scholarly journals Variations in time and space of trace metal aerosol concentrations in urban areas and their surroundings

2011 ◽  
Vol 11 (17) ◽  
pp. 9415-9430 ◽  
Author(s):  
T. Moreno ◽  
X. Querol ◽  
A. Alastuey ◽  
C. Reche ◽  
M. Cusack ◽  
...  
Keyword(s):  
Trace Metal ◽  
Urban Areas ◽  
Urban Pollution ◽  
Sea Breeze ◽  
Point Sources ◽  
Fuel Oil ◽  
Physical Parameters ◽  
Spatial And Temporal Variability ◽  
Metal Concentrations ◽  
The City

Abstract. Using an unprecedentedly large geochemical database, we compare temporal and spatial variations in inhalable trace metal background concentrations in a major city (Barcelona, Spain) and at a nearby mountainous site (Montseny) affected by the urban plume. Both sites are contaminated by technogenic metals, with V, Pb, Cu, Zn, Mn, Sn, Bi, Sb and Cd all showing upper continental crust (UCC) normalised values >1 in broadly increasing order. The highest metal concentrations usually occur during winter at Barcelona and summer in Montseny. This seasonal difference was especially marked at the remote mountain site in several elements such as Ti and Rare Earth Elements, which recorded campaign maxima, exceeding PM10 concentrations seen in Barcelona. The most common metals were Zn, Ti, Cu, Mn, Pb and V. Both V and Ni show highest concentrations in summer, and preferentially fractionate into the finest PM sizes (PM1/PM10 > 0.5) especially in Barcelona, this being attributed to regionally dispersed contamination from fuel oil combustion point sources. Within the city, hourly metal concentrations are controlled either by traffic (rush hour double peak for Cu, Sb, Sn, Ba) or industrial plumes (morning peak of Ni, Mn, Cr generated outside the city overnight), whereas at Montseny metal concentrations rise during the morning to a single, prolonged afternoon peak as contaminated air transported by the sea breeze moves into the mountains. Our exceptional database, which includes hourly measurements of chemical concentrations, demonstrates in more detail than previous studies the spatial and temporal variability of urban pollution by trace metals in a given city. Technogenic metalliferous aerosols are commonly fine in size and therefore potentially bioavailable, emphasising the case for basing urban background PM characterisation not only on physical parameters such as mass but also on sample chemistry and with special emphasis on trace metal content.

scholarly journals Variations in time and space of trace metal aerosol concentrations in urban areas and their surroundings

2011 ◽  
Vol 11 (5) ◽  
pp. 14747-14776
Author(s):  
T. Moreno ◽  
X. Querol ◽  
A. Alastuey ◽  
C. Reche ◽  
M. Cusack ◽  
...  
Keyword(s):  
Trace Metal ◽  
Urban Areas ◽  
Urban Pollution ◽  
Sea Breeze ◽  
Point Sources ◽  
Fuel Oil ◽  
Physical Parameters ◽  
Spatial And Temporal Variability ◽  
Metal Concentrations ◽  
The City

Abstract. Using an unprecedentedly large geochemical database, we compare temporal and spatial variations in inhalable trace metal background concentrations in a major city (Barcelona, Spain) and at a nearby mountainous site (Montseny) affected by the urban plume. Both sites are contaminated by technogenic metals, with V, Pb, Cu, Zn, Mn, Sn, Bi, Sb and Cd all showing upper continental crust (UCC) normalised values >1 in broadly increasing order. The highest metal concentrations usually occur during winter at Barcelona and summer in Montseny. This seasonal difference was especially marked at the remote mountain site in several elements such as Ti and Rare Earth Elements, which recorded campaign maxima, exceeding PM10 concentrations seen in Barcelona. The most common metals were Zn, Ti, Cu, Mn, Pb and V. Both V and Ni show highest concentrations in summer, and preferentially fractionate into the finest PM sizes (PM1/PM10 > 0.5) especially in Barcelona, this being attributed to regionally dispersed contamination from fuel oil combustion point sources. Within the city, hourly metal concentrations are controlled either by traffic (rush hour double peak for Cu, Sb, Sn, Ba) or industrial plumes (morning peak of Ni, Mn, Cr generated outside the city overnight), whereas at Montseny metal concentrations rise during the morning to a single, prolonged afternoon peak as contaminated air transported by the sea breeze moves into the mountains. Our exceptional database, which includes hourly measurements of chemical concentrations, demonstrates in more detail than previous studies the spatial and temporal variability of urban pollution by trace metals in a given city. Technogenic metalliferous aerosols are commonly fine in size and therefore potentially bioavailable, emphasising the case for basing urban background PM characterisation not only on physical parameters such as mass but also on sample chemistry and with special emphasis on trace metal content.

