Here's why you should think twice before turning off the AC vents on an airplane

Whether you are a frequent flyer or a once-in-while-hopper on the plane, if you are turning the AC vent off, whether feeling chilly or afraid of getting sick, you might want to reconsider.

In fact, using the vent may help you from getting sick by keeping the infectious microbes at bay.

Dr Mark Gendreau, the medical director and vice chair of emergency medicine at Lahey Medical Center-Peabody, and an expert on the spread of infectious diseases associated with air travel told Travel+Leisure that, surely, the air ventilation system on aeroplanes have got a bad reputation but those are completely unfounded.

The people have grown this misconception that they may get sick because what they are breathing might be the air which has come from someone else’s lungs. The reason behind this misinformation is that there has been hardly any research on the topic until the last 15 years.

“The flow pattern of air on an aircraft doesn’t necessarily work front to back, or back to front. It’s actually compartmentalized into various sections on the aircraft. As a rule of thumb, the air that you’re typically breathing and exposed to is usually anywhere from two to five rows surrounding your seat,” the Travel+Leisure report quoted Dr Gendreau.

Airborne viruses like Tuberculosis or Measles can hang in the air for more than five hours, hence it is very imperative to ventilate. “For airborne viruses, it is incredibly important to ventilate, since ventilation becomes your main means of control besides isolating the affected person,” Gendreau said.

How ventilation on a plane works

The air we breathe out exits from a grill, often located below the window where the wall meets the floor. The outgoing air combines with air outside before going through an air filtration system called HEPA (High-Efficiency Particulate Air) which clears away the dust and microbes.

The video above shows the overhead air distribution vent. The air is 'smoky' because cold air from air conditioning system gets condensed when it mixes with the hot air inside

The cleaned air then re-enters the plane to come out from the overhead distribution nozzle. However, only half of the air we breathe out re-enters the plane. Typically, this process happens once every two to four minutes.

HEPA filters are pretty efficient and can filter out more than 99 percent of the microbes and dust present inside the plane.