The committee reached the following conclusions with respect to exposure conditions and health concerns:
* Reduced cabin pressure may adversely affect health-compromised people, particularly those with cardiopulmonary disease.
* Elevated O3 concentrations have been associated with airway irritation, decreased lung function, exacerbation of asthma, and impairments of the immune system.
* Exposures to allergens (such as cat dander) have been reported to cause health effects, but have not been definitively documented in aircraft.
* Transmission of infectious agents from person to person has been documented in aircraft, but the most important transmission factors appear to be high occupant density and the proximity of passengers. Transmission does not appear to be facilitated by aircraft ventilation systems.
* Low relative humidity might cause some temporary discomfort (e.g., drying eyes, nasal passages, and skin), but other possible short- or long-term effects have not been established.
* Pesticides that are used on some international flights can cause skin irritation and are reported to be neurotoxic, although of low toxicity in humans.
* During abnormal operating conditions, exposure to engine oils, hydraulic fluids, and their degradation products (such as CO and formaldehyde) might occur. No data have definitively linked exposure to these compounds with reported effects in cabin occupants.
http://www7.nationalacademies.org/ocga/testimony/Aircraft_Cabin_Environment.asp
