scholarly journals Effect of COVID-19 lockdown on regional pollution in Ireland

2021 ◽  
Author(s):  
Teresa K. Spohn ◽  
Damien Martin ◽  
Michael Geever ◽  
Colin O’Dowd
Keyword(s):  
Urban Areas ◽  
Initial Increase ◽  
Emission Sources ◽  
Particle Measurements ◽  
Wind Speeds ◽  
Suburban Areas ◽  
Average Wind ◽  
Volatile Organic ◽  
Rural Sites ◽  
Agricultural Regions

AbstractThis study examines the regional impact of the COVID-19 lockdown restrictions on pollution in Ireland by comparing the 2020 measurements of ozone (O3), nitrogen dioxide (NO2), and particulate matter (PM) from monitoring stations around the country to the previous 3-year average. Results indicate that O3 was 5.6% lower and 13.7% higher than previous years during the lockdown at rural and suburban sites, respectively. NO2 decreased by 50.7% in urban areas, but increased slightly in agricultural regions, consistent with satellite observations. PM concentrations did not change significantly compared to previous years; however, a reduction in the signal variability in the smaller size particle measurements may be the result of different emission sources. The reduction in NO2 likely increased the ratio of volatile organic compounds (VOCs) to NOx (nitrogen oxides), creating a NOx limited environment, which resulted in an initial increase in O3 in suburban areas, and the lower than usual levels observed at rural sites. Meteorology showed higher than average wind speeds prior to lockdown, which likely acted to disperse PM and NO2.

scholarly journals Characteristics of wintertime VOCs in suburban and urban Beijing: concentrations, emission ratios, and festival effects

2019 ◽  
Author(s):  
Kun Li ◽  
Junling Li ◽  
Shengrui Tong ◽  
Weigang Wang ◽  
Ru-Jin Huang ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Urban Areas ◽  
Diurnal Variations ◽  
Urban Site ◽  
Anthropogenic Emissions ◽  
Suburban Areas ◽  
Key Characteristics ◽  
Volatile Organic ◽  
Suburban Site ◽  
Emission Ratios

Abstract. Measurements of volatile organic compounds (VOCs) were performed at a suburban site and an urban site in Beijing during the winter of 2014–2015. The VOC concentrations and emission ratios (ERs) to CO were compared at these two sites. It is found that though the VOC concentrations at the urban site are 2.67 ± 1.15 times of those at the suburban site, the ERs are similar (within a factor of 1.5). It is indicated that: (1) the VOCs at suburban areas are mainly from the transportation from the urban areas; (2) the ERs measured at the urban areas are also valid for the surrounding suburban areas. By comparing the diurnal variations and the contribution of anthropogenic emissions at both sites, we find that the photochemical processes are very active at the urban site, and these processes play an important role in the daytime oxygenated VOCs (OVOCs) formation. The methanol at the urban site and the formic acid at the suburban site probably have additional sources, which are attributed to be solvent use and soil/agriculture, respectively. The festival effects from Chinese New Year (CNY) were investigated. The VOC concentrations decreased ~ 60 % during CNY holidays, probably due to the population migration during festival holidays. In addition, fireworks are found to be an important source of acetonitrile, aromatics, and some OVOCs during CNY festival, and should be controlled more strictly. This study provides key characteristics of wintertime VOCs in suburban and urban Beijing, and has implications for better understanding the atmospheric chemistry of VOCs in and around this megacity.

scholarly journals Characteristics of wintertime VOCs in suburban and urban Beijing: concentrations, emission ratios, and festival effects

2019 ◽  
Vol 19 (12) ◽  
pp. 8021-8036 ◽  
Author(s):  
Kun Li ◽  
Junling Li ◽  
Shengrui Tong ◽  
Weigang Wang ◽  
Ru-Jin Huang ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Urban Areas ◽  
Diurnal Variations ◽  
Urban Site ◽  
Anthropogenic Emissions ◽  
Suburban Areas ◽  
Key Characteristics ◽  
Volatile Organic ◽  
Suburban Site ◽  
Emission Ratios

