Anyone who grew up between the 1940s and 1970s has undergone what the Bigots' Action Group of the British Medical Association would term 'child abuse'. Upstairs on the bus, schoolchildren and smokers would share a journey in a thick fug of tobacco smoke; at school, the head's office leaked smoke from around the door and masters would stand chatting in corridors with ciggies in their hands. At the cinema, smoke writhed in wonderful swirls in the projector's beam, and on the tube the smoking carriages were packed with a score of smokers all competing to wreath the carriage in a dove-grey mist.
Since those days, smoking has dramatically declined, has disappeared altogether from public transport and buildings, to the extent that most children now never even get a whiff of a ciggie.
Yet over the same time, Asthma rates in children have increased exponentially. Indeed, one can convincingly correlate the decrease in childhood exposure to tobacco smoke and the increase in childhood Asthma.
In developing countries, where smoking is increasing and tobacco companies are expanding markets, there has been no increase in childhood Asthma. At all.
Honest scientists admit they have no idea why childhood Asthma has increased in the developed world, but that it's unlikely to have anything to do with tobacco smoke. An increase in antibiotics prescribed by doctors is statistically more significant than other causes.
Dishonest factions, such as the untutored bigots in the BMA and the medical colleges, will happily lie in support of their spurious claims as dishonestly as climate change experts or politicians.
Don't believe their lies.