Measurements of CO2, aerosol scattering, condensation nuclei, and ozone made continuously at the NOAA baseline observatory at Barrow, Alaska, have been analyzed in conjunction with low-level trajectories of airflow arriving at Barrow during periods from January to March of 1977 and 1978. Ozone concentrations had no dependence on wind direction whereas CO2 and aerosol values did show directional dependence; higher values occurred with airflow from the Arctic Basin than with that from the south. The aerosol analyses support the hypothesis that Arctic haze results from advection of aerosols to the Arctic from European or North American anthropogenic sources. CO2 results suggest two possible sources for the higher concentrations: transfer from the ocean through annual sea ice to the Arctic atmosphere or advection from midlatitude anthropogenic sources similar to that for the Arctic haze.