When fuel is burned in automobile engines at high temperatures, nitrogen oxides emissions are created. More than half of all nitrogen oxides emissions in the United States of America are caused by both on-road and non-road mobile sources which are a major polluter of nitrogen oxides emissions. Because of these facts, it is understandable that there is an immediate need for the control of nitrogen oxides emissions.
By the ability of nitrogen oxides to travel long distances, they are the cause of a wide variety of environmental and health concerns far from the sources of their emissions. The control of nitrogen oxides emissions is needed. When nitrogen oxides, hydrocarbons and sunlight are combined, the product is smog and ozone depletion. On high smog days, you will have difficulty seeing objects far away as well as having trouble breathing. In addition, the control of nitrogen oxides emissions is needed because they are a contributing factor to the formation of particulate matter in the atmosphere through chemical reaction with atmospheric gasses.
Nitrogen oxides also known as NOx is a generalized term for a family of colourless and odourless gasses, all containing various levels of, which are highly reactive. Nitrogen dioxide, another common chemical known for pollution, along with many air particles combine into a layer of brownish red tones. This filmy layer often can be seen over many large cities.
Particulate Matter also known as PM are tiny particles or liquid droplets that become suspended in the air containing a wide range of chemicals. Larger particles become visible as smoke or dust and settle from their suspension in the air rapidly. The most harmful to human health are the smallest particles, which can be suspended for long periods. These smallest particles can penetrate deep into lungs. Particles directly emitted into the air come from a variety of sources including buses, trucks and cars. In addition to vehicle pollution, other sources may include construction sites, factories unpaved roads and different wood burning items.
Particulate Matter 2.5 known as PM2.5 but often referred to as “PM fine” are particles that have a diameter less than 2.5 microns and make up the majority of particulate matter from mobile sources. PM fine particles are not usually visible with your eyes because they are so small are significant contributors to haze in the atmosphere. Because they can penetrate deeper into the lungs than larger particles, the smaller the particles the more harmful to humans.
Particulate filters are an anti-pollution filter device designed to trap particles in the exhaust from diesel engines before they enter the atmosphere.