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Category: Solutions

PHE Review of interventions to improve outdoor air quality and public health – Key Quotes

Public Health England published a very important report on the evidence, feasibility and effectiveness of measures to improve outdoor air quality. This helps government bodies focus their resources on measures that are actually beneficial and value for money. I’m still absorbing the report but in a first reading, I found many key quotes that I think are worth sharing. I skipped the sections on industrial and agricultural measures since they are less relevant to Portsmouth. The report confirms much of what we have been saying in #LetPompeyBreathe for some time.

P.S. A motion to declare a climate emergency in Portsmouth is going to be debated 19th March. Includes pledge to achieve net zero carbon emissions in the Portsmouth by 2030 – this could have a drastic impact on air quality. Demonstration in support by XRPortsmouth at 11am. See item 16a in the agenda.

General principles, background

“Neighbouring authorities therefore need to work together, especially on interventions that apply to defined spatial areas, such as clean air zones.”

“It is better to reduce air pollution at source that to mitigate the consequences.” “Prioritising interventions that prevent or reduce emissions over those that address pollution once it has occurred.”

“Improving air quality can go hand in hand with economic growth. A common misconception is that air pollution is a necessary consequence of economic prosperity, whereas a clean environment is increasingly understood to support, rather than hinder, economic growth.”

“those whose livelihoods depend on driving but who do not have access to or the resources for cleaner vehicles may need particular support because some of the most effective interventions target road vehicle emissions. Without such support, action on air quality may have the perverse impact of increasing inequalities.”

“Systematically evaluating all interventions. Evaluation should be embedded in the design and costing of all future interventions, from their outset, to systematically gather evidence to inform best practice in the future.”

“A joined-up spatial planning and transport strategy is one of the most effective ways of increasing public transport use and active travel and reducing emissions from existing vehicles over time – some local authorities have successfully used workplace or other levies to fund improvement and use of public transport. Spatial planning can be used to reduce the need for vehicle use by design, and has a wider role in reducing emissions from buildings through energy-efficiency measures and use of renewable energy technologies. Promising local interventions that can help reduce demand for more polluting forms of transport are associated with use of public transport and active travel and include: subsidising public transport, designating new and priority bus measures, new tram and taxi schemes, providing school buses, providing infrastructure to enable walking and cycling, and promoting walking and cycling, which provide significant health benefits associated with physical exercise.”

‘This report proposes the adoption of a “net health gain” principle in any new policy or work programme which affects air pollution. If this is adopted, then any new development or proposal for change to existing developments will intend to deliver an overall benefit to people’s public health.’

“Children are particulary vulnerable to the effects of air pollution. […] We therefore recommend taking a particularly focused approach on reducing the impact of air pollution on children.”

“Those with lower socioeconomic status and those from ethnic minorities can be disproportionately exposed to environmental hazards, including proximity to industrial facilities, hazardous waste sites, air pollution, noise and occupational exposures (13). […] As it requires actions across social classes to reduce the gap between them, this includes measures to promote changes among those who are wealthier to reduce their impacts, especially if they affect the poorest or most vulnerable groups or areas.”

“During the course of 2 recorded episodes of poor air quality in March-April 2014, and for 2 days afterwards, there were statistically significant increases in the proportion of daily telephone calls to NHS 111 for difficulty breathing, daily consultation rates for GP in-hours for severe asthma and wheeze or breathlessness, and in the proportion of GP out-of-hours consultations for difficulty breathing or wheeze or asthma and attendances at sentinel emergency departments (16).”

Fraction of mortality attributable to particulate air pollution 2017, South east – 5.6%

Vehicle/fuel interventions

“Use of taxation is one of the most cost-effective measures and typically straightforward as it is implemented within an existing system. The literature is clear that any pricing mechanism scheme, whether it is a national tax duty or local road toll, should be designed with care as the unintended social inequality impacts of increased cost of transport affects the most deprived in society (51).”

“Very effective interventions for enhancing public health were road pricing measures, particularly in the case of low and integrated fares (for more than one public transport mode) which facilitate greater public transport use and help reduce social exclusion, and congestion and parking charges, which can help reduce car use (68).

