An indoor air quality (IAQ) expert has warned businesses and consumers against using ‘air purifiers’ that emit ozone as a byproduct, which are touted to have the ability to kill germs that may be present in the air.

Ozone gas plays a crucial role in the upper atmosphere by filtering out much of the sun’s UV radiation.

But on the ground, International Islamic University of Malaysia (IIUM) assistant professor Maryam Zahaba said its highly reactive nature makes ozone hazardous to humans.

It can also react with other common substances to produce more pollutants...