The Link Between Diesel Emissions and Poor Health – Something in the Air?
Every year 3.7 million premature deaths worldwide are attributed to illnesses caused by air pollution.1 Around half a million of these occur in Europe.2 Pollutants caused by traffic – specifically, nitrogen dioxide and particulates – are estimated to be responsible for tens of thousands of premature deaths each year in the UK, nearly 10,000 people a year in London alone.3
Air pollution has also been recognized as one of the environmental factors that can cause asthma. In 2013, the impact of air pollution on lung cancer prompted the International Agency on Research on Cancer (IARC) to recognise it as a carcinogen.4
Cars with diesel engines have been promoted as a lower pollutant alternative to petrol-fuel because of their lower levels of carbon dioxide (CO2) emissions. It has been widely thought that promoting diesels makes sense for reducing the warming effects of this “greenhouse gas.”
As emphasis has shifted from global warming to climate change over the past decade, more evidence of the public health threat posed by diesel exhaust emissions has emerged. While diesel engines emit less CO2 than petrol engines, they produce increased levels of nitric oxide, which negatively affects air quality.
Nitric oxide is the primary pollutant in all vehicle exhaust, and it reacts with ozone to form nitrogen dioxide or NO2, which is harmful to health. NO2 deactivates vitamin components of enzymes essential for normal DNA production affecting the blood, neurological, immune and reproductive systems. It also reacts with other substances in the air to form corrosive nitric acid and toxic organic nitrates.
Nitric oxide and nitrogen dioxide combine to create nitrogen oxides (NOx). Emissions analysis has pointed out the much higher levels of NOx caused by diesel cars. NOx is responsible for forming particle pollution - a complex mix of solids and liquids in the air. Particles can include acids, chemicals, metals, dust and allergens. The constituents of particles vary by location, and may even differ in the same place every day.
The very smallest particles – visible only through an electron microscope – penetrate deep into the lungs. For healthy people, this causes airway inflammation at the beginning, and for those already suffering from chronic lung disease it leads to the worsening of symptoms. It can trigger asthma. Long-term exposure to high concentrations of particulate matter increases risk for heart attack and arrhythmia, chronic obstructive pulmonary disease and emphysema.5
All air pollution is linked with higher mortality from cardiovascular disease, respiratory illness and cancer. Estimations of the threat to health are based on the concentration of pollutants in the air, time spent in the polluted environment and the amount inhaled.
Increased medical consultations, hospital admissions and sickness absence have an inevitable impact on life and disability claims. If air pollution levels rise or an increase occurs in medical conditions covered by insurance policies with a long lag-time, these effects may have to be reflected in product pricing.
World Asthma Day on May 3 is a campaign aimed at improving asthma awareness and care around the world. Asthma is largely a disease of polluted cities and means reducing exposure to vehicle emissions is important to this effort. (Read my blog, Asthma – Cause and Effect.)
- Global Burden of Disease Study, Institute of Health Metrics and Evaluation, University of Washington, Seattle.
- WHO figures.
- Walton. H, et al., “Understanding the Health Impacts of Air Pollution in London,” Kings College London, 2015.
- Brook. R et al., ”Air pollution and cardiovascular disease, a statement for healthcare professionals from the expert panel on population and prevention science for the American Heart Association,” 2004.