178 SOFT TTT oT Ty to TT — | | | (7) ALTITUDE, KM 4 | 25 [— A >0.15 p RADIUS X 0,02 TO 0.15 p RADIUS @ <0.02 p RADIUS ptt iitl 197! aiil + 10! iif 10? py ail i 10° Mce/%S- ACTIVITY RATIO ity 104 TT TT? “Tit atig TT TT? TUT TT bt p y 1 ex {| | | a ALTITUDE, KM | 4 | BB 30 | 10° pie 107! 30 pitt 10° | iit 10! 1iil 957 -/95- ACTIVITY RATIO 10° tit 103 rT 20 -— | 7 ALTITUDE, KM Le 10 a 5K _ 0 1072 | ttl 107! | L tut 10° 957 -/“4Ce ACTIVITY RATIO L L {i 10! . Fig. 8—Activity ratios for impactor —filter collections over Minneap- olis, Minn. (45°N 93°W), on Aug. 15, 1963.