Air Quality Monitoring All aircraft at Farnborough are classified as International Civil Aviation (ICAO) Chapter 3 or above. While this classification relates predominantly to noise emissions from engines, it can be taken as a measure of efficiency of the engine. Higher technological specifications of aircraft engines subject to regular routine maintenance produce fewer exhaust emissions. The airport has direct control over emissions produced while aircraft are taxiing and on the airport. Emissions at this level have the potential to affect local air quality. the noise abatement procedures limit ground running of aircraft engines and therefore reduce ground level exhaust emissions. Nitrogen Oxides are recommended as indicator pollutants for aircraft exhaust emissions. Nitrogen Oxides are monitored at the airport using two methods, located at a total of 13 monitoring positions. Passive diffusion tubes are located at all 13 monitoring sites. These measure the concentration of gases through the chemical change produced in chemical reagents caused by contact with the required gas as it is present in the atmosphere. The second monitoring method used is an active sampling method, pumping samples of air into an analysis chamber, producing results as 15 minute sample averages. Farnborough Air Quality Monitoring sites can be found here No results of air quality sampling outside those expected for "urban background * " locations have been recorded so far. As yet, no trends indicate any discernible impact on local air quality by the airports activities have been observed, monitoring activities in this area are ongoing. * As defined by the National Air Quality Strategy 2000 ENVIRONMENT PAGES FARNBOROUGH AERODROME CONSULTATIVE COMMITTEE An independent Consultative Committee established by TAG Farnborough in accordance with a Section 106 agreement of the Town and Country Planning Act