What name was given to noxious vapour, rising from organic matter, which pollutes the atmosphere? ?

The noxious vapor that rises from organic matter is known as methane. Methane is one of the greatest contributors to the greenhouse effect, and one of the greatest sources of methane on the planet is from cattle farms. Cattle produce tons of methane per year, and there are massive cattle farms across the globe to keep up with the demand of milk and red meat.

You would be correct, boiling water does disinfect contamination.    the property of disinfecting means to kill  germs, bacteria and other pathogens or contamination  that might cause an infection or cause a person to become sickly. a couple methods of disinfecting are using soap, other cleaning supplies or by simply "boiling" the contaminate.  the reason why boiling water disinfects certain attributes is because some cells cannot survive the heat and pressure.

The velocity would be 2