What is – Oxides of Nitrogen (NO, N2O, NO2 and other) are generated by all combustion processes, regardless of the fuel used. The Nitrogen Dioxide gas is presented as a red-brown and strong odor and pungent. You may find one of the most dangerous air pollutants, its irritating nature, is because under conditions of strong sunlight causes of secondary photochemical reactions that create other pollutants (photochemical smog). The exhaust fumes of motor vehicles contribute greatly to pollution by NO2; the amount of emissions depends on the characteristics of the motor and the method of its use (speed, acceleration, ecc.). In general, the presence of NO2 increases when the engine operates at high rpm (arteries urban freeway, highways, ecc..)etc..
Method of measurement - For the determination of oxides of nitrogen using a chemiluminescence method. The method is based on the chemical reaction between nitrogen monoxide and ozone, capable of producing a luminescence characteristic, intensity proportional to the concentration of NO. A special detector allows to measure the intensity of light radiation produced. To measure dioxide is necessary to reduce it to Monoxide, through a converter to Molybdenum. The unit of measure in which is expressed the concentrations of nitrogen dioxide is microgram per meter per cubic meter (µg/m3).
Damage caused - It is a toxic gas irritates mucous membranes and responsible for specific diseases of the respiratory (bronchiti, allergy, irritation). As the CO NO2 also acts on hemoglobin, In fact, this gas oxidizes the iron in hemoglobin that loses its ability to carry oxygen. Among other effects, nitrogen oxides contribute to the formation of acid rain, thus causing the deterioration of the ecological balance environmental.
Evolution - The introduction of catalytic converters has not reduced in an incisive manner that the concentration of NO2, the last decade, didn't have a drop as much as the net CO. This is also due to the fact that the petrol engines are not the only source of NO2, but are equally polluting diesel vehicles and equipment for the production of energy.
