SYMPOSIUM ABSTRACT: This symposium will feature presentations by experts in the development, deployment, and interpretation of sensors for measuring human exposure to air quality, with a focus on transportation-related exposure to fine particulate matter, carbon monoxide, ozone, and other traffic-related air pollutants (TRAP). The symposium participants represent active research teams in Europe, the United States, and China. Issues to be addressed during the symposium include user and policy needs, research needs and opportunities, instrumentation and capabilities, study objectives, study design, field data collection methods, quality assurance, data processing and analysis, and inferences from data. Methods for measurement, study design, and data analysis will be illustrated based on case studies. The case studies include measurements of traffic-related air pollution in the cities of Surrey (UK), Raleigh (USA), and Hong Kong.