wu_ming2

Have you ever tried refill stations? You will discover filling up with just the amount you need saves space, weight and also doesn’t require single use packaging.

Dear Dr Zetland,

thanks for this AMA. I found the working paper "The Environmental Bias of Trade Policy" from Dr Shapiro at the National Bureau of Economic Research in the US quite interesting. As example he wrote "global subsidy to CO2 emissions totals $550 to $800 billion dollars per year." and "The implicit subsidy I estimate, of $85 to $120 per ton of CO2" and "current trade policy is subsidizing pollution for political economy (not efficiency) reasons".

Did you conduct researches about the optimal price of a global carbon tax?

Not in the air quality business but I had to do some research before buying my first air purifier.

In my understanding ISO 14644-1 Cleanroom Standards defines the maximum particles count in a volume for different applications. To obtain ISO 8 indoor air quality - good for pharmaceutical packaging application and 10x cleaner than ISO 9 representing the “average“ room - an EPA filter is suggested.

Considering volumes and guesstimating air leakages from windows and door I decided to buy EN 1822:2009 certified E12 (EPA) filters in a tightly sealed box. I decided against H13 (HEPA) filters because ISO 8 is good enough. And other options were not delivering enough air volume over time. Also because of noise considerations. And often were non certified and / or in a loosely sealed box.

Care to comment?