1)Blue zone: It is near the base of the flame. Here the fresh air rapidly mixes with was vapour formed from the molten wax.A part of wax vapour completely burns and gives rise to blue flame.
2)Dark inner zone: This part consists of unburnt wax vapour given off by molten wax.It is the coldest part of the flame It is dark because of of decomposed carbon particles.
3) Luminous zone: In this zone partial combustion takes place with liberation of a lot of heat. This zone is hotter than the dark inner zone.
4) Non luminous zone:It is a zone were complete combustion takes placeIt is hottest part of the flame and is hardly visible.
so , the blue zone and the non - luminous zone of a candle flame are the two most polluting zones.
