Ever larger proportion of diesel road vehicles which produce carginogenic exhaust contribute to airport air pollution

Whereas people hoped that ever more advanced engine technology would reduce the amount of air pollution produced from road vehicles, it seems that air pollution continues to rise. There is mounting evidence that the tiny particulates produced from incompletely combusted diesel fuel are carcinogenic.  As diesel vehicles can be slightly more fuel-efficient in miles per gallon, there has been a shift in the UK towards more and more diesel vehicles, since around 2000. At present there are around 50% diesel and 50% petrol cars, though this balance may swing back towards petrol. Diesel engines often do not appear to be as “clean” as their manufacturer spec would indicate, especially if there is slow moving traffic or traffic jams. The net effect has been no reduction in air pollution – for example around busy airports.  For airports such as Heathrow, which have a higher proportion of diesel vehicles, including lorries, the air pollution – and therefore risk to health – has been growing, as the diesel proportion has grown.


New runways (or airports) would breach legal limits for air pollution

by   (Clean Air in London)

(extracts) …..

Nitrogen dioxide and aviation

NO2 emissions are produced by both airside operations (aircraft and airport vehicles) and also by road traffic accessing airports.  Whilst many major airports contribute towards local exceedances of NO2 limit values, the problems are most acute at Heathrow due to its status as the UK’s largest and busiest airport and the proximity of two major motorways.

The 2008 consultation ‘Adding Capacity at Heathrow Airport’ presented the results of air quality modelling that suggested that oxides of nitrogen (NOx) emissions from road vehicles would fall over future years as older vehicles were replaced by newer, cleaner vehicles.  As a result ‘headroom’ would be created for the airport to expand whilst meeting NO2 limit values.  This assumption was challenged by CAL and others, who suggested that a wider range of NO2 scenarios should be investigated.  As a result, following the consultation, the Government announced that the operational use of new capacity (e.g. a new runway) would be restricted until air quality limit values were met, with the Environment Agency given responsibility for ensuring that air quality around Heathrow did not breach these limits.

CAL understands that the modelling of aviation’s impact on air quality assumes no impact when aircraft are above 1,000 metres i.e. other than the landing and take-off cycle.

Changes since 2008

Since 2008 the air quality policy landscape has changed significantly.  First, as detailed above, the UK hasnot obtained a time extension until 2015 to comply with NO2 limit values throughout the Greater London zone.  This brings the threat of enforcement action, but also means that planning decisions must consider a 2010 deadline for NO2 compliance in the zone rather than the 2015 deadline previously assumed in airport expansion consultations.

The 2008 Heathrow consultation document stated that ‘The ability to meet air quality limits in future years largely results from substantial improvements in road vehicle emissions due to further developments in European emission standards’ (page 67).  However, evidence (Note 3) is now increasingly showing that:

  • roadside NO2 concentrations are static or even increasing in some locations;
  • vehicle emission standards (Euro standards) for diesel vehicles are having little impact on ‘real world’ NOx emissions, with new diesel vehicles showing little improvement in emissions over far older vehicles;  ( see link )
  • the new car market has undergone (and continues to undergo) a large shift from petrol to diesel, with diesel cars now making up more than half of new car sales; and
  • NO2 has increased as a percentage of NOx emissions from around 5% to nearly 25%.

Policy Exchange has estimated that diesel vehicles are responsible for some 91% of PM2.5 and 95% of NO2 road traffic exhaust emissions in London.  See:


This evidence means that it is unrealistic to assume a downwards trend in NOx emissions and associated NO2 concentrations to provide ‘headroom’ for increased emissions from airport expansion.  Even if the forthcoming Euro 6/VI standard successfully addresses the problems of ‘real world’ diesel emissions it will be many years before this has an appreciable impact on emissions from the UK’s vehicle fleet as a whole.

The Government blames the European engine emission standards for its failure to comply with NO2 limit values.  But: Euro standards never set limits on NO2; and successive Governments have incentivised the purchase of diesel vehicles when they knew doing so would cause more problems than petrol and after they knew the proportion of NO2 as a fraction of NOx emissions was rising.  Successive Governments have failed to mitigate or adapt to this public health crisis.

