This is a study undertaken by the Building Research Establishment Ltd (BRE) for the UK cross-departmental Aviation Health Working Group ("AHWG") to monitor cabin air quality aboard older aircraft types utilised in high volume short haul operations.
The purpose of this work is to address two key recommendations made in the House of Lords report on Air Travel and Health with regard to in-flight measurements of air quality parameters.
The AHWG acknowledged that the current European CabinAir project would satisfy most of the elements with regard to these recommendations.
CabinAir has monitored key air quality parameters on board 50 flights representing the four generic commercial passenger aircraft types. However, the choice of aircraft types and operators in that project excluded older, classic types and operators other than "flag carriers".
To determine whether the cabin air quality of the older aircraft - specifically the BAe 146 and Boeing 737 Classic aircraft - was in any way an issue, and whether they differed significantly from newer types of aircraft.
Two aircraft types, the BAe 146 (ventilation mode selected to provide 100% outside air to the cabin) and Boeing 737-300 (supply into the cabin is a mixture of outside and recirculated air) were selected.
The intention of this current study was not to compare the two aircraft types with one another, nor to carry out detailed statistical analysis of the monitored data, nor to monitor the air quality during any "unusual circumstances".
The emphasis was on obtaining data from scheduled flights, reporting the results, and comparing with any health-based guidance levels that exist. In total, fourteen flights (8x BAe146, 6x B737) were monitored. These comprised both UK domestic flights and flights between the UK and other European countries. The flight times ranged between approximately 1 and 3 hours. Air quality parameters were monitored not only during passenger boarding and disembarkation, but also during all phases of flight - from take off, through cruise, and then to descent.
The measurements were carried out not only at specific stationary locations within the cabin, but also through traverses across seat rows and along the aisles.
The results of monitoring the following air quality parameters within the cabin, were as follows:
- Cabin pressure – the average cabin altitude in cruise never exceeded the regulatory ceiling of 8000 ft. For periods during climb and descent, the rates of altitude increase and decrease did exceed the recommended values;
- Air and globe temperature – mean values usually below 26°C;
- Relative humidity – during cruise, mean RH within the BAe146 was 12.7%, and 20.0% for the B737;
- Air speed – at head height were typically below 0.2 m/s;
- Carbon monoxide – all values were of a similar level or less than those found in studies of air quality in homes in England. Mean levels somewhat higher on the ground than during cruise;
- Carbon dioxide – mean levels were typically between 700 and 2000 ppm during cruise, and did not exceed regulatory requirements;
- Nitrogen dioxide – all levels were below the WHO recommendations, as well as below those values found within a sample of kitchens in gas cooking homes in England. Levels of nitrogen dioxide were higher whilst on the ground than during cruise;
- Volatile organic compounds – all measured values are well within the available guidance on air quality for internal environments. Typically, the highest concentrations were found while the aircraft were on the ground;
- Carbonyls (e.g. formaldehyde, acetaldehyde, acetone, and acrolein) – low levels of all compounds, and well below World Health Organisation (WHO) limits, and HSE guidelines;
- Semi volatile organic compounds - For the BAe 146, analysis focused on testing for Exxon 2380 (used for engine and APU oil) and Skydrol (used for hydraulic oil). For the Boeing 737 flights, analysis focused on Aeroshell Turbine oil 560 (used for engine oil) and Skydrol. Very low (if any) indication of these oils present in the cabin environment of those monitored flights;
- Bacteria and fungi – higher levels whilst the aircraft is on the ground than during cruise;
- Surface dust, dust mite allergens and cat allergens – very low levels found on board;
- Ultrafine particles – elevated levels were always found during the ground phases – levels in cruise are several orders of magnitude lower.
Overall, levels of measured air pollutants on board the scheduled 14 flights were always below any recommended health limits. Although it was not possible to make detailed comparisons with the newer types of aircraft monitored within the CabinAir project, the results from this study indicated that the levels of parameters measured in this project were broadly in line with the CabinAir measurements. Therefore, no obvious difference in the cabin environment between these older types of aircraft and the newer types was seen.
User aspects: No results directly relevant to this theme. However, please note that some findings relevant to the project's key theme (Air) are generically applicable.
Safety and security: No results directly relevant to this theme. However, please note that some findings relevant to the project's key theme (Air) are generically applicable.