Air protection

Srebrenkoska, Vineta and Spasova, Sanja (2013) Air protection. In: Sustainable technologies. Univerzitet u Novom Sadu, Tehnološki fakultet, Novi Sad, Srbija, pp. 209-219. ISBN 978-86-6253-011-0

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Abstract

Аn air pollutant is defined as a substance that is present in the atmosphere at a concentration that is sufficient to cause harm to humans, other animals, vegetation, or materials. Each day humans inhale approximately 20 000 l of air. If harmful gases or fine toxic particles are present in the air, they are also drawn into the lungs, where they may cause serious respiratory diseases and other health problems. Approximately 90% of all air pollution is caused by five primary air pollutants: carbon monoxide (CO), sulfur dioxide (SO2), nitrogen oxides (NOx), volatile organic compounds (VOCs; mostly hydrocarbons [HCs]), and suspended particles. The transportation industry is responsible for nearly 50% of all air pollution from anthropogenic sources. In addition to CO, automobiles emit NOx and HCs. The burning of fossil fuels by stationary sources (power plants and industrial plants) accounts for approximately one-third of air pollutants, mainly in the form of sulfur oxides. Other industrial activities, along with variety of processes, including incineration of solid wastes, contribute smaller amounts. If pollutants were distributed evenly over the entire country, their harmful effects would be greatly reduced. Because the pollutants tend to be concentrated in urban areas, where industry is more common and automobile traffic is congested, large segments of the population are exposed to their harmful effects, particularly during daily rush hours. In addition to the five primary air pollutants, the atmosphere is contaminated with secondary air pollutants, which are harmful substances produced by chemical reactions between primary pollutants and other constituents of the atmosphere. Secondary pollutants include sulfuric acid, nitric acid, sulfates and nitrites (which contribute to acid deposition), and ozone and other photochemical oxidants (which contribute to photochemical smog). Biomass is material from vegetation and it can be used as a fuel in various boilers and combustors. The main components of biomass are carbon, oxygen and hydrogen but it also contains nitrogen, sulphur and, normally, small amounts of chlorides. The main part of the ash comprises Ca, K, Si, Mg, Mn, Al, Fe, P, Na and Zn. During combustion, various kinds of impurities are generated and some of them there are in the flue gas. Most of them are related to the composition of the biomass: particles from ash, NOx from nitrogen, SO2 from sulphur, etc. There is impurities related to incomplete or bad combustion e.g. particles such as soot and unburned matter, carbon monoxide and other gaseous organic compounds (TOC) such as dioxin. The impurities in the flue gas are harmful if they are emitted to the atmosphere. Flue gas cleaning must be installed to eliminate or at least reduce this problem.

Item Type: Book Section
Subjects: Engineering and Technology > Materials engineering
Divisions: Faculty of Technology
Depositing User: Vineta Srebrenkoska
Date Deposited: 04 Sep 2013 08:05
Last Modified: 02 Oct 2013 13:58
URI: http://eprints.ugd.edu.mk/id/eprint/7107

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