How do you propose to control:

(a) carbon monoxide emission

(b) SO_x emission

(a) Carbon monoxide pollution can be controlled in the following ways:

1. By switching over from internal combustion engines to electrically powered cars.
2. Many pollution control devices are now installed in cars. Most of these devices help reduce pollution by burning gasoline completely. Complete combustion of gasoline produces only carbon dioxide and water vapour.
   2C₈H₁₈ + 25O₂ ⟶ 16CO₂ + 18H₂O
3. By using substitute fuels for gasoline: Natural gas in both compressed (CNG) and liquefied forms (LNG) is now increasingly being used as fuel. Alcohols are other feasible substitutes.
4. By using catalytic convertors :
   Carbon monoxide changes to carbon dioxide in the presence of finely divided platinum as a catalyst.
   $2\text{CO} \xrightarrow[\text{[O]}]{\text{Pt}} \text{CO}$2 + \text{H}2\text{O}

(b) The main source of SO_x emissions are industrial and metallurgical processes. Such emissions can be reduced by using a scrubber, a device which absorbs gaseous pollutants. It consists of a fine spray of water. The gas rising from the stack is passed through the scrubber where water absorbs sulphur dioxide.