Damp environments, poorly maintained heating and air-conditioning systems as well as carpeting could negatively affect indoor air quality, according to experts.

Researchers at the annual meeting of the American College of Allergy, Asthma and Immunology (ACAAI) in Miami Beach, Fla., said that repeated exposure to indoor allergens and airborne particles could lead to respiratory symptoms and conditions.

Doug Garrett, CEM, CDSM, building scientist and president of Building Performance and Comfort, Leander, Texas, said: “If there was just one thing I could do to fix buildings, it would be to change the relative humidity.

“Moisture leads to conditions that are conducive to dust mites and mold, as well as bacteria, yeast and other living organisms.”

Poorly maintained air-conditioning and carpeting were said to be among the most problematic culprits that contribute to poor indoor air quality.

Carpeting was also dubbed as a major source of harbouring allergens since it provided an ideal environment for mold growth in damp environments.

Jeffrey May, M.A., principal scientist of May Indoor Air Investigations LLC, Tyngsborough, Mass., said: “Many schools shampoo their carpeting right before school starts at the end of summer when it’s humid outside. There couldn’t be a worse time.”