To solve London’s housing crisis, we need to think small – and empower the planners

A small brownfield site ripe for redevelopment. Image: Matthew Carmona.

Politicians are finally waking up to the fact that London has a housing crisis. And everyone from the candidates to be London’s next mayor to the prime minister himself have talking about the urgent need to address the crisis.

One reason for the crisis is that London’s population is growing dramatically, and is on a trajectory to reach 11m in 25 years or so.  To address this growth, as well as the backlog in provision we now need to build somewhere between 49,000 and 62,000 homes a year.  Currently we are building just 23,000.

Debating the causes

Many commentators have blamed the dysfunctional housing market on poor planning decisions, or on housebuilders who are more interested in hording land and speculating on its increasing value. Others suggest that the problem stems from all the international money flooding into London’s housing market, buying up housing and leaving it empty as investments rather than homes.

The reality, however, is that we have been building too few homes for other reasons First, we no longer have a viable public led housing programme: we leave it almost entirely to the market.  Second, we over-rely on very few large housebuilders, whose primary focus as private companies is – quite rightly – on their shareholder value rather than on solving the housing crisis.

Third, we don't do enough to seek out and encourage the development of small sites across the city, relying instead on a small numbers of much larger sites.  And lastly, we have allowed our small builders (who once built vast swathes of post war suburban London) to wither in the face of the perverse lending practices of our banks who no longer wish to take the “risk” on housebuilding – this despite the huge amounts of money that those international investors seem to be making.

The potential of small sites and builders

So what is the solution? The very ordinary local mixed streets that form the prime connective tissue weaving its way across London also contains, within 500m of their frontages, 75 per cent of London’s developable brownfield land.

Although small and complex sites, they are sustainable – well-connected to public transport and well serviced by local facilities and amenities. They often need a new purpose as retail declines. And they are already part and parcel of London’s existing communities. They should be the first place we look, not the last – so why don't we look there?

Another site that could be redeveloped as housing. Image: Matthew Carmona.

Part of the problem seems to be that they are not always immediately obvious and viable development propositions. They are often hidden behind existing activities, partially used, or even fully utilised but at a very low level (for example, for single storey developments).

There is also the issue that many of the existing uses on these sites will themselves be valuable activities providing a wealth of employment and other opportunities, either temporary or long-established. Simply clearing all such backland sites for housing would clearly be hugely damaging.

So are there any other options? Today London remains surrounded by its greenbelt, which remains a popular device to constrain the city’s growth. There seems to be little political will to challenge that.

So this leaves only one viable option: the city needs to densify.

London remains a low density city by international standards (around 75 people to the hectare), and there are plenty of opportunities to densify it. We could start by bringing forward the sort of sites referred to earlier, but there and many other opportunities as well. The acres and acres of land alongside, over (and occasionally under) the city’s roads and rail infrastructure for example; the voluminous quantities of space given over solely to parking; the low grade space, within and surrounding many of our public housing estates; and all the wasted “spaces left over after planning” that are liberally dotted across the city, offering us maintenance headaches but no real amenity value to their localities. Once you start looking, the opportunities are vast.


A generational challenge

Yet densification is not an easy option. To grasp it, our public authorities will need to work much harder on planning and design strategies that engage with existing uses and communities – and that work to optimise the local opportunities whilst avoiding stripping out the sorts of marginal uses that still have tremendous value to London.

This will not be achieved by cutting back on the role of the public sector and by deregulating planning. Instead, to stand any chance of bringing forward the legions of smaller sites that we will need across the city, we will require a renewed investment in these vital functions of the state. In particular, we need to free planners up from the sorts of reactive planning that typically dominate their in-trays.

We will also need to convince communities of this strategy. They can often be highly sceptical of any mention of increasing density, associating it with the discredited high rises of the past, rather than with the sorts of terraces of townhouses and mansion blocks that characterise the highest density and highest value parts of London today.

Ultimately, I contend, we need to think small to think big. We need to unleash a new dynamic and entrepreneurial spirit in the city – among the smaller developers, but also among local communities, housing associations and the public sector, who will also all need to be part of this effort. We are facing a generational challenge, but the next generation will not thank us if we fail to deal with it.

London has always risen to such challenges in the past, and will do so now. We owe it to all our future Londoners, from wherever they hail.

Matthew Carmona is professor of planning & urban design at the Bartlett School of Planning, UCL.

UCL’s Question Time on London’s Housing Crisis will be held on Wednesday 13 April at the Darwin Lecture Theatre, Gower Street.

 
 
 
 

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.