handheld particle counter  knowledge
1.Under 100 micron particles for total suspended particles in the air (TSP)
2.Above 10 micron particles can be inhaled particulate matter(PM10)
3.Under 2.5 micron particles for particulate matter can go into the lungs (PM2.5)
4.Single filter net rate: refers to the mesh inhalation of air into the fresh air from a single

process, by comparing the change of air particles number to determine the mesh filter net
5.Use the instrument to measure the purification efficiency of air purifier , prepare a new filter,

And let the machine work more than 20 minutes, Usually use within 3 months, if the machine

use for a long time, need to replace a new purifier HEPA filter, so that make the effect is obvious.