Emission inventory of airport activities in Lombardy (Italy): methodologies and results

Within the framework of the atmospheric emission inventory of the Lombardy Region, a region with 9 million inhabitants in Nor-them Italy, a detailed assessment of emissions from aircrafts and airport land activities in the three main airports of the region has been made for the year 2001, 2003 and 2005. The inventory is based on a daily evaluation of LTO (Landing and Take-Oft) cycle for each aircraft category, derived from data recorded in every airport, and on emission factors proposed by the EMEP/CORINAIR Emission Inventory Guidebook for the main aircraft types. The paper shows hourly, daily and monthly emission patterns computed for every airport, as well as average emission factors. Results point out that airports in Lombardy represent an interesting source of NOx emissions (about 1% of total NO(x) emissions in Lombardy in 2005), whereas for PM and other pollutants the contribution is lower. A critical point of the emission assessment is the availability of reliable emission factors: for 35% of flights the emission factors were not available for the exact aircraft model and were hence based on similar types in size and engine characteristics. Ground support equipments are also considered basing on fleet data and fuel consumption in every airport, as well as average emission factors proposed by the reference methodology for airport land activities. LTO emissions are far higher than emissions from diesel vehicles used in land activities. NO(x) emission density for airport area is comparable to those in urban areas, although emission elevation is far higher.