Methodology for Estimating Emissions from Small Domestic Fuelwood Appliances in Lombardy

Abstract

Estimates from many national emission inventories and air quality measurements (Gianelle et al., 2013) are showing the relevance of biomass burning in small domestic appliances as source of particulate matter and benzo(a)pyrene (BaP). For Lombardy region, the highest populated of Italy, domestic heating is determining 38% of the total particulate and among this fuelwood contributes for 99% of PM and is responsible of 66% of the total regional emission of BaP (INEMAR, 2018). In the framework of the emissions inventories, estimates are due to a combination of an average emission factor detailed for technology and pollutant and an activity indicator defined as the annual energy burned detailed for technology, reference year and geographic detail (e.g., region, district, sampling statistical cells, …). This paper presents the methodologies and tools for monitoring combustion technologies evolution during the years, estimating annual energy amount burned and accounting the different profile of use. From CATI (Computer Aided Telephonic Interview) surveys it is possible by sampling statistics to obtain information on technologies diffusion and to estimate energy burned (Pastorello et al., 2011). Unfortunately, this data are quite discontinuous in the years. A methodology linking statistics and information arising from producers, chimneysweeper’s associations and preliminary filling of biomass heater regional register has been developed to consider the evolution and substitution rate of burning technologies. A first picture of the numbers of biomass heaters for a reference year is evolved in the next years considering market information and technology share in new installations from installers and regional register. Obsolete and substituted appliances are calculated for each year considering a probability function due to appliance age. The probability of a technology to be substituted will increase with the age of the installation moving up to the appliances average lifetime and newly installed burners are not capable to a substitution in the next year. With the developed procedure it is possible to obtain the evolution during the years of the number of different appliances and to project their evolution in the future. The introduction of coefficient for energy usage (overall annual energy burned from single user in a specific device) can allow the best evaluation of the positive effect of more efficient devices. Information from regional energy balances can be used as propagating coefficients of the sampling statistics for calculating municipal information on total energy burned in domestic wood heaters, alternatively an algorithm for estimating the heating demand of dwellings can be implemented on the base of annual heating degree days (HDD), thermal dispersion coefficients, building age and heated total volume. The HHDs can be obtained from the diagnostic system of ARPA Lombardia for the time series between 2008 and 2016 and are commonly considered as a proxy of the thermal season allowing to calculate the biomass energy consumption for those years not covered by CATI surveys (GSE, 2017).