Air quality and public health impacts of UK airports. Part I: Emissions

The potential adverse human health and climate impacts of emissions from UK airports have become a significant political issue, yet the emissions, air quality impacts and health impacts attributable to UK airports remain largely unstudied. We produce an inventory of UK airport emissions – including aircraft landing and takeoff (LTO) operations and airside support equipment – with uncertainties quantified. The airports studied account for more than 95% of UK air passengers in 2005. We estimate that in 2005, UK airports emitted 10.2 Gg [−23 to +29%] of NOx, 0.73 Gg [−29 to +32%] of SO2, 11.7 Gg [−42 to +77%] of CO, 1.8 Gg [−59 to +155%] of HC, 2.4 Tg [−13 to +12%] of CO2, and 0.31 Gg [−36 to +45%] of PM2.5. This translates to 2.5 Tg [−12 to +12%] CO2-eq using Global Warming Potentials for a 100-year time horizon. Uncertainty estimates were based on analysis of data from aircraft emissions measurement campaigns and analyses of aircraft operations. The First-Order Approximation (FOA3) – currently the standard approach used to estimate particulate matter emissions from aircraft – is compared to measurements and it is shown that there are discrepancies greater than an order of magnitude for 40% of cases for both organic carbon and black carbon emissions indices. Modified methods to approximate organic carbon emissions, arising from incomplete combustion and lubrication oil, and black carbon are proposed. These alterations lead to factor 8 and a 44% increase in the annual emissions estimates of black and organic carbon particulate matter, respectively, leading to a factor 3.4 increase in total PM2.5 emissions compared to the current FOA3 methodology. Our estimates of emissions are used in Part II to quantify the air quality and health impacts of UK airports, to assess mitigation options, and to estimate the impacts of a potential London airport expansion.