Abstract. Measurements of volatile organic compounds (VOCs) were performed at a suburban site and an urban site in Beijing during the winter of 2014–2015. The VOC concentrations and emission ratios (ERs) to CO were compared at these two sites. It is found that though the VOC concentrations at the urban site are 2.67±1.15 times of those at the suburban site, the ERs are similar (within a factor of 1.5). It is indicated that (1) the VOCs at suburban areas are mainly from the transportation from the urban areas and (2) the ERs measured at the urban areas are also valid for the surrounding suburban areas. By comparing the diurnal variations and the contribution of anthropogenic emissions at both sites, we find that the photochemical processes are very active at the urban site, and these processes play an important role in the daytime oxygenated VOC (OVOC) formation. The methanol at the urban site and the formic acid at the suburban site probably have additional sources, which are attributed to be solvent use and soil/agriculture, respectively. The festival effects from the Chinese New Year (CNY) were investigated. The VOC concentrations decreased ∼60 % during CNY holidays, probably due to the population migration during festival holidays. In addition, fireworks are found to be an important source of acetonitrile, aromatics, and some OVOCs during the CNY festival and should be controlled more strictly. This study provides key characteristics of wintertime VOCs in suburban and urban Beijing and has implications for better understanding the atmospheric chemistry of VOCs in and around this megacity.

SHAPING OF AN AUTONOMOUS POWER SYSTEM FOR GUARANTEED POWER SUPPLY WITH THE PREDOMINANCE WIND ENERGY

2018 ◽  
pp. 28-50
Author(s):  
S. G. Ignatiev ◽  
S. V. Kiseleva
Keyword(s):  
Energy Storage ◽  
Wind Speed ◽  
Wind Energy ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Energy Demand ◽  
Diesel Generator ◽  
Average Wind Speed ◽  
Wind Speeds ◽  
Average Wind

Optimization of the autonomous wind-diesel plants composition and of their power for guaranteed energy supply, despite the long history of research, the diversity of approaches and methods, is an urgent problem. In this paper, a detailed analysis of the wind energy characteristics is proposed to shape an autonomous power system for a guaranteed power supply with predominance wind energy. The analysis was carried out on the basis of wind speed measurements in the south of the European part of Russia during 8 months at different heights with a discreteness of 10 minutes. As a result, we have obtained a sequence of average daily wind speeds and the sequences constructed by arbitrary variations in the distribution of average daily wind speeds in this interval. These sequences have been used to calculate energy balances in systems (wind turbines + diesel generator + consumer with constant and limited daily energy demand) and (wind turbines + diesel generator + consumer with constant and limited daily energy demand + energy storage). In order to maximize the use of wind energy, the wind turbine integrally for the period in question is assumed to produce the required amount of energy. For the generality of consideration, we have introduced the relative values of the required energy, relative energy produced by the wind turbine and the diesel generator and relative storage capacity by normalizing them to the swept area of the wind wheel. The paper shows the effect of the average wind speed over the period on the energy characteristics of the system (wind turbine + diesel generator + consumer). It was found that the wind turbine energy produced, wind turbine energy used by the consumer, fuel consumption, and fuel economy depend (close to cubic dependence) upon the specified average wind speed. It was found that, for the same system with a limited amount of required energy and high average wind speed over the period, the wind turbines with lower generator power and smaller wind wheel radius use wind energy more efficiently than the wind turbines with higher generator power and larger wind wheel radius at less average wind speed. For the system (wind turbine + diesel generator + energy storage + consumer) with increasing average speed for a given amount of energy required, which in general is covered by the energy production of wind turbines for the period, the maximum size capacity of the storage device decreases. With decreasing the energy storage capacity, the influence of the random nature of the change in wind speed decreases, and at some values of the relative capacity, it can be neglected.

