Which of the following is a natural activity that causes pollution?

1) Forest fires release carbon particles (ash) into the air and pollute the air.

2) Volcanic eruption releases various gases and ash into the atmosphere.

3) Decay of organic matter releases Ammonia gas into the air.

4) Decay of organic matter lying under water releases Methane gas.

5) The pollen grains released by plants remain suspended in the air and pollute it.