Written by Krishna Bora, B.Sc. (Microbiology) | 
Medically Reviewed by dr. simi paknikar, MD on Jun 18, 2014

What Grows Inside The Air Conditioner

Several micro-organisms tend to grow in the moist and humid environment of the air conditioner.

The air conditioners suck air from the indoors to keep the indoor atmosphere clean and healthy. They trap all the dust particles, pollen and animal dander, but due to the presence of moisture and humidity, these factors lead to growth of microorganisms in the air conditioner and pose the risk of harmful microbial diseases to people in the near vicinity.

There are several microorganisms such as bacteria and mold, which grow in the humid and moist interior of the air conditioner. Clostridia, Streptococci, Staphylococci, Listeria and Legionella are some of the microorganisms that grow in an air conditioner and can cause harmful diseases and infections to people exposed to the cooled air.

Clostridia are not generally harmful but some selected species such as Clostridium perfringes can cause tissue death and gas gangrene. Streptoococcus pyogenes causes throat and other infections that could lead to pneumonia and meningitis. Staphylococci causes skin infections such as boils, pustules, and infections in bones, wounds and joints. Pregnant women, their fetus or the newborn babies living in a room with a contaminated air conditioner can get affected by Listeria monocytogenes. Bacillus anthracis causes anthrax, that results in open sores on the skin. Legionella pneumophila leads to life-threatening form of pneumonia.

The U.S. National Library of Medicine says that all these survive and grow in moist environments such as refrigerators, large air conditioning systems and air coolers.

Molds are fungi, which break down dead materials and recycle or return the nutrients back to the environment. They travel through the air and are harmless when are present outdoors but dangerous when they grow in the house.

Molds do not affect all individuals, but patients allergic to molds can suffer from wheezing, stuffy or runny nose, rashes, hives, and itchy and watery eyes. They also affect the asthma patients and cause other respiratory problems.


  1. Air Conditioners and Health Issues - (http://www.streetdirectory.com/travel_guide/32391/home_improvement/ air_conditioners_and_health_issues.html)
  2. The Hidden Hazards Of Air Conditioners - (http://ezinearticles.com/?The-Hidden-Hazards-Of-Air-Conditioners&id=266708)
  3. Mold Classes & Classes of Mold-Related Illness - (http://www.inspectapedia.com/sickhouse/moldclasses.htm)
  4. Problems Caused by a Dirty Air Conditioner Filter - (http://www.ehow.com/facts_7653739_ac-air-filter-dirty.html)
  5. How to Remove Smells From Your Air Conditioner - (http://www.doityourself.com/stry/how-to-remove-smells-from-your-air-conditioner)


alex17pat Wednesday, June 28, 2017

Turning on the AC in the car as as soon as you enter can cause cancer as benzene gets accumulated..Please do not turn on the A/C as soon as you enter the car. Open the windows after you enter your car for few minutes and then turn on the AC after a couple of minutes.

greensandal Monday, June 10, 2013

air conditioners that uses new technology and are becoming advanced day by day.To ensure proper working and make best use of it we should check it periodically

Most Popular on Medindia