In 2024, transit buses accounted for approximately 50.4% of total public transportation ridership in the United States, serving more than 3.86 billion riders. In-bus environmental quality plays a critical role in the health and safety of operators and passengers, as well as in overall system performance. Even on short trips, poor indoor air quality can cause discomfort and symptoms such as drowsiness, dizziness, nausea, and fatigue.
TCRP Research Report 261: Air Quality Inside Buses presents research findings and practical approaches to air management in transit buses to help maintain a comfortable and safe environment for operators and passengers under normal and emergency conditions, including those involving airborne infectious diseases. The report also provides a comprehensive review of existing studies and current air management practices, with a focus on system configurations and their performance.
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