The idea of subliminal scents was rumored to have started with Coco Chanel’s 1921 launch of No.5 when her boutique was thoroughly sprayed with the scent before opening the doors to the public.

Marketers are taking advantage of smell, the most powerful human sense, to influence consumer behavior.

From hotel lobbies to top designer shops, airline cabins to home improvement stores, scents are being pumped into the air, but at what risk to consumer health?

When diffused through HVAC ducts, studies have shown fragrance can influence purchases and create an emotional bond to brands.

The amount of fragrance particles pushed into the air is said to be safe by the International Fragrance Association and meets OSHA standards, but with chemicals being inhaled into the body, critics have called diffusion a public health issue and claim it can cause allergic reaction and illness.

This controversy over scented air could be seen as an advantage to online shopping.