Photochemical smog is highly oxidizing polluted atmosphere comprising largely of ozone $\left( O _{3}\right)$, oxides of nitrogen $\left(N O_{x}\right)$, hydrogen peroxide $\left(H_{2} O_{2}\right)$, organic peroxides, peroxy acetyl nitrate (PAN) and peroxy benzyl nitrate $\left(P B_{z} N\right)$. Some sulphates and nitrates can also be formed in photochemical smog due to oxidation of sulphur containing components $\left( SO _{2}, H _{2} S \right)$ and $NO _{x}\left( N _{2} O _{5}, NO _{2}\right)$ but it does not contain $CO _{2}$. Photochemical smog materials cause damage to plants, human health, hazards and corrosion problems.