Vertical-distribution Characteristics of Atmospheric Aerosols under Different Thermodynamic Conditions in Beijing

Hua, Wei; Sun, Zhian; Li, Hongyu; Gao, Yang; Jin, Wu; Cheng, Tiantao

doi:10.4209/aaqr.2018.03.0078

Cited by 25 publications

(21 citation statements)

References 30 publications

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“…S3). This is mainly due to the decrease of the relative humidity and aerosol concentrations with altitude (Mishra et al, 2015;Wang et al, 2018).…”

Section: Ph Variation With Heightmentioning

confidence: 99%

Size-resolved aerosol pH over Europe during summer

Ζακούρα¹,

Kakavas²,

Nenes³

et al. 2020

Preprint

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Abstract. The dependence of aerosol acidity on particle size, location and altitude over Europe during a summertime period is investigated using the hybrid version of aerosol dynamics in the chemical transport model PMCAMx. The pH changes more with particle size in northern and southern Europe owing to the enhanced presence of non-volatile cations (Na, Ca, K, Mg) in the larger particles. Differences of up to 1&#8211;4 pH units are predicted between sub- and super-micron particles, while the average pH of PM1&#8211;2.5 can be as much as 1 unit higher than that of PM1. Most aerosol water over continental Europe is associated with PM1, while PM2.5&#8211;5 and PM5&#8211;10 dominate the water content in the marine and coastal areas due to the relatively higher levels of hygroscopic sea salt. Particles of all sizes become increasingly acidic with altitude (0.5&#8211;2 units pH decrease over 2.5&#8201;km) primarily because of the decrease in aerosol liquid water content (driven by humidity changes) with height. Inorganic nitrate is strongly affected by aerosol pH with the highest average nitrate levels predicted for the PM2.5&#8211;5 range and over locations where the pH exceeds 3. Dust tends to increase aerosol water levels, aerosol pH and nitrate concentrations for all particle sizes. This effect of dust is quite sensitive to its calcium content. The size-dependent pH differences carry important implications for pH-sensitive processes in the aerosol.

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“…S3). This is mainly due to the decrease of the relative humidity and aerosol concentrations with altitude (Mishra et al, 2015;Wang et al, 2018).…”

Section: Ph Variation With Heightmentioning

confidence: 99%

Size-resolved aerosol pH over Europe during summer

Ζακούρα¹,

Kakavas²,

Nenes³

et al. 2020

Preprint

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“…When the particles reach a certain height, they will transmit laterally under the influence of horizontal drag force. The height of 500 kV insulators is about 20 meters from the ground, and the pollution particle size around the insulator is about 50 µm [16]. Therefore, based on the distribution range of pollution particle diameter around the insulator and the suspension height of the insulator, the force of pollution particles can be divided into three types: the electrical force, the fluid drag force and the gravity force.…”

Section: A the Force Analysis Of Pollution Particlementioning

confidence: 99%

“…Atmospheric particulate matter is generally divided into three mode distributions: Aitken mode (dp ≤ 0.08 µm), accumulation mode (0.08< dp ≤ 2 µm) and coarse particle mode (dp > 2 µm) [15]. The pollution particles of Aitken mode form larger diameter particles by chemical reaction, resulting in a short time in the air for the particles of Aitken mode; The accumulated modal particles are mainly composed of organic matter, metal and various ions, which can be suspended in the air for a long time and can be transmitted in the air for a long distance; The coarse particles (dp > 2 µm) are mainly composed of dust and coal ash, which are transported in the air for several hundred meters to several tens of kilometres, landed on the ground by sedimentation [16].…”

Section: E Particle Size and Wind Speedmentioning

confidence: 99%

Numerical Investigation on Collision of Pollution Particles on Outdoor Insulators

Liu

Kong

et al. 2019

IEEE Access

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Accumulation of pollution particles on outdoor insulators is the premise of pollution flashover accidents in power systems. In this paper, according to the actual operating polymer insulators, the wind velocity, the concentration of pollution particles, the diameter of pollution particles, and the hanging angle of insulator were considered to investigate the accumulation characteristic of pollution particles by using FLUENT software. The pressure nephogram of polymer insulator, the velocity vector of air flow field, movement trajectory of pollution particles, and collision rate were obtained. It is found that the pressure of the insulator surface on the windward side is bigger than that on the leeward side, and the pressure difference increases with increasing the wind velocity. As the increase in particle diameter, the collision rate between pollution particles and insulator surface shows the increasing tendency. When the diameter of pollution particles is small, the easier the particles follow the airflow to bypass the insulator surface without colliding with it. However, due to the influence of gravity force and inertia, the collision rate of pollution particles increases significantly with the increase in particle diameter. Under the strong wind velocity, the air swirls are generated on the leeward side of the insulator surface, causing the collision rate of the pollution particles increases slowly with the increase in the wind velocity. While the concentration of pollution particle increases, the collision number between insulator surface and pollution particles shows the increasing tendency at different wind velocity. When the particle diameter is in range of 1 to 8 µm, with increasing the hanging angle of ''V'' type insulator from 0 • to 60 • , the collision rate of pollution particles shows the increasing tendency. When the particle diameter is 9 to 50 µm, the collision rate of particles shows the increasing tendency when the insulator angle is lower than 30 • , but shows the decreasing tendency from 30 • to 60 •. As the humidity increases, the water vapor in the air prevents the movement of pollution particles, resulting in a decrease in the collision rate. With increasing the pollution particles diameter, the influence of air humidity on the collision rate of pollution particles is gradually weakened.

