# Sustainability in Italian Ceramic Tile Production: Evaluation of the Environmental Impact
## 3 Results  
### Pollutants by Gaseous Emissions  
All the reported data generally cover a period of 9 years from 2010 to 2018, except data for emission factor of particulate matter and fluorine element collected from 1996 to 2018, and data for lead emissions collected from 2005 and 2018. Figure 3 reports the trend for the emission factor (EF\({}_{\text{PM}}\)) of the most common pollutant produced by the ceramic sector: the particulate matter. The plot shows a significant reduction of the emitted PM along the years. A value of 4.4 g/m\({}^{2}\) was collectively recorded as mean value for the whole Italian tile production in the years 1996-1997. A decreasing trend is then observed, especially in the timespan ranging from 2005 to 2014. In the following years up to 2018, the EF\({}_{\text{PM}}\) shows modest changes with a nearly constant values (around 0.95, 1.30 and 0.35 g/m\({}^{2}\) for classes 1, 2 and 3, respectively). This trend shows that the most optimized abatement technologies are being currently employed by all the Italian ceramic tiles manufacturers and in recent years, very low values of EF\({}_{\text{PM}}\) have been recorded. In the BAT document for the Italian ceramic sector, the EF\({}_{\text{PM}}\) limit is 7.5 g/m\({}^{2}\), over five time higher than the highest values recorded in 2018, related to Class 2, thus indicating an outstanding performance of the Sassuolo ceramic district. The noteworthy reduction of PM emission is also confirmed if the EF\({}_{\text{PM}}\) trend reported in Figure 3 is compared with the EU Ecolabel limit (5.2 g/m\({}^{2}\)). It is interesting to note how EF\({}_{\text{PM}}\) for the three different production classes differs, but of an almost constant factor along the years. This is related to the fact that plants belonging to Class 2, which produce an excess of spray-dried powders to be sold, have to manage higher fluxes of raw materials for the same square meters of tiles manufactured, for example, in plants belonging to Class 1. Conversely, industrial plants belonging to Class 3 which buy the spray-dried powders, can avoid the initial production steps and, thus, exhibit lower values for the considered indicator. Indeed, the storage of raw materials, milling and spray-drying of the ceramic slurry are all stages widely affecting PM production. The trend of the emission factor of fluorine (EF\({}_{\text{F}}\)), another major pollutant of the ceramic tiles production, is reported in Figure 4. This indicator takes into account all the chemical species of fluorine generated at the high temperatures inside the kiln. The recorded mean value of this pollutant for the years 1996-1997 was equal to 0.48 g/m\({}^{2}\). A decreasing trend of EF\({}_{\text{F}}\) is then clearly evident for Class 1, 2 and 3, moving from 0.20, 0.18 and 0.165 g/m\({}^{2}\) in the years 2005-2007, to 0.09, 0.066 and 0.07 g/m\({}^{2}\) in 2018, respectively. However, two main differences between the trends of EF\({}_{