How to make the green belt productive - but keep it green

Walkers on Box Hill, in the North Downs. Most green belt doesn't look like this. Image: Getty.

England’s green belts have had, and continue to have, a major impact on town planning. The idea of a ring of countryside surrounding an urban area to prevent sprawl originated in the 1930s, spread to post-war London and was adopted nationally in 1955. Today, about 13% of England is green belt land

But what made sense in the 1950s seems outdated and rather stale now. A one-size-fits-all approach to tackling complex planning issues tends to create more problems than it solves. You don’t need a belt-shaped area of land to check urban sprawl; you don’t need to block all development to promote greener outcomes. Perhaps in the 21st century it is time to admit that green belts are no longer fit for purpose.

In theory, the idea of still has strong protection within the government’s planning framework. That document identifies five strategic functions for the green belt:

  • To check the unrestricted sprawl of large built-up areas;
  • To prevent neighbouring towns merging into one another;
  • To assist in safeguarding the countryside from encroachment;
  • To preserve the setting and special character of historic towns; and
  • To assist in urban regeneration, by encouraging the recycling of derelict and other urban land.

But green belts have been attacked for failing to meet these purposes by a range of vested interests, who've proposed a range of different ideas in response. The head of Persimmon housebuilders, for instance, has called for a relaxation of green belt controls to ease the housing crisis. The chancellor wants more imagination from local planning authorities in where houses are built – including possible incursions into the green belt. Even Natural England, the government body responsible for safeguarding England’s natural environment, has previously called for a major policy rethink

In any case green belt protection is potentially illusory. Greenfield sites, including green belt, are increasingly favoured by developers as they are cheaper to exploit than brownfield sites which have much higher transaction costs. Here economic growth priorities and national planning policy tend to push development pressures onto the urban fringe areas, rather than to more costly brownfield land.

There is clear evidence that while green belts have stopped urban expansion (at least, in some cities), they have resulted in unintended consequences: higher-density development at the urban fringe, including disconnected “edge cities”, and “leapfrogging” development over the green belt to undermine other areas of countryside.

Green belts have a presumption against development, and thus come with little incentive to be positively managed for environmental, community or economic purposes. This leads to degraded landscapes which, while having a valid planning function, produce limited benefit to communities and the environment – unless, of course, you are lucky enough to live in or next to one.

As with natural assets more generally, it's this lack of incentive for active management that is the greatest cause for concern. It's therefore time for a fundamental rethink of the green belt.

Beyond the belt

For one thing, the “belt” metaphor has had its day. We should define bespoke areas that are functional to local geography and the needs of the cities and towns concerned; so wedges, fingers, belts, bananas or whatever shapes may equally apply.

Rather than have green belts used for just major cities we should also create a more inclusive, ubiquitous and positive set of zoning policies, that apply to large towns and major settlements.

Rather than a impose a rigid presumption against development, we should aim for zones that encourage innovative uses that generate investment in environmental and community benefits in keeping with the principles of sustainable development.

Finally, rather than enabling politically convenient incursions into the green belt under the guise of sustainable urban extensions, local planning authorities should define these zones by considering the long-term development needs of their area looking 50 years into the future rather than the present 25 years.

Positive spaces

These principles lead me to propose the idea of “green investment zones”: new positive spaces to invest in. The urban fringe could be rejuvenated by, for example, community food-growing initiatives for health and recreation, or wetland creation for flood protection and biodiversity. A green investment zone would be flexible enough to incorporate whatever new initiative an entrepreneur might propose.

This would require local planning authorities to think strategically, and come up with bolder and longer term visions about the kind of town or city they want to create. The current 25-year planning lifecycle is not long enough.

Developers shouldn’t see these zones as automatic no-go areas. While housing should not normally be allowed in them, they should act as valuable green spaces that can help to protect new and existing housing development from floods and drought. They can provide local food growing areas. and spaces for play and recreation. They also can be used to protect our agriculture and, perhaps more controversially, for energy production (solar, anaerobic digestion or biomass) – neglected planning factors, all.

In this green belt debate we need to move out of the silo thinking. Separating housing, industry, transport, community, landscape and environment needs just leads to disintegrated development.

The green belt may no longer be fit for purpose – but it must not be allowed to become a developers’ charter for nothing more than the short-term pursuit of economic growth. We need to create a more equitable, environmentally-friendly and socially-responsible zoning tool. In that way, we could address current planning shortfalls, and promote a more positive image for planning. The Conversation

Alister Scott is Professor of Environment and Spatial Planning at Birmingham City University.

He has received funding from Research Councils UK, Defra, Scottish and Welsh Governments as part of the Rural Economy and Land Use Programme for work on the urban rural fringe. He has also received funding from Research Councils UK, Defra and the Welsh Government as part of the National Ecosystem Assessment Follow on Programme. The ideas in this article stem from these research projects but are personal views and do not reflect the views of other partners in the research.

This article was originally published on The Conversation. Read the original article.