“For road transport, interventions that aim to reduce the use of polluting forms of transport, such as national road pricing, increased fuel duty and LEZs, can be effective at reducing traffic emissions. This is mainly at local level, but they can also have national benefits if implemented at many areas across the country. However, such measures can be unpopular because of their restrictive nature, if not handled sensitively with considerable prior consultation and engagement. […] The promotion of walking and cycling, as well as subsidising public transport, have the greatest overall health benefits, providing flexibility to select routes away from heavily trafficked main roads whilst active travelling. Furthermore, these transport modes increase physical activity that leads to multiple health co-benefits. They also have potential to improve health inequalities, as they can be made equally accessible to all population categories.”

Measures found to be effective for improving air quality locally (Table 16 & 17):

  • Promote walking and cycling (mainly for potential for public health co- benefits rather than air quality)
  • National road pricing
  • Increase fuel duty/target at diesels
  • Promote abatement retrofit

Planning

“the interventions with the highest potential to be effective both at national but mainly at local level are related to traffic. Driving restrictions produced the largest scale and most consistent reductions in air pollution levels for all the interventions, the effectiveness strength was low, and the uncertainty range was high, with only 1 exception: driving restrictions. However, the paucity of evidence of effectiveness should not be confused with or assumed to be evidence of ineffectiveness […] measures, such as Low Emission Zone (LEZ) and road pricing, produced reductions in traffic, but not necessarily great improvements in air quality, perhaps due to localisation of emissions, for example by displacement. LEZ are potentially effective at reducing air pollutant levels (more effective for particulate matter, PM 10 than for nitrogen dioxide, NO 2 ) in cities. […] green infrastructure is potentially effective not only to improve air quality related public health outcomes, but also to improve health inequalities in urban areas and promote our health and well-being

“From the interventions identified for spatial/transport planning, driving restrictions produced the largest scale and most consistent reductions in air pollution levels at a city level, and seem to be an effective way to both reduce air pollution and improve public health. However, these restrictions may require changes in the political thinking and practice in the UK, and their longer-term effectiveness is not well evidenced.”

“There is evidence that appropriately designed urban green infrastructure can improve air quality and reduce exposure to noise on a local scale but should not be used in isolation to address air pollution (121).”

“Although the implementation of LEZs seems to be effective at reducing PM 10 levels, there is less evidence that LEZs are effective at reducing NOx. […] Although road pricing (congestion charge) is an effective mean of controlling traffic and reducing emissions (eg, in Stockholm), the impact on air quality is not always clear. […] They are expected to work best if combined with interventions that incentivise the use of both heavy and light duty vehicles with the most recent Euro 6 standards, which have a greater impact than earlier emission standards. The practical feasibility of this intervention should not be an issue, as it is mainly a matter of political will.”

“Health benefits from speed limits that slow down traffic mainly derive from the need to prevent fatalities and serious injuries to motorists, cyclists and pedestrians, and promote active travel. However, this measure does not necessarily result in significant decreases in ambient air pollution levels, even within the intervention zone.”

“Based on the results from ex-ante health impact assessments, the implementation of multiple traffic-related and infrastructure interventions is more likely to produce benefits for air quality and population than single interventions. The most effective combinations of these interventions depend on the issues and contexts of each local area.”

“The evidence from this rapid evidence assessment suggested that planning interventions are crucial for improving air quality and reducing population exposure to air pollution. The interventions with the highest potential to be effective both at national but mainly at local scale are related to traffic.”

“For some interventions, public health ‘co-benefits’ outweigh benefits of reduction of exposure to air pollution. […] there is a wealth of high-quality evidence showing that investing in infrastructure to support walking and cycling can increase physical activity, leading to multiple public health benefits, such as improved cardiovascular outcomes and improved weight status among children, adults and older adults (137). These are convincing reasons to promote these interventions.”

Measures found to be effective for improving air quality locally (Table 18):

  • Encouraging walking and cycling (for its health benefits rather than just for air quality)
  • Driving restriction (plus it has stronger evidence than most measures)
  • Co-implementation of various measures

Behaviour changes

“Little evidence was identified of behavioural interventions that promote alternative methods of transport as having a direct impact on air pollution or health outcomes. However, they should not be discounted, as there is a wealth of evidence showing that removing vehicles from the road can reduce emissions. There is also strong evidence for the health benefits of physical activity associated with active travel, such as walking and cycling. Raising awareness in itself is not enough to effect change: it must be done in conjunction with other behavioural and non-behavioural interventions.”

