T&E highlights air pollution problem of particulates from petrol vehicles without correct filters

One of the most significant environmental problems of Heathrow, in relation to wanting to add a 3rd runway, is its ability to keep air pollution on local roads down to legal limits. We hear most about Nitrogen Dioxide (NO2) but there is also significant particulate pollution. The tiny particles, especially the smallest (PM2.5) can penetrate deep in to the lung and cause damage. Heathrow has local air pollution monitors, and regularly limits for PM10 and PM2.5 are breached. A recent report, by Ricardo, for the Heathrow area in 2015, said at the LHR2, Green Gates and Harlington sites 3 exceedances were recorded. At another site, Oaks Road, registered 5 exceedances. The AQS  (Air Quality Strategy) objective is a daily mean limit value of 50 µg m-3 for PM10 should not to be exceeded.  Now clean transport campaigners, Transport & Environment, say we could be on the verge of a “petrolgate” scandal, not unlike the “dieselgate” one, due to inadequate filters to prevent the emission of particulates from petrol cars. T&E say they have obtained documents showing that governments and car makers are delaying ensuring petrol cars have these €25 filters (most diesel cars have them).  Governments are using theoretical particle emission, rather than the higher real world ones. T&E says the car industry is lobbying to be allowed to overshoot particle limits, and not to have to install filters.

Heathrow is one of the UK’s air pollution hotspots. In 2012, it breached safety thresholds for nitrogen dioxide and particulate matter air content at several different locations – and times – according to the airport’s own measurements.


The Borough of Hillingdon keeps air pollution data for a number of sites close to Heathrow, showing dates and levels. These can be seen here.

There are many incidents where levels of PM2.5 and PM10 are relatively high.

A ‘Petrolgate’ scandal in the making

November 10th 2016

(Transport & Environment. T&E)

Governments and carmakers are paving the way for a ‘Petrolgate’ scandal. That warning came from T&E after it obtained documents showing some governments and the car industry are trying to weaken the proposed new EU legislation on measuring particulate emissions from cars in real-world tests.

Carmakers are trying to avoid having to pay €25 for a gasoline particulate filter, despite the new petrol fleet endangering human health.

Emissions of particulate matter, in particular micro-particles of soot, are harmful to human health. Up to now, discussion about particulate emissions has focused on diesel engines, where the filter has been mandatory for all new vehicles since 2011.

But now the focus has moved to petrol because of a new generation of gasoline direct-injection (GDI) engines that pump out micro-particles that can get into the bloodstream via the lungs and whose share is rapidly increasing. A particulate filter costing €25 per car is already available and can reduce emissions by 100 times, but records of negotiations and briefings obtained by T&E show the car industry is lobbying to allow them to overshoot the particulate limits for petrol cars by 300%, so they would not have to fit the filter.

The documents also record that some governments, including those of Spain and Sweden, want to delay the new tests’ introduction by one year, while no government is opposing the flexibility to exceed the limit that the Commission has proposed by 50%.

T&E’s clean vehicles engineer Florent Grelier said: ‘This is a Petrolgate scandal in the making. The Commission was warned about the risks of new petrol engines three years ago. Now, because of the rigging of type approval tests, it is preparing legislation on emissions from real-world driving, but its already inadequate proposal is being further threatened by carmakers, and by governments friendly towards them. The Commission and governments need to stand firm to prevent hundreds of thousands of avoidable premature deaths.’

Harmful levels of air pollution cause around 500,000 premature deaths a year and are estimated to cost the EU economies around €1 trillion annually.

Discrepancies between emissions measured in tests and emissions on the road contributed to a legal judgement in London last week that found the British government’s air pollution strategy inadequate and illegal. ClientEarth, a legal NGO, won its case against the UK government, with the judge saying ministers used the well-known over-optimistic pollution modelling based on flawed laboratory testing of diesel vehicles rather than on emissions from real-world driving.




