Tag
#PM2.5
Every article tagged “PM2.5”.
2 articles
Environmental Science
A virus is far smaller than the gaps in an N95. The mask catches it anyway, and it catches it better than a bigger particle
The argument that a mask cannot stop a virus because the virus is smaller than the holes assumes a filter is a sieve. It is not. Four separate capture mechanisms operate, and the size a filter struggles most with is in the middle — which is why very small particles are caught more easily than medium ones.
Read more →
Environmental Science
Your phone says AQI 180 and the government board says 300. Both can be right.
The AQI is not a measurement. It is a formula applied to measurements, and knowing how the formula works explains why two apps disagree, why the number lags a bad evening by hours, and why 'satisfactory' is not the same as clean.
Read more →