of flammable gases and air. These shock waves destroy the structure of the temperature inversion layer in the atmosphere and restore natural convection. Restoring vertical movements within the atmosphere causes a reduction in air pollution at the ground level. The system was tested at full technical scale in the environment. Preliminary effects indicate an average 24% reduction in PM10 concentration in the smog layer at ground level up to 20 m, with the device operating in 11-min series consisting of 66 explosions. It was also shown that the device is able to affect a larger area, at least 4 km2.

scholarly journals Temperature Inversion Breakup with Impacts on Air Quality in Urban Valleys Influenced by Topographic Shading

2015 ◽  
Vol 54 (2) ◽  
pp. 302-321 ◽  
Author(s):  
Angela M. Rendón ◽  
Juan F. Salazar ◽  
Carlos A. Palacio ◽  
Volkmar Wirth
Keyword(s):  
Air Pollution ◽  
Urban Heat Island ◽  
Urban Areas ◽  
Inversion Layer ◽  
Temperature Inversion ◽  
Topographic Effects ◽  
Heat Island ◽  
Pollution Transport ◽  
High Emission ◽  
Urban Heat

AbstractUrban valleys can experience serious air pollution problems as a combined result of their limited ventilation and the high emission of pollutants from the urban areas. Idealized simulations were analyzed to elucidate the breakup of an inversion layer in urban valleys subject to a strong low-level temperature inversion and topographic effects on surface heating such as topographic shading, as well as the associated air pollution transport mechanisms. The results indicate that the presence and evolution in time of the inversion layer and its interplay with an urban heat island within the valley strongly influence the venting of pollutants out of urban valleys. Three mechanisms of air pollution transport were identified. These are transport by upslope winds, transport by an urban heat island–induced circulation, and transport within a closed slope-flow circulation below an inversion layer.

scholarly journals Investigation of the Air Pollution Event in Beijing-Tianjin-Hebei Region in December 2016 Using WRF-Chem

2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Dongdong Wang ◽  
Baolin Jiang ◽  
Fangzhou Li ◽  
Wenshi Lin
Keyword(s):  
Air Pollution ◽  
High Surface ◽  
Inversion Layer ◽  
Weather Conditions ◽  
Temperature Inversion ◽  
Blocking Effect ◽  
Weather Research And Forecasting ◽  
Atmospheric Flows ◽  
Pollution Event ◽  
Local Emissions

The online coupled weather research and forecasting model with chemistry (WRF-Chem) was used to investigate an air pollution event during December 2016 in Beijing-Tianjin-Hebei urban agglomeration. Evaluation indicates that WRF-Chem captured the main weather conditions and pollutant distribution in this event. The primary meteorological drivers of air pollution formation were stationary atmospheric flows in both vertical and horizontal directions. High relative humidity and a strong temperature inversion accelerated event formation. In the shallow temperature inversion layer, aerosol particles were strongly confined near the surface, producing high surface contaminant concentrations. In addition, based on a normal experiment, three sensitivity experiments were constructed by adding hypothetical terrain (HT) of 400, 300, and 200 meters, over the region 115°E, 38.8°N to 117.54°E, 38.8°N. The results indicate that pollutants were diffused and transported below 400 meters, and the pollutant amounts concentrated south of the HT because of the HT blocking effect. Nevertheless, because there were less total contaminants north of the HT in the normal run, there was a slight decrease in pollutants north of the HT. There were some increases in pollution north of the HT because of local emissions, which were obstructed by the HT. The higher the HT, the stronger the blocking effect.

Some Air Pollution Aspects of the Los Angeles Temperature Inversion

1952 ◽  
Vol 33 (6) ◽  
pp. 247-250 ◽  
Author(s):  
Elmer Robinson
Keyword(s):  
Air Pollution ◽  
Los Angeles ◽  
Inversion Layer ◽  
Temperature Inversion ◽  
Mathematical Formula ◽  
Correlation Studies ◽  
Early Fall ◽  
The Stability

During research on air pollution in Los Angeles, various meteorological aspects of the problem have been studied. One of these was the derivation of a mathematical formula which combines measures of the stability, height, and thickness of the inversion layer to give an overall value for its intensity. This formula has been useful in describing inversions and in various correlation studies. A file of data on inversion conditions in the Los Angeles area has been accumulated in the course of the smog program. These data, which apply to mean inversion conditions from May through November, are interesting not only for the smog problem but also in evaluating the climate of the area. They should prove useful in other studies where an appreciation of the climatic nature of the inversion surface is required. The cycle of the inversion indicates that the base gradually lowers during the summer and early fall and that as early as June, inversions are present 90% of the time. The “smog season” generally coincides with the latter part of the inversion cycle.