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“…The vertical structure of the pollutant concentration strongly depends on many factors, including season, meteorological conditions (Wang et al, 2018), topography (Trompetter et al, 2013;Strbova et al, 2017), seasonal variability of local emissions and long-range transport (Li and Han, 2016). Due to this fact it is necessary to continuously study the spatial and vertical distribution of air pollution concentration in urbanized areas to better determine its sources and processes leading to abundant air pollution.…”

Section: Introductionmentioning

confidence: 99%

“…-two layers with significantly different concentration, i.e. high concentration in the stratum from the ground level to a certain height, then a transition layer with a rapid decrease in pollutant concentration with height, and a stratum with a low concentration in the profile above; usually linked to thermal inversion occurrence (Strbova et al, 2017;Wang et al, 2018;Samad et al, 2020); -a large, constant decrease of a pollutant concentration with height, resulting e.g. from a strong surface emission of a pollutant during stable conditions, or from katabatic flows bringing the pollutants (Strbova et al, 2017), and from removal of the pollutants from upper layers;…”

Section: Introductionmentioning

confidence: 99%

Measurement report: Effect of wind shear on PM10 concentration vertical structure in urban boundary layer in a complex terrain

Sekula¹,

Bokwa²,

Bartyzel³

et al. 2021

Preprint

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Abstract. The paper shows wind shear impact on PM10 vertical profiles, in Kraków, southern Poland. The data used consist of background data for two cold seasons (Sep. 2018 to Apr. 2019, and Sep. 2019 to Apr. 2020), and data for several case studies from November 2019 to March 2020. The data is composed of PM10 measurements, model data, and wind speed and direction data. The background model data come from operational forecast results of AROME model. PM10 concentration in the vertical profile was measured with a sightseeing balloon. Significant spatial variability of wind field was found. The case studies represent the conditions with much lower wind speed and a much higher PM10 levels than the seasonal average. The inversions were much more frequent than on average, too. Wind shear turned out to be the most important factor in terms of PM10 vertical profile modification. It is generated due to the relief impact, i.e. the presence of a large valley, blocked on one side with the hills. The analysis of PM10 profiles from all flights allows to distinguish three vertical zones of potential air pollution hazard within the valley (about 100 m deep) and the city of Kraków: 1. up to about 60 m a.g.l. – the zone where during periods of low wind speed, air pollution is potentially the highest and the duration of such high levels is the longest, i.e. the zone with the worst aerosanitary conditions; 2. about 60–100 m a.g.l. – transitional zone where the large decrease of PM10 levels with height is observed; 3. above 100–120 m a.g.l. – the zone where air quality is significantly better than in the zone 1, either due to the increase of the wind speed, or due to the wind direction change and advection of different, clean air masses.

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Vertical-distribution Characteristics of Atmospheric Aerosols under Different Thermodynamic Conditions in Beijing

Cited by 25 publications

References 30 publications

Size-resolved aerosol pH over Europe during summer

Size-resolved aerosol pH over Europe during summer

Numerical Investigation on Collision of Pollution Particles on Outdoor Insulators

Measurement report: Effect of wind shear on PM<sub>10</sub> concentration vertical structure in urban boundary layer in a complex terrain

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Vertical-distribution Characteristics of Atmospheric Aerosols under Different Thermodynamic Conditions in Beijing

Cited by 25 publications

References 30 publications

Size-resolved aerosol pH over Europe during summer

Size-resolved aerosol pH over Europe during summer

Numerical Investigation on Collision of Pollution Particles on Outdoor Insulators

Measurement report: Effect of wind shear on PM&lt;sub&gt;10&lt;/sub&gt; concentration vertical structure in urban boundary layer in a complex terrain

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Measurement report: Effect of wind shear on PM<sub>10</sub> concentration vertical structure in urban boundary layer in a complex terrain