Elevated concentrations of corona ions have been measured in the vicinity of high voltage overhead lines. It is shown that the integrated ion exposure of aerosols in the corona plume is of the order of (x/u)n(x) where n(x) is the ion concentration at distance x downwind from the line and u is the wind speed. Estimated ion exposures are of order 10(11) m(-3) x s, less then 1% of the 10(13) m(-3) x s needed to cause saturation charging of 20 nm aerosols. It is suggested that it is not valid to postulate that AC corona is a health hazard as a consequence of its charging aerosols in the size range 20-125 nm.