Assessment of nitrous oxide emission from cement plants: Real data measured with both Fourier transform infrared and nondispersive infrared techniques

Nitrous oxide (N2O) is the third most important greenhouse gas after carbon dioxide and methane, and contributes about 6% to the greenhouse effect. Nitrous oxide is a minor component of the atmosphere, and it is a thousand times less than carbon dioxide (CO2). Nevertheless, it is much more potent than CO2 and methane, owing to its long stay in the atmosphere of approximately 120 yr and the high global warming potential (GWP) of 298 times that of CO2. Although greenhouse gases are natural in the atmosphere, human activities have changed the atmospheric concentrations. Most of the values of emission of nitrous oxide are still obtained by means of emission factors and not actually measured; the lack of real data may result in an underestimation of current emissions. The emission factors used for the calculation of N2O can be obtained from the "Guidelines for the implementation of the national inventory of emissions" of the Intergovernmental Panel on Climate Change, which refer to all nations for the realization of their inventory. This study will present real data, measured in several Italian cement plants with different characteristics. The work also shows a comparison between N2O concentration measured with in situ Fourier transform IR (FTIR) and the reference method EN ISO 21258 based on nondispersive IR (NDIR), in order to investigate the interfering compounds in the measurement with NDIR. [GRAPHICS]