Contribution of pig farming to particulate emissions: analysis of emission factors and simulations

Abstract. France is committed to reducing its emissions of fine particulate matter less than 2.5 microns in size (PM2.5) by 57% by 2030 compared to 2005 emissions. Compliance with the commitments is based on the annual inventory published by Citepa, which calculates the contribution of pig farming by multiplying the number of pigs by the emission factor (EF) published by the European Monitoring and Evaluation Programme (EMEP, 2019). First, we reviewed the evolution of EMEP’s EF since 2006 as well as EF currently available in the literature, based on available information and most influential parameters. A database has been built including the main parameters influencing particules emissions and a total of 107 EF were collected on the three main animal categories (sows, piglets, pigs). EF show wide variability due to the diversity of housing characteristics and measurement methods used. Most of published EF concern fattening pigs but with few information about rearing conditions (e.g. type of floor, feed). Piglets and sows are poorly documented, as an example, no EF is available for piglets on strawdust litter. In parallel, EMEP’s EF values have been drastically decreased since 2006. This evolution is explained by EMEP as the result of the increase of publications concerning PM. Nevertheless, since 2019, the distinction between emission factor for pigs bred on litter or slatted systems is stopped because of the lack of published EF concerning litter systems. Second, we compared five scenarios for PM emissions to the 2019 inventory. These scenarios were developed using EMEP’s EF, but also average EF estimated with published EF, including French specific one. The results show the relevancy of establishing national EF including production specificities and enabling the calculation of representative inventories which can be the basis for realistic policies to reduce PM.