Tracking urban air pollution
Research scientists from the European Commission's Joint Research Centre have helped to develop and trial a cost-effective sensor that will allow urban air pollution to be mapped across Europe. Background The quality of air in European cities has long been of concern, and there have been some well-reported attempts to limit the use of cars in cities such as Paris and Athens. Now the European Commission is proposing an 'air quality' directive that will limit the amount of benzene - a traffic pollutant - that can be present in the atmosphere. To support the directive, the Environment Directorate-General asked JRC's European Reference Laboratory for Air Pollution (ERLAP) to measure benzene levels in various cities across Europe in a project named MACBETH. To achieve this, ERLAP first collaborated in the development of a simple, yet innovative air-sampling technology. Working partnerships ERLAP is part of the Joint Research Centre's (JRC) Environment Institute at Ispra. The new sampling technology - Radiello sensors - was developed in conjunction with the Fondazione Salvatore Maugeri, a private research institute based in Padua, Italy. The sensors are being marketed by the Italian company Aquaria. To carry out the pollution measurements ERLAP collaborated with Environmental Research Institutes in France (INERIS), Denmark (NERI), Flanders (VITO), Italy (FSP)and the University of Murcia, Spain. Description, impact and results The concept of the Radiello sensors, or passive samplers, is simple. A short slim tube contains a pollutant-absorbing material at its centre. The cap is removed once the tube is on-site, pollutants are absorbed over a given period, then the tube is sent to a laboratory for analysis. In the past, pollution measurements have been taken from a few isolated points. Because the Radiello sensors are very cheap to produce, a large number of sampling sites can be used and a pollution map built up. This is important because it provides valuable information not only on the presence of pollutants, but also on the area where the population is most exposed and consequently where clean-up action would be best employed. In the MACBETH project, ERLAP used such tubes to measure benzene levels in six EU cities including Copenhagen in the north and Athens in the south. The results, which were presented at an international conference on air quality held in Venice in May, showed that benzene concentrations increase southwards across Europe. The different levels are caused by several factors such as the weather, lifestyles, urban structure and traffic density. ERLAP was responsible for the validation of the sensors and the quality assurance of the measurements, and its researchers are now working on materials that will absorb other key pollutants such as carbon monoxide, nitrogen oxide and polyaromatic hydrocarbons. Air-quality management organisations across Europe have already shown considerable interest in the sensors. Part of JRC's remit is to use its scientific and technical facilities and skills to help Member States implement the new directive. This assistance will include validating supervision methods, ensuring harmonisation and checking the quality of measurements.