Chemicals in car exhaust

Car exhaust is a source of carbon dioxide and this component tends to get most of the coverage these days, but there’s a whole bunch of nasty toxic chemicals in car exhaust that damage our environment. Let’s take a look at a few.

Carbon Monoxide

Colorless, odorless, tasteless, yet highly toxic. Automobile and industrial emissions may also contribute to the greenhouse effect and global warming; it’s one of the other greenhouse gases we don’t usually hear much about. It occurs naturally in our atmosphere at around 0.1 ppm, but car exhaust without a catalytic converter contains 7,000 parts per million.

Nitrogen dioxide

Toxic by inhalation and can cause adverse health effects at low levels over a long period. It can contribute to acid rain and eutrophication in coastal waters.

Sulfur dioxide

Can cause pulmonary and respiratory distress and acidification of waterways.

Particulate matter

This is basically soot – it’s most apparent effect is reducing visibility. It impacts on breathing and respiratory systems, damages lung tissues and causes cancer. Hundreds of thousands, if not millions of people and animals die prematurely each year due to the health effects of inhaling particulate matter.


A carcinogen in humans, benzene is also very toxic aquatic life and can cause death in plants. It is a “precursor” component for formation of photochemical smog.


Another known carcinogen for humans, with similar effects to many animals and birds. In an aquatic environment, formaldehyde has a half life of between a day and ten days.

Polycyclic hydrocarbons
The U.S. Department of Health and Human Services states that some Polycyclic hydrocarbons may  be carcinogens in humans and animals and can cause harmful effects on skin and the auto-immune system.

Some recent studies have also found car exhaust can create hydrocarbon-based free radicals which can linger indefinitely. These free radicals are believed to cause lung cancer and cardiovascular diseases. Even with the use of catalytic converters to help break down pollutants that cause smog, it may be creating conditions for the creation of  these free radicals to form.

So when you reduce your car usage, take public transport or car pool, even just a bit of gentle exercise by walking to the store instead of driving,  it’s not just carbon dioxide you’re keeping out of the atmosphere, but a lot of other environmentally damaging chemicals too. Even if you do need to drive your car regularly, by using simple gas saving strategies you can reduce your environmental impact and save a stack of cash at the same time.