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Air quality
Published in Stephen Battersby, Clay's Handbook of Environmental Health, 2023
Acid gases can be produced naturally; it is those gases, including both oxides of sulphur and oxides of nitrogen, produced by anthropogenic combustion processes that are of greatest importance. Acid deposition refers to the reaction of these gases with water to produce weak solutions of either sulphuric acid or nitric acid. All rain is naturally slightly acidic due to the presence of carbon dioxide, however acid rain normally refers to a pH of less than 5, although the pH can be even more acidic and less than pH 4.
International Legislation for Containment of Persistent Organic Pollutants and Hazardous Chemicals
Published in Narendra Kumar, Vertika Shukla, Persistent Organic Pollutants in the Environment, 2021
Mahiya Kulsoom, Vertika Shukla, Narendra Kumar
The Convention on Long-Range Transboundary Air Pollution (LRTAP) is a structured convention adopted in 1979 which came into force in 1983. It focuses on reducing and preventing air pollution—the main cause of acid rain—as much as possible. The convention is based on scientific assessments made so that parties can take coordinated actions to improve human health and ecosystems. It also helps with coordinating research, information exchange, and consultation between the parties. To date, more than 51 countries have joined, and eight agreements have been added to address the specific environmental concerns of ground-level ozone, heavy metals, POPs, sulfur and nitrogen oxides, volatile organic compounds, and monitoring and evaluation of air pollution across boundaries. LRTAP set tight emission limits for each source (combustion, electricity plants, thermal plants, plastic and other production, and manufacturing units). The LRTAP POPS Protocol was opened for signature at the United Nations Economic Commission for Europe meeting in Aarhus in June 1998. It is one of the eight protocols—or focused parts of a large global agreement—aimed specifically at persistent organic pollutants (UNEP, 2019a; UNECE, 2020).
Thermodynamics
Published in Mary K. Theodore, Louis Theodore, Introduction to Environmental Management, 2021
Most industrial processes generate some amount of by-products which may be released into the environment (i.e., emissions). Examples of such emissions include the exhaust from a car engine, the flue gas from an incinerator, etc. These emissions are generally not in equilibrium with the environment, and hence contain exergy. From an energy conservation point of view, this is significant because the emissions still contain the capacity to perform additional useful work. From an environmentalist perspective, the emissions may be damaging to the environment. For example, the sulfur dioxide (SO2) and nitric oxides (NOX), which are often found in fossil fuel emissions, can rise high into the Earth’s atmosphere where they react with oxygen and water vapor (hence, evolving toward chemical equilibrium) to form other acidic compounds such as sulfuric acid and nitric acid [10]. These processes result in the formation of acid rain. It is well documented that acid rain can affect alkaline or nonacidic substances such as limestone and soil, and can increase the acidity of lakes and streams. Such changes can negatively impact both aquatic and land-dwelling flora and fauna.
Impact of Sawmill Waste on SO2 Emissions from Co-firing with Lignite
Published in Combustion Science and Technology, 2023
S. A. Jankovsky, G. V. Kuznetsov, K.D. Fedorko, A.A. Ivanov
In accordance with the hypothesis proposed earlier (Yankovsky and Kuznetsov 2019), a significant decrease in the concentration of sulfur oxides in the gaseous combustion products of coal and wood mixtures occurs as a result of the interaction of these oxides with water vapor. These vapors are formed during the thermal decomposition of wood. Sulfuric acid vapors react with metal oxides of the mineral part of coals at high temperatures (Gogebakan, Gogebakan, Selçuk 2008). Such mechanism for suppressing sulfur oxides formed during bituminous coal combustion is confirmed by statistical data (for example, Liu et al. 2020; Tabakaev et al. 2019) on acid rain in the areas located near coal-fired power plants. The well-known statistics of such rains (Liu et al. 2020) allows drawing a conclusion that they do not fall with regular frequency throughout the year. Traces of acid rain are consistently recorded on the surface of plants and, especially, on snow on the territories of European, Asian and American States (Finkelman, Dai, French no date). Based on the above, it can be reasonably concluded that since water vapor in the atmosphere (as a rule) is sufficient for the formation of sulfuric acid vapors, the cause of acid rain formation is most likely the processes of sulfur oxides release in flue gases that occur after coal combustion in the furnaces of large and small power boilers.
Nonlinear modeling of industrial boiler NOx emissions
Published in Journal of the Air & Waste Management Association, 2022
Guillermo Ronquillo-Lomeli, Noé Amir Rodríguez-Olivares, Leonardo Barriga-Rodríguez, Antonio Ramírez-Martínez, Jorge Alberto Soto-Cajiga, Luciano Nava-Balanzar
Nitrogen oxides () are one of the pollutants generated during combustion processes. NOx in the combustion gases consists of 90% to 95% nitric oxide (NO), and the rest is nitrogen dioxide (NO2). NOx emissions react in the atmosphere with the presence of sunlight and water to form acid components and ozone in the shallow altitude environment (tropospheric ozone). Low-altitude ozone is one of the significant components of smog in cities and some rural areas. Ozone well above the earth in the stratosphere provides a protective layer, but the ozone that we breathe at ground level has been related to respiratory diseases and other health problems. Acid rain can damage ecosystems by directly destroying plant tissues, and it can also be combined with other pollutants, such as ozone, weakening trees and leaving them vulnerable to pests. NOx emission reduction is the primary requirement for a power plant.
Bacterial desulphurization of low-rank coal: A case study of Eocene Lignite of Western Rajasthan, India
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2018
Alok K. Singh, Aniruddha Kumar, Prakash K. Singh, Asha Lata Singh, Alok Kumar
Coal is the most abundant fossil fuel resource for the generation of electricity and industrial processes. When coal/lignite is used as an energy source, it causes numerous problem associated with the environment (Singh and Singh 2010). Sulfur is a hindrance to effective utilization of coal/lignite in view of the environmental problems. During coal combustion, its sulfur content combines with oxygen to produce sulfur dioxide (SO2) and contributes to cause acid rain, ash generation, and pollution. Acid rain consequently causes a harmful impact on agriculture and affects the ecological balance (Karimi et al. 2014; Ratanakandilok, Ngamprasertsith, and Prasassarakich 2001; Singh et al. 2012a, 2013). Coal and lignite contain sulfur that varies substantially but in most commonly within the range of 0.5% to 5% which occurs as organic and inorganic forms (Chou 2012). Coal with sulfur in the range of 4% to 11% is called super high-organic–sulfur (SHOS) coals (Chou 2012). Sulfur content in coal is present mainly as, pyritic sulfur, sulfate sulfur, organic sulfur and elemental sulfur (Li, Sun, and Jia 2010). Pyritic and organic sulfur generally account for the bulk of sulfur in coal. Pyrite is the predominant sulfide mineral in coal (Singh et al. 2013). A negligible amount of sulfate sulfur occurs in weathered coals. Organic sulfur occurs in coal matrix which makes it most recalcitrant form of sulfur.