The on-board carbon dioxide concentrations and ventilation performance in passenger cabins of US domestic flights

Abstract

Billions of people travel on airplanes every year, making the aircraft cabin a critical environment to understand with regard to public health. The main control over indoor environmental quality in the cabin is ventilation; therefore, maintaining sufficient ventilation rates on-board is essential for creating healthy and comfortable cabin environments. We measured real-time CO₂ concentrations, an indicator of ventilation rates, and cabin pressure in the passenger cabins of 179 US domestic flights from boarding through deplaning. The average CO₂ concentrations were 1353 ± 290 ppmv (mean ± SD) and the estimated outside airflow rates were 5.77 ± 2.09 L/s/p across all flights. The results indicated that 96% of observations met the minimum recommended outside airflow rates for acceptable air quality (3.5 L/s/p), but only 73% met the rate required in FAA design requirements (4.7 L/s/p), during flying phases. The CO₂ levels on all flights were well below the occupational exposure limit of 5000 ppmv. Statistical analysis indicated that the ventilation rates during boarding phases were significantly lower than the others. The findings are of particular interest because low ventilation in other settings has been associated with increased rates of disease transmission, increased upper respiratory symptoms, and worse performance on cognitive function tests. Verification of ventilation performance rather than reliance on design estimates for determining compliance with ventilation standards is recommended.