Accumulate in the body, can not be ruled out, accumulate more and more, then be poisoned, and then die.
take for example
Blood lead
Where did the blood lead incident in Hunan last year not be reported?
2. Automobile exhaust pollution
nitric oxide
Mainly carcinogenic.
Step 3 burn garbage
Mainly dioxins
One of the most important carcinogenic species, and it is difficult to eliminate.
4. Acid rain
Serious areas, unable to go out,
5.sandstorm
Needless to say