Emission of non CO2 greenhouse gases from landfills of different age located in central Italy

Abstract

Landfill gas is a product of the natural biological decomposition of organic material contained in wastes deposited in landfills. This denomination generically indicates a gas mixture made of methane and carbon dioxide. These gases are produced until most of the organic material in the waste has been degraded. Emissions from municipal landfill sites are therefore potentially harmful to both local and global air quality; the global emissions of an important greenhouse gas such as methane are estimated to be between 20 and 70 Tg year−1. Moreover, landfills have been shown to be a major source of anthropogenic halogenated greenhouse gases such as chlorofluorocarbons (CFCs) and their hydrogenated substitutes (HCFCs, HFCs). These long-living gases are emitted into the atmosphere as a consequence of leakage occurring in landfills where chlorine containing equipment and materials have been dumped. In this study, municipal landfills of different ages located in Tuscany (central Italy) have been investigated. Grab samples, collected at gas collection facilities, were analysed in gas chromatography with flame ionization detection for major gas measurements and in gas chromatography-mass spectrometry for halocarbon measurements. Furthermore, fluxes from the landfill surface were measured by means of a flux chamber. This approach allows an estimation of the total yearly emissions of non-CO2 greenhouse gases from a landfill.