Question

which of the following is not a pollutant unless present in excess?1-carbon dioxcide 2-nitrogen dioxid 3-carbon monoxide 4-sulphur dioxide

Answer 1

Carbon dioxide is a green house gas , though it's important for the process of photosynthesis so it isn't a "so harmful" pollutant till present in excess.

Answer 2

carbon dioxide is less pollutant as compared to the given gases. It also very useful for the plants for the process of photosynthesis.