scholarly journals Identificação de Ilhas de Calor na Cidade de Campina Grande-PB Utilizando Sensoriamento Remoto (Identification of Heat Islands in Campina Grande City-PB Using Remote Sensing)

2016 ◽  
Vol 9 (2) ◽  
pp. 614 ◽  
Author(s):  
Elânia Daniele Silva Araújo
Keyword(s):  
Remote Sensing ◽  
Surface Temperature ◽  
Rural Areas ◽  
Urban Areas ◽  
Spatial And Temporal Variability ◽  
Heat Islands ◽  
Social Nature ◽  
Spatial Changes ◽  
Remote Sensing Techniques ◽  
The City

A intensa urbanização causa diversos problemas de natureza ambiental, climática e social. O crescimento não planejado da população urbana e a remoção da vegetação são fatores que intensificam estes problemas. As temperaturas na cidade são significativamente mais quentes do que as suas zonas rurais circundantes devido às atividades humanas. As intensas mudanças espaciais em áreas urbanas, promovem significativo aumento na temperatura, causando o chamado efeito de Ilha de Calor Urbano (ICU). Campina Grande é uma cidade de tamanho médio que experimentou um crescimento desordenado, desde o tempo do comércio de algodão e, como qualquer cidade de grande ou médio porte, sofre alterações em seu espaço. Dessa forma, este estudo teve por objetivo analisar a variabilidade espaço-temporal da temperatura da superfície (Ts) e detectar ICU, através de técnicas de sensoriamento remoto. Para o efeito, foram utilizadas imagens dos satélites Landsat 5 e 8, dos anos de 1995, 2007 e 2014. Aumentos da Ts foram bem evidentes e foram detectadas duas ICU. Campina Grande mostra um padrão de tendência: o crescimento urbano não planejado é responsável por mudanças no ambiente físico e na forma e estrutura espacial da cidade, o que se reflete sobre o microclima e, em última análise, na qualidade de vida das pessoas.   ABSTRACT The intense urbanization causes several problems of environmental, climate and social nature. The unplanned growth of urban population and the vegetation removal are factors that deepen these problems. Temperatures in the city are significantly warmer than its surrounding rural areas due to human activities. Large spatial changes in urban areas promote significant increase in temperature, causing the so-called Urban Heat Island effect (UHI). Campina Grande is a medium-sized town that experienced an uncontrolled growth since the time of the cotton trade and like any large or medium-sized city, undergoes changes in its space. Therefore, this study aimed to analyze surface temperature spatial and temporal variability and to detect potential UHI, through remote sensing techniques. Spectral images from Landsat 5 and 8 satellites were used. Using images from years 1995, 2007 and 2014, considerable increases in temperature were identified and two UHI were recognize. Campina Grande shows a trend pattern: the urban unplanned growth is responsible for changes in the physical environment and in the form and spatial structure of the city, reflecting on people quality of life. Keywords: change detection, surface temperature, heat islands, urbanization.   

scholarly journals Physico-chemical and bacteriological characterisation of surface water in Bamenda (North West Cameroon)

