Nitric oxide (NOx)
Sources of NOx Pollution NOx is produced from the reaction of nitrogen and oxygen gases in the air during combustion, especially at high temperatures. In areas of high motor vehicle traffic, such as in large cities, the amount of nitrogen oxides emitted into the atmosphere as air pollution can be significant.
Likewise, what are NOx gases? Nitrogen oxides (NOx) are poisonous gases derived from nitrogen and oxygen combustion under high pressure and temperatures. NOx is composed of nitric oxide (NO), and a smaller percentage of more poisonous nitrogen dioxide (NO2).
how do you reduce NOx emissions?
NOx emission can be reduced by primary methods such as retard injection, fuel nozzle modification, change of compression ratio, water direct injection, water emulsification, exhaust gas recirculation (EGR) and secondary method such as selective catalytic reduction (SCR).
What is the main source for nitrogen oxides NOx in the atmosphere?
Sources. Nitrogen oxides are produced in combustion processes, partly from nitrogen compounds in the fuel, but mostly by direct combination of atmospheric oxygen and nitrogen in flames. Nitrogen oxides are produced naturally by lightning, and also, to a small extent, by microbial processes in soils.
Do cars emit NOx?
Among the air pollutants gasoline and diesel engines emit are oxides of nitrogen—NO and NO2, generically abbreviated as NOx. Nitrogen oxides have harmful direct effects on human health, and indirect effects through the damage they do to agricultural crops and ecosystems.
How are NOx emissions measured?
In practice, the main methods employed for the measurement of NOx are infrared, chemiluminescence and electrochemical. Infrared analysers measure the absorption of an emitted infrared light source through a gas sample.
Is NOx heavier than air?
Nitric oxide is rapidly oxidized in air at high concentrations to form nitrogen dioxide. exposures. Nitrogen dioxide is heavier than air, such that exposure in poorly ventilated, enclosed, or low-lying areas can result in asphyxiation. Both nitrogen dioxide and nitric oxide are gases at room temperature.
What does NOx stand for?
Does nitrogen dioxide cause global warming?
The two most common and hazardous oxides of nitrogen are nitric oxide and nitrogen dioxide. Nitrous oxide, commonly called laughing gas, is a greenhouse gas that contributes to global warming.
What is the primary source of NOx emissions?
Most airborne NOx comes from combustion-related emissions sources of human origin, primarily fossil fuel combustion in electric utilities, high-temperature operations at other industrial sources, and operation of motor vehicles.
Does a catalytic converter reduce NOx?
Catalytic Converters – Lean NOx Catalyst In the oxygen-rich environment of diesel exhaust, it is difficult to chemically reduce NOx to molecular nitrogen. Without the added fuel and catalyst, reduction reactions that convert NOx to N2 would not take place because of excess oxygen present in the exhaust.
How does nitrogen oxides affect the environment?
Nitrogen monoxide reacts with oxygen or ozone in the air to produce nitrogen dioxide. However, high levels of nitrogen dioxide and nitrogen monoxide damage plant life. Nitrogen dioxide also contributes to the formation of acid rain which damages vegetation, buildings and water bodies.
How do I control SOx emissions?
Approaches for Limiting Emissions Since sulfur emissions are proportional to the sulfur content of the fuel, an effective means of reducing SOx emissions is to burn low-sulfur fuel such as natural gas, low-sulfur oil, or low-sulfur coal. Natural gas has the added advantage of emitting no particulate matter when burned.
What technology is used to reduce NOx emissions from cars?
Exhaust Gas Recirculation technology is able to reduce diesel nitrogen oxide (NOx) emissions by taking a carefully controlled portion of the inert exhaust gases, cooling it and re-introducing it to the combustion chamber when conditions are right to do so.
What is low NOx emissions?
NOx is an abbreviation for nitrogen oxides – a collection of harmful and toxic greenhouse gases. Low NOx and Ultra-Low NOx refers to emission limits on these products and are determined by local EPA standards and will vary for each type of heating equipment.
How much NOx does a diesel produce?
Nitrogen oxides are highly active ozone precursors playing an important role in the smog chemistry. They can also form secondary nitrate particulates in the atmosphere. Concentrations of NOx in untreated diesel exhaust are typically between 50 and 1000 ppm.
Is n2o a NOx?
The term ‘nitrogen oxides’ (NOx) is usually used to include two gases-nitric oxide (NO), which is a colourless, odourless gas and nitrogen dioxide (NO2), which is a reddish-brown gas with a pungent odour. Other oxides of nitrogen include NO3 (nitrogen trioxide), N2O (nitrous oxide), N2O4 and N2O5.
How are nitrogen oxides formed?
Nitrogen oxides are produced in combustion processes, partly from nitrogen compounds in the fuel, but mostly by direct combination of atmospheric oxygen and nitrogen in flames. Nitrogen oxides are produced naturally by lightning, and also, to a small extent, by microbial processes in soils.