In Dec 2010, the UK government released a report estimating that air pollution causes a ‘mortality burden’ of 340,000 years of life spread over an affected population of 200,000, equivalent to about 29,000 deaths each year in the UK, or a drop in average life expectancy across the whole population of 6 months. It also costs the NHS £27B per year. See:
There is no more recent report as yet, although the figures in it refer to 2008.
Particulate matter (PM) is the worst offender and diesel engines are one of the main sources of PM, but they also emit some of the other offenders. COMEAP estimates that a quarter of PM-related deaths are caused by diesel engines, 7250 lives per year. Some of the PM comes from private vehicles. To save regeneration costs, some diesel drivers apparently remove the diesel particulate filters from their cars, which is illegal, and doing so would mean failing an MOT. See:
The government encouraged people to go diesel by offering significant tax advantages. Road tax and company car tax are lower for diesels, resulting in more than half of new cars now being diesels. (https://www.gov.uk/government/publications/vehicle-licensing-statistics-2013) Almost all public buses and taxis and still many trains are diesel.
7250 lives per year caused by diesel vehicles is a lot, and let’s remember that was an estimate based on 2008 particulates. There are many more diesels on our roads now than then (https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/301636/veh0203.xls shows the number of diesel cars licensed has increased from 7163 to 10,064), but fuel efficiency has also improved in that period so total fuel use hasn’t increased much, only from 8788 to 9197 thousand tons of diesel. So the result isn’t as bad as it could have been and the proportionately scaled figure for 2012 would be 7587 deaths from diesel emissions. In 2013 there were only 1730 road deaths so 4.4 times as many people were killed by diesel emissions than road accidents.
I thought it would be interesting to compare deaths from just buses to those in road accidents, since buses are thought of by many as some sort of panacea whereas some of us see them as filthy environmental monsters. The proportion of diesel used by buses has fallen from 17% to 13.7% between 2008 and 2012. (I couldn’t find figures for the numbers of taxis, also officially included in public transport, since the fuel usage stats lump all cars together, but then I’ve never understood why taxis should be listed as public transport anyway.)
17% of the 7250 figure for 2008 gives 1232 deaths from public transport diesel emissions compared to 2538 road deaths that year, roughly half as many. However, for 2012, 13.7% of 7587 is 1039 deaths from public transport diesel emissions compared to 1754 people killed in road accidents in 2012. That ratio has grown from 48.5% to 59% in just 4 years. Buses may use less fuel than cars but they certainly aren’t saints.
So, headline result: 60% as many people are killed by diesel emissions from buses as in road accidents, but altogether, 4.4 times as many people die due to diesel. The government is very noisy when it comes to reducing road deaths, but it should look at the far bigger gains that would be made by reducing diesel use. Perhaps it is time that the deaths arising from diesel emissions should be added to the road deaths figures. At least then there might be some better action against it.
As I wrote in a recent blog
more still could be saved by just slightly improving the NHS. The £27B per year health costs saved by getting rid of diesel might go some way to doing both.
As a final observation, diesel was encouraged so much because it should help to reduce CO2 emissions, seen as a major contributor to global warming. In the last year or two, the sensitivity to CO2 emissions has been observed to be lower than originally thought. However, another major contribution to warming is the black carbon PM, noted especially for its contribution to melting glaciers by making them darker, also arising in large part from diesel. The efforts to reduce one contributor have increased another. Diesel doesn’t even solve the problem it was aimed at, but still causes others.