Why are these three things considered pollutants? Hydrocarbons, particulate matter, carbon monoxide.?

Question

Why is EACH dangerous to humans and the environment?

Answer 1

When hydrocarbons are burned, it causes all sorts of problems. If it is pure hydrocarbon and is burned completely, it releases CO2 which is a green house gas.

If it is not burned completely (in low oxygen conditions), it relases CO, which is toxic, and particulates (soot) which can cause respiratory problems.

Unburned hydrocarbons are bad too. Many hydrocarbons are volatile (vaporize easily) and form VOC (volatile organic compunds). This, in presence of sunlight, also creates ozone (smog).

Answer 2

It isn't.... particularly anyway... the only poisons coming from those are CO and Mercury