In the elevator, PM2.5 increased 23 times when smoke

Air pollution become more and more Serious because of the environment pollution.
PM2.5 increase day by day. many people geting to sick because of the pollution.
When somebody smoke around us, we feel uncomfortable. but what is the reason.
Use the particle counter to check the PM2.5 when smoke. let try in a elevator.
You can see the result has increased 23 times before smoke. so we can know how bad smoke it.