Atmospheric transport and deposition of trace elements to lake erie from Urban areas

1996 ◽  
Vol 33 (4-5) ◽  
pp. 259-265
Author(s):  
Gerald J. Keeler ◽  
Nicola Pirrone
Keyword(s):  
Trace Elements ◽  
Urban Areas ◽  
Lake Erie ◽  
Atmospheric Transport ◽  
Spatial And Temporal Variation ◽  
Deposition Flux ◽  
Emission Sources ◽  
Dry Deposition Flux ◽  
Ambient Concentration ◽  
Ambient Concentrations

A hybrid receptor-deposition (HRD) modeling approach was used to determine the spatial and temporal variation in the ambient concentration and dry deposition flux of trace elements on fine (< 2.5 mm) and coarse (> 2.5 mm) particulate matter over Lake Erie. Upper-air observations from the National Weather Service (NWS) and ambient concentrations measured at two sampling sites downwind of major emission sources in the Lake Erie basin were input to the model. An evaluation of the deposition flux of size-segregated trace elements to the lake during the over-water transport was performed. The average total (fine + coarse) deposition flux was 9.6 ng/m2-h for V, 70 ng/m2-h for Mn, 3.2 ng/m2-h for As, 4.2 ng/m2-h for Se, 10 ng/m2-h for Cd, and 43.3 ng/m2-h for Pb.

scholarly journals Canard optimization for enhancing the performance of small horizontal axis wind turbine at low wind speeds

2020 ◽  
Vol 37 ◽  
pp. 63-71
Author(s):  
Yui-Chuin Shiah ◽  
Chia Hsiang Chang ◽  
Yu-Jen Chen ◽  
Ankam Vinod Kumar Reddy
Keyword(s):  
Wind Turbine ◽  
Urban Areas ◽  
Horizontal Axis ◽  
Power Coefficient ◽  
Peak Performance ◽  
Small Scale ◽  
Horizontal Axis Wind Turbine ◽  
Wind Speeds ◽  
Optimum Parameters ◽  
Low Wind Speeds

ABSTRACT Generally, the environmental wind speeds in urban areas are relatively low due to clustered buildings. At low wind speeds, an aerodynamic stall occurs near the blade roots of a horizontal axis wind turbine (HAWT), leading to decay of the power coefficient. The research targets to design canards with optimal parameters for a small-scale HAWT system operated at variable rotational speeds. The design was to enhance the performance by delaying the aerodynamic stall near blade roots of the HAWT to be operated at low wind speeds. For the optimal design of canards, flow fields of the sample blades with and without canards were both simulated and compared with the experimental data. With the verification of our simulations, Taguchi analyses were performed to seek the optimum parameters of canards. This study revealed that the peak performance of the optimized canard system operated at 540 rpm might be improved by ∼35%.

scholarly journals A multiscale assessment of Red-tailed Hawk reproductive success relative to urban density and habitat type

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Justin H White ◽  
Jessi L Brown ◽  
Zachary E Ormsby
Keyword(s):  
Urban Areas ◽  
Urban Expansion ◽  
Habitat Type ◽  
Nesting Success ◽  
Arid Environments ◽  
Hatch Date ◽  
Urban Density ◽  
Landscape Characteristics ◽  
Suburban Areas ◽  
Breeding Seasons

Abstract Despite the unique threats to wildlife in urban areas, many raptors have established successfully reproducing urban populations. To identify variations in raptor breeding ecology within an urban area, we compared metrics of Red-tailed Hawk reproductive attempts to landscape characteristics in Reno and Sparks, NV, USA during the 2015 and 2016 breeding seasons. We used the Apparent Nesting Success and logistic exposure methods to measure nesting success of the Red-tailed Hawks. We used generalized linear models to relate nesting success and fledge rate to habitat type, productivity to hatch date (Julian day) and hatch date to urban density. Nesting success was 86% and 83% for the respective years. Nesting success increased in grassland-agricultural and shrub habitats and decreased in riparian habitat within the urban landscape. Productivity was 2.23 and 2.03 per nest for the breeding seasons. Fledge rates were 72% and 77%, respectively, and decreased in riparian areas. Nestlings hatched earlier with increased urban density and earliest in suburban areas, following a negative quadratic curve. Nesting success and productivity for this population were high relative to others in North America. Productivity increased in habitats where ground prey was more accessible. We suggest that suburban areas, if not frequently disturbed, provide sufficient resources to sustain Red-tailed Hawks over extended periods. As urban expansion continues in arid environments globally, we stress that researchers monitor reproductive output across the urban predator guild to elucidate patterns in population dynamics and adaptation.

