Wet cleaning of the street of the fine dust hotspot Neckarktor was intended to remove the dangerous particles from the ground. Now the city is stopping this pointless measure.
Again and again, cities try to combat particulate matter with a wide variety of tools. Since 2017, the city of Stuttgart had been wet mopping the B14 federal road at night to remove fine dust particles from the ground. In the last six months of winter alone, 400,000 euros were spent on this questionable measure.
Particulate matter is emitted directly from vehicles while driving. But it is also deposited on the road and is stirred up again by the traffic. However, the hope that removing these deposited particles could contribute to reducing particulate matter remained unfounded.
Other attempts to combat particulate matter pollution also showed only limited success: the city set up filter columns, reduced the speed limit on important traffic routes and erected a wall of moss to filter particles from the air and thus reduce particulate matter.
Nevertheless, Stuttgart had repeatedly called out fine dust alarms in recent years, as the daily average fine dust pollution was more than 50 micrograms per cubic metre of air. This may be the case on a maximum of 35 days per year. In 2018, the pollution was too high on 21 days at the barely cleaned Neckartor, and in 2019 it was even too high again on 27 days. This year, only 8 days of excessive pollution have been measured so far, but this could also be due to reduced traffic as a result of the Corona pandemic.
The particulate matter alarm has now been abolished, as the excess days of the past years no longer approach the 35-day mark. In general, however, it is difficult to say which measures contribute most to reducing particulate matter and whether enough has been done in the long term to combat dangerous particles. It is estimated that street cleaning only removed around 1.7 micrograms of particulate matter per cubic metre of air, and this is only in the immediate vicinity of the Neckartor. Too little to spend a lot of taxpayers' money on it.
Whether the particulate matter pollution will remain halfway under control in Stuttgart next year, or whether the city will have to come up with expensive measures again to avoid unpopular driving bans... we are curious.