Thousands of air passengers are at risk from toxic fumes leaking into aircraft cabins, according to the Global Cabin Air Quality Executive pressure group.I know that I have experienced this on more than one flight. The practice of re-circulating air in cabins started as fuel prices rose. Taking in fresh air at high altitudes requires considerable amounts of energy - because it is bloody cold up there. But fuel is expensive to buy and to carry around. And heating up frigid fresh air uses fuel. So the air on board most planes is dry and stale - and mostly recycled. So even the smallest amount of pollution gets concentrated.
This is just one more way in which the reality of air travel departs from the imaginary world portrayed in airline commercials. Flying is, by and large, a lot less fun than it once was.