The Institute of Air Quality Management (IAQM), the professional body for air quality professionals, has published a Position Statement on Mitigation of Development Air Quality Impacts.

The IAQM Position Statement explains that, where significant operational adverse effects are predicted due to non-point sources, i.e. roads, consultants face difficulties when recommending mitigation solutions that would reduce the impact to an acceptable level.  The difficulty arises due to the limited quantitative evidence on the efficacy of the mitigation options available.

There is limited planning guidance available on the choice of, or the efficacy of, mitigation options for general development purposes.  Therefore, the IAQM has taken a position that an appropriate mitigation solution should be principle-led rather than specified by detailed prescription.  The IAQM recommend using the following basic hierarchy of principles as the basis for mitigating the operational air quality impacts:

I.  Preference should be given to preventing or avoiding exposure/impacts to the pollutant in the first place by eliminating or isolating potential sources or by replacing sources or activities with alternatives. This is usually best achieved through taking air quality considerations into account at the development scheme design stage.

II.  Reduction and minimisation of exposure/impacts should next be considered, once all options for prevention/avoidance have been implemented so far as is reasonably practicable (both technically and economically). To achieve this reduction/minimisation, preference should be given first to:

a.  mitigation measures that act on the source; before

b.  mitigation measures that act on the pathway; which in turn should take preference over

c.  mitigation measures at or close to the point of receptor exposure, all subject to the efficacy, cost practicability of the available solutions. In each case, measures that are designed or engineered to operate passively are preferred to active measures that require continual intervention, management or a change in people’s behaviours.

III.  Off-setting a new development’s air quality impact by proportionately contributing to air quality improvements elsewhere (including those identified in air quality action plans and low emission strategies) should only be considered once the solutions for preventing/avoiding, and then for reducing/minimising, impacts have been exhausted.

The full Position Statement is available for download here.

A White Paper by the International Council on Clean Transportation (ICCT) has presented evidence that real world emissions of NOx from diesel cars are much higher than the Euro 6 emission limit.  On average, on-road emission levels of NOx were estimated at 7 times the certified emission limit for Euro 6 vehicles.  Only one of 15 cars tested achieved the Euro 6 limit, with the worst performing car emitting NOx at over 20 times above the Euro 6 emission limit of 80 mg/km.

High NOx emissions occurred across manufacturers, whatever abatement technologies were used in the vehicles, and during both demanding and normal driving conditions.  The vehicles on-board NOx abatement control systems are thought to be optimized to perform well during the current type-approval test procedure for Euro 6; however, these emissions controls do not provide acceptable on-road performance.

Portable emissions measurement systems (PEMS) of the sort used in the study will be used for the type-approval of passenger cars in the EU from 2017; however, cars that do not achieve the Euro 6 emission limit in the real world will continue to be sold up to this date.  This leads the authors of the report to warn that “unless sound regulatory action is taken, the gradual introduction of these vehicles into the fleets will have a disproportionate negative impact upon air quality, especially in Europe where the popularity of diesel cars remains high.”

The ongoing issue of real world vehicle emissions from diesel cars being much higher than the Euro emission limits shows that little progress has been made since 2011, when a report suggested that the disparity between historical monitoring data and the projected background NOx and NO₂ concentrations published by Defra was due to the on-road emissions performance of diesel vehicles falling below that required by the Euro standards.

It is essential that the car manufacturing industry are prevented from weakening the proposed PEMS tests, and to ensure that the tests are robust and representative of real-world driving, especially given the interest in extending low emission zones as a means of improving air quality.  After all, a low emissions zone that encourages the use of vehicles that are just as polluting as those that the scheme is trying to keep out will be a costly white elephant.

52% of people consider air pollution in the UK as the main environmental issue that they are worried about. The results are from an Attitudes to the Environment survey undertaken by the European Union in April/May 2014.  The survey also shows that 54% of people in the UK personally consider protecting the environment as very important.  However, only 32% of people in the UK agree that environmental issues have a direct effect on their daily life, despite the fact that particulate pollution has no safe threshold, and contributes to almost 30,000 deaths per year in the UK.

The sensitivity of the UK population to air pollution needs to be considered by developers and planners, as planning applications where air quality is an issue are likely to come under close scrutiny from the local population.  It is essential that air quality assessments submitted in support of planning applications have been completed by competent, qualified air quality consultants.

The Greater London Authority (GLA) has now published Supplementary Planning Guidance (SPG) on Sustainable Design and Construction.  The SPG sets out how development proposals can be ‘air quality neutral’, as required under Policy 7.14 of The London Plan.

