Atmospheric pollutants nitrates

Another important phytotoxic atmospheric pollutant that has been studied with respect to its inhibitory effects on plant photosynthesis is peroxyacetyl nitrate (PAN). This phytotoxicant applied for 30 min at 1 ppm depressed the incorporation of 1 C02 into intact pinto bean leaves, but only after visible tissue injury started to develop (20). From companion studies on isolated chloroplasts, it was concluded that PAN-induced inhibition was probably associated with the carboxylating reaction or the chloroplast light-energy conversion system leading to assimilative power. The inhibition appeared to result in a quantitative reduction (but not a qualitative change) in the early products of photosynthesis. 

Nitrogen monoxide, also known as nitric oxide, NO, is a precursor to nitrate fertilizers and a common atmospheric pollutant, but it also plays a multitude of vital roles in our human biology. Use nitric oxide as a keyword in your Internet search engine to find a plethora of websites devoted to the many roles this small but important molecule plays in our physiology and in various diseases, such as Alzheimer s, Parkinsons, asthma, heart disease, and infections. 

As a rule the amount of nitrate nitrogen is approximately half that of the ammoniacal. The ammonia appears to arise from several sources. The sea, the soil, and the atmospheric pollution consequent upon inhabited areas may all contribute. That the soil is an important... 

Additives may be used to improve the fuel performance, and additives such as alkyl nitrates and nitrites (ASTM D-1839, ASTM D-4046) can improve ignition quality. Pour point depressants can improve low-temperature performance. Antismoke additives reduce exhaust smoke, which is of growing concern as more and more attention is paid to atmospheric pollution. Antioxidant and sludge dispersants may also be used, particularly with fuels formulated with cracked components, to prevent the formation of insoluble compounds that could cause line and filter plugging (ASTM D-2068, ASTM D-6371, IP 309). 

As was mentioned above, at the first stage of the investigations we assessed the dynamics of the emissions of sulphur and nitrogen dioxides and of dust which pollute the atmosphere in Almalyk, the levels of atmospheric pollution of these components and their content in humid and dry atmospheric fallouts. The town of Almalyk was chosen as a model for the investigation of the chemical reactions in the atmosphere causing the formation of nitrates and sulphates in precipitation. Total annual emissions and annual mean concentrations of each component were also caleulated. The results obtained are presented in Table 1 (for 2 years). 

Meixner, F. X., K. P. Muller, G. Aheimer, and K. D. Hofken (1985). Measurements of gaseous nitric acid and particulate nitrate. In Physico-chemical Behaviour of Atmospheric Pollutants , (F. A. A. M. De Leeuw and N. D. Van Egmond, eds.) COST Action 611, Proc. Workshop Pollut. Cycles Transport-Modelling Field Experiments, Bilthoven, The Netherlands, pp. 103-114. 

Meyrahn, H., J. Hahn, G. Helas, P. Warneck, and S. A. Penkett (1984). Cryogenic sampling and analysis of peroxyacetyl nitrate in the atmosphere. In Physico-chemical Behaviour of Atmospheric Pollutants (B. Versino and G. Angeletti, eds.), pp. 39-43. Reidel, Dordrecht, The Netherlands. 

No further work was done with N(V) nitration however, on the basis of these observations, we assert that nitric acid itself does not nitrate pyrene in methylene chloride. This finding can be contrasted with the results of Grosjean et al. (3), who concluded in atmospheric pollutant studies that the opposite view is correct. Specifically, their results from vapor-phase experiments suggested that N02 was not active in nitration of filter-deposited PAHs, whereas nitric acid was necessary for nitration. The differences in conditions must be considered when comparing these data with those from this work. Nonetheless, it is difficult to refute the absence of nitration activity by N(V) under our conditions, and the important questions concerning the nitrating species in the environmental work remain. 

The nitric acid can further react in the polluted atmosphere, forming nitrates, which are washed out from the atmosphere as the final stage. 

Plants for the production of nitric acid are serious sources of atmospheric pollution in spite of many improvements and the development of numerous combined procedures. As much as 0.30% by volume of oxides of nitrogen may occur in the final gases, even in the case of properly operating absorbers even higher concentrations are sometimes encountered. Nitrogen oxides can also enter into the atmosphere during nitration processes. 

Temperature dependence of reactions of the nitrate radical with alkanes, in G. Restelli, G. Angeletti (eds). Fifth European Symp. on Physico-Chemical Behaviour of Atmospheric Pollutants, Kluwer Academic PubL, Dordrecht 1990, pp. 328-333. 

In the spherodizer granulation process, the molten ammonium nitrate is sprayed onto the rolling bed of solid particles in the drum, forming granules, which arc cooled and screened. Advantages of spherodizing include the following there is variation in product size, atmospheric pollution from the prill tower is eliminated, and a harder product is made, A yield of over 99,5 percent from ammonia and nitric acid is claimed ... 

Most corrosion processes in copper and copper alloys generally start at the surface layer of the metal or alloy. When exposed to the atmosphere at ambient temperature, the surface reacts with oxygen, water, carbon dioxide, and air pollutants in buried objects the surface layer reacts with the components of the soil and with soil pollutants. In either case it gradually acquires a more or less thick patina under which the metallic core of an object may remain substantially unchanged. At particular sites, however, the corrosion processes may penetrate beyond the surface, and buried objects in particular may become severely corroded. At times, only extremely small remains of the original metal or alloy may be left underneath the corrosion layers. Very small amounts of active ions in the soil, such as chloride and nitrate under moist conditions, for example, may result, first in the corrosion of the surface layer and eventually, of the entire object. The process usually starts when surface atoms of the metal react with, say, chloride ions in the groundwater and form compounds of copper and chlorine, mainly cuprous chloride, cupric chloride, and/or hydrated cupric chloride. 

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