Nitrogen dioxide (NO2) is a well-known enemy. Part of a group of highly reactive gasses known as nitrogen oxides, NO2 forms quickly when fossil fuels are burned, for example petrol or diesel in a car or natural gas in a domestic boiler or power station. There is clear evidence that high levels of NO2 are linked to adverse effects on health including increased risk of respiratory illnesses, such as bronchitis and even heart attacks; World Health Organisation statistics show 1.3 million deaths worldwide result from outdoor air pollution.
Closer to home, in the World Health Organisation European Region, exposure to air pollution is said to decrease the life expectancy of every person by an average of one year. While lower than other parts of the world a recent study saw this figure rise to 22 months in at least 25 European Cities. Defra (the Department for Environment, Food and Rural Affairs) estimates that air pollution reduces average life expectancy in the UK by 7-8 months, costing the UK up to £20bn per annum.
While much is known about the causes of air pollution as well as their effect on public health there would appear to be a significant gap in the understanding of how this enemy behaves in our environment.
In 2013 scientists at the University of Leicester revealed ground breaking pollution detecting technology that can be used to map levels of nitrogen dioxide across an entire city. Working with aerial mapping company Bluesky the Airborne Air Quality Mapping (AQM) project utilises the University of Leicester's world leading Compact Air Quality Spectrometer, mounted on an aerial survey aircraft.
The device monitors visible light and measures how much light is lost at specific wavelengths absorbed by NO2 and has previously been used as part the CityScan project with devices mounted on tall buildings in Leicester, Bologna and London, during the 2012 Olympics, to build 3D maps of pollution across the cities. The colour coded images can then be analysed and even overlaid on Google Earth to reveal distinct differences in air quality between green, wooded areas and busy road junctions and areas of industry, for example.
Additional monitoring is also being undertaken closer to earth. Scientists armed with specially developed air quality sensors are taking to the streets of Leicester in electric vehicles. To begin with two electric cars, leased from local company Cenex, have been fitted with specially developed sensors that can measure pollution concentrations around the city at ground level. The cars recorded air quality measurements during every day work for the project team, including the installation and maintenance of a static air quality monitoring network, which feeds live data via 3G back to a central server. The collected data will then be spatially referenced for use in Geographic Information Systems (GIS) and other mapping software allowing for comparison with data on potential sources of pollution and other recorded measurements.
This particular project is part of a programme funded by the European Regional Development Fund (ERDF) to partner graduate research experience with growing SME's, such as Bluesky, in the East Midlands region. Innovation through the Research Support Accelerator (IRSA) aims to accelerate the development and exploitation of novel research via a unique collaboration between business, academic expertise and a high quality graduate who will be given the opportunity of using a full year of research and development to enrol for a postgraduate degree.
Successful development and trials of these systems have also led to additional funding and therefore further research. For the first time the Bluesky-University of Leicester partnership aims to provide a quantitative understanding of the levels of nitrogen dioxide across a city. Results from the AQM trials will be integrated with the ground based sensors and the mobile monitoring results to explore the complex concepts of gas-phase tomography in order to retrieve 3d structures of pollution. This new, NERC-funded, PhD project will build on results to date and will fine tune the instrument design and data manipulation.
By collecting data from a variety of sensors including the aerial platform, moving vehicles and the growing network of ground based monitoring stations it is hoped that scientists can better understand how these toxic gases behave in the environment. This data and the wider understanding derived from it will then be used to better inform future planning policy with long term solutions and support the wider introduction of preventative schemes such as the London Low Emission Zone.