Executive Travel

* Name: Leonard Kane

* Position: Airline pilot, USAir

Let’s talk about some facts and figures from the scientific investigations on in-flight air quality.

* Airflow: The total volume of cabin air is exchanged approximately every two to three minutes. Airflow for first class and business class is the same as coach. But coach’s higher-density seating creates a lower airflow per passenger. The flight station has a higher airflow than the cabin to provide cooling for electrical equipment and account for increased solar loads and nighttime heat loss through the large windows. The higher air flow also gives a positive pressure to the flight station to prevent the ingress of smoke from adjacent areas in the event of an emergency.

Virtually all newer-production jet airplanes provide 50% conditioned fresh air and 50% recirculated air for a total air supply of approximately 20 cubic feet per minute per passenger. Most older jets don’t have an air-recirculating system. The average office building uses 75% to 95% recirculated air.

The recirculated air is filtered and cleaned through high-efficiency filters that are similar to those used in a “clean room,” where computer chips and other stuff that needs to be better than squeaky clean are made.

Some critics suggest increasing the conditioned fresh air to 100% and eliminating all recirculated air. That would lower the cabin’s concentration of carbon dioxide an insignificant amount. However, it would raise the potential cabin ozone concentration and lower the relative humidity, which, according to an Air Transportation Assn. study, could cause sore throats and headaches.

* Microbial aerosols: These are the bad buggies that reporters complain about. They include viruses, bacteria, fungal spores and other scary stuff with weird-sounding medical names. The TV program “20/20” covered these in detail. What they didn’t say was that these same buggies are everywhere--in your house, your car, your workplace, your office, etc. You can’t avoid these things.

The same high-efficiency filters mentioned earlier remove these contaminants from the cabin. These are the same types of filters used by hospitals to keep the air clean in their organ transplant and burn treatment rooms. If doctors and patients are comfortable with the clean air in these hospital areas, maybe we can relax and enjoy the clean air in the cabin.

* Oxygen: There have been articles alleging that the airlines are starving you of oxygen. How silly! But some people believe everything they read. The air we breathe at cruise altitude is approximately 21% oxygen. Remember, we breathe at a rate of approximately one-third of a cubic foot per minute while sitting in an airplane. In the worst-case scenario, you’re getting at least 6.5 to 8 cubic feet per minute of conditioned fresh air. In other words, it’s impossible to breathe all the oxygen in the air that’s provided.

The bottom line is: Worry about crime, drugs, your family, our schools or whatever else. The cabin air quality is A-OK.