Urban atmosphere pollution

Urban atmospheric pollution in countries without strict regulations for automobile exhaust control is currently an important consideration in relation to possible threats to health. Many growing cities like Caracas, have increasingly high air pollution levels,... 

Photochemical Urban Atmospheric Pollution.—Many of the reactions discussed in the headings above are of importance in an understanding of photochemically induced atmospheric pollution in urban situations, and are also important in stratospheric aeronomy. The remote sensing of airborne pollutants has been covered in Section 11, but we present here briefly the subject of some papers of general interest to atmospheric pollution. 

Villeneuve PJ, Burnett RT, Shi Y, Krewski D, Goldberg MS, Heitzman C, Chen Y, Brook J (2003) A time-series study of air pollution, socioeconomic status, and mortality in Vancouver, Canada. J Expo Anal Environ Epidemiol 13 427-435 Violante FS, Barbieri A, Curti S, Sanguinetti G, Graziosi F, Matdoli S (2006) Urban atmospheric pollution personal exposure versus fixed monitoring station measurements. Chemosphete 64 1722-1729... 

Table 7 gives the sources of urban atmospheric pollutants, on the one hand in the USA in the 1970s, and on the other in Great Britain in the 1990s. Note that the means of transport are the main producers of CO, NO and solid particles, thermal electricity of... 

H. Edner, P. Ragnarson, S. Spannare, S. Svanberg A differential optical absorption spectroscopy (DOAS) system for urban atmospheric pollution monitoring. Appl. Opt. 32, 327 (1993) and Lund Reports on Atomic Physics LRAP-133 (Lund Institute of Technology, Lund 1992)... 

Northern Ireland thus provides a particular opportunity to study natural patterns and causes of building stone decay and also the impact of local pollution sources. To do this we examine in this paper first, the nature of rural and urban atmospheric pollution in Northern Ireland second, decay of sandstone buildings in Belfast together with the nature of associated particulate pollution and finally, decay associated with atmospheric pollution is compared to that caused by other agencies in both rural and urban environments. 

In a polluted or urban atmosphere, O formation by the CH oxidation mechanism is overshadowed by the oxidation of other VOCs. Seed OH can be produced from reactions 4 and 5, but the photodisassociation of carbonyls and nitrous acid [7782-77-6] HNO2, (formed from the reaction of OH + NO and other reactions) are also important sources of OH ia polluted environments. An imperfect, but useful, measure of the rate of O formation by VOC oxidation is the rate of the initial OH-VOC reaction, shown ia Table 4 relative to the OH-CH rate for some commonly occurring VOCs. Also given are the median VOC concentrations. Shown for comparison are the relative reaction rates for two VOC species that are emitted by vegetation isoprene and a-piuene. In general, internally bonded olefins are the most reactive, followed ia decreasiag order by terminally bonded olefins, multi alkyl aromatics, monoalkyl aromatics, C and higher paraffins, C2—C paraffins, benzene, acetylene, and ethane. 

Hundreds of chemical species are present in urban atmospheres. The gaseous air pollutants most commonly monitored are CO, O3, NO2, SO2, and nonmethane volatile organic compounds (NMVOCs), Measurement of specific hydrocarbon compounds is becoming routine in the United States for two reasons (1) their potential role as air toxics and (2) the need for detailed hydrocarbon data for control of urban ozone concentrations. Hydrochloric acid (HCl), ammonia (NH3), and hydrogen fluoride (HF) are occasionally measured. Calibration standards and procedures are available for all of these analytic techniques, ensuring the quality of the analytical results... 

As mentioned in the previous section, the increased number of nuclei in polluted urban atmospheres can cause dense persistent fogs due to the many small droplets formed. Fog formation is very dependent on humidity and, in some situations, humidity is increased by release of moisture from industrial processes. Low atmospheric moisture content can also occur, especicilly in urban areas two causes are lack of vegetation and rapid runoff of rainwater through storm sewers. Also, slightly higher temperatures in urban areas lower the relative humidity. 

The nutrition needs of the future will be met with more limitations than in the past on the use of energy and restrictions on contamination of the environment. The maintenance of natural resources will receive much more attention than in the past. Concerns will increase regarding desertification, deforestation, urbanization, salinification, soil and water degradation, and atmospheric pollution. There is considerable difficulty in delineating these limitations, particularly as one considers the responsibilities and interests of developed and developing countries. The role of economics offers an additional challenge in working out these relationships. 