“The rapid evidence assessment found no substantive evidence of economic costs and benefits associated with behavioural interventions in any of the papers identified.” “The rapid evidence assessment of behavioural interventions found little direct evidence of public health benefits from any individual intervention or group of interventions. To achieve significant changes in behaviour (and associated reductions in emissions), a wide range of soft and hard measures need to be combined to maximise the effectiveness of the overall package of interventions.”

Measures found to be effective for improving air quality locally (Table 22):

  • No highly effective measures found, although several potentially effective measures identified

Discussion

“Strategies that deliver the highest public health benefit relative to transport are actions or interventions aimed at reducing the use of polluting forms of transport, such as low emission zones and road pricing.”

Selected transport interventions’ evaluated public health impact (Figure 23):

  • Subsidising public transport (higher impact)
  • Promote abatement retrofit
  • National road pricing
  • Provision of school buses
  • Promote walking and cycling
  • Promotion of low emission zones
  • Increase fuel duty/target at diesels (lower impact)

“Planning policy focuses on ensuring air quality standards are achieved, rather than reducing emissions to as low as possible.”

Figure 24: Selected planning interventions’ evaluated public health impact:

  • Co-implementation of various measures (Planning) (higher impact)
  • Green infrastructure – urban vegetation
  • Driving restriction
  • Road pricing/Congestion charge
  • Encouraging walking and cycling (lower impact)

Figure 28: Selected behavioural interventions’ evaluated public health impact

  • Exposure reduction programmes (higher impact)
  • Public engagement
  • Eco-driver training
  • Investment in public transport (Encouraging)
  • Air quality messages/alerts/indices
  • No idling campaigns (lower impact)

Impact of Charging Clean Air Zones: Saviour of Cities or a Red Herring?

Given the lack of progress by Portsmouth City Council in addressing air pollution, I began wondering how a Clean Air Zone (CAZ) might be implemented in the city and what effect it might have. There are several types of Clean Air Zones but most interest has been in charging older vehicles that enter busy areas. Since less polluting vehicles attract lesser or no charges, this intended to encourage a shift to less polluting vehicles. This has an impact on residents and businesses that have to replace their vehicles. The revenue from charges is typically invested in sustainable transport.

Arguably, this approach does not go far enough. As even the Portsmouth transport cabinet member says, “We simply have too many vehicles in this city“. Punitive prices could be used to quickly force a change in transport usage, but this is hardly going to be popular.

It is important to remember that our current transport situation is unsustainable. A significant chunk of pollution is created by diesel cars. To comply with air quality law, these vehicles need to be replaced. The question is how we go about doing that in a fair manner considering many people can barely afford the essentials. Studies have found that the economic benefits to health may outweigh the cost of updating vehicles. The necessity to act has already been established in the High Court and for the benefit of public health.

Predicting the impact of CAZ is complicated because people may switch to other forms of transport or cancel their trip completely. Local and national government often use computer models to try and predict the impact on air quality. Alternatively, we can look at how other cities have implemented CAZs however other air quality initiatives and different transport usages complicate the picture. DEFRA has presented a rosy picture of the effectiveness of CAZ. According to a 2017 DEFRA technical report:

From the options considered, establishing Clean Air Zones (CAZs) is the most effective way to bring the UK into compliance with NO2 concentration levels in the shortest possible time (Table Ex.3). […] CAZs are predicted to have their greatest impact on air quality in the year of implementation […], leading to an 18% reduction in NO2 concentrations. […] These projections have been produced from the SL-PCM model.