Parameterization of clear sky effective emissivity under surface-based temperature inversion at Dome C and South Pole, Antarctica

2013 ◽  
Vol 25 (5) ◽  
pp. 697-710 ◽  
Author(s):  
Maurizio Busetto ◽  
Christian Lanconelli ◽  
Mauro Mazzola ◽  
Angelo Lupi ◽  
Boyan Petkov ◽  
...  
Keyword(s):  
Inversion Layer ◽  
Lower Troposphere ◽  
Longwave Radiation ◽  
Ground Level ◽  
Temperature Inversion ◽  
Maximum Temperature ◽  
South Pole ◽  
Effective Emissivity ◽  
Clear Sky ◽  
Good Proxy

AbstractFor most parts of the year the Antarctic Plateau has a surface temperature inversion with strength c. 20 K. Under such conditions the warmer air at the top of the inversion layer contributes more to the clear sky atmospheric longwave radiation at surface level than does the colder air near the ground. Hence, it is more appropriate to relate longwave irradiance (LWI) to the top of the inversion layer temperature (Tm) than to the ground level temperature (Tg). Analysis of radio soundings carried out at Dome C and South Pole during 2006–08 shows that the temperature at 400 m above the surface (T400) is a good proxy for Tm and is linearly related to Tg with correlation coefficients greater than 0.8. During summer, radiosonde measurements show almost isothermal conditions, hence T400 still remains a good proxy for the lower troposphere maximum temperature. A methodology is presented to parameterize the clear sky effective emissivity in terms of the troposphere maximum temperature, using ground temperature measurements. The predicted LWI values for both sites are comparable with those obtained using radiative transfer models, while for Dome C the bias of 0.8 W m-2 and the root mean square (RMS) of 6.2 W m-2 are lower than those calculated with previously published parametric equations.

scholarly journals Subtle Changes or Dramatic Perceptions of Air Pollution in Sydney during COVID-19

Environments ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 2
Author(s):  
Peter Brimblecombe ◽  
Yonghang Lai
Keyword(s):  
Air Pollution ◽  
Air Quality ◽  
New South ◽  
Human Mobility ◽  
Ground Level ◽  
Physical Reality ◽  
Social Perceptions ◽  
Search Terms ◽  
South Wales ◽  
Significant Difference

The COVID-19 pandemic made it critical to limit the spread of the disease by enforcing human isolation, restricting travel and reducing social activities. Dramatic improvements to air quality, especially NO2, have often characterised places under COVID-19 restrictions. Air pollution measurements in Sydney in April 2019 and during the lockdown period in April 2020 show reduced daily averaged NO2 concentrations: 8.52 ± 1.92 and 7.85 ± 2.92 ppb, though not significantly so (p1~0.15) and PM2.5 8.91 ± 4.94 and 7.95 ± 2.64 µg m−3, again a non-significant difference (p1~0.18). Satellite imagery suggests changes that parallel those at ground level, but the column densities averaged over space and time, in false-colour, are more dramatic. Changed human mobility could be traced in increasing times spent at home, assessed from Google Mobility Reports and mirrored in decreased traffic flow on a major road, suggesting compliance with the restrictions. Electricity demand for the State of New South Wales was low under lockdown in early April 2020, but it recovered rapidly. Analysis of the uses of search terms: bushfires, air quality, haze and air pollution using Google Trends showed strong links between bushfires and pollution-related terms. The smoke from bushfires in late 2019 may well have added to the general impression of improved air quality during lockdown, despite only modest changes in the ground level measurements. This gives hints that successful regulation of air quality requires maintaining a delicate balance between our social perceptions and the physical reality.

scholarly journals Spatial Analysis (Measurements at Heights of 10 m and 20 m above Ground Level) of the Concentrations of Particulate Matter (PM10, PM2.5, and PM1.0) and Gaseous Pollutants (H2S) on the University Campus: A Case Study

Atmosphere ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 62
Author(s):  
Robert Cichowicz ◽  
Maciej Dobrzański
Keyword(s):  
Spatial Distribution ◽  
Hydrogen Sulfide ◽  
Particulate Matter ◽  
Air Quality ◽  
Spatial Analysis ◽  
Ground Level ◽  
Leeward Side ◽  
High Concentration ◽  
Above Ground Level ◽  
High Concentrations

Spatial analysis of the distribution of particulate matter PM10, PM2.5, PM1.0, and hydrogen sulfide (H2S) gas pollution was performed in the area around a university library building. The reasons for the subject matter were reports related to the perceptible odor characteristic of hydrogen sulfide and a general poor assessment of air quality by employees and students. Due to the area of analysis, it was decided to perform measurements at two heights, 10 m and 20 m above ground level, using measuring equipment attached to a DJI Matrice 600 unmanned aerial vehicle (UAV). The aim of the measurements was air quality assessment and investigate the convergence of the theory of air flow around the building with the spatial distribution of air pollutants. Considerable differences of up to 63% were observed in the concentrations of pollutants measured around the building, especially between opposite sides, depending on the direction of the wind. To explain these differences, the theory of aerodynamics was applied to visualize the probable airflow in the direction of the wind. A strong convergence was observed between the aerodynamic model and the spatial distribution of pollutants. This was evidenced by the high concentrations of dust in the areas of strong turbulence at the edges of the building and on the leeward side. The accumulation of pollutants was also clearly noticeable in these locations. A high concentration of H2S was recorded around the library building on the side of the car park. On the other hand, the air turbulence around the building dispersed the gas pollution, causing the concentration of H2S to drop on the leeward side. It was confirmed that in some analyzed areas the permissible concentration of H2S was exceeded.

