FIG. 1. Schematic of cloud dynamics and transport of ozone
precursors (CO, NO, and HC = hydrocarbons). Ozone is initially
reduced in upper troposphere when unpolluted air is pumped upward.
Soluble gases like nitric acid (HNO3
), hydrogen peroxide (H2
O2
),
and sulfuric acid modify chemical composition of precipitation. Nitric
and sulfuric acids are chief components of acid rain.