Effects of Rainfall on PM2.5 and PM10 in the Middle Reaches of the Yangtze River

Based on the PM2.5 and PM10 mass concentration data obtained from 51 national air quality monitoring stations and the corresponding rainfall intensity data in automatic meteorological stations in Hubei Province from 1 January 2015 to 31 December 2017, the impact of rainfall intensity on PM mass concentrations under relatively different humidity conditions was analyzed. The results showed that light rain occurred most frequently in the pollution process, with Xiangyang being affected for up to 587 h. PM concentration would not change drastically under the effect of precipitation. Mean rainfall intensity responsible for wet growth of PM10 and PM2.5 was mainly <0.5 mm/h, while that responsible for wet removal of PM2.5 was significantly higher (>1.4 mm/h) than that of PM10 (>1.0 mm/h). Precipitation was more likely to produce a wet removal effect for a greater initial value of PM mass concentration, and on the contrary, a wet growth effect was more likely, with the threshold of PM10 mass concentration being 150 μg/m3 and that of PM2.5 mass concentration being 95 μg/m3. Wet removal played a leading role in lower humidity (∼60%) and greater rainfall intensity, but wet growth played a leading role in higher humidity (∼90%) and lower rainfall intensity. As the precipitation level increased (rainfall ≥1.5 mm·h−1), the wet removal to PM10 mass concentration was enhanced more obviously. The variations of PM2.5 had similar distributions to those of PM10 under the effect of precipitation, but the wet removal effect of precipitation was weakened and the wet growth effect was enhanced.

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Evolution of Gaseous and Particulate Pollutants in the Air: What Changed after Five Lockdown Weeks at a Southwest Atlantic European Region (Northwest of Spain) Due to the SARS-CoV-2 Pandemic?

Atmosphere ◽

10.3390/atmos12050562 ◽

2021 ◽

Vol 12 (5) ◽

pp. 562

Author(s):

Jorge Moreda-Piñeiro ◽

Joel Sánchez-Piñero ◽

María Fernández-Amado ◽

Paula Costa-Tomé ◽

Nuria Gallego-Fernández ◽

...

Keyword(s):

Air Quality ◽

Road Traffic ◽

Statistical Significance ◽

Temporal Trends ◽

Air Pollutant ◽

Concentration Data ◽

Southwest Atlantic ◽

Pollutant Concentrations ◽

Air Quality Monitoring Stations ◽

Almost All

Due to the exponential growth of the SARS-CoV-2 pandemic in Spain (2020), the Spanish Government adopted lockdown measures as mitigating strategies to reduce the spread of the pandemic from 14 March. In this paper, we report the results of the change in air quality at two Atlantic Coastal European cities (Northwest Spain) during five lockdown weeks. The temporal evolution of gaseous (nitrogen oxides, comprising NOx, NO, and NO2; sulfur dioxide, SO2; carbon monoxide, CO; and ozone, O3) and particulate matter (PM10; PM2.5; and equivalent black carbon, eBC) pollutants were recorded before (7 February to 13 March 2020) and during the first five lockdown weeks (14 March to 20 April 2020) at seven air quality monitoring stations (urban background, traffic, and industrial) in the cities of A Coruña and Vigo. The influences of the backward trajectories and meteorological parameters on air pollutant concentrations were considered during the studied period. The temporal trends indicate that the concentrations of almost all species steadily decreased during the lockdown period with statistical significance, with respect to the pre-lockdown period. In this context, great reductions were observed for pollutants related mainly to fossil fuel combustion, road traffic, and shipping emissions (−38 to −78% for NO, −22 to −69% for NO2, −26 to −75% for NOx, −3 to −77% for SO2, −21% for CO, −25 to −49% for PM10, −10 to −38% for PM2.5, and −29 to −51% for eBC). Conversely, O3 concentrations increased from +5 to +16%. Finally, pollutant concentration data for 14 March to 20 April of 2020 were compared with those of the previous two years. The results show that the overall air pollutants levels were higher during 2018–2019 than during the lockdown period.

