Background: 210Pb in air has yielded insight on the sources and transit times of aerosols. In an ideal enclosed air mass (closed system with respect to these nuclides)

the residence times of aerosols can be obtained from the activity ratios of 210Pb/222Rn

210Bi/210Pb

and 210Po/210Pb. Through measuring the activity-size distribution of 210Pb in the atmospheric particulates

it is conducive to the use of 210Pb tracer study in atmosphere. Purpose: This study aims to determine the activity-size distribution of 210Pb in the atmospheric particulates. Methods: Inhalable particles samples at different particle size levels were collected by M235 impact large flow classification sampler. The activity distribution of 210Pb in different particle size scales was determined by detecting β rays of 210Bi (the first generation progeny of 210Pb)

and radioactivity of 210Pb was determined by using γ spectrometer

respectively. Results: Experimental results show that the distribution range of the specific activity (mBq·m?3) of 210Pb in atmospheric particulates is 0.0044–1.8321mBq·m?3 and the maximum are within 0.49–0.95μm size distribution. Conclusion: The activity-size distribution of 210Pb in the atmospheric particulates is mainly due to the effects of temperature

humidity

rainfall

wind speed

wind direction and other natural factors; the discrete of β counting measured data is larger than the discrete of γ counting measured data. Abstract