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All about diesel fumes

Anyone who works with or around diesel-powered equipment or vehicles may be concerned about the fumes. These are called diesel exhaust emissions. Find out what they are and why they’re harmful, along with how to reduce exposure. Our guidance is for business owners, managers, workers and health and safety professionals.

What are diesel engine exhaust emissions?

Diesel exhaust emissions are a mixture of gases, vapours, liquid aerosols and particles created by burning diesel fuels. They can contain:

  • alcohols
  • aldehydes
  • ammonia
  • aromatic compounds (benzene, polycyclic aromatic hydrocarbons and toluene)
  • carbon dioxide
  • carbon monoxide
  • carbon (soot particles)
  • (fine) diesel particulate matter (ash, carbon, soot, metallic abrasion particles, polycyclic aromatic hydrocarbons, silicates and sulphates) – this can stay in the air for long periods of time, which allows the particulates to enter and penetrate deep into the lungs
  • hydrocarbons
  • ketones
  • nitrogen
  • nitrogen dioxide
  • nitrogen oxide
  • oxygen
  • sulphur dioxide
  • water vapour.

Diesel exhaust emissions may contain more than 10 times the amount of soot particles than petrol exhaust fumes, and the mixture includes several carcinogenic substances, meaning they are classified as a carcinogen.

Diesel exhaust fumes were classified as “probable carcinogens” back in 1988, but the International Agency for Research on Cancer (IARC), part of the World Health Organization (WHO), has upgraded them to a Group One carcinogen. Diesel exhaust emissions are now treated as a cause of cancer in humans.