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Can Architectural Surfaces Capture Atmospheric Particulate Matter Like Trees? A Design Strategy to Mimic Leaf Traits

Sustainability ◽

10.3390/su13147637 ◽

2021 ◽

Vol 13 (14) ◽

pp. 7637

Author(s):

Taekyoung Lee ◽

Jieun Cha ◽

Sohyun Sung

Keyword(s):

Leaf Traits ◽

Design Strategy ◽

Atmospheric Particulate Matter ◽

Porous Surface ◽

Base Surface ◽

Different Types ◽

Pm2.5 And Pm10 ◽

Micro Morphology ◽

The Impact ◽

Cluster Pattern

Trees’ ability to capture atmospheric Particular Matter (PM) is related to morphological traits (shape, size, and micro-morphology) of the leaves. The objectives of this study were (1) to find out whether cluster pattern of the leaves is also a parameter that affects trees’ PM capturing performance and (2) to apply the cluster patterns of the leaves on architectural surfaces to confirm its impact on PM capturing performance. Two series of chamber experiments were designed to observe the impact of cluster patterns on PM capturing performance whilst other influential variables were controlled. First, we exposed synthetic leaf structures of different cluster patterns (a large and sparsely arranged cluster pattern and a small and densely arranged cluster pattern) to artificially generated PM in a chamber for 60 min and recorded the changing levels of PM2.5 and PM10 every minute. The results confirmed that the small and densely arranged cluster pattern has more significant effect on reducing PM2.5 and PM10 than the large and sparsely arranged cluster pattern. Secondly, we created three different types of architectural surfaces mimicking the cluster patterns of the leaves: a base surface, a folded surface, and a folded and porous surface. The surfaces were also exposed to artificially generated PM in the chamber and the levels of PM2.5 and PM10 were recorded. The results confirmed that the folded and porous surface has a more significant effect on reducing PM2.5 and PM10 than other surfaces. The study has confirmed that the PM capturing performance of architectural surfaces can be improved by mimicking cluster pattern of the leaves.

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Cooperation/Competition between Halogen Bonds and Hydrogen Bonds in Complexes of 2,6-Diaminopyridines and X-CY3 (X = Cl, Br; Y = H, F)

Symmetry ◽

10.3390/sym13050766 ◽

2021 ◽

Vol 13 (5) ◽

pp. 766

Author(s):

Barbara Bankiewicz ◽

Marcin Palusiak

Keyword(s):

Complex Formation ◽

Hydrogen Bonds ◽

Dft Calculations ◽

Electrostatic Interactions ◽

Dipole Moments ◽

Main Role ◽

Halogen Bonds ◽

Topological Parameters ◽

Leading Role ◽

The Impact

The DFT calculations have been performed on a series of two-element complexes formed by substituted 2,6-diaminopyridine (R−PDA) and pyridine (R−Pyr) with X−CY3 molecules (where X = Cl, Br and Y = H, F). The primary aim of this study was to examine the intermolecular hydrogen and halogen bonds in the condition of their mutual coexistence. Symmetry/antisymmetry of the interrelation between three individual interactions is addressed. It appears that halogen bonds play the main role in the stabilization of the structures of the selected systems. However, the occurrence of one or two hydrogen bonds was associated with the favourable geometry of the complexes. Moreover, the impact of different substituent groups attached in the para position to the aromatic ring of the 2,6-diaminopyridine and pyridine on the character of the intermolecular hydrogen and halogen bonds was examined. The results indicate that the presence of electron-donating substituents strengthens the bonds. In turn, the presence of electron-withdrawing substituents reduces the strength of halogen bonds. Additionally, when hydrogen and halogen bonds lose their leading role in the complex formation, the nonspecific electrostatic interactions between dipole moments take their place. Analysis was based on geometric, energetic, and topological parameters of the studied systems.

