There are two environments that can be regularly encountered which are notorious for breeding illness. One of them applies only to small children and their parents—the plastic ball pits at Chuck E. Cheeses are utterly filthy and impossible to sterilize. A responsible parent will never let their booger eater near them; you might as well let your kid play with a used hospital bedpan…at least there is only one person’s shit in them.

The other environment is nearly any mode of public transportation. Planes, trains, and buses are ridiculously unhealthy places to spend any kind of time. Let’s explore why after the jump.

Despite what many people might assume, the New York City Subway cars are actually quite clean; as they are built entirely of plastic and steel, they are all hosed down top to bottom with soapy hot disinfectant spray several times per week. (I still wouldn’t recommend that a straphanger touch his eye, nose, mouth, or ears after a ride until he’s had the chance to wash his hands.)

However, any mode of public transportation that features upholstery or fiber seats are hotbeds of filth and viruses. The deceptively clean Washington DC transit system or the Bay Area Rapid Transit are great examples; with their carpet and woven fiber seats, they may get vacuumed on a regular basis, but the seats and armrests are rarely washed thoroughly. Multiply this lack of infrequency by two for any trains or buses with vinyl upholstery. In other words, the nicer the public environment, the more difficult/expensive it is to clean, and therefore the less often it is.

Of all public transportation modes, planes are far and away the most hazardous to your health; because you’re dealing with a closed environment with recirculated air, any airborne illnesses tend to stay in the cabin. Airborne bacterial diseases that can be caught in airplane cabins include pneumonia, meningitis, and TB. Airborne viruses that can be caught in airplane cabins include the flu, measles, mumps, chicken pox, SARS, and the common cold.

Up to 50% of the air you breathe while flying is recirculated—the greater the percentage of fresh air, the more fuel is spent, and the airlines are cutting every corner possible these days. The pilot is in charge of the amount of fresh air the cabin receives, and as the cockpit is on a separate bank, you’d better believe that the cockpit’s air is invariably fresher than yours. Up to ten times fresher.

You are probably breathing too low a percentage of fresh air while flying if:

•You are having difficulty concentrating on tasks such as reading or business work.
•Your lungs ache.
•Your skin feels clammy.
•You feel nauseated (and there’s no turbulence).
•You have a headache.

Airborne diseases spread when we cough, sneeze or just breathe, and when the air is highly recirculated there is little protection from the coughing guy who sits fifteen rows behind you; there is nothing to prevent his illness from hitting you on the rebound. Plus, there is usually no fresh air in the plane at all until the plane is in the air, so the longer you sit on the tarmac, the more recirculated air you are breathing.

Kind of makes you want to just stay home, doesn’t it?

ADDENDUM 2/22/07 : My claim above of the cockpit being on a separate (fresh) air bank is rather contested; the “Ask A Pilot” column has a reputation for credibility, and if that columnist maintains that this is a myth, this calls my (as yet unnamed) sources into question. My initial source was none other than the Diana Fairechild of the Air Travel Health News website, who I referenced later in this post. Now, call me a suspicious and doubtful guest, but I would imagine that a health-centric whistle blower would have less to cover up than a pilot over this issue. In the end, whatever; it’s about the quality of air in the cabin that matters to you in the end, and one thing that isn’t being contested is who is in charge of that…it’s the pilot. Short answer: complain if the recycled air is getting to you, what are they going to do, pull over and kick you out?