In this work we describe sampling and analytical methodologies for nitrogen dioxide and respirable particles in indoor environments. Advantages and disadvantages of each technique are explored. To indicate the utility of certain of these techniques, results from large-scale surveys of exposure to nitrogen dioxide are presented. These surveys include (a) population-based home characterizations and personal monitoring designed to assess exposures, (b) investigations of nitrogen dioxide and respirable particle concentrations and associated health effects from an epidemiological point of view, and (c) the investigation of shortterm exposures to nitrogen dioxide during commuting and cooking events. Issues associated with field implementation of the samplers, such as quality control and ease of use, are discussed.