Understanding Diesel Emissions
Diesel engines, like other internal combustion engines, convert chemical energy contained in the fuel into mechanical power. This power does not come without harmful emission being emitted. This article will explore and help with understanding diesel emissions and diesel particulate matter.
Understanding Diesel Emissions
Diesel engines, much like other internal combustion engines, convert the chemical energy in fuel into mechanical power. Diesel fuel, a blend of hydrocarbons, ideally produces only carbon dioxide (CO₂) and water vapor (H2O) during combustion. Understanding Diesel Emissions and Diesel Particulate Matter is of upmost importance when working with or being exposed to diesel emissions.
Diesel Emissions
The emissions from diesel engines depend on the engine load. As the engine load increases, CO₂ and H2O emissions increase, while O₂ emissions decrease. Notably, these primary emissions do not pose significant health or environmental risks, except for CO₂’s role as a greenhouse gas.
Pollutants from Older Diesel Engines
However, older diesel engines emit pollutants that can harm health and the environment. These pollutants arise from non-ideal combustion processes, such as incomplete fuel combustion, high-temperature and high-pressure reactions, and the burning of lubricating oil and fuel additives. Common pollutants include:
- Unburned hydrocarbons (HC)
- Carbon monoxide (CO)
- Nitrogen oxides (NOₓ)
- Particulate matter (PM)
Reducing Diesel Emissions with Modern Technology
Modern diesel engines, equipped with advanced after-treatment devices like NOₓ and CO reduction catalysts and particulate filters, emit much lower levels of these pollutants. These technologies significantly reduce the harmful emissions traditionally associated with diesel engines.
Where diesel engines aren’t already fitted with these technologies. John Ratcliffe, can assist with the needed Diesel Particulate Filters and Diesel Oxidation Catalysts for such engines to help reduce emissions.
Diesel Particulate Matter (DPM)
Diesel Particulate Matter (DPM), also known as black smoke or soot, is a significant pollutant from diesel engines. DPM consists of fine and ultra-fine particles that can deeply penetrate the lungs, posing severe health risks. The International Agency for Research on Cancer (IARC) and the World Health Organization (WHO) have classified DPM as a Group 1 carcinogen, underscoring its potential to cause cancer.
Health Impacts and Regulatory Standards
Exposure to DPM is most common in environments like mines, factories, and storage facilities where diesel-powered equipment operates. The Australian Institute of Occupational Hygienists (AIOH) recommends keeping DPM levels below 100µg/m³ over an 8-hour average, measured as submicron elemental carbon (EC).
In South Africa, regulations under the Mine Health and Safety Act (Act 29 of 1996) aim to control DPM exposure in the mining sector. While there are no personal occupational exposure limits for DPM, mining companies must conduct risk assessments and implement mitigation measures.
John Ratcliffe’s Approach
At John Ratcliffe, we adopt a holistic approach to managing DPM contamination. By targeting the source of DPM, we focus on reducing risks rather than merely managing them. This proactive strategy aligns with international standards and aims to protect workers’ health and safety.
In conclusion, understanding and controlling diesel emissions is crucial for protecting both the environment and human health. By leveraging modern technologies and adhering to stringent standards, we can significantly reduce the harmful impact of diesel engines.
What are the exposure limits for Diesel Particulate Matter?
The Australian Institute of Occupational Hygienists (AIOH) has issued updated guidelines on diesel exhaust particulate and health risks. The document retains the original recommendation that levels of DPM should be controlled to; below 100µg/m³, as an 8-hour average value, measured as submicron elemental carbon (EC).
In South Africa, the regulatory authority (Department of Minerals and Energy) for Mine Health and Safety would normally promulgate regulations controlling the exposure of the workforce to below a specified Occupational Exposure Limit (OEL), which has a similar definition to a TLV. Under the Mine Health and Safety Act (Act 29 of 1996) a Guideline for a Mandatory Code of Practice on the use of diesel engines should also be considered from a health and explosion prevention perspective. The South African Bureau of Standards (SABS) also publishes engine performance standards that can be made legally binding to OEMs and industry when referred to in legislation.
There are currently no personal occupational exposure limits or legally binding tailpipe emissions standards in South Africa for DPM. Mining companies are however obliged to conduct risk assessments in terms of Section 11 of the Mine Health and Safety Act (Act 29 of 1996) on all factors that could adversely affect the health and safety of the workforce and institute appropriate mitigation measures. Where no local regulations exist, international best practice should be utilised. OEMs are also required to provide full disclosure, in terms of Section 21 of the Mine Health and Safety Act (Act 29 of 1996) of the health and safety impact of the equipment being sold to a mining company and provide advice on appropriate measures that can be taken to eliminate or reduce the risk.
The Group Environmental Engineers “GEE” committee recognised that several International Agencies have imposed limits for DPM, but also that these limits have been developed in countries where:
- Higher quality diesel fuel with low sulphur content is used;
- Latest generation diesel engines are used;
- Maintenance staff is adequately trained and available for employment to work on these units; and
- Exhaust purification and filter systems are used extensively.
To this extent, the GEE’s recommendation for action was to introduce an interim DPM exposure control value and gradually lower this exposure control value by means of a “phased-in” approach as follows:
- A DPM exposure control value of 350µg/m3 (TC) up to 31 December 2013;
- A DPM exposure control value of 250µg/m3 (TC) for 01 January 2014 to 31 December 2014;
- A DPM exposure control value of 200µg/m3 (TC) for 01 January 2015.
As of 01 January 2016 a DPM exposure control value of 160ug/m3 (TC) was supposed to be adopted. This level was however also subjected to review should new knowledge on the risks associated with excessive exposure to DPM become available.
At the date of the GEE’s position, the exposure limits in Australia, Canada, United Kingdom and United States of America were as follows and were based on the measurement of particulate constituents as indicated in the table below:
Regulatory/Agency Exposure Guidelines/Limits Substance Measured
- Canada (Ontario) 400µg/m³ Total Carbon(TC)
- US MSHA 160µg/m³ Total Carbon(TC)
- Australia 160µg/m³ Total Carbon(TC)
- Australia 120µg/m³ Elemental Carbon(EC)
Internationally, DPM is regulated via two mechanisms i.e. Occupational Health and Safety Standards and Tailpipe Emission Standards. Where diesel engines are used in confined spaces, their operation is regulated by occupational health standards in addition to tailpipe emissions.
John Ratcliffe’s Position
Rather than following various international standards on countless different diesel equipment and applications, we have adopted a holistic approach. This approach is based on the facts already published by the World Health Organisation and the hierarchy of hazard control. This approach targets the source of the DPM contamination in the workplace and focuses on the elimination of the risk, rather than management thereof!
This approach could save billions in litigation and compensation where operators and employees could prove that management has not applied all knowledge and available technology to eliminate the risks. We already have an example of this in the asbestos claims recently awarded.
Contact us today for more on our Emission Quality Solutions, Diesel Particulate Filters and Catalytic Converters.
