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Brian,
The techniques Dr. Cohen used were primarily short
term (several days) charcoal based measurements generally performed in
the lowest level of the homes.
In the Iowa study, were used both year long alpha
tracks and glass-based measurements in various parts of the house to reconstruct
both past radon gas and progeny exposure.
Regarding your observation below. Yes,
people in lower socioeconomic group have a higher smoking rate. In
addition, they generally do not have as much use of central air
conditioning as others in higher socioeconomic groups. Lower
socioeconomic individuals may have more radiator heating or gravity floor
heating that can stratify radon concentrations more between the floors. On
the other hand stratification can also occur by the more modern use of electric
heat that does have a forced air component. Forced air furnaces in the
basement tend to circulate the radon into the upper floors and create a negative
pressure in the basement as compared to the upper floors. Have you ever
noticed how much air goes under the door toward the basement when a forced air
furnace is running?
Regards, Bill
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