[kaybe]

Funfact: The highest concentration of NO2 is not found around pedestrians but inside the cars. Most models don't have suitable filter in the standard issue outside of Europe and Japan (and there only the higher-class private ones).

[copperx]

Are we talking about the cabin air filter? and do you know of any 3rd party suitable replacements?

[copperx]

Post append: According to [1], a simple activated charcoal cabin air filter is better than the stock one in removing diesel exhaust particles.

[1]: https://www.ncbi.nlm.nih.gov/pubmed/24621126

[kaybe]

Thanks, I didn't know this paper. We just measure the NO2.

edit: Seriously, how did they get that through the ethics committee.. I'm astonished and a little bit appalled. There is a second study too.

[kaybe]

Yes, the issue is the cabin air filter. The simple paper pollen filters don't do anything against NO2 - we measure the same values inside and outside.

Most filters with active charcoal will reduce the NO2 concentration a lot. It is recommended to replace them after 1-2 years or a certain distance, but we don't have numbers on this - still, it is clear the filters degrade after a while.

[megy]

Good, exactly where it should be highest.

[kaybe]

Sometimes I can't help but think so too, but many people are not on the road by choice. Many commercial vehicles don't have filters.