There have always been topical issues in diesel exhaust emission conversations and surely one cannot go past the question – Can diesel emissions cause cancer? Diesel exhaust emissions are created by burning diesel fuels that consists of a mixture of chemicals that can be harmful to people. When breathed in, these chemicals increase your risk of developing long-term health problems. This includes lung cancer and possibly bladder cancer. In Australia, diesel exhaust emissions are the second most common cancer-causing agent workers are exposed to, behind ultraviolet radiation exposure. Statistics from 10 years ago, estimate that about 1.2 million Australian workers were exposed to diesel emissions. Diesel exhaust emissions contain a mixture of gases and soot, which is also called particulate matter. Several other substances including carcinogens, may stick to the soot. Because soot particles are very small, they can easily get deep into the lungs. This is how they cause a range of short-term and long-term health problems, including cancer. Regular exposure to high levels of soot, over a long period of time, increases the risk of getting lung and bladder cancer. Diesel emissions do not only after workers. Proximity to highways for heavy transport and port activities for residents can results in a high proportion of respiratory disease and cancers from diesel particulate pollution. To appreciate how ‘grave’ exposure to diesel emissions is, this article will focus on how diesel vehicles came about, chemistry of diesel emissions and cancer links, and round off with what the world is doing in response to diesel emissions.
History of diesel vehicles – Debacle of good intentions with unforeseen circumstances
What was the good intention with promoting purchase of diesel vehicles? – Post the Kyoto Protocol in 1997 most European Union governments began promoting the purchase of diesel vehicles to cut CO2 emissions and thereby meet targets for reduction of greenhouse gas emissions. To drive this for this move diesel was even subsidized by governments and tax was reduced on diesel vehicles. Consequently, sales of diesel vehicles which obviously used diesel shot up to almost half the market. Fast forward we then also question what where the unintended consequences which have led to unforeseen circumstances? – Studies began showing that nitrogen oxides and particulates from diesel fumes were much more harmful to human health than previously anticipated. About 15 years after the Kyoto Protocol, diesel emissions were announced as a Group 1 carcinogen by the International Agency for Research on Cancer (IARC). Diesel was announced as carcinogenic to humans. 3 years later from the announcement, the emission-cheating scandals came to light and sullied the image of diesel even further. As it stands, governments are now trying to discourage diesel and sales have plummeted but obviously people that bought diesel vehicles in good faith are concerned about diesel bans in cities and being stuck with vehicles that are more expensive to run and with very low resale value.
Chemistry and resultant health effects of diesel emissions linked to cancer.
Diesel engine operations result in formation of pollutants that negatively impact human life. Some commonly measured pollutants are:
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- Volatile Organic Compounds (VOCs)
- Carbon Monoxide (CO)
- Oxides of Nitrogen (NOx)
- Oxides of Sulphur (SO2)
- Particulate Matter (PM)
VOCs are pollutants that react with nitrogen oxides in the presence of sunlight to form ground level ozone, a main ingredient in smog. Though beneficial in the upper atmosphere, at ground level this gas irritates the respiratory system, causing coughing, choking and reduced lung capacity. VOCs emitted from diesel engines include toxic air pollutants such as benzene, acetaldehyde, and 1,3-butadiene which are linked to different types of cancer. CO is an odorless, colorless, and poisonous gas formed from the combustion of diesel and is emitted from diesel trucks used in mining. When inhaled, CO blocks oxygen from the brain, heart, and other vital organs. NOx forms ground level ozone and particulate matter which is secondary. The harmful primary pollutant, NOx can cause lung irritation and weaken the body’s defenses against respiratory infections such as pneumonia and influenza. SO2 is obtained from combustion of sulfur-containing fuels such as diesel. Sulfur dioxide can react in the atmosphere to form fine particles and poses the largest health risk to young children and asthmatics. Diesel particulate matter is the soot seen in vehicle exhausts. It poses serious threat to human health, as it can penetrate deep into the lungs. PM can be a primary pollutant or a secondary pollutant from VOCs, NOx and SO2. Diesel exhaust emission are a major contributor to PM pollution.
What is the global response to diesel emissions?
We cite an example of France. In 2018 the French government introduced an environmentally friendly new diesel fuel tax. It was met with a lot of protests across France. The tax seemed to have penalized ordinary people who had purchased diesel vehicles when they had been encouraged by the government to do so. Typical cross-roads moment for most governments given the declaration by World Health Organization of diesel as a carcinogen and the reversal of lobbying for diesel vehicles by most governments. The difficulties often roll-over to introduction of ‘carbon taxes’ as it seems contradictory to the initial recommendations to purchase diesel vehicles. The good intention of course is to reduce diesel emissions and to change consumer behavior. However, the unintended consequence is very potent populist anger at taxes which hit ordinary people. The chain reaction also raises more questions of whether decision making is always futuristic or only driven by present gains. The most obvious narrative taking to account whether it’s a matter of climate-change denialism, support for fossil-fuel exploitation for the political right as opposed to regulations on business and industry. The tragedy is the paradox of environmental and health problems faced versus those who just don’t care about the environment and human health at all. Unfortunately, cancer has ‘no holiday’ to take the more the disagreements affect decisive action the more the body count from diesel emissions. A sad ending to an article where there is no resolve unless affirmative action is taken which leads us to the last words – ‘Diesel emissions can cause cancer and cancer kills’.
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