scholarly journals InSAR Multitemporal Data over Persistent Scatterers to Detect Floodwater in Urban Areas: A Case Study in Beletweyne, Somalia

2020 ◽  
Vol 13 (1) ◽  
pp. 37
Author(s):  
Luca Pulvirenti ◽  
Marco Chini ◽  
Nazzareno Pierdicca
Keyword(s):  
Urban Area ◽  
Urban Areas ◽  
The Other ◽  
Spatial Average ◽  
Calibration Data ◽  
Suburban Areas ◽  
Persistent Scatterers ◽  
Optical Images ◽  
Interferometric Phase ◽  
Multitemporal Data

A stack of Sentinel-1 InSAR data in an urban area where flood events recurrently occur, namely Beletweyne town in Somalia, has been analyzed. From this analysis, a novel method to deal with the problem of flood mapping in urban areas has been derived. The approach assumes the availability of a map of persistent scatterers (PSs) inside the urban settlement and is based on the analysis of the temporal trend of the InSAR coherence and the spatial average of the exponential of the InSAR phase in each PS. Both interferometric products are expected to have high and stable values in the PSs; therefore, anomalous decreases may indicate that floodwater is present in an urban area. The stack of Sentinel-1 data has been divided into two subsets. The first one has been used as a calibration set to identify the PSs and determine, for each PS, reference values of the coherence and the spatial average of the exponential of the interferometric phase under standard non-flooded conditions. The other subset has been used for validation purposes. Flood maps produced by UNOSAT, analyzing very-high-resolution optical images of the floods that occurred in Beletweyne in April–May 2018, October–November 2019, and April–May 2020, have been used as reference data. In particular, the map of the April–May 2018 flood has been used for training purposes together with the subset of Sentinel-1 calibration data, whilst the other two maps have been used to validate the products generated by applying the proposed method. The main product is a binary map of flooded PSs that complements the floodwater map of rural/suburban areas produced by applying a well-consolidated algorithm based on intensity data. In addition, a flood severity map that labels the different districts of Beletweyne, as not, partially, or totally flooded has been generated to consolidate the validation. The results have confirmed the effectiveness of the proposed method.

scholarly journals Analysis of Performance of the Wind-Driven Pulverizing Aerator Based on Average Wind Speeds in the Conditions of Góreckie Lake

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2796
Author(s):  
Andrzej Osuch ◽  
Ewa Osuch ◽  
Stanisław Podsiadłowski ◽  
Piotr Rybacki
Keyword(s):  
Mathematical Model ◽  
Wind Speed ◽  
Water Pump ◽  
Average Wind Speed ◽  
Flow Rates ◽  
Wind Speeds ◽  
Average Wind ◽  
Flow Through ◽  
Analysis Of Performance ◽  
Research Period

In the introduction to this paper, the characteristics of Góreckie lake and the construction and operation of the wind-driven pulverizing aerator are presented. The purpose of this manuscript is to determine the efficiency of the pulverizing aerator unit in the windy conditions of Góreckie Lake. The efficiency of the pulverization aerator depends on the wind conditions at the lake. It was necessary to conduct thorough research to determine the efficiency of water flow through the pulverization segment (water pump). It was necessary to determine the rotational speed of the paddle wheel, which depended on the average wind speed. Throughout the research period, measurements of hourly average wind speed were carried out. It was possible to determine the efficiency of the machine by developing a dedicated mathematical model. The latest method was used in the research, consisting of determining the theoretical volumetric flow rates of water in the pulverizing aerator unit, based on average hourly wind speeds. Pulverization efficiency under the conditions of Góreckie Lake was determined based on 6600 average wind speeds for spring, summer and autumn, 2018. Based on the model, the theoretical efficiency of the machine was calculated, which, under the conditions of Góreckie Lake, amounted to 75,000 m3 per year.

