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Motor vehicles and air quality

Motor vehicles produce emissions that can affect human health and the environment.

Vehicle emissions are generally not a major contributor to air pollution in the Waikato region, but the volumes produced do increase depending on urban population and traffic density. 

Vehicle emissions

Motor vehicles produce a range of contaminants that can affect the environment and human health. These include:

  • carbon monoxide
  • carbon dioxide - a greenhouse gas associated with climate change
  • fine particles (smoke)
  • volatile organic compounds (VOCs) - partly burnt fuel
  • sulphur oxides
  • nitrogen oxides..

In Hamilton city, air pollution from vehicles varies from suburb to suburb and is highest in central Hamilton. Vehicle emissions are highest when traffic density is greatest - usually between 10am and 4pm.

Are petrol and diesel emissions different?

Petrol and diesel engines work in slightly different ways and burn different fuels, so they produce different exhausts.

Compared with petrol engines, diesel engines produce smaller amounts of unburnt and partially burnt fuel (hydrocarbons and carbon monoxide) but can produce more nitrogen oxides and large amounts of smoke (fine particulates). These particles consist of soot, hydrocarbons, sulphur-based chemicals and volatile organic compounds (VOCs).

Heavy duty diesel vehicles, such as trucks, can be very polluting because they produce large amounts of particulates and nitrogen oxides. Diesel exhaust has also been shown to be a probable cause of cancer.

Drive smart and keep in tune

You can help reduce the amount of air contaminants polluting our air by reducing the number of times you use a motor vehicle:

  • Carpool.
  • Use public transport (trains, buses and shuttles).
  • Cycle or scooter.
  • Walk.