I understand that smoke is noxious, but I am still somewhat bewildered by the lack of corroborating historical data. My own grandparents grew up in fairly mode

I understand that smoke is noxious, but I am still somewhat bewildered by the lack of corroborating historical data. My own grandparents grew up in fairly modest rural settings, where burning wood was literally the only way not to freeze (I am talking about the 1930s here). At least one of their native villages was located in a tight valley where smoke tends to stay. But lung disease wasn't that much of a problem among them and their neighbors. People typically died of heart attacks, strokes etc., or lived to be fairly old. (Two of my four grandparents made it to 90.) I would expect a much more prominent data peak there. With other toxic substances, we often have it. With asbestos, even ancient Romans knew that slaves who mined asbestos died early of some weird lung disease etc.; the ancients lacked equipment, but were often good observers anyway.