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What is nitrogen oxide and how do cars create it?

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June 11th 2020 info

Car pollution isn’t all about carbon dioxide. Before 2015, a low-emission car was simply one that produced a low volume of carbon dioxide – the pollutant was seen as the major concern, so others weren’t given as much scrutiny.

However, in 2015, car manufacturer Volkswagen found itself at the heart of a scandal known as “dieselgate”. The manufacturer was caught red-handed intentionally using emissions controls during laboratory testing only, meaning their cars produced up to 40 times more nitrogen oxide in actual driving than reported.

This put nitrogen oxide, and its damaging effects on public health, into the limelight. Now, carbon dioxide isn’t the only emission car manufacturers need to control.

So, why is nitrogen oxide pollution so dangerous, how do cars produce it, what are its effects and why are car manufacturers so concerned about it? We’ll tell you all the car pollution facts you need to know below.

What is nitrogen oxide and how do cars produce it?

Airborne nitrogen, in isolation, isn’t harmful to humans. It makes up 80% of our atmosphere, but it becomes particularly troublesome when it becomes bonded with another prominent element: oxygen.

When a car engine runs, it causes a type of combustion by heating up quickly. This process acts as a catalyst which binds together nitrogen (N) and oxygen (O2) to form nitric oxide (NO) or nitrogen dioxide (NO2). Both are described by the generic term nitrogen oxide (NOx). This isn’t the intended result, so nitrogen oxide is merely a by-product.

In sterile lab conditions, pure combustion uses hydrocarbons (gasoline, diesel, etc.) and oxygen to produce carbon dioxide and water. The world, however, isn’t a lab, and car manufacturers need to factor in and reduce the production of unwanted by-products.

From asthma to infections: the effects of nitrogen oxide

If nitrogen oxide was harmless, then there wouldn’t be any problems. Even if the effects were small, there wouldn’t be as much widespread concern over its production.

Nitrogen oxide pollution, however, has profound negative effects on public health. In the UK, the Committee on the Medical Effects of Air Pollutants has stated that “studies of long-term exposure to NO2 report associations with all-cause, respiratory and cardiovascular mortality, children’s respiratory symptoms and lung function.”

For those who live in urban and metropolitan areas, this exposure to nitrogen oxide is high. Some of the short-term and long-term consequences of the pollutant include:

  • Nausea
  • Difficulty breathing
  • Coughing
  • Aggravation of respiratory diseases
  • Asthma
  • Infection
  • Links to decreased fertility

There is a range of other diseases that have had a causal link to nitrogen oxide, too. As you can see from just this shortlist, the consequences of NOx emissions from cars are a cause of concern for manufacturers, city councils and governments to worry.

What type of fuel produces more nitrogen oxide?

When it comes to buying a car, you may want to consider the environmental consequences of your purchase.

While diesel engines tend to have better fuel efficiency, it comes at a cost. You may expect diesel to win the NOx emissions diesel vs gasoline fight, but the result is the opposite.

Better efficiency means diesel engines operate at a higher temperature and pressure than their petrol counterparts. This increases the volatility of combustion, leading to the production of stronger, more abundant nitrogen oxide.

Petrol engines still produce nitrogen oxide, but not to the same volume as diesel engines. This doesn’t mean petrol engines don’t need to be modernised and changed, as the volume they produce can still be a threat to public health.

Do older cars produce more nitrogen oxide?

By and large, yes. Newer models have made a concerted effort to reduce the production of nitrogen oxide, with these models producing more carbon dioxide than older versions to compensate.

While newer cars may produce more carbon dioxide than older vehicles, they produce considerably less carbon monoxide and nitrogen oxide. The increase in carbon dioxide is minimal, too, compared to the much larger decrease in other pollutants.

For modern cars, it’s better to have a slight increase in carbon dioxide production if it means harmful gases are significantly reduced.

Get all the information you need with our dealers

When buying a used car, there are a lot of factors to consider. From environmental concerns to fuel efficiency, it can be tough to balance your economic and personal needs with that of the greater good.

That’s why our dealers list all the information you need so you can make the right decision for you. Discover competitive, economical used car deals from findandfundmycar.com today.

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