In addition to the causes of asthma proposed by Dr John Mansfield in his book Asthma Epidemic (WDDTY vol 8, no 8), there appears to be a more fundamental cause which has been overlooked. The clues are to be found in his text.
The year 1958, the date from which the massive increase in asthma began, was also the same year as the fallout from the worst ever nuclear disaster in Kyshtym (former USSR).
Then 1986, the date of the next "dramatic increase" in asthma was the year of the Chernobyl explosion, with similar consequences. Coincidence? I don't think so.
By previously understood medical standards, we are no longer "normal", and we have consequently been subject to new and unusual diseases, whose pattern is otherwise not explainable by accepted medical knowledge. Ali Bense, Wales.....