Newer versions of diesel engines contain less toxic material compared to older equipment. If the fuel’s combustion is incomplete, the exhaust expels gases such as hydrocarbons, carbon monoxide and aldehydes. Engine lube oil is responsible for a large part of the exhaust hydrocarbons. Engines that are being operated in closed spaces like tunnels, warehouses, underground mines and inside buildings being constructed, the carbon monoxide will build up in the atmosphere and may cause undesirable results to humans –dizziness, headaches and lethargy. While aldehydes and hydrocarbons that accumulates in the same condition may result to eye irritation and even choking. Diesel smell is mainly because of components like hydrocarbons and aldehydes. The environment also suffers from negative effects caused by hydrocarbons such as smog.
Nitrogen and oxygen are both derived from nitrogen oxides, more commonly known as NOx, which are emitted by the engine cylinder during conditions of high pressure and temperature. A big part of NOx is made up of nitric oxide while nitrogen dioxide occupies only a small fraction. Nitrogen dioxide or NOx is known to be toxic and a great contributor to smog formation which is harmful for the environment.
Sulfur dioxide is one of diesel engine emissions generated due to the presence of sulfur in the fuel. The fuel’s sulphur content determines the concentration of the emitted sulphur dioxide. SUlfur dioxide is a colorless gas and is found to be toxic. Its strong odor can cause irritation and it is one of the major causes in the formation of acid rain.
Diesel particulate matter, also known for its abbreviation DPM, is another form of diesel engine emissions. DMP is a combination of solid and liquid components produced during the combustion of the engine cylinder. Diesel particulate matter is classified into three fractions:
- Solids. It is often referred to as soot and is made up of dry particles of carbon.
- Soluble Organic Fraction. These are heavy hydrocarbons that carbon particles absorb and condense.
- Sulfate fraction or SO4. This is made up of hydrated sulfuric acid.
There are factors that affect the actual composition of a diesel particulate matter such as the type of engine used, the load applied and the speed on operation. 60% of wet particulates is made up of soluble organic fraction while dry particulates contains a large part of dry carbon. A diesel fuel’s sulphur content is also what determines the approximate amount of sulfates in the composition.
Because diesel particulates are very fine particles, they are considered a hazard to human’s health. It is respirable and is considered as a human carcinogen. DPM can also cause heart and respiratory diseases.