scholarly journals Spatial Distribution, Source Apportionment, Ozone Formation Potential, and Health Risks of Volatile Organic Compounds over a Typical Central Plain City in China

Atmosphere ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1365
Author(s):  
Kun He ◽  
Zhenxing Shen ◽  
Jian Sun ◽  
Yali Lei ◽  
Yue Zhang ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Source Apportionment ◽  
Organic Compounds ◽  
Health Risks ◽  
Urban Areas ◽  
High Time Resolution ◽  
Ozone Formation ◽  
Industrial Site ◽  
Industrial Emissions ◽  
Volatile Organic

The profiles, contributions to ozone formation, and associated health risks of 56 volatile organic compounds (VOCs) species were investigated using high time resolution observations from photochemical assessment monitoring stations (PAMs) in Luoyang, China. The daily averaged concentration of total VOCs (TVOCs) was 21.66 ± 10.34 ppbv in urban areas, 14.45 ± 7.40 ppbv in suburbs, and 37.58 ± 13.99 ppbv in an industrial zone. Overall, the VOCs levels in these nine sites followed a decreasing sequence of alkanes > aromatics > alkenes > alkyne. Diurnal variations in VOCs exhibited two peaks at 8:00–9:00 and 19:00–20:00, with one valley at 23:00–24:00. Source apportionment indicated that vehicle and industrial emissions were the dominant sources of VOCs in urban and suburban sites. The industrial site displayed extreme levels, with contributions from petrochemical-related sources of up to 38.3%. Alkenes and aromatics displayed the highest ozone formation potentials because of their high photochemical reactivity. Cancer and noncancer risks in the industrial site were higher than those in the urban and suburban areas, and USEPA possible risk thresholds were reached in the industrial site, indicating PAMs VOC–related health problems cannot be ignored. Therefore, vehicle and industrial emissions should be prioritized when considering VOCs and O3 control strategies in Luoyang.

What Kind of People Use Carsharing for Commuting? Case Study in Shanghai

2019 ◽  
Vol 2673 (5) ◽  
pp. 770-778 ◽  
Author(s):  
Jianhong Ye ◽  
Daoge Wang ◽  
Hua Zhang ◽  
Hong Yang
Keyword(s):  
High Frequency ◽  
Urban Areas ◽  
Descriptive Analysis ◽  
User Characteristics ◽  
Logistic Regression Models ◽  
Highly Educated ◽  
Suburban Areas ◽  
Commuting Mode ◽  
Study Offer

Carsharing as a service has been growing rapidly worldwide. Its expansion has drawn wide attention in the research community with regard to the underlying driving factors and user characteristics. Despite these extensive investigations, there are still limited studies focusing on the examination of users using carsharing as a commuting mode. The answers to questions such as what kind of people would like to use carsharing for commuting and why they frequently use carsharing to commute are not clear. To enrich our understanding of these problems, this paper aims to investigate carsharing commuters in a mega city. Specifically, it intends to integrate the actual user order data with survey data from 1,920 participants to uncover the characteristics of carsharing commuters. Data from the Evcard carsharing systems in Shanghai were explicitly analyzed. Through descriptive analysis and logistic regression models, the characteristics and critical factors that affect the choice of carsharing as a commuting mode were captured. The results show that: 1. carsharing commuters mostly live or work in suburban areas in which public transport accessibility is limited; 2. carsharing commuters are more likely to be highly educated, in a higher income bracket, and older than other carsharing members; 3. high-frequency carsharing commuters own a reduced number of private cars; and 4. those high-frequency carsharing commuters with higher income are less sensitive to the carsharing costs caused by congestion. The findings in the study offer some insights into carsharing commuters and provide some supportive information for considering policies in developing carsharing systems in urban areas.

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