Percentiles Site Year Min. 10 30 50 70 90 95 99 Max No. of Obs. Ny 1989 .000 .018 .023 .028 .032 .042 .045 .049 .061 3946 Alesund 1990 .000 .017 .028 .032 .035 .040 .043 .048 .059 4895 Norway 1991 .000 .024 .030 .033 .036 .040 .042 .047 .062 4972 1992 .000 .021 .028 .032 .035 .043 .046 .051 .059 5067 1993 .000 .022 .028 .031 .034 .040 .044 .047 .051 5122 Pt. Barrow,1973 .003 .009 .015 .020 .024 .031 .034 .036 .038 5118 AK 1974 .003 .013 .018 .022 .028 .034 .036 .040 .043 3913 1975 .003 .015 .019 .023 .028 .033 .035 .040 .048 4602 1976 .001 .005 .015 .019 .023 .032 .034 .036 .041 4965 1977 .001 .007 .018 .022 .025 .030 .033 .036 .042 4818 1978 .003 .014 .021 .025 .028 .035 .038 .041 .047 4675 1979 .003 .013 .017 .021 .028 .036 .039 .044 .052 4665 1980 .000 .011 .019 .023 .026 .032 .034 .038 .044 4829 1981 .000 .017 .022 .025 .029 .034 .037 .043 .048 5027 1982 .000 .005 .022 .025 .031 .036 .037 .043 .046 5019 1983 .001 .014 .021 .025 .029 .035 .038 .040 .045 4967 1984 .000 .002 .019 .024 .027 .037 .040 .042 .049 4423 1985 .000 .018 .022 .027 .030 .034 .035 .040 .051 4388 1986 .000 .009 .019 .023 .027 .032 .035 .041 .067 4958 1987 .001 .016 .023 .027 .031 .037 .040 .044 .051 4892 1988 .000 .015 .022 .026 .030 .034 .036 .047 .092 5122 1989 .000 .012 .019 .025 .032 .040 .042 .047 .053 5093 1990 .000 .015 .022 .026 .031 .036 .038 .046 .052 5123 1991 .000 .014 .023 .027 .031 .036 .040 .043 .051 5053 1992 .000 .012 .017 .020 .024 .029 .030 .034 .044 4801 1993 .000 .013 .018 .021 .025 .030 .032 .034 .037 5021 1994 .000 .005 .017 .023 .028 .032 .034 .037 .044 4516 South 1975-76 .012 .020 .024 .027 .033 .037 .038 .040 .043 4892 Pole 1976-77 .012 .019 .022 .024 .026 .029 .030 .034 .041 4888 1977-78 .014 .021 .025 .028 .031 .033 .035 .037 .044 3465 1978-79 .016 .021 .025 .028 .032 .034 .036 .041 .045 4896 1979-80 .014 .020 .022 .025 .027 .034 .035 .037 .040 4034 1980-81 .010 .017 .021 .023 .026 .030 .032 .037 .039 4927 1981-82 .018 .022 .027 .032 .034 .039 .041 .043 .045 3575 1982-83 .014 .019 .022 .024 .027 .030 .030 .032 .033 5043 1983-84 .013 .019 .021 .025 .028 .032 .033 .035 .037 4677 1984-85 .014 .019 .022 .026 .031 .035 .037 .041 .046 4407 1985-86 .012 .018 .022 .024 .027 .030 .031 .033 .035 4989 1986-87 .012 .017 .020 .023 .028 .034 .035 .037 .039 5014 1987-88 .011 .018 .021 .023 .027 .029 .031 .035 .038 4245 1988-89 .009 .018 .021 .025 .028 .032 .033 .037 .041 4849 1989-90 .013 .018 .022 .023 .025 .029 .031 .035 .038 4617 1990-91 .013 .018 .021 .023 .026 .029 .032 .035 .040 4927 1991-92 .007 .015 .018 .021 .025 .027 .029 .031 .032 4849 1992-93 .012 .017 .020 .024 .026 .031 .033 .037 .040 5060 1993-94 .012 .016 .019 .023 .027 .031 .032 .036 .040 4895 Teddy Roos.1983 .000 .018 .026 .033 .039 .050 .056 .066 .080 2091 NP, ND 1984 .000 .017 .025 .032 .039 .047 .050 .059 .068 4923 1985 .000 .019 .026 .032 .038 .046 .049 .054 .061 4211 1986 .004 .017 .027 .033 .039 .047 .050 .056 .062 4332 1987 .003 .016 .026 .032 .038 .046 .049 .054 .064 3726 1988 .001 .026 .036 .043 .049 .057 .061 .067 .078 2826 1989 .004 .023 .032 .039 .045 .054 .058 .065 .073 4206 1990 .004 .019 .028 .035 .041 .050 .053 .063 .070 2874 1991 .006 .021 .030 .036 .042 .050 .055 .061 .070 3276 1992 .005 .019 .027 .033 .039 .047 .050 .056 .063 4332 1993 .004 .018 .025 .031 .037 .045 .048 .055 .064 4281 1994 .000 .018 .028 .035 .041 .049 .052 .058 .079 4644 Badlands1989 .006 .020 .027 .034 .041 .049 .053 .060 .071 4840 SD 1990 .006 .019 .027 .032 .037 .044 .048 .054 .063 4783 1991 .005 .020 .028 .033 .040 .047 .050 .056 .066 4584 Yellowstone1988 .002 .020 .029 .037 .044 .054 .058 .070 .098 4257 NP, WY 1989 .002 .018 .027 .036 .044 .051 .056 .063 .071 4079 1990 .000 .015 .023 .029 .036 .043 .046 .053 .060 4663 1991 .004 .020 .030 .037 .042 .048 .051 .057 .064 4453 1992 .001 .018 .029 .036 .042 .051 .056 .064 .075 4384 1993 .000 .018 .028 .036 .042 .047 .050 .054 .060 4399 1994 .003 .022 .033 .040 .046 .053 .056 .062 .072 4825 Denali, 1988 .003 .018 .024 .028 .033 .044 .050 .053 .056 4726 NP, AK 1990 .003 .017 .024 .029 .034 .040 .043 .048 .050 3978 1991 .005 .018 .024 .028 .034 .041 .043 .047 .057 4809 1992 .003 .016 .023 .028 .034 .044 .047 .050 .054 4800 1993 .002 .017 .023 .028 .033 .041 .043 .048 .055 4773 1994 .003 .017 .022 .027 .033 .042 .045 .049 .053 4807 Sand Dunes 1989 .011 .031 .037 .041 .045 .050 .051 .056 .063 4436 NM, CO 1990 .010 .030 .037 .041 .045 .051 .055 .061 .070 4624 1991 .008 .029 .037 .043 .048 .055 .058 .065 .077 4130 Glacier NP1989 .000 .003 .015 .026 .036 .046 .050 .058 .067 4770 MT 1990 .000 .001 .014 .026 .035 .044 .047 .052 .066 5092 1991 .000 .001 .014 .027 .036 .046 .049 .056 .062 5060 1992 .000 .001 .013 .025 .033 .043 .048 .055 .077 4909 We wish to acknowledge the U.S. National Park Service, NOAA, and NILU (Norwegian Institute for Air Research) for supporting the collection of the O3 monitoring data at these rural and remote sites.