All major developments in London, defined in The London Plan as residential use with over 10 dwellings and other use with floor space ≥1,000 m², will now need to be assessed against emissions benchmarks for buildings and transport.  Developments with emissions of NOx and PM₁₀ below these benchmarks will be considered to avoid increasing concentrations across London as a whole, and will be ‘air quality neutral’.

Developments that are not ‘air quality neutral’ and cannot reduce emissions further through on-site mitigation will be required to work with local planning authorities to off-set emissions through off-site measures, either provided directly by the developer, or as part of an existing scheme to improve air quality.  The local planning authority will secure these measures through conditions or s106 agreements.

The SPG also introduces emissions limits for combustion plant, i.e. gas boilers, biomass boilers and combined heat and power plant (CHP).  Any development that includes decentralised energy provision will now need to meet these emissions standards.

The requirements for ‘air quality neutral’ and combustion plant emissions limits are in addition to requirements for air quality assessment.  Air Quality Assessments Ltd are able to offer a full air quality assessment service, and will include ‘air quality neutral’ assessments for all developments in London.

The environmental law group ClientEarth has published a guide to EU air quality law called the The Clean Air Handbook.  The purpose of the handbook is to provide individuals, groups and lawyers with a straightforward, easy to use guide to EU air quality.  The guide gives an overview of EU air quality legislation and provides practical tips on how relevant aspects of EU law can be used by those concerned about air quality in the UK.

The University of Sheffield has unveiled a 20 m high ‘catalytic poem’ mounted on a wall at the university, overlooking the A57.  The poem, In Praise of Air by Simon Armitage, has been printed on a giant banner coated with photocatalytic titanium dioxide (TiO₂).

Light shining on the photocatalyst excites electrons in the TiO₂ molecule, which then react with oxygen in the air to form oxygen free radicals.  The highly reactive free radicals then react with water in the air to form peroxide, which then oxidise pollutants, forming harmless by products.  Nitrogen oxides (NOx) are converted to soluble nitrate, and volatile organic compounds (VOCs) are converted into fatty acids and soaps.

One square meter of treated material can remove around 2g of NOx per day, with the banner itself removing NOx equivalent to that released by a bus, or around 20 cars per day.  The daily average traffic flow on the A57 adjacent to the banner was 14,789 in 2012; therefore, the poster will remove the NOx from just 0.001% of the traffic flow.

Although this project has highlighted the issue of poor air quality in the UK, it is unlikely that the use of catalytic surfaces will improve air quality, and trials carried out in the UK investigating the impact of NOx reducing paint have been inconclusive (LAQM Helpdesk, 2010).  The technology works; however, given the large volumes of air that need to be cleaned, it is unlikely to be effective in reducing ambient concentrations of air pollutants.  The only way to clean up the air is to not pollute in the first place.

In Praise of Air by Simon Armitage.

I write in praise of air.  I was six or five

when a conjurer opened my knotted fist

and I held in my palm the whole of the sky.

I’ve carried it with me ever since.

Let air be a major god, its being

and touch, its breast-milk always tilted

to the lips.  Both dragonfly and Boeing

dangle in its see-through nothingness…

Among the jumbled bric-a-brac I keep

a padlocked treasure-chest of empty space,

and on days when thoughts are fuddled with smog

or civilization crosses the street

with a white handkerchief over its mouth

and cars blow kisses to our lips from theirs

I turn the key, throw back the lid, breathe deep.

My first word, everyone’s  first word, was air.

Public Health England (PHE) has issued a report estimating mortality burdens associated with particulate air pollution for each local authority in the UK.  Particulates (PM₁₀ and PM_2.5, particles with a diameter of less than 10 µm and 2.5 µm respectively), can travel deep into the lungs, leading to short-term respiratory and cardiovascular health effects.  Long term exposure is associated with an increase in mortality risk.

In the UK, annual mean objectives for the protection of human health have been set at 40 µg/m³ for PM₁₀ and 25 µg/m³ for PM_2.5; however, there is no safe level below which no adverse health effects occur.

The PHE report focuses on the long-term effects of background PM_2.5 due to human activity, i.e. fuel combustion (vehicles, industry, power generation, etc.).  The report found that, in some parts of London, PM_2.5 pollution contributes to 8.3% of deaths in people aged over 25, while the estimate for Somerset is 4.4%.  The national estimate for the UK is that PM_2.5 pollution contributes to 5.3% of deaths, which is 28,969 deaths per year.