Air quality monitor to test indoor air pollution?

[timonoj]

@timonoj have you considered sealing windows /doors with tape while running the purifier to see if that makes a difference? It's been said that this is helpful.

Nope, didn't go as far. Just stopping the aircons as a way to reduce the outside air intake. The pm2.5 levels fell much faster with no aircon in a small 2.5m x 2.5m closed room. ...so there's that.

[HKthe]

Pretty big discrepancies. "good" on china can equal "unhealthy" in the US.
So 1 of the methods has to be way out of line. I wonder which?
I think it's safe to say China has much lower standards in terms of what's considered acceptable in terms of air.

[jgl]

Pretty big discrepancies. "good" on china can equal "unhealthy" in the US.
So 1 of the methods has to be way out of line. I wonder which?

Rhetorical question, right?

[HKthe]

Rhetorical question, right?

Haha yep.

[MerMer]

It would seem to be ug/m3.
Interesting that it's stated as "good", when the WHO says anything above 10 is unacceptable and dangerous.
There was an article about pollution in London stating that "pm2.5 levels on some days were double the recommended amount!". Which is like 20. Which is like better than an average day in HK.

Isn't there a difference between the acceptable amount in one day versus a whole year? I thought the average recommended/acceptable levels for a year were lower.

[merchantms]

Pretty big discrepancies. "good" on china can equal "unhealthy" in the US.
So 1 of the methods has to be way out of line. I wonder which?
I think it's safe to say China has much lower standards in terms of what's considered acceptable in terms of air.

There are two broad standards, one for developed countries and one for developing countries. Developing countries have lower standards supposedly because they're poorer so can't combat pollution as effectively.

On the US AQI standard it's basically unhealthy in HK all winter.