Grandma's moistening kettle may have held off flu:
The correlation with flu and low humidity is important because in cold winter weather, when flu is most common, even a high relative humidity reading may indicate little actual moisture in the air, and the less moisture there is, the happier the flu virus seems to be.Shaman and co-author Melvin Kohn, an epidemiologist with the Oregon Department of Health Services, reanalyzed data from a study published in 2007 in the journal PLoS Pathogens by researchers at Mount Sinai School of Medicine in New York. That report found there were more flu cases when it was colder and drier.
The Oregon researchers said relative humidity could only explain about 12 percent of the variability of influenza virus transmission and 36 percent of virus survival in the 2007 study.
In their new analysis, Shaman and Kohn said using absolute humidity explains 50 percent of influenza transmission and 90 percent of virus survival.
Warm air “holds” more water at the same relative humidity.