Despite the considerable amount of basic research, neither the formation of PM in the engine cylinder, nor its physical and chemical properties or human health effects are fully understood. Nevertheless, the existing medical research suggests that PM is one of the major harmful emissions produced by diesel engines. This black smoke is not only carcinogenic, affecting the operators’ lungs, but deposits will stain paintwork and/or contaminate products manufactured or stored where diesel vehicles frequently work.
Diesel Particulate Matter (DPM) has been classified as a carcinogen to humans (Group 1) by the International Agency for Research on Cancer (IARC) and the World Health Organisation (WHO) in June 2012. Diesel particulates are subject to diesel emission regulations worldwide, and have become the focus in diesel emission control technology.
Particulate matter, perhaps the most characteristic of diesel emissions, is responsible for the black smoke/soot traditionally associated with diesel powered vehicles. The diesel particulate matter emission is usually abbreviated as PM or DPM, the latter acronym being more common in occupational health applications. Diesel particulates form a very complex aerosol system.
Diesel particulate matter also has many different types of particles that can be classified by size or composition. The size of diesel particulates that are of greatest concern are in the categories of fine, and ultra-fine particles which can get deep into the lung when inhaled.
The composition of these fine and ultra-fine particles may be composed of elemental carbon with absorbed compounds such as organic compounds, sulphate, nitrate, metals and other trace elements.
The most common exposures to diesel particulate matter occur underground in mining, or indoors within factories and storage facilities with the use of diesel-powered equipment.