The WHO has recently classified diesel exhaust as carcinogenic for humans.

…… and it continues …………. at





BBC’s Bang Goes the Theory take on air pollution

By Angela Stegner

May 4, 2013 (Client Earth blog)

With an estimated 29,000 premature deaths from air pollution every year in the UK, it is second only to killer number one – smoking. However, air pollution is still too easily ignored because it is pretty much invisible nowadays – in comparison to the foggy pea-souper of the 50s. Now the most recent episode of the BBC’s Bang Goes the Theory series has made the dangers of air pollution visible – and really brought home the facts. Watch it while it’s still available online for another couple of days. Here is a little summary to preserve it for the afterworld.

On average, every one of us breathes in a total of 14 cubic metres (14,000 litres) of air every day. Therefore the health effects of any tiny amount of pollutants such as toxic nitrogen dioxide and dangerous particulate matter – basically soot particles, or particles of carbon – breathed in regularly, even if only in short bursts every day, add up over time (nicely demonstrated at 3:55).

Mobile pollution monitors can show us exactly how much pollution we breathe in. They can measure tiny dust particles of lower than 2.5 microns floating in the air – more than 10 times smaller than what we can see with our eyes. A monitoring test with commuters in Birmingham was particularly shocking in that it showed that all modes of commuting – whether biking, driving the car or taking the train – expose us to considerable pollution levels close to the WHO global guideline limit (an average of no more than 25 micrograms per cubic metre anytime during the day).

As a tip for the daily commute, cycling in green areas rather than along road traffic can reduce exposure to pollution by an impressive 30 to 60%. Car drivers are recommended to avoid peak hour traffic, which can reduce air pollutant exposure by 15 to 30%.

I wasn’t aware of how instantly air pollution actually affects our health, not only the lung and respiratory system, but also the cardiovascular system. A test showed that in the matter of an hour, blood vessel functions become impaired, arteries stiffen and stress within the blood vessels increases, all over time leading to a greater risk of heart attacks.

The biggest contributors to air pollution are clearly diesel powered vehicles.

Their engines give off at least twice the amount of nitrogen dioxide and 10 to 20 times more soot than cars with petrol engines. This is due to the properties of the fuel itself.

An explosive experiment in the programme visualised the different inflammability of the two fuels. Petrol vaporises readily and burns “cleaner”, that is without soot, because it burns completely. Diesel however does not vaporise readily, so the fuel is injected into the air, basically as fine mist, to make it flammable – there is no time for the diesel to burn completely, so a visible proportion of it reduces down to soot. Unfortunately, filters which are designed and fitted to trap the soot are not able to catch all particles in the diesel exhaust.

There are many different UK schemes to clean up the air, such as those to give up the car for a day and to encourage cycling. Scientists come up with many creative ways of cleaning up the air, such as through clothes made “active” with the help of an invisible coating made of nanoparticles of titanium dioxide – which could be sprayed on, delivered in washing powder or dry-cleaning. Professor Tony Ryan from the University of Sheffield claims that if half a million people in Sheffield wore treated jeans, the NO2 level would get the city close to the EU limit of 40 micrograms per cubic metre. Another attempt to clean up the air was to stick pollutants to the roads in London, using a dust suppressant, which has however been deemed ineffective.

In order to noticeably cut down pollution across the UK, a far more comprehensive approach to air pollution control is required. Most importantly, there must be incentive for fewer vehicles on UK roads – especially diesel, which is carcinogenic.

Cleaner cars, more people walking and using bikes and better public transport are all essential. In Berlin for example, the introduction of much stricter environmental zones (i.e. low emission zones) has lead to a drop of diesel soot by over 60% in the last four years. This has statistically already saved 500 lives per year.

Clearly some drastic decisions will need to be taken in the UK in order to reduce the number of cars on the roads, the most effective of which would be to have stricter low emission zones in the cities. This will be necessary in order to achieve compliance with EU levels. ClientEarth have recently taken this issue through the courts, to try to force the government to take meaningful action. The Supreme Court this week took a strong stand, formally declaring that the UK Government had failed in its duty to protect people from the significant health impacts of air pollution.





