Multiple choice A powerful eye irritant present in smog is ozone nitric oxide peroxyacetyl nitrate sulphur dioxide Reveal answer Fill a bubble to check yourself C Correct answer Explanation Peroxyacetyl nitrate (PAN) is a secondary pollutant formed in photochemical smog that causes severe eye irritation. While ozone is also present in smog, PAN is specifically known as a powerful eye irritant.