2021 ◽  
Vol 11 (12) ◽  
Author(s):  
Alice Magha Mufur ◽  
Margaret Tita Awah ◽  
Gus Djibril Kouankap Nono ◽  
Primus Azinwi Tamfuh ◽  
Pierre Wotchoko ◽  
...  
Keyword(s):  
River Water ◽  
Principal Component ◽  
Point Sources ◽  
Ion Concentration ◽  
City Centre ◽  
Physical Parameters ◽  
Water Type ◽  
North West ◽  
Physico Chemical ◽  
The City

AbstractThe Mezam River and its tributaries constitute a prominent water source for domestic use and vegetable irrigation in Bamenda Town (North West Cameroon). The river flows through the city and is thus vulnerable to impairment by substances from point and non-point sources. This current research aims to assess the degree of pollution of the Mezam River water to ascertain its suitability for various uses. A total of 24 water samples were collected from six segments of the Mezam River basin in the dry and rainy seasons during the years 2015 and 2016 in view of physico-chemical and bacteriological analyses. In situ measurement of physical parameters was taken in the field. The data were analysed by multivariate statistical techniques (principal component analysis and factor analysis). The results revealed that the river water is slightly acidic (pH = 5.45–6.47) and ion concentration is low (41.67–237.00 µS/cm). The water type is Ca-SO4 and Ca-Mg-(Cl + NO3) in the dry season and Ca-Mg-SO4 in the rainy season. High NO3− values (50 mg/l) are recorded at Nkimefueh. The Mezam River water is heavily polluted with indicator bacteria (0–500 CFU/100 ml) whose concentrations steadily increase from the reference point (YB) through sampling points in the city centre, suggesting the influence of human-induced activities. The population is urged to adopt a responsible behaviour towards waste disposal and refrain from disposing waste in water courses in order to safeguard the aquatic environment and also protect the health of the population.

scholarly journals The Content of Lead, Cadmium and Mercury in Sediments from Rainwater Reservoirs Situated Along the National Road 4

2015 ◽  
Vol 20 (1-2) ◽  
pp. 75-83
Author(s):  
Marcin Niemiec
Keyword(s):  
Cadmium Concentration ◽  
Lead Level ◽  
Urban Pollution ◽  
Considerable Effect ◽  
Pollution Level ◽  
Metal Concentrations ◽  
The World ◽  
Similar Materials ◽  
National Road ◽  
The City

Abstract The paper aimed at determining the pollution level of sediments collected from reservoirs receiving rainwater. The sediments were sampled from11 reservoirs on three dates: in May 2007, in April 2008 and in June 2008 in the following localities: Sulkow, Biskupice, Bodzanow and Suchoraba situated at a distance of ca 15 from each other. The contents of lead, cadmium, mercury and organic matter were assessed in the sediments. Lead content in the analysed sediments ranged from 9.87 to 61 mg · kg−2 with average for all samples 28.08 mg · kg−1. Mean cadmium concentration in the studied sediments was 0.637 mg · kg−1 and fluctuated from 0.20 to 1.58 mg Cd · kg−1. The quantities of mercury assessed in the sediments from rainwater reservoirs ranged from 0.337 to 0.864 mg · kg−1. Considerable differences between studied metal concentrations were assessed among the studied reservoirs, however the trends of differences were similar at each sampling. Generally, the levels of cadmium and mercury assessed in the analyzed sediments were comparable to the sediments from urbanized areas of various cities in the world, whereas lead level in the sediments of the analysed reservoirs was generally much lower than reported for similar materials in literature. Regularly decreasing contents of all elements with growing distance from the Krakow agglomeration was noted. The reservoir situated closest to Krakow, in Sulkow is located 7 km from the city boundaries and borders on Wieliczka town, whereas the reservoir in Suchoraba is located 17 km from Krakow. At this distance metal concentrations in the sediments from rainwater reservoirs were diminishing several times, which suggests considerable effect of urban pollution on metal level in these sediments.

scholarly journals Network design for quantifying urban CO<sub>2</sub> emissions: Assessing trade-offs between precision and network density

