Abstract for presentation at 14th IUAPPA World Congress

Gas fired home heating appliances are widely utilized in urban areas, where their concentration and limited height of flue gas release into the atmosphere might lead to significant effects on air quality. Nevertheless, the characterization of their emission factors results generally lacking or very poorly documented, thus making rather difficult the evaluation of their contribution in emission inventories and their apportionment to pollutant levels in the atmosphere. Data missing or uncertainty is of particular issue for advanced units equipped with low emission burners, predicted to increase significantly their actual market share in the next few years, and for transient exercise regimes at partial heating loads, representing the most frequent operating conditions of the apparatus. The paper reports the results of the experimental characterization of the atmospheric emissions of natural gas domestic appliances for combined ambient heating/hot water production. The study was conducted with a standard certification laboratory test bench on different type of boilers representative of the actual range of configurations available, including some units equipped with burners designed for reducing pollutants production and included in the best actually available technologies in the field. The evaluations were performed at continuous full and partial heat loads as well as in transient conditions, with operating cycles specifically developed for simulating real exercise regimes of utilization, and included conventional pollutants from combustion (CO, NO_x, VOC and NMVOC) as well as trace organics of interest (aromatics, aldehydes, PAH).