Dutch town cleans the air with concrete
Follow the green brick road.. follow, follow... well, okay, fine. So, it's not literally green, but the Dutch town of Hengelo is at least greening up one of its roads with air-purifying bricks. The concrete was developed by the University of Twente and features a titanium dioxide-based additive which is said to soak up some of the nitrogen oxide particles emitted by car exhausts as they drive over. So far, only half of one road will be paved with bricks of this special concrete to see if any measurable improvement in air quality can be achieved. So far, no real-world testing has been done, though the creation has proven successful at binding the nitrogen oxide particles and turning them into harmless nitrates in the lab setting.
Sunlight is necessary for the reaction to take place, but afterwards, the roadway will be washed clean with the next rain. If the first trial proves the concept, more roads will soon follow. By next summer, early results will be in. Stay tuned.
[Source: Yahoo via Engadget]
Reader Comments (Page 1 of 1)
Joce03 8:28PM (8/08/2008)
Not to be cynical, but does the amount of nitrogen that this picks up compensate for the added energy (and pollution) that is required to build a road using this special concrete?
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Brent 8:47PM (8/08/2008)
Probably not.
S10 9:07PM (8/08/2008)
That's why they are testing it...
Chris M 10:00PM (8/08/2008)
Yes. As a photocatalyst, it doesn't break down, so should function for years, even decades, until the concrete gets worn away - it might be better to use this on walls, rather than in paving!
Titanium dioxide is a commonly used white pigment, easy to make, and the manufacture of it isn't considered environmentally hazardous.
Chris M 9:18PM (8/08/2008)
Titanium Dioxide is a white pigment used in paints, it has replaced the toxic white lead that proved to be troublesome. Of course it can be used in concrete, though only the surface layer will be active.
Exposed to sunlight, it acts as a photocatalyst, breaking down certain compounds, not just nitrous oxides but ozone and some hydrocarbons as well. It is inexpensive enough to find widespread use if it is successful.
It need not be used as pavers, it could also be used in walls and roofing and other places. It has even been used as a thin coating on glass, making it almost self cleaning!
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jon 10:10AM (8/09/2008)
Ah, but nothing is free. "the trapped nitrates will be washed away with the next rain" Into the storm drains, and either directly into other streams and rivers, or into a treatment plant. If they go into natural waterways, won't this pollutant cause issues there? Nitrate runoff from farming and other uses already is causing significant problems worldwide.
tankd0g 5:24PM (8/09/2008)
If they start adding platinum to these can I take off my catalytic converters? :)
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nick l 8:16PM (8/09/2008)
Does anyone know if this is cost effective? What a good idea if so. Is it ecological vs regular surfaces considering how they get the additive?
Maybe I can promote it in Portland. We just made the first solar highway in the US the other day. So cool that way up here.
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