scholarly journals Environmental and Air Pollution Factors Affecting Allergic Eye Disease in Children and Adolescents in India

2021 ◽  
Vol 18 (11) ◽  
pp. 5611
Author(s):  
Anthony Vipin Das ◽  
Sayan Basu
Keyword(s):  
Air Pollution ◽  
Children And Adolescents ◽  
Temporal Pattern ◽  
Environmental Parameters ◽  
Ground Level ◽  
Significant Negative Correlation ◽  
Eye Disease ◽  
Cross Sectional ◽  
Recent Onset ◽  
Ground Level Ozone

The aim of this study was to describe the correlation between the meteorological and air pollution parameters with the temporal pattern of presentation of recent onset allergic eye disease (AED). This cross-sectional hospital-based study included new patients (≤21 years of age) presenting between January 2016 and August 2018 from the district of Hyderabad with a clinical diagnosis of AED and an acute exacerbation of recent onset of symptoms of less than 3 months duration. Correlation analysis was performed with the local environmental rainfall, temperature, humidity, windspeed, and air pollution. Of the 25,354 new patients hailing from the district of Hyderabad, 2494 (9.84%) patients were diagnosed with AED, of which 1062 (4.19%) patients had recent onset of symptoms. The mean monthly prevalence in this cohort was 4.13%, and the month of May (6.09%) showed the highest levels. The environmental parameters of humidity (r2 = 0.83/p = < 0.0001) and rainfall (r2 = 0.41/p = 0.0232) showed significant negative correlation, while temperature (r2 = 0.43/p = 0.0206) and ground-level ozone (r2 = 0.41/p = 0.0005) showed significant positive correlation with the temporal pattern of AED in the population. An increase in rainfall and humidity was associated with a lower prevalence, and an increase of temperature and ground-level ozone was associated with a higher prevalence of AED cases during the year among children and adolescents.

scholarly journals Development of a Line Source Dispersion Model for Gaseous Pollutants by Incorporating Wind Shear near the Ground under Stable Atmospheric Conditions

2020 ◽  
Vol 4 (1) ◽  
pp. 17
Author(s):  
Saisantosh Vamshi Harsha Madiraju ◽  
Ashok Kumar
Keyword(s):  
Air Pollution ◽  
Urban Areas ◽  
Wind Shear ◽  
Dispersion Model ◽  
Near Field ◽  
Ground Level ◽  
Gaseous Pollutants ◽  
Air Pollution Control ◽  
Mobile Sources ◽  
Input Variables

Transportation sources are a major contributor to air pollution in urban areas. The role of air quality modeling is vital in the formulation of air pollution control and management strategies. Many models have appeared in the literature to estimate near-field ground level concentrations from mobile sources moving on a highway. However, current models do not account explicitly for the effect of wind shear (magnitude) near the ground while computing the ground level concentrations near highways from mobile sources. This study presents an analytical model based on the solution of the convective-diffusion equation by incorporating the wind shear near the ground for gaseous pollutants. The model input includes emission rate, wind speed, wind direction, turbulence, and terrain features. The dispersion coefficients are based on the near field parameterization. The sensitivity of the model to compute ground level concentrations for different inputs is presented for three different downwind distances. In general, the model shows Type III sensitivity (i.e., the errors in the input will show a corresponding change in the computed ground level concentrations) for most of the input variables. However, the model equations should be re-examined for three input variables (wind velocity at the reference height and two variables related to the vertical spread of the plume) to make sure that that the model is valid for computing ground level concentrations.

scholarly journals Winter Ozone Pollution in Utah’s Uinta Basin is Attenuating

Atmosphere ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 4
Author(s):  
Marc L. Mansfield ◽  
Seth N. Lyman
Keyword(s):  
Ground Level ◽  
Ambient Air ◽  
Quality Standard ◽  
Ozone Pollution ◽  
Uinta Basin ◽  
Concentration Data ◽  
Previous Decade ◽  
High Concentrations ◽  
Ambient Air Quality Standard ◽  
Ozone Precursor

High concentrations of ground-level ozone have been observed during wintertime in the Uinta Basin of western Utah, USA, beginning in 2010. We analyze existing ozone and ozone precursor concentration data from 38 sites over 11 winter seasons and conclude that there has been a statistically significant (p < 0.02) decline in ozone concentration over the previous decade. Daily exceedances of the National Ambient Air Quality Standard for ozone (70 ppb) have been trending downward at the rate of nearly four per year. Ozone and NOx concentrations have been trending downward at the rates of about 3 and 0.3 ppb per year, respectively. Concentrations of organics in 2018 were at about 30% of their values in 2012 or 2013. Several markers, annual ozone exceedance counts and median ozone and NOx concentrations, were at their largest values in the period 2010 to 2013 and have never recovered since then. We attribute the decline to (1) weakening global demand for oil and natural gas and (2) more stringent pollution regulations and controls, both of which have occurred over the previous decade. We also see evidence of ozone titration when snow cover is absent.

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