 
 
 
 

How bad is the air pollution on the average subway network?

The New York Subway. Image: Getty.

Four more major Indian cities will soon have their own metro lines, the country’s government has announced. On the other side of the Himalayas, Shanghai is building its 14th subway line, set to open in 2020, adding 38.5 km and 32 stations to the world’s largest subway network. And New Yorkers can finally enjoy their Second Avenue Subway line after waiting for almost 100 years for it to arrive.

In Europe alone, commuters in more than 60 cities use rail subways. Internationally, more than 120m people commute by them every day. We count around 4.8m riders per day in London, 5.3m in Paris, 6.8m in Tokyo, 9.7m in Moscow and 10m in Beijing.

Subways are vital for commuting in crowded cities, something that will become more and more important over time – according to a United Nations 2014 report, half of the world’s population is now urban. They can also play a part in reducing outdoor air pollution in large metropolises by helping to reduce motor-vehicle use.

Large amounts of breathable particles (particulate matter, or PM) and nitrogen dioxide (NO2), produced in part by industrial emissions and road traffic, are responsible for shortening the lifespans of city dwellers. Public transportation systems such as subways have thus seemed like a solution to reduce air pollution in the urban environment.

But what is the air like that we breathe underground, on the rail platforms and inside trains?

Mixed air quality

Over the last decade, several pioneering studies have monitored subway air quality across a range of cities in Europe, Asia and the Americas. The database is incomplete, but is growing and is already valuable.

Subway, Tokyo, 2016. Image: Mildiou/Flickr/creative commons.

For example, comparing air quality on subway, bus, tram and walking journeys from the same origin to the same destination in Barcelona, revealed that subway air had higher levels of air pollution than in trams or walking in the street, but slightly lower than those in buses. Similar lower values for subway environments compared to other public transport modes have been demonstrated by studies in Hong Kong, Mexico City, Istanbul and Santiago de Chile.

Of wheels and brakes

Such differences have been attributed to different wheel materials and braking mechanisms, as well as to variations in ventilation and air conditioning systems, but may also relate to differences in measurement campaign protocols and choice of sampling sites.

Second Avenue Subway in the making, New York, 2013. Image: MTA Capital Construction/Rehema Trimiew/Wikimedia Commons.

Key factors influencing subway air pollution will include station depth, date of construction, type of ventilation (natural/air conditioning), types of brakes (electromagnetic or conventional brake pads) and wheels (rubber or steel) used on the trains, train frequency and more recently the presence or absence of platform screen-door systems.

In particular, much subway particulate matter is sourced from moving train parts such as wheels and brake pads, as well as from the steel rails and power-supply materials, making the particles dominantly iron-containing.


To date, there is no clear epidemiological indication of abnormal health effects on underground workers and commuters. New York subway workers have been exposed to such air without significant observed impacts on their health, and no increased risk of lung cancer was found among subway train drivers in the Stockholm subway system.

But a note of caution is struck by the observations of scholars who found that employees working on the platforms of Stockholm underground, where PM concentrations were greatest, tended to have higher levels of risk markers for cardiovascular disease than ticket sellers and train drivers.

The dominantly ferrous particles are mixed with particles from a range of other sources, including rock ballast from the track, biological aerosols (such as bacteria and viruses), and air from the outdoors, and driven through the tunnel system on turbulent air currents generated by the trains themselves and ventilation systems.

Comparing platforms

The most extensive measurement programme on subway platforms to date has been carried out in the Barcelona subway system, where 30 stations with differing designs were studied under the frame of IMPROVE LIFE project with additional support from the AXA Research Fund.

It reveals substantial variations in particle-matter concentrations. The stations with just a single tunnel with one rail track separated from the platform by glass barrier systems showed on average half the concentration of such particles in comparison with conventional stations, which have no barrier between the platform and tracks. The use of air-conditioning has been shown to produce lower particle-matter concentrations inside carriages.

In trains where it is possible to open the windows, such as in Athens, concentrations can be shown generally to increase inside the train when passing through tunnels and more specifically when the train enters the tunnel at high speed.

According to their construction material, you may breath different kind of particles on various platforms worldwide. Image: London Tube/Wikimedia Commons.

Monitoring stations

Although there are no existing legal controls on air quality in the subway environment, research should be moving towards realistic methods of mitigating particle pollution. Our experience in the Barcelona subway system, with its considerable range of different station designs and operating ventilation systems, is that each platform has its own specific atmospheric micro environment.

To design solutions, one will need to take into account local conditions of each station. Only then can researchers assess the influences of pollution generated from moving train parts.

The ConversationSuch research is still growing and will increase as subway operating companies are now more aware about how cleaner air leads directly to better health for city commuters.

Fulvio Amato is a tenured scientist at the Spanish National Research CouncilTeresa Moreno is a tenured scientist at the Institute of Environmental Assessment and Water Research (IDAEA), Spanish Scientific Research Council CSIC.

This article was originally published on The Conversation. Read the original article.