I've seen warnings, referencing high dew points, as "oppressive" and dangerous to "high risk" groups or people. What is the definition of high risk person? and what is the danger level at oppressive to the high risk people?

MIKE MOSS SAYS:        Mick,      Specifics are usually lacking in such warnings and I don't have precise listings or thresholds available to pass along. The "high risk" individuals for high humidity levels (the "oppressive" description is usually reserved for dew points over 70 and especially those in the mid 70s and up) would typically include those with serious cases of emphysema, asthma and more generally COPD syndromes and other respiratory illnesses that have been clinically or anectdotally observed to be exacerbated by high humidity levels (and conversely in some cases by very low humidity levels as well). Likewise, I don't know of a good source for quantification of the risk levels stratified by dew point or relative humidity. It seems likely this would vary greatly by individual with contributions from age, height, weight, severity of diseas and the like - in other words, a good question for those with respiratory illnesses to discuss with their doctor.