Public debate tends to revolve around two recurring topics: how to bring about a significant reduction in air pollutants, such as particulate matter and how to achieve internationally ratified climate protection targets to prevent the continued progress of global warming. To date, these two questions have been viewed separately. Researchers at the University of Stuttgart now want to help resolve these issues by developing a holistic concept for the City of Stuttgart aimed at air pollution control and minimizing greenhouse gas emissions.
How could something be beneficial to the climate but damaging to the city's air? That seems like a paradox at first glance, but Professor Rainer Friedrich cites a simple example: replacing natural gas with wood-fired heating is CO2-neutral, because wood is a renewable resource. “However”, as the Director of the Department of Technology Assessment and Environment at the University of Stuttgart’s Institute of Energy Economics and the Rational Use of Energy (IER) explains, “the health problems caused by the pollutants emitted by wood-fire heating plant far outweigh the benefits of the CO2 reduction”.
Until now, people have viewed climate protection and air pollution control as two separate challenges for which different departments within the relevant authorities are responsible. However, this approach is inappropriate, because the respective countermeasures have reciprocal effects, which is why the IER is participating in the ICARUS (Integrated Climate Forcing and Air Pollution Reduction in Urban Systems) project. In the course of the research project, which is scheduled to run until 2020 and has a project budget of 6.5 million euro, and is part of the “Horizon 2020” EU program, institutes from various countries will be striving , on behalf of Stuttgart and eight other European cities, to find ways to maintain air purity and keep the cities climate neutral.
Short-term Measures, Long-term Vision
The University of Stuttgart plays an important role within the project. “We're initially developing and testing the methodology for Stuttgart before it’s implemented in the other cities”, explains Friedrich. In addition to the IER and the City of Stuttgart, other participants include Professor Günter Scheffknecht and his team from the Institute of Combustion and Power Plant Technology (IFK) as well as the Institute of Road and Transportation Science (ISV)’s Chair for Transport Planning and Traffic Engineering under the aegis of Professor Markus Friedrich. The ISV's traffic planning models can be used, for example, to calculate the effect of a city-wide congestion charge.
The IFK is analyzing air pollutants and associating them with their respective sources to discover what is responsible for which elements of the high concentrations of air pollutants. “For example, this has revealed that almost a quarter of the air-borne particulates in Stuttgart originate in wood-fired heating systems”, says Friedrich. “We have two objectives”, the physicist explains: “First, we want to identify particularly effective short- and medium-term measures”. To this end, the researchers have compiled lists of proposals, which they are currently discussing. The subject selected measures to a holistic assessment in terms of their respective advantages and disadvantages, such as associated health risks, costs, convenience and time savings or losses as well as climate protection. The respective research groups will then develop strategies for each of the model cities based on the most efficient measures.
“However”, Friedrich continues, “these measures will only have a limited positive impact in terms of air pollution control and climate protection They won't help us to achieve the drastic improvements we wish to see. So, the second objective we've set ourselves is to develop a vision of how these cities could develop over the longer term, such that they really do become climate neutral and restrict air pollution to a bare minimum – and do so without negatively impacting the well-being and welfare of the resident populations”.
Going Off-Road
Friedrich cites an example from Stuttgart to emphasise the fact that the ICARUS project goes far beyond debates around statutory thresholds: The maximum exceeded threshold for PM10, a slightly coarser particulate, is around 50 micrograms per cubic metre of air on no more than 35 days per year. However, the lighter particulates are significantly more damaging. Significant chronic health risks are due more to long-term exposure than short-term peaks. Despite the fact that the threshold values for the lighter particulates are not being exceeded, the current air pollution level is damaging to health.
“Therefore, whilst complying with threshold limits is necessary, it is far more important to minimise health risks from air pollutants”. The ICARUS study is set to deliver even more accurate results by taking account of the values measured at places where people tend to spend much of their time, rather than just those recorded at monitoring stations along the main roads. Above all, this applies to indoor spaces: “We want to determine which specific pollutants people are exposed to in their homes. This will enable us to consider health-protection measures that have nothing to do with the outside air”.
Based on the respective results, the intention is to develop a vision for a “green” Stuttgart by 2050. The most important areas to redesign will be traffic and heating systems, which are the main sources of the city’s current environmental issues. In the researcher’s opinion, the likely tendency will be to migrate both to electrically-powered systems – heating with heat pumps in combination with local and district heating networks in addition to solar heating systems. Transportation will be based on driverless vehicles, probably with electric motors, perhaps also with fuel cells in which the necessary hydrogen will be produced using power from renewable sources.
These visions are based on contemporary science informed by projected future trends, “whereby”, says Friedrich, “we're well aware that our visions will not be realised in their current forms. However, they are necessary to point the way for developments in energy and traffic systems, And will be continuously updated to reflect new findings”. The City of Stuttgart and the other model cities have committed to discuss the results of the ICARUS project at the political level “so that our objective of bringing about a holistic improvement of air pollution control and climate protection won't remain just a vision”.
Daniel Völpel