Composition, breakdown, and carcinogenicity of diesel exhaust
| Gas-Phase Emission Components | Atmospheric Reaction Products | Biological Impact |
|---|---|---|
| Carbon dioxide | – | Global warming |
| Carbon monoxide | – | Asphyxiation |
| Nitrogen oxides | Nitric acid, ozone | Respiratory tract irritants, acid rain |
| Sulfur dioxide | Sulfuric acid | Respiratory tract irritant, acid rain |
| Hydrocarbons | ||
| Alkanes | Aldehydes, alkyl nitrates, ketones | Respiratory tract irritants |
| Alkenes | Aldehydes, ketones | Respiratory tract irritants, mutagenic and carcinogenic |
| Aldehydes | ||
| Formaldehyde | Carbon monoxide, hydroperoxyl radicals | Carcinogenic |
| Higher aldehydes (eg, acetaldehyde, acrolein) | Peroxyacyl nitrates | Respiratory tract and eye irritants, plant damage |
| Monocyclic aromatic compounds (eg, toluene) | Hydroxylated-nitro derivatives | Carcinogenic |
| Benzene | Nitro-PAH | Mutagenic and carcinogenic |
| Particle-phase emission components | ||
| Elemental carbon | – | Nuclei adsorb organic compounds |
| Inorganic sulfate and nitrate | – | Respiratory tract irritant |
| Hydrocarbons (C14-C35) | Aldehydes, ketones, and alkyl nitrates | Unknown |
| PAH | Nitro-PAH and nitro-PAH lactones | Mutagenic and carcinogenic |
PAH, polycyclic aromatic hydrocarbons; C, carbon.