There's asecondalternative: A growing number of New Yorkers are going for duct-free AC systems that involve a small, wall-mounted indoor fan powered by a separate outdoor unit the size of suitcase.
"The risk is then clear to the end user, and they can then run asecond simulator showing how alternative software can be used to mitigate the risk, " explained Mr Wilkinson.
It is clear from over 40 years of research on heart disease that the first alternative has a strong effect, whereas data for the secondalternative are much weaker.