What is the WHO standard request for the PM2.5

^{Different country with the different level of PM2.5. the pollution didn't same.
China's PM2.5 request is under 35μg/m³. what about your country?
But what is the request for the WHO for the fine particulate matters? it is under 10μg/m³.
Particle counter can check both PM2.5 and PM10 result in the air around us.
It can tell you what kind of air you are breath and also it is good for health or not.}