"London breaches annual pollution levels" - Contemplating green ideas and potential solutions.

According to new data, parts of London have already breached the EU hourly limits for nitrogen dioxide pollution. The EU has set an hourly limit of 200 micrograms of NO2 per cubic metre of air and this may only be breached 18 times annually. However, it was just over a week into 2016 and locations in Putney and Chelsea and Kensington had broken the limit for the 19th time.

This is not a new occurance as the UK has been in breach of the NO2 pollution limits for 5 years and as such was taken to court last spring and subsequently ordered to draw up an action plan to tackle the air pollution problem.

Around 30,000 people in the UK die prematurely each year due to particulate pollution according to figures released by Public Health England. This figure, however, has not been revised to include the health impacts of NO2 which has been linked to respiratory and heart problems.

2010 nitrogen dioxide levels in London shown in map form.

Nitrogen dioxide is a gas that is mainly produced by motor vehicles and although the human health impacts of this pollutant are known, it has been difficult to find sufficient evidence to determine the mortality rates and impacts of NO2 specifically, when people are also being exposed to particulate pollution and various combinations of other harmful gases.

So what can be done?

Some cities like Paris, have introduced Odd/Even schemes which serve as an access restriction. Vehicles are regulated by their number plates and whether the number ends with an odd or even digit. In addition to the odd even scheme they also implement speed restrictions and free public transport is available during the days that the alternating numberplate scheme is being enforced. Encouraging more people to use public transport can be a very positive way to tackle air pollution by decreasing the numbers of vehicles within the city.

Green roof, green wall and other foliage installations can be very good for improving air quality. Trees, shrubs and turf have been shown to remove pollutants as well as smoke and dust from the air. One tree can remove 26 pounds of carbon dioxide from the atmosphere anually which equates to approximately 11,000 miles of car emissions.

A Chicago study estimated that 1,675kg of pollutants including nitrogen dioxide, sulfur dioxide and particulates were being removed by 19.8 hectares of green roofs annually in Chicago. Green roof installations are already being implemented in London. I got the opportunity to visit a variety of completed roofs that have been put on numerous Transport for London properties and depots when I carried out a work placement with them. My project was on the biodiversity benefits of the green roofs but these sites also play an important role in saving energy and countering air pollution which is why they are becoming increasingly popular in the capital.

The green roof at 55 Broadway, (TFL headquarters at the time of the project).

Overall, it is going to be very difficult to solve a problem like this, especially for a city such as London. Schemes are being put in place and green solutions are becoming more popular, but the fact is, in the whole of the EU the population of London is huge in comparison to other capital cities. In 2014 the official population of London was over 8.5 million people and this is followed by Berlin, the second largest city in the EU, with around 3.6 million people. Perhaps the problem lies with the UK being too London-centric, and therefore the only way to reduce pollution as a result of such a dense population, may be to further encourage and promote the use of other major cities and relocation, through better funding and improved infrastructure.