Estimation of airborne ¹⁰⁶Ru activity concentration from total beta activity of PM₁₀ particle fractions

Airborne radio-ruthenium, as a result of an accidental release, presents a risk for occupational and public exposure. In fall 2017, a detection of ¹⁰⁶Ru was reported by the European atmospheric radioactive contamination monitoring networks. We investigated the daily specific total beta activity of PM₁₀ particle fractions samples. The presented method enables indirect determination of airborne ¹⁰⁶Ru activity concentration from total beta activity, in case ¹⁰⁶Ru was confirmed as single excess radiological pollutant. This allows for daily measurements and time-resolved ¹⁰⁶Ru activity concentration data. We estimated the indicative committed effective dose due to ¹⁰⁶Ru inhalation for the Croatian population during the exposure period. Although the estimated dose value of ∼169.7 nSv, for ∼6-d duration of ruthenium air pollution, was very low, it was ∼40 times higher than the value for H_inh from inhalation of other radionuclides (⁹⁰Sr + ¹³⁷Cs + ⁴⁰K + ⁷Be). (authors)