Question

compare primary and secondary pollutants. which is more harmful?

Explanation:

Primary pollutants are emitted directly into the atmosphere, like sulfur - dioxide from coal - burning. Secondary pollutants form through chemical reactions in the atmosphere, such as ozone from the reaction of nitrogen oxides and volatile organic compounds. Harmfulness depends on exposure levels and context. Ozone (a secondary pollutant) can harm human health and plants, while sulfur - dioxide (a primary pollutant) can cause respiratory problems and acid rain. It's hard to simply say which is more harmful as it varies by situation.

Answer:

It's not possible to simply state that primary or secondary pollutants are more harmful as it depends on various factors like exposure levels and environmental context.