Question

why is combustion of coke harmful,Carbon Dioxide is not a pollutant,.?

Answer 1

Coke is naturally made up of carbon.combustion of Coke is harmful because when carbon enters into the air that pollutes and causes many diseases.mainly to the growing children.
Carbon dioxide is not a pollutant it is a gas which is exhaled by the humans and the other animals and is absorbed by the leaves of the plants and trees. But it is not good to sleep under the tree during the night Times because they release carbon dioxide in a very large quantity which is harmful to health..

Answer 2

Combustion of coke can give two product depending on the extent of combustion.

#On partial combustion:
2C+O₂⇒ 2CO           [which is highly poisonous]

Carbon monoxide is a harmful pollutant,it creates lots of breathing problem in human beings. It binds with hemoglobin,reducing its affinity with oxygen. 

#On complete combustion:
C+O₂⇒ CO₂            [not much harmful,but still a pollutant if in excess]

Its true that we exhale CO₂ , and plants need CO₂ for respiration. But if CO₂ is more than required it becomes a pollutant. excess CO₂ is the reason for GLOBAL WARMING.CO₂ is known to be a green house gas,which traps the heat from the sun,increasing the average temperature of earth.