In 2012 the UN World Health Organisation (WHO) declared that Diesel Exhaust Emissions are a Class 1 Carcinogen. Diesel Exhaust Emissions comprise of; Gaseous components (CO, NOx, SOx, HC etc) Particulate components- Diesel Particulate matter (DPM).

Diesel Particulate Matter (DPM) is made up of Carbon soot chains ( a byproduct of the combustion process and are covered with solid metals, hydrocarbons, aldehydes and other chemicals.