Birmingham has been told to implement a CAZ. Their projections are slightly less optimistic with a 9% NO2 reduction for a CAZ covering Buses, coaches, taxis, HGVs and LGVs (in jargon, a “class C-CAZ”), up to a 13% NO2 reduction in a CAZ that also covers private cars (“a class D-CAZ”). These are smaller but still significant improvements. However, these predictions don’t seem to match the experience cities that have already implemented similar zones. According to other DEFRA reports, CAZ projects around Europe have been effective in reducing particulate pollution but have a limited impact on NO2 levels. Germany has been most successful in reducing NO2 pollution using CAZ probably because their schemes include private cars. Outside of Germany, most CAZ schemes ignore private cars and have generally seen no NO2 improvements. Lisbon is also an exception which has reduced NO2 by 1-7% because they including private cars in their CAZ scheme. According to a review of CAZ schemes:

In German cities reductions in annual mean PM10 and NO2 concentrations up to 7% and 4% respectively due to the implementation of an LEZ have been reported. […] In other countries the picture is much more mixed with no effects [on NO2] generally being observed. This may be explained by the German LEZs restricting passenger cars, particularly diesel cars as well as HDVs.[Heavy Duty Vehicles …] Many of the studies, however, have used simple statistical methods that have not taken sufficient account of the confounding factors that affect urban air quality.

This finding is repeated in the London Low Emission Zone, which did not include cars in their scheme and have seen no appreciable drop in NO2. (London has recently started charging older vehicles which might help.) Similar results were seen in the Netherlands. A study of CAZ in Beijing, which only included light duty goods vehicles, predicted a fairly minor drop of 2% in NO2 levels.

In summary, Clean Air Zones are only effective in tackling NO2 levels if private cars are included in the charging scheme. This targets diesel cars, which are a major source of pollution in cities. Even if private cars are included, the impact of a charging CAZ may be less than predicted by current modelling. This might be due to different vehicle usage in the UK compared to European cities, but I doubt that is significant enough to account for the discrepancy. Portsmouth needs about a 10% drop in NO2 to come into legal compliance.

Given that we need a strong tool to improve air quality, we can look at cities that have banned older diesel vehicles. Older diesel bans are being introduced in some London neighbourhoods, as well as several German cities. We should watch their progress closely to see if improvements can be achieved elsewhere.

Isle of Wight Objects to Southampton Charging Clean Air Zone

Southampton is planning to introduce a charging Clean Air Zone (CAZ) in an effort to reduce air pollution. This is generally accepted to be the fastest and most reliable method to improve air quality. However, the Isle of Wight council has objected to the plans saying it would badly affect manufacturing and tourism.

This is a tricky problem because Southampton is one of the main routes to the Isle of Wight. If the charges go into effect, the cost will eventually be imposed on consumers and tourists. However, the people of Southampton (and Portsmouth) are exposed to traffic fumes, mainly from diesel cars and HGVs, of people traveling to the ferry terminal. Shipping itself also worsens air pollution, although Wightlink has just introduced a hybrid power ferry for the Portsmouth route.

I think what is important to remember is that the status quo is not sustainable. We can’t have tens of thousands of people (UK wide) dying each year from preventable causes. Yes, jobs may be lost but people will shop and do leisure activities more locally, which will create different jobs.

Also, the money generated from the CAZ should be (will be?) used to subsidize public transport, which will make getting around easier and more sustainable.

A problem for Portsmouth residents is that the most polluting vehicles will be threatened with the biggest charges, and be most incentivized to find another route. The most obvious route at this time is via Portsmouth. So we might be seeing the quantity of the most polluting vehicles increase in Portsmouth because of the Southampton clean air zone! This effect is called “displacement”. What we need is a charging CAZ in Portsmouth as well, to balance the scales.

In the long term, ferry ports constructed within major cities might need to be relocated (or existing ferries need to be low emission and only take cargo/passengers moved sustainably).

PS. 19th September, I’m going to the second air quality steering group at PCC.

Anti-Idling Signs To Reduce Pollution Outside Schools

Tracey designed these rather awesome anti-idling signs for use outside schools. This is to encourage parents doing their school run to switch off their engines while waiting. This should reduce pollution for children (and adults!) entering and leaving the school gates.

High quality PDF file: LPBidlingfreezoneV2

While “Stationary idling is an offence under section 42 of the Road Traffic Act 1988″, it is a common habit and it is difficult to inform drivers about this issue. The act enforces rule 123 of the Highway Code “You MUST NOT leave a parked vehicle unattended with the engine running or leave a vehicle engine running unnecessarily while that vehicle is stationary on a public road. Generally, if the vehicle is stationary and is likely to remain so for more than a couple of minutes, you should apply the parking brake and switch off the engine to reduce emissions and noise pollution. However it is permissible to leave the engine running if the vehicle is stationary in traffic or for diagnosing faults.”