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Impact of Topography and Rainfall Intensity on the Accuracy of IMERG Precipitation Estimates in an Arid Region

Remote Sensing ◽

10.3390/rs13010013 ◽

2020 ◽

Vol 13 (1) ◽

pp. 13

Author(s):

Mohammed T. Mahmoud ◽

Safa A. Mohammed ◽

Mohamed A. Hamouda ◽

Mohamed M. Mohamed

Keyword(s):

Rainfall Intensity ◽

Poor Performance ◽

Rain Gauge ◽

Detection Accuracy ◽

Rain Gauge Data ◽

Light Rain ◽

Mountainous Regions ◽

Data Gaps ◽

Precipitation Estimates ◽

Evaluation Techniques

The influence of topographical characteristics and rainfall intensity on the accuracy of satellite precipitation estimates is of importance to the adoption of satellite data for hydrological applications. This study evaluates the three GPM IMERG V05B products over the arid country of Saudi Arabia. Statistical indices quantifying the performance of IMERG products were calculated under three evaluation techniques: seasonal-based, topographical, and rainfall intensity-based. Results indicated that IMERG products have the capability to detect seasons with the highest precipitation values (spring) and seasons with the lowest precipitation (summer). Moreover, results showed that IMERG products performed well under various rainfall intensities, particularly under light rain, which is the most common rainfall in arid regions. Furthermore, IMERG products exhibited high detection accuracy over moderate elevations, whereas it had poor performance over coastal and mountainous regions. Overall, the results confirmed that the performance of the final-run product surpassed the near-real-time products in terms of consistency and errors. IMERG products can improve temporal resolution and play a significant role in filling data gaps in poorly gauged regions. However, due to the errors in IMERG products, it is recommended to use sub-daily rain gauge data in satellite calibration for better rainfall estimation over arid and semiarid regions.

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Prediction of factors affecting activation of soil erosion by mathematical modeling at pedon scale under laboratory conditions

Scientific Reports ◽

10.1038/s41598-020-76926-1 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Saeed Shojaei ◽

Zahra Kalantari ◽

Jesús Rodrigo-Comino

Keyword(s):

Soil Loss ◽

Rainfall Intensity ◽

Quadratic Function ◽

Interactive Effects ◽

Soil Protection ◽

Single Factor ◽

Rainfall Events ◽

Rainfall Duration ◽

The Impact ◽

Runoff Production

AbstractSoil degradation due to erosion is a significant worldwide problem at different spatial (from pedon to watershed) and temporal scales. All stages and factors in the erosion process must be detected and evaluated to reduce this environmental issue and protect existing fertile soils and natural ecosystems. Laboratory studies using rainfall simulators allow single factors and interactive effects to be investigated under controlled conditions during extreme rainfall events. In this study, three main factors (rainfall intensity, inclination, and rainfall duration) were assessed to obtain empirical data for modeling water erosion during single rainfall events. Each factor was divided into three levels (− 1, 0, + 1), which were applied in different combinations using a rainfall simulator on beds (6 × 1 m) filled with soil from a study plot located in the arid Sistan region, Iran. The rainfall duration levels tested were 3, 5, and 7 min, the rainfall intensity levels were 30, 60, and 90 mm/h, and the inclination levels were 5, 15, and 25%. The results showed that the highest rainfall intensity tested (90 mm/h) for the longest duration (7 min) caused the highest runoff (62 mm3/s) and soil loss (1580 g/m2/h). Based on the empirical results, a quadratic function was the best mathematical model (R2 = 0.90) for predicting runoff (Q) and soil loss. Single-factor analysis revealed that rainfall intensity was more influential for runoff production than changes in time and inclination, while rainfall duration was the most influential single factor for soil loss. Modeling and three-dimensional depictions of the data revealed that sediment production was high and runoff production lower at the beginning of the experiment, but this trend was reversed over time as the soil became saturated. These results indicate that avoiding the initial stage of erosion is critical, so all soil protection measures should be taken to reduce the impact at this stage. The final stages of erosion appeared too complicated to be modeled, because different factors showed differing effects on erosion.

