Urban environment distributions

Carbon monoxide (CO) Is one of the most widely distributed air pollutants. It Is formed by natural biological and oxidation processes, the Incomplete combustion of carbon-containing fuels and various Industrial processes. However, the largest Individual source of man-made emissions Is motor vehicle exhausts which account for virtually all CO emitted In some urban environments. It has been estimated that global man-made emissions range from 300-1600 million tons per year, which Is approximately 60% of the total global CO emissions (22-23). 

Studies on the particulate distributions from compressed natural gas (CNG) or diesel-fuelled engines with diesel oxidation catalyst (DOC) or partial diesel particle filter (pDPF) have also been performed. The results obtained are used as data for the model, to study the particle penetration into the human respiratory tracts. As a result, the number distribution of particles in different parts of lungs can be modeled [99-101]. Understanding the particle formation and their effects and finding the methods to ehminate the formed particulates from exhaust gas contribute to a cleaner urban environment and thus to a better quality of life. 

Steinhausler, F., W. Hofmann, E. Pohl, and J. Pohl-Ruling, Local and Temporal Distribution Pattern of Radon and Daughters in an Urban Environment and Determination of Organ Dose Frequency Distributions With Demoscopical Methods, in Proceedings of the Symposium on Natural Radiation Environment. III. Houston. Conf-780422, DOE Sym. Ser. 51, Vol. II, pp. 1145-1161, Houston NM,... 

Airborne nanoparticles empirically fit well to log normal distributions and exhibit bimodal distributions in atmospheric urban environments. These arise from both natural and anthropogenic sources. Road vehicles remain a dominant source, contributing up to 90% of total PNCs, in polluted urban environments. 

ENPs are emerging class of airborne nanoparticles having a main impact on the air quality of indoor environments these are unintentionally released into the ambient environment during the manufacture (commercial or research), handling, use or disposal of nanomaterials integrated products. Their physical and chemical characteristics differ from other nanoparticles produced through traffic [4], The health consequences of their inhalation are not yet well known. A number of studies have reported their number concentrations and size distributions in workplaces but their concentrations in ambient urban environments are largely unknown and warrant further research. Adequate methods have yet to be developed to quantify them in the presence of nanoparticles from other sources. 

In this context, modern geographical information systems (GIS) represent an indispensable tool for better understanding the distribution, dispersion and interaction processes of some toxic and potentially toxic elements. Discussion on the use of GIS in the urban environment is, therefore, also provided. 

Figure 8.1 Regional and local anomaly threshold applied to an urban environment. The concentration graph shows the influence of anthropogenic sources (industrial area, downtown and main roads) on pollutant distribution in soils.

Figure 6.3 The fate of reactive chemicals anthracene, pyrene and benzofa]pyrene In an urban environment, (a) The mass distribution of anthracene, pyrene and benzofa]pyrene considering three wind speeds and (b) percentage losses due to advection and reaction ofbenzofajpyrene at three wind speeds. (Reproduced with permission from Kwamena et al., 2007 Elsevier)...

The extensive use of lead antiknock additives in gasoline has made lead perhaps the most widely distributed toxic heavy metal in the urban environment and has greatly increased its availability for solution in natural waters. It is important for this reason to know whether its introduction into surface and ground waters by rainfall and runoff will make it available for solution or whether chemical processes will place a safe upper limit on its solubility. 

Monaci et al. (1997) performed a lichen-biomonitoring study in Siena by means of two different methods. The pattern of air quality in the study area was examined on the basis of the in situ frequency of different species of epiphytic lichens, i.e. using their species-specific sensitivity to the complex mixture of phytotoxic pollutants in the urban environment. The distribution of trace elements was evaluated quantitatively by an analysis of thalli of a tolerant species, P. caperata, known to be a reliable bioaccumulator of persistent atmospheric pollutants. The values obtained for Al, Ba, Cr, Cu, Fe, Pb and S were significantly higher in Sienese lichens over and above controls. Traffic was found to be the major source of atmospheric pollution. The pattern of trace-elemental deposition did not always coincide with air quality. lAP values were found to reflect essentially the emission of gaseous phytotoxic pollutants in the urban environment. 

Chao MR, Hu CW, Ma HW, Chang-Chien GP, Lee WJ, Chang LW, Wu KY (2003) Size distribution of particle-bound polychlorinated dibenzo-p-dioxins and dibenzofurans in the ambient air of a municipal incinerator. Atmos Environ 37 4945-4954 Chiysikou LP, Gemenetzis PG, Samara CA (2009) Wintertime size distributions of polycyclic aromatic hydrocarbons (PAH), polychlorinated biphenyls (PCB) and organochlorine pesticides (OCPs) in the urban environment street- vs. rooftop-level measurements. Atmos Environ 43 290-300... 

Vertical Distribution of Airborne Particulate Matter in a Tropical Urban Environment Changes in Physical and Chemical Characteristics... 

Haque, A., H. Gruttke, W. Kratz, U. Kielhom, G. Weigmann, G. Meyer, R. Bomkamm, I. Schuphan, and W. Ebing. 1988. Environmental fate and distribution of sodium [14C]pentachlorophenate in a section of urban wasteland ecosystem. Sci. Total Environ. 68 127-139. 

McLaren R, Singleton DL, Lai JYK, et al. 1996. Analysis of motor vehicle sources and their contribution to ambient hydrocarbon distributions at urban sites in Toronto during the Southern Ontario oxidants study. Atmos Environ 30(12) 2219-2232. 

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