Overview Emissions Regulations and Environmental Zones
Diesel engine emissions can contribute to airborne pollution including:
- Particulate Matter (PM) mostly consisting of soot (carbon) and ash (from the combustion of fuel and oil additives).
- Nitrogen Oxide, NO and Nitrogen Dioxide, NO2 (collectively known as NOx).
- Unburnt hydrocarbons from fuel (HC).
- Carbon Monoxide (CO)
Legislation has been passed around the world to combat airborne pollution and to help reduce the accompanying health risks. This includes the Euro regulations (covering the EU), the EPA regulations in the US as well as regional standards in China, India, Japan and Brazil. Airborne pollution is at worst in major urban centres. Cities such as London, Berlin, Rome, Amsterdam, Paris and Beijing have all created Low Emissions Zones to help improve local air quality.
In order to successfully meet these emissions regulations, most diesel vehicles are fitted with exhaust after-treatment devices. These can be retro-fitted to older vehicles although it is quickly becoming a standard feature on most new vehicles. The many exhaust after-treatment systems include various catalysts to reduce levels of CO, HC or NOx along with a Diesel Particulate Filter (DPF) to reduce PM.
DPFs have been fitted to diesel cars in Europe since 2001, becoming more widespread from 2009 onwards while all new heavy-duty vehicles sold after January 2014 must now be fitted with DPFs. In the US the introduction of the EPA07 legislation means that all US trucks must be fitted with DPFs. They are also becoming increasingly common in non-road/off-highway markets, like agriculture and construction, to meet the latest legislation.