2016 ◽  
Author(s):  
Alexander J. Turner ◽  
Alexis A. Shusterman ◽  
Brian C. McDonald ◽  
Virginia Teige ◽  
Robert A Harley ◽  
...  
Keyword(s):  
Co2 Emissions ◽  
Urban Areas ◽  
Cost Effective ◽  
Point Sources ◽  
Urban Region ◽  
Dense Network ◽  
Industrial Facilities ◽  
Trade Offs ◽  
Combined Uncertainty ◽  
The City

Abstract. The majority of anthropogenic CO2 emissions are attributable to urban areas. While the emissions from urban electricity generation often occur in locations remote from consumption, many of the other emissions occur within the city limits. Evaluating the effectiveness of strategies for controlling these emissions depends on our ability to observe urban CO2 emissions and attribute them to specific activities. Cost effective strategies for doing so have yet to be described. Here we characterize the ability of a prototype measurement network, modeled after the BEACO2N network, in combination with an inverse model based on WRF-STILT to improve our understanding of urban emissions. The pseudo-measurement network includes 34 sites at roughly 2 km spacing covering an area of roughly 400 km2. The model uses an hourly 1 × 1 km2 emission inventory and 1 × 1 km2 meteorological calculations. We perform an ensemble of Bayesian atmospheric inversions to sample the combined effects of uncertainties of the pseudo-measurements and the model. We vary the estimates of the combined uncertainty of the pseudo-observations and model over a range of 20 ppm to 0.005 ppm and vary the number of sites from 1 to 34. We use these inversions to develop statistical models that estimate the efficacy of the combined model-observing system at reducing uncertainty in CO2 emissions. We examine uncertainty in estimated CO2 fluxes at the urban scale, as well as for sources embedded within the city such as a line source (e.g., a highway) or a point source (e.g., emissions from the stacks of small industrial facilities). We find that a dense network with moderate precision is the preferred setup for estimating area, line, and point sources from a combined uncertainty and cost perspective. The dense network considered here could estimate weekly CO2 emissions from an urban region with less than 5 % error, given our characterization of the combined observation and model uncertainty.

scholarly journals Environmental issues due to organohalogenated compounds diffuse pollution in groundwater. Emerging issue in the Roman area?

2017 ◽  
Vol 6 (2) ◽  
Author(s):  
Isidoro Bonfà ◽  
Francesco La Vigna ◽  
Simona Martelli ◽  
Lucilla Ticconi
Keyword(s):  
Urban Areas ◽  
Industrial Development ◽  
Environmental Issues ◽  
Point Sources ◽  
Multiple Point ◽  
Industrial Activities ◽  
Clear Point ◽  
Source Contamination ◽  
The City ◽  
Very High

Most of the large urban areas, especially those with a strong industrial vocation, present important contamination of organohlaogenated compunds. Even in the City of Rome, although it has a very limited industrial development, some sites interested by this kind of contamination have been notified in recent years. The distribution of these sites is prevalent in the eastern sector of the city where the few industrial activities present are also located. Concentrations are varied and show both cases of clear point source contamination, where values are very high, and cases where a possible contamination from multiple point sources can be hypothesized. The sites reported fall into a crucial area for the hydrogeology of Rome, that is the "Paleotiber Graben" aquifer, exploited for various uses. To date, there is no proven diffuse contamination of organohalogenated compounds in Rome, nevertheless the purpose of this work is to frame this emerging issue on the basis of the available data.

scholarly journals Calculating Energy and Its Spatial Distribution for a Subsurface Urban Heat Island Using a GIS-Approach

Geosciences ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 24
Author(s):  
Julian A. V. Schweighofer ◽  
Michael Wehrl ◽  
Sebastian Baumgärtel ◽  
Joachim Rohn
Keyword(s):  
Energy Density ◽  
Urban Heat Island ◽  
Urban Areas ◽  
Average Energy ◽  
Ground Level ◽  
Physical Parameters ◽  
Heat Island ◽  
Below Ground ◽  
Urban Heat ◽  
The City

