Airline cabin air quality is worse than before smoking ban (2016)
traveller.com.au
traveller.com.au
Here you go:
https://www.fsis.usda.gov/sites/default/files/media_file/202...
High CO2 levels may be bad, but it's a huge leap to go from there to saying that the air was better when it had cigarette smoke.
For that matter, both of your links say that CO2 levels below 5,000 ppm have no ill health effects other than perhaps drowsiness. And it looks like planes cabins are usually about 1,000-1,500 ppm -- elevated, but again, not clearly worse than having cigarette smoke in the air.
From the article:
> They don't change the air as regularly, as it costs money to bring fresh subzero air in from outside and heat it to cabin temperature. By the time you reach your destination the percentage of carbon dioxide in the cabin from breathing is much higher than it should be.