Munier, I., Lefevre, R., Geotti-Bianchini, F. and Verita, M. (2002). Influence of polluted urban atmosphere on the weathering of low durability glasses. Glass Technology 43 225-237. 

The photochemistry of the polluted atmosphere is exceedingly complex. Even if one considers only a single hydrocarbon pollutant, with typical concentrations of nitrogen oxides, carbon monoxide, water vapor, and other trace components of air, several hundred chemical reactions are involved in a realistic assessment of the chemical evolution of such a system. The actual urban atmosphere contains not just one but hundreds of different hydrocarbons, each with its own reactivity and oxidation products. 

Cadle, R. D. Experimental studies of Los Angeles air and kinetics of atmospheric reaction, pp. 27-59. In L. H. Rogers, Ed. Proceedings of the Conference on Chemical Reactions in Urban Atmospheres. Technical Report 15. Los Angeles Air Pollution Foundation, 1956. 

Sawicki, E., S. P. McPherson, T. W. Stanley, J. Meeker, and W. C. Elbert. Quantitative composition of the urban atmosphere in terms of polynuclear aza heterocyclic compounds and aliphatic and polynuclear aromatic hydrocarbons. Int. J. Air Water Pollut. 9 515-524, 1%5. 

Ktts, J. N., Jr., A. C. Lloyd, and J. L. Sprung. Chemical Reactions in Urban Atmosphere and Their Application to Air Pollution Control Strategies. Paper Presented at the International Symposium on Environment Measurements. Geneva, Oct. 2-4, 1973. 35 pp. 

Chang, T. Y., and B. Weinstock. Rollback modeling for urban air pollution control, pp. 184-189. In Preprints. Symposium on Atmospheric Diffusion and Air Pollution of the American Meteorological Society. Santa Barbara, California, September 9-13,... 

Hanna, S. R. Urban Air Pollution Model— Why ATDL (Atmospheric Turbulence and Diffusion Laboratory) Contribution File No. 83. (In-house Report) Oak Ridge, Tenn. National Oceanic and Atmospheric Administration, 1973. 19 pp. 

Wayne, L. G., and L. A. Chambers. Biological effects of urban air pollution. V. A study of effects of Los Angeles atmosphere on labwatory rodents. Arch. Environ. Health 16 871-885. 1968. 

FIGURE 1.5 Predicted rates of generation of OH/H02 in a polluted urban atmosphere as a function of time of day for three free radical sources (adapted from Winer, 1985). 

Figure 11.3 shows typical ambient air spectra in two regions in which HNO-, (Fig. 11.3a) and NH-, (Fig. 11.3b), respectively, have characteristic absorption bands (Biermann et al., 1988). Figure 11.4 shows, for comparison, some typical reference spectra for HN03 and NH-, taken at much higher concentrations in a 25-cm-long cell (see Problem 6). It can be seen that the absorption bands in air even in a polluted urban area are relatively weak. However, FTIR has also proven particularly useful as a standard for intercomparison studies in polluted urban atmospheres (e.g., see Hering et al., 1988). 

These studies were carried out in a polluted urban atmosphere where the concentrations are relatively high it might be expected that the agreement (or lack thereof) would certainly not improve at the much smaller concentrations found in rural and remote regions. Similar disagreements have been observed in other intercomparison studies (e.g., Anlauf et al., 1985 Gregory et al., 1990b Huebert et al., 1990), even in synthetic atmospheres (e.g., Fox et al., 1988). 

Morawaska, L., S. Thomas, N. Bofinger, D. Wainwright, and D. Neale, Comprehensive Characterization of Aerosols in a Subtropical Urban Atmosphere Particle Size Distribution and Correlation with Gaseous Pollutants, Atmos. Enriron., 32, 2467-2478 (1998). 

Storm water runoff from cities and villages presents another problem. This runoff contains salts from road deicing, street refuse, animal waste, food litter, residue from atmospheric deposition of sulfuric and nitric acid, metals, asbestos from automobile brakes, rubber from tires, hydrocarbons from motor vehicle exhaust condensates, oil and grease, soil and inorganic nutrients from construction sites, and a variety of other chemicals. Research shows a heavy impact of urban nonpoint pollution on freshwater quality (World Resources Institute, 1988). 

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