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Chemical reactions and pollutants

Formation of NOx- Higher tier

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When fuels are burned in vehicle engines, high temperatures are reached. At these high temperatures nitrogen and oxygen from the air combine to produce nitrogen monoxide.

one nitrogen molecule reacts with one oxygen molecule to make two nitrogen monoxide molecules

Nitrogen reacting with oxygen to form nitrogen monoxide

nitrogen + oxygen → nitrogen monoxide

Coal is made mainly of carbon. This burns to produce carbon dioxide.

When this nitrogen monoxide is released from vehicle exhaust systems, it combines with oxygen in the air to form nitrogen dioxide.

one nitrogen molecule reacts with two oxygen molecules to make two nitrogen dioxide molecules

Nitrogen reacting with oxygen to form nitrogen dioxide

nitrogen monoxide + oxygen → nitrogen dioxide

Nitrogen dioxide causes acid rain [acid rain: Rain that contains a high level of acids. It is believed to be caused by pollution and, maybe, natural activity such as volcanic eruptions. ]. It also causes breathing problems and can worsen the effects of asthma.

Nitrogen monoxide and nitrogen dioxide are jointly referred to as NOx

Back to Air quality index

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