NOx is a term for a family of highly reactive gases, including nitric oxide and nitrogen dioxide. These gases are produced from the reaction of nitrogen and oxygen gases during combustion at high temperatures. These reactions are often the result of the burning of fossil fuels. NOx pollution is emitted from vehicle exhaust, electric utilities, industrial boilers, power plants, cement kilns, and turbines, among other sources.
Increased NOx in the environment creates more ozone, which can effect both terrestrial and aquatic life. Excess nitrogen in the air causes excess nitrogen in bodies of water, which can lead to eutrophication, a process that occurs when a body of water has an increase in nutrients that leads to a reduction of the amount of oxygen in the water, potentially suffocating fish and other aquatic life.
NOx is a strong oxidizer, and when present in the air it can lead to the formation of corrosive nitric acid, resulting in acid rain and acidic environments. This oxidizing property also makes it a key player in the atmospheric reactions that cause smog. NOx also reacts with common organic compounds to form a wide variety of toxic products, including nitrate radical, nitroarenes, and nitrosamines. Nitrous oxide is a greenhouse gas contributing to climate change.
NOx in the air affects the human respiratory system. Side effects of NOx exposure include increased inflammation in the airways, worsened cough and wheezing, reduced lung function, increased asthma attacks,and increased risk of respiratory infection or disease. The small particles cause damage to lung tissue in the deep sensitive parts of the lungs, and can cause or worsen respiratory disease, and aggravate existing heart disease.These health problems can lead to premature death.
SOx
SOx refers to all sulphur oxides, the two major ones being sulphur dioxide (SO2) and sulphur trioxide (SO3). Sulfur dioxide is a very utilized resource in many industries. It is used for things such as chemical preparation, refining, pulp-making, solvent extraction, and the preparation and preservation of food. SO2 emissions can come from fossil-fuel burning industries like gas processing, oil sands production, goal combustion, ore refining, and chemical manufacturing.
Sulfur dioxide can come from natural sources as well, including volcanoes and hot springs. Marshes and other places where biological decay is taking place can also be a source of sulphur dioxide. These places emit hydrogen sulphide, a toxic gas that smells like rotten eggs. Hydrogen sulphide is oxidized when it combines with the oxygen in the air, producing sulphur dioxide. Sulpur trioxide is slowly formed when sulphur dioxide combines with oxygen in the air, and sulphur trioxide rapidly combines with water to produce sulphuric acid.
Sulfur oxides are also a major player in acid rain and smog. SOx tend to irritate the throat and lungs more often than the deep tissue, but if small particles are present, they can reach the respiratory system.
Effects on Candelaria concolor and Physica Millegrana
Lichens Candelaria concolor and Physica millegrana thrive when faced with N heavy environments, including N inputs from fertilizer application in agricultural areas or N emissions from power plants, vehicle exhaust, and other industries. They are both classified as a Nitrophiles. Physica millegrana is also classified as a Tolerant species, as it generally responds positively to most pollutants, including NOx and SOx.
Candelaria concolor. Source
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