Explanation of Airflow

Airflow has been measured by the traditional cubic feet per minute per passenger (cfm) of air infused by the over-head dispenser. This measurement contains an area component (cubic feet) and a passenger component. According to this formula, ventilation is specific to each passenger’s seat space.

The accumulation of expired human waste gas, known as Carbon Dioxide (CO2), is distributed through-out the entire cabin and measured as parts per million (ppm). Passengers cannot control their exposure to this collective accumulation of CO2. Passengers can control individual air-flow providing the pilot turns on the ventilation system. Each person has a unique tolerance to accumulated CO2 & perceived ventilation. The FAA has determined that in-flight CO2 concentrations not exceed 5000 ppm. A public building is less then 1000 ppm.

The calculation of cubic footage per passenger seat space is challenging, especially since these spaces keep getting smaller and smaller.

Optimal airflow in a building is 15 cfm.

The FAA has determined that optimal ventilation during flight is 10 cfm.

Ventilation on the ground while at the gate, tarmac. or awaiting departure has been described as zero on occasion.