Report on 2015 on the Heathrow Airwatch website


Air Quality at Heathrow Airport 2015

Report for Heathrow Airport Ltd ED59405

By Ricardo Energy & Environment. Date 21/07/2016



Particulate Matter (PM) The AQS  (Air Quality Strategy) objective establishes a daily mean limit value of 50 µg m-3 for PM10, not to be exceeded more than 35 times a year, this limit was achieved at all sites for 2015. At LHR2, Green Gates and Harlington 3 exceedances were recorded. These sites have measured high concentrations of PM10 on 17th and 18th March and on 27th December. (2015)

Oaks Road has registered 5 exceedances: 17th and 18th March, 09th and 10th April, and 27th December.

These exceedances match with the exact days where some of the previously mentioned high pollution episodes were registered.

The origin of the high concentration peaks registered in March/April in all sites are the result of UK-wide pollution/trans-boundary episodes that have struck the UK during that particular period in time. Some high values of PM10 were also registered during October.

These episodes were not high enough to cause an exceedance, since they were all the values were below 50 µg m-3.

However, they have influenced the seasonal variation of this pollutant and their contribution should be acknowledged. At the moment, no AQS objective exists for PM2.5. An annual mean objective of 25 µg m-3 , as a nonmandatory target exists for 2020. The highest annual mean for this pollutant was registered at Oaks Road at 10 µg m-3 . All the other sites have registered average values of 9 µg m-3 , less than half of the average concentration target limit for 2020.


The diurnal patterns of concentrations of all pollutants were similar to those observed at other urban monitoring sites. Peak concentrations of NO, NO2, particulate matter and BC coincided with the morning and evening rush hour periods, and levels of ozone peaked in the afternoons.



Quarterly reports on Heathrow air quality.

These are produced by Heathrow Airwatch and go back several years.




Humans can be adversely affected by exposure to air pollutants in ambient air. In response, the European Union has developed an extensive body of legislation which establishes health based standards and objectives for a number of pollutants in air. These standards and objectives are summarised in the table below. These apply over differing periods of time because the observed health impacts associated with the various pollutants occur over different exposure times.

[ Part of the EU table is copied below (there is more at the link above)  ]

PollutantConcentrationAveraging periodLegal naturePermitted exceedences each year
Fine particles (PM2.5)25 µg/m3***1 yearTarget value entered into force 1.1.2010
Limit value enters into force 1.1.2015


Sulphur dioxide (SO2)350 µg/m31 hourLimit value entered into force 1.1.2005


125 µg/m324 hoursLimit value entered into force 1.1.2005


Nitrogen dioxide (NO2)200 µg/m31 hourLimit value entered into force 1.1.2010


40 µg/m31 yearLimit value entered into force 1.1.2010*


PM1050 µg/m324 hoursLimit value entered into force 1.1.2005**


40 µg/m31 yearLimit value entered into force 1.1.2005**


Lead (Pb)0.5 µg/m31 yearLimit value entered into force 1.1.2005 (or 1.1.2010 in the immediate vicinity of specific, notified industrial sources; and a 1.0 µg/m3 limit value applied from 1.1.2005 to 31.12.2009)


Carbon monoxide (CO)10 mg/m3Maximum daily 8 hour meanLimit value entered into force 1.1.2005


Benzene5 µg/m31 yearLimit value entered into force 1.1.2010**




The new Directive is introducing additional PM2.5 objectives targetting the exposure of the population to fine particles. These objectives are set at the national level and are based on the average exposure indicator (AEI).

AEI is determined as a 3-year running annual mean PM2.5 concentration averaged over the selected monitoring stations in agglomerations and larger urban areas, set in urban background locations to best assess the PM2.5 exposure to the general population.

TitleMetricAveraging periodLegal naturePermitted exceedences each year
Exposure concentration obligation
20 µg/m3
Based on 3 year averageLegally binding in 2015 (years 2013,2014,2015)n/a
Exposure reduction target

Percentage reduction*
+ all measures to reach 18 µg/m3

Based on 3 year average

Reduction to be attained where possible in 2020, determined on the basis of the value of exposure indicator in 2010


* Depending on the value of AEI in 2010, a percentage reduction requirement ( 0,10,15, or 20%) is set in the Directive. If AEI in 2010 is assessed to be over 22 µg/m3, all appropriate measures need to be taken to achieve 18 µg/m3 by 2020.


Heathrow AirWatch


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