Diesel exhaust can cause cancer, World Health Organization says

June 15, 2012  ( Los Angeles Times)

Diesel engines power commerce and transportation around the world, but the exhaust they produce can prove deadly. The World Health Organization (WHO) announced on Tuesday that it now classifies diesel exhaust as a cause of cancer. While major advances in technology have helped clean up some diesel pollution in the United States, the findings could have serious implications for developing countries still relying on dirty diesel power.

Following a week-long meeting of experts, the WHO’s International Agency for Research on Cancer concluded there was sufficient evidence that diesel exhaust can cause lung cancer, and noted it may also increase the risk of bladder cancer. Gasoline exhaust remains classified as a “possible” carcinogen, a WHO status that has not changed since a 1989 evaluation.

and it continues …… at




From the American Cancer Society

What expert agencies say on diesel exhaust:

Several national and international agencies study substances in the environment to determine if they can cause cancer. The American Cancer Society looks to these organizations to evaluate the risks based on evidence from laboratory, animal, and human research studies.

Some of these expert agencies have classified diesel exhaust as to whether it can cause cancer, based largely on the possible link to lung cancer.

The International Agency for Research on Cancer (IARC) is part of the World Health Organization (WHO). Its major goal is to identify causes of cancer. IARC classifies diesel engine exhaust as “carcinogenic to humans,” based on sufficient evidence that it is linked to an increased risk of lung cancer, as well as limited evidence linking it to an increased risk of bladder cancer.

The National Toxicology Program (NTP) is formed from parts of several different US government agencies, including the National Institutes of Health (NIH), the Centers for Disease Control and Prevention (CDC), and the Food and Drug Administration (FDA). The NTP has classified exposure to diesel exhaust particulates as “reasonably anticipated to be a human carcinogen,” based on limited evidence from studies in humans and supporting evidence from lab studies.

The US Environmental Protection Agency (EPA) maintains the Integrated Risk Information System (IRIS), an electronic database that contains information on human health effects from exposure to various substances in the environment. The EPA classifies diesel exhaust as “likely to be carcinogenic to humans.”

The National Institute for Occupational Safety and Health (NIOSH) is part of the CDC that studies exposures in the workplace. NIOSH has determined that diesel exhaust is a “potential occupational carcinogen.”






Reducing exhaust emissions of nitrogen oxides (and particles) from diesel vehicles

3.4.2013  (Clean Air in London)

 Includes this statement:

“Government policy deliberately encouraged people to purchase diesel fuelled cars despite it being known from the outset that these vehicles would have higher emissions of NOx and PM10 than their petrol equivalents. Evidence has pointed for many years towards NOx emissions from diesel vehicles being higher in the real world than expected. Successive Governments did little to investigate the problem and continued with tax policies that encouraged the adoption of diesel cars. Worse, Governments have failed even to establish a testing regime that ensures that basic engine and emission control equipment is operating effectively.”

(19 pages)




Are buyers rethinking petrol cars? 

Tuesday 9th April, 2013.

The Green Piece Column.


…… While the AA reports that sales of petrol have fallen in the last five years, driven by a big consumer switch to diesel cars in recent years (see story), there is evidence to suggest that the perhaps buyers are thinking of switching back to dependable old petrol models.

……… But while we worry about the impact on more diesels on the road, there are signs that petrol models are showing signs of recovery, even in the new car market, as private registrations pick up.

The latest figures from SMMT show …….  petrols outperformed diesels, taking 51.2% of the market last month, as the new registration plate came out for the year. The same was true of February, when petrols accounted for 50.3%of sales. Prior to that, it’s been a diesel dominated scene for the past couple of years.

…….. There is something else that should mean that diesels have hit their peak and might now start to decline – Euro 6 emission standards. With stricter emissions standards coming into force from 2015 and even tighter Euro 7 emission standards already being planned, there will come a point when the extra cost needed to make diesels meet these standards will make their higher efficiency not worth paying for, especially as petrol improve their economy too.