Urban AIR PURIFICATION / de-NOx

 

NOx pollution from traffic is a serious public health problem. EU has passed strict regulations for air quality standards. However, despite stricter emission limits for new cars, total pollution continues to increase. The European Enivronmental Agency estimates that NO2 pollution causes 75000 premature deaths in EU every year, and many cities are looking for other solutions than just restricting traffic.

Biofuels can cut the CO2 footprint of the fuel production cycle, but emit the same amounts of NO2 and PM. Electric cars are a good long-term solution, but it will take more than a decade to replace the existing cars, and electric trucks still have far to go to be competitive . What we really need is technical solutions for directly improving the air quality, independent of, and in addition to, behavioral changes by individuals and companies.

One proven solution is photocatalysis, and NOx-degradation is the test standard for photocatalytic activity. However, good performance in the ISO test does not necessarily mean good results in field tests. Part of the answer is blowing in the wind: the air purified from blowing along a treated surface is not necessarily the same as the one reaching the NOx sensor, and coating your own wall will likely benefit your neighbours more than yourself. Successful projects must take air flow patterns into account when deciding where to coat and how to measure the effect.

Another key factor is the way the ISO test is set up. A material can get a very high activity score by transforming NO to NO2 without actually breaking down the NO2. Since the health problem is the NO2, the best material has not just high activity but also very high NO2 selectivity[link]. This is a an important detail: a material with “high activity” that transforms NO to NO2 faster than it transforms NO2 to nitrates will give more toxic NO2 in the air. That material is not necessarily bad for other photocatalysis applications, but for air purification it will just make matters worse.

Joma nanoparticles have a patented surface composition which gives a very high NO2/NOx selectvity compared to other commercial photocatalytic particles.

 

  • ·         PROBLEM: Good lab results does not equal good field performance. Breaking down the wrong molecules adds to the problem.
  • ·        SOLUTION: Use Joma nanoparticles with record high selectivity for NO2 degradation. Take flow patterns into account when deciding where to treat and where to measure.

 

 

 

 

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