Iodine, bromine, and chlorine in winter aerosols and snow from Barrow, Alaska

Iodine, bromine, and chlorine have been determined in atmospheric aerosols and in snow collected in Barrow, Alaska, during January, 1965, by means of neutron activation analysis. Aerosols collected using both an aircraft collector by impaction and a ground-based 1.0 µ Type EA Millipore filter collector show concentrations of Cl to be much more variable than either Br or I, and I/Br points cluster at 0.1-0.2 gI/gBr for the filter samples. Cl varies from <0.02 to 4 µg Cl/m3STP in the filter samples, and the aircraft concentrations agree with those taken by filter on the same days. Filter Br is 1–30 ngBr/m3STP and I is 0.3–10 ngI/m3STP, and the ratios I/Cl and Br/Cl increase sharply with decreasing Cl.

Snow samples from the ground have Br/Cl somewhat greater than in sea water, although all halogen concentrations decrease with increasing distance from the sea up to 10 km. Assuming a mixture of undifferentiated sea salt and a more permanent atmospheric component, we estimate for the atmospheric component in the snows I/Br ~ 0.2. Sea water, sea ice, and related samples were analyzed, and I/Cl = 4 x 10-6 gI/gCl is normal for sea water, although Br/Cl = 3.8 times 10-3 gBr/gCl stands a little high.