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Regulation and Critical Threshold of Grass Cover on Slope Runoff in LoessHilly Gully Region under Artificial

10.5194/egusphere-egu21-4363 ◽

2021 ◽

Author(s):

Qiufen Zhang ◽

Xizhi Lv ◽

Rongxin Chen ◽

Yongxin Ni ◽

Li Ma

Keyword(s):

Soil Erosion ◽

Rainfall Intensity ◽

Climatic Conditions ◽

Vegetation Coverage ◽

Critical Threshold ◽

Runoff Generation ◽

Grassland Vegetation ◽

Slope Flow ◽

The Impact ◽

Slope Runoff

The slope runoff caused by rainstorm is the main cause of serious soil and water loss in the loess hilly area, the grassland vegetation has a good inhibitory effect on the slope runoff, it is of great significance to reveal the role of grassland vegetation in the process of runoff generation and control mechanism for controlling soil erosion in this area. In this study, typical grassland slopes in hilly and gully regions of the loess plateau were taken as research objects. Through artificial rainfall in the field, the response rules of slope rainfall-runoff process to different grass coverage were explored. The results show that: (1) The time for the slope flow to stabilize is prolonged with the increase of vegetation coverage, and shortened with the increase of rainfall intensity; (2) At 60 mm&#183;h &#8722;1 rainfall intensity, the threshold of grassland vegetation coverage is 75.38%; at 90 mm&#183;h &#8722;1 rainfall intensity, the threshold of grassland vegetation coverage is 90.54%; at 120 mm&#183;h &#8722;1 rainfall intensity, the impact of grassland vegetation coverage on runoff is not significant; (3) the Reynolds number and Froude number of slope flow are 40.07&#8210;695.22 and 0.33&#8210;1.56 respectively, the drag coefficient is 1.42&#8210;43.53. Under conditions of heavy rainfall, the ability of grassland to regulate slope runoff is limited. If only turf protection is considered, about 90% of grassland coverage can effectively cope with soil erosion caused by climatic conditions in loess hilly and gully regions. Therefore, in loess hilly areas where heavy rains frequently occur, grassland's protective effect on soil erosion is obviously insufficient, and investment in vegetation measures for trees and shrubs should be strengthened.

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Herbicide loss in runoff: effects of herbicide properties, slope, and rainfall intensity

Soil Research ◽

10.1071/sr03090 ◽

2004 ◽

Vol 42 (1) ◽

pp. 17 ◽

Cited By ~ 26

Author(s):

K. Müller ◽

M. Trolove ◽

T. K. James ◽

A. Rahman

Keyword(s):

Rainfall Intensity ◽

Water Solubility ◽

Small Scale ◽

Herbicide Application ◽

Rainfall Events ◽

Kd Values ◽

Loam Soil ◽

The Impact ◽

Field Plots ◽

Dissolved Form

Runoff potential of 5 herbicides (acetochlor, atrazine, hexazinone, pendimethalin, and terbuthylazine) was evaluated in a small-scale study under simulated rainfall on a cultivated Hamilton clay loam soil. At 24 h after herbicide application, rainfall events of different intensities were simulated to 0.5-m2 field plots with 20% (70, 88, and 111 mm/h) and 30% (60, 70, and 80 mm/h) slope, respectively. The objective of this study was to compare the behaviour of pesticides covering a range of properties under identical hydrodynamic conditions. Sediment amounts and herbicide concentrations were determined in the runoff samples. As the transported sediment amounts were not sufficient for chemical analyses, herbicide residues attached to sediment were estimated using Kd values determined locally for the soil. Whereas pendimethalin concentrations followed no noticeable pattern, the concentrations for the other herbicides were highest in the first runoff samples, and decreased exponentially with further rain. Results show that herbicides were primarily transported in their dissolved form with the exception of pendimethalin. Slope affected cumulative runoff, sediment, and herbicide losses significantly (P < 0.05). The impact of increased rainfall intensity on runoff initiation followed a similar trend, but herbicide losses from plots exposed to different intensities were not always significant. Losses dissolved in runoff from plots with 20% slope were ≤1% of the applied herbicide, whereas on plots with 30% slope the maximum recorded loss was 65%. Here, losses for all herbicides ranged between 1 and 7% at 60 mm/h and 8 and 65% at 80 mm/h. Exports of herbicides with moderate solubility were negatively correlated with their Kd values and their water solubility.

