Re re Sy SR aRak le ad ol kee ak os RESULTS Most of the samples have been collected in the streets and buildings of New York City. A few have been collected on the rivers around Manhattan and in mines in the northeastern part of the United States. are listed in the appendix. Individual measurements A summary of the radon flask data appears in the following table. TABLE I SUMMARY OF RADON CONCENTRATIONS MEASURED WITH FLASK SAMPLES No. of Description No. of Locations Samples Avg. Ro Conc. 10-15 c/1 Range 10715 efi - Manhattan Streets 23 Precipitation _ No Precipitation Buildings Precipitation 7 OWS 14 — «§ No Precipitation Rivers . Subway Station 9 33 4 20-490 142 20-490 102 10 190 28 3 127 LT 23 20-230 211 70-10 220 100-410 70-300 6 1 8 2 111 220 "10-170 180-260 4 T 73 10-150 15 he -- 80-110,000 “Iron 5 29 -- Salt, Gypsum, etc. 4 5 Vehicular Tunnel 1 2 120 50-190 Rural and Suburban Surface Mines* Zine Tale — 3 3 5 3 -ee -- " 80-41 ,000 100-2 ,100 8,000-20,000 100-110 ,000_ Hess has been measuring radon concentration in New York City for many years. His reported average concentrations are listed in Table II. Average radon concentrations inside and outside of buildings in Sweden reported by Hultqvist are also shown for comparison. * Much of these data have been published by Saul J. Harris (3) . aay wae f, (8 0