SULFUR-DIOXIDE AND NITROGEN-DIOXIDE LEVELS INSIDE AND OUTSIDE HOMES AND THE IMPLICATIONS ON HEALTH-EFFECTS RESEARCH

This paper presents the results of 1 year's indoor and outdoor monitoring for SO2 and NO2 in six communities with widely varying outdoor levels. The representativeness of the monitoring in defining exposure is discussed for each city. In four of the communities, outdoor SO2 levels are less than 50% of the annual NAAQS, while violations are found in the other two. Annual average indoor levels of SO2 are never found to exceed the standard. In fact, indoor SO2 concentrations are 20 to 70% of the outdoor levels. Indoor NO2 levels, on the other hand, can exceed outdoor levels by a factor of two, depending on the type of cooking appliance used, but do not exceed the standard. The impact of various heating and cooking systems on the indoor concentrations of these gases, as well as the type of appliances used in the house, is evaluated. © 1979, American Chemical Society. All rights reserved.