This paper presents the first results of 7Be and 210Pb specific activities in cloudwater and investigates their respective differences in cloudwater and rainwater. Our data and analysis show that temporal variation of the 7Be/210Pb activity ratio in cloudwater are caused by multiple sources of air masses, with increased 7Be/210Pb activity ratios corresponding to the advent of maritime or high-altitude air masses. The measured specific activities of 7Be and 210Pb in cloudwater samples span three orders of magnitude and correlate strongly with the acidity of the samples. From this correlation and the observation that specific activities of 7Be and 210Pb are higher in the more acidic cloudwater, we suggest that 7Be and 210Pb in aerosol particles can be desorbed by H+ ions.