Air pollution is a hazard that many people are exposed to in their daily activities and this is why it has become a serious public health issue.
A recent Public Health England Report found that air pollution now accounts for approximately 29,000 premature deaths a year, which equates to 5% of the UKs mortality. On a global scale, air pollution was linked to around 7million deaths in 2012 leading to the World Health Organisation (WHO) branding it the single biggest environmental health risk.
From a financial point of view, the risks also are immense. A recent report by the Global Commission on the Economy and Climate estimated that the health and mortality costs of air pollution in the top 15 greenhouse gas emitting countries averages 4.4% of GDP. In China the figures is above 10% of the country’s economic output.
A main factor causing air pollution is said to be diesel combustion, which creates Nitrogen Dioxide (NO2) and Particulate Matter (PM). Diesel poses a particular problem in urban environments where 40% of air pollution comes from diesel exhausts in passing traffic. Research conducted by Edinburgh University and the British Heart Foundation found that exposure to diesel pollution is one of the main triggers of heart attacks.
Over the past 10-15 years, the UK has a seen a trend toward Diesel vehicles as car taxation favoured vehicles with lower emissions. Diesel cars with reduced CO2 levels and high miles to the gallon therefore proved economically and tax friendly to both individuals and businesses. This has meant that level of diesel pollution, particularly in our cities has continued to rise.
Furthermore, cleaner vehicles that have passed regulatory standards on the production line have proven to perform very differently in real world driving circumstances. More aggressive driving and higher levels of congestion results in vehicle pollution levels up to 5 times higher than test conditions. This has meant that air quality improvement predicted on the use of these vehicles has unfortunately not become a reality.
THE VALUE OF GREEN INFRASTRUCTURE
New developments in our cities therefore must try to improve air quality. For this to happen, consideration must be given to air quality right from the out set. Air Quality Assessment which form a key aspect of an Environmental Statement on larger projects can help to prioritise air quality through Construction Phase and Operational Phase of a development.
Green Infrastructure (GI) brings much benefit to a development from improving the aesthetical environment, providing habitat to a variety of ecological species or helping attenuate water run-off. Importantly, it also helps improve air quality by acting as an urban pollutant filter as trees can act as low cost pollution detectors and deterrents. A recent study by Lancaster University demonstrated that PM levels in residential properties along a busy road reduced by as much as 50% after installation of silver birch trees. Further research by the University found that the planting of vegetation in streets can reduce outdoor street-level of concentrations of NO2 by 40% and PMs by 60%.
Given the severity of the impacts on public health and the associated financial costs, new developments should incorporate GI mitigation measures. Ecological services offered by Greengage such as surveys & assessments can identify which type of GI is best suited for either large or small developments. Within development we can promote biodiverse landscapes, integration of ‘blue’ and ‘green’ infrastructure, adaptation to climate change and minimisation of the heat island effect. Greengage can also identify habitat restoration and creation requirements (including naturalised amenity and play space) and provide multifunctional solutions, tailored to the location and mix of the proposed development.
About the authors: Lesley Treacy is an Associate Partner and Kerri Dobson is a Graduate Sustainability Consultant at Greengage Environmental LLP. For more information on their respective specialisms, please see the Greengage website.