(N/A) Tropospheric pollution is caused by the presence of undesirable solid or gaseous particles in the lowest layer of the atmosphere. The main gaseous pollutants include oxides of sulphur ($SO_{2}$,$SO_{3}$),nitrogen ($NO$,$NO_{2}$),and carbon ($CO$,$CO_{2}$),along with hydrocarbons.
Oxides of sulphur and nitrogen are produced by burning fossil fuels. They react with atmospheric oxygen and water to form sulphuric acid $(H_{2}SO_{4})$ and nitric acid $(HNO_{3})$,leading to acid rain,which damages vegetation and buildings.
$2SO_{2(g)} + O_{2(g)} + 2H_{2}O_{(l)} \rightarrow 2H_{2}SO_{4(aq)}$
$4NO_{2(g)} + O_{2(g)} + 2H_{2}O_{(l)} \rightarrow 4HNO_{3(aq)}$
Carbon monoxide $(CO)$ is highly toxic as it binds to hemoglobin,while carbon dioxide $(CO_{2})$ contributes to global warming. Particulate pollutants like dust,mist,and smog also cause respiratory diseases.