In urban areas, the human influence on the city-ecosystem often results in a Subsurface Urban Heat Island (SUHI), which can be used geothermally. Unfortunately, a model of a SUHI does not consider the geology and hydrogeology of the subsoil. These can vary significantly over short distances, and are of considerable importance for the energy balance. In this work, we calculated the energy and its density stored in the subsoil via a SUHI. For this so-called energy-SUHI (e-SUHI), we evaluated the geology and its physical parameters for the first 20 m below ground level in the German city of Nuremberg and linked them to measured underground temperatures in a GIS application. This approach revealed stored energy of 1.634 × 1010 MJ within the soil and water for the study area with an area of 163 km2 and a volume of 3.26 × 109 m3. It corresponds to an average energy density of 5.0 MJ/m3. The highest energy density of 16.5 MJ/m3 was found in the city center area and correlated well to increases in subsurface temperature. As expected, our model reacts sensitively to thickness changes in the geological layers and the unsaturated zone.

scholarly journals A comparison of methyl and gaseous elemental mercury in the urban atmosphere

2021 ◽  
Author(s):  
Elaine Cairns
Keyword(s):  
Urban Areas ◽  
Elemental Mercury ◽  
Point Sources ◽  
Urban Atmosphere ◽  
Mercury Vapour ◽  
Mercury Species ◽  
Gaseous Elemental Mercury ◽  
Location Function ◽  
Air Circulation ◽  
The City

This study was carried out to compare the levels of mercury species, i.e., elemental mercury (Hg°) and methyl mercury (MeHg), in indoor and outdoor air in urban areas in Canada. Offices, laboratories for undergraduate studies, and laboratories for research, in a public building located in the downtown core of the city of Toronto, were selected. Hg° was measured using an automated mercury vapour analyzer. MeHg in the air was collected using a carbotrap, and the trapped MeHg was thermally desorbed and analyzed using a CVAFS. The results showed that both indoor MeHg and Hg° levels were related to location function and air circulation. Outdoor MeHg levels were significantly elevated, ranging between 21 and 41% of total mercury (THg) levels, compared to those reported from previous studies. Outdoor Hg° fluctuations were not found to be significantly related to temperature or sunlight exposure, and outdoor MeHg levels were connected to soil and vegetation abundance. Average indoor Hg° levels were found to be between 1.4 and 15 times higher than outdoor levels, whereas MeHg indoor levels were not consistently higher than outdoor levels. Although the mercury concentrations in the indoor environment are still lower than the safety standard for Hg° and organic mercury, they are comparable to those observed near point sources. Thus, indoor air can be a source of mercury to the atmosphere.

scholarly journals Regulation of air exchange in urban areas to improve their environment

2018 ◽  
Vol 193 ◽  
pp. 01034 ◽  
Author(s):  
Botir Giyasov ◽  
Irina Giyasova
Keyword(s):  
Urban Areas ◽  
Negative Impact ◽  
Urban Pollution ◽  
Average Life Expectancy ◽  
Sources Of Pollution ◽  
Modern Cities ◽  
Incidence And Mortality ◽  
Significant Negative Impact ◽  
The City ◽  
Air Exchange

Environmental issues in cities are some of the causes of reduction in the average life expectancy of people, increase in the incidence and mortality of the population. According to scientists, health of the urban population is 20% dependent on the state of the natural environment. Urban residents are more likely to suffer from cardiovascular diseases, respiratory diseases, and blood circulation problems. In the course of urban development, people have a significant negative impact on the biosphere, changing it and being a part of it, they experience the consequences of these changes on themselves. This situation is complicated by the lack of a unified approach among civil engineers, architects, hygienists and environmentalists in the matters of organizing a residential environment. The article focuses on identification and analysis of sources of pollution affecting the air basin of modern cities. A comparative analysis of the transport and construction industries and their role in urban pollution is carried out. Using the example of the city of Moscow, calculations have been made and the indicators of the wind speed variation along the height of the building have been determined, depending on the type of terrain. These data allow assessing the formation of air exchange in urban areas and can be used to solve the problems of improving the urban environment.

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