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Effectiveness of Three Post-Harvest Rehabilitation Treatments for Runoff and Sediment Reduction on Skid Trails in the Hyrcanian Forests

Croatian journal of forest engineering ◽

10.5552/crojfe.2020.732 ◽

2020 ◽

Vol 41 (2) ◽

pp. 309-324

Author(s):

Meghdad Jourgholami ◽

Masoumeh Ahmadi ◽

Farzam Tavankar ◽

Rodolfo Picchio

Keyword(s):

Leaf Litter ◽

Sediment Yield ◽

Rainfall Intensity ◽

Regression Equations ◽

Negative Effects ◽

Diverse Range ◽

Straw Mulch ◽

The Impact ◽

Different Levels ◽

Runoff And Sediment Yield

Ground-based skidding operations can lead to soil compaction and displacement, which could cause negative effects on forest soil. Hence, some efforts such as forestry best management practices (BMPs) must be implemented in the prone area to mitigate these possible impacts. Several materials and treatments have been adopted to suppress these adverse effects by increasing the ground cover. However, the effects of mulch treatments on runoff and sediment yield are inconclusive with a diverse range of effectiveness. For these reasons, in this research mulch treatments were tested as to determine how the application of organic mulch amendments such as straw and leaf litter and contour-felled logs would alleviate the runoff and sediment yield on machine operating trails and ensure successful hillslope stabilization. The aims of the study were to analyse and compare the effectiveness of leaf litter (LM) and straw mulch (SM) rate and different distances of contour-felled logs (CFL) to mitigate the runoff and sediment yield, and examine the impact of rainfall intensity on effectiveness of litter mulch, straw mulch, and contour-felled logs. Totally, 30 bounded runoff plots in the machine operating trails and four treatments including litter mulch (LMR1: 0.62, LMR2: 1.24, and LMR3: 1.86 kg m-2), straw mulch (SMR1: 0.45, SMR2: 0.92, and SMR3: 1.34 kg m-2), contour-felled logs (CFL10: 10, CFL20: 20, and CFL30: 30 m), and untreated area were established in triplicate with 4 m width and 100 m length. During the study period, the runoff and sediment yield in the untreated trails (U) were 2.36 mm and 11.84 g m-2. Straw (from 41.5 to 60.6%) and litter mulch (from 38.1 to 55.1%), and contour-felled logs treatments (from 70.8 to 88.1%) significantly decreased the runoff, compared to U treatment. Results show that mulch treatments with three different levels of Litter Mulch Rate, LMR1, LMR2, and LMR3 decreased mean sediment by 46.6, 64.0 and 71.8%, in the treatments with three different levels of Straw Mulch Rate, SMR1, SMR2, and SMR3 decreased mean sediment by 42.9, 62.1, and 69.9%, and in the treatments with three different distances of Contour-Felled Logs, CFL10, CFL20, and CFL30 decreased mean sediment by 90.6, 94.7 and 88.3% comparing to U, respectively. The relationships of the runoff and sediment responses to increasing mulching rate of litter and straw followed as negative logarithmic curves, but the decreasing-increasing trends were observed in runoff and sediment yield as the distance between contour-felled logs increased from 10 to 30 m. Polynomial regression equations were developed for predicting the runoff and sediment yield as a function of the application rate of litter and straw mulch and the distance between contour-felled logs, and rainfall intensity. We concluded that contour-felled logs treatment was more effective than both litter and straw mulch to mitigate the runoff, runoff coefficient, and sediment yield on machine operating trails. As a management measure, it could be possible to propose that the contour-felled logs with a distance of 20 m be prescribed to protect the machine operating trails from the negative effects of surface waterflow.

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Spatio-Temporal Characteristics and Variation Pattern of the Atmospheric Particulate Matter Concentration: A Case Study of the Beijing–Tianjin–Hebei Region, China

Atmosphere ◽

10.3390/atmos13010120 ◽

2022 ◽

Vol 13 (1) ◽

pp. 120

Author(s):

Haoran Zhai ◽

Jiaqi Yao ◽

Guanghui Wang ◽

Xinming Tang

Keyword(s):

Particulate Matter ◽

Measurement Data ◽

Atmospheric Particulate Matter ◽

Temporal Characteristics ◽

Double Peaks ◽

Spatio Temporal ◽

Pm2.5 And Pm10 ◽

Air Quality Monitoring Stations ◽

Matter Concentration

Based on measurement data from air quality monitoring stations, the spatio-temporal characteristics of the concentrations of particles with aerodynamic equivalent diameters smaller than 2.5 and 10 μm (PM2.5 and PM10, respectively) in the Beijing–Tianjin–Hebei (BTH) region from 2015 to 2018 were analysed at yearly, seasonal, monthly, daily and hourly scales. The results indicated that (1) from 2015 to 2018, the annual average values of PM2.5 and PM10 concentrations and the PM2.5/PM10 ratio in the study area decreased each year; (2) the particulate matter (PM) concentration in winter was significantly higher than that in summer, and the PM2.5/PM10 ratio was highest in winter and lowest in spring; (3) the PM2.5 and PM10 concentrations exhibited a pattern of double peaks and valleys throughout the day, reaching peak values at night and in the morning and valleys in the morning and afternoon; and (4) with the use of an improved sine function to simulate the change trend of the monthly mean PM concentration, the fitting R2 values for PM2.5 and PM10 in the whole study area were 0.74 and 0.58, respectively. Moreover, the high-value duration was shorter, the low-value duration was longer, and the concentration decrease rate was slower than the increase rate.

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Research on Power Grid Investment Assistant Decision Model Adapting to Power Reform Situation

E3S Web of Conferences ◽

10.1051/e3sconf/202021802026 ◽

2020 ◽

Vol 218 ◽

pp. 02026

Author(s):

Yidi Wan ◽

Wei Xie ◽

Haihong Du ◽

Wenming Pan ◽

Jianqing Li ◽

...

Keyword(s):

Decision Making ◽

Investment Decision ◽

Power Grid ◽

Scale Structure ◽

Leading Role ◽

Investment Decision Making ◽

Investment Structure ◽

External Management ◽

Power Grid Planning ◽

The Impact

in order to thoroughly implement the new energy security strategy of “four revolutions and one cooperation”, meet the requirements of power grid planning and management of energy administration, realize the strategic objectives of State Grid Corporation of China, actively respond to the severe external economic situation, alleviate the impact of policy-based price reduction, and improve the performance of internal investment management, the company needs scientific front-end decision-making, improve the efficiency of investment decision-making, scientifically determine the investment scale, structure and timing, and play a strategic leading role in investment decision-making. Through the analysis of internal and external management requirements, this paper constructs an auxiliary decision-making model of power grid investment to support the determination of investment scale, structure and time sequence, to realize the reasonable investment scale calculation of provincial companies, the calculation of investment structure of different voltage levels and the optimization of project delivery under the condition of given investment scale, which comprehensively considers the external supervision, economic development and internal management objectives, so as to assist the prior investment decision-making, improve the input-output efficiency, effectively improve the Advisory decision-making ability of investment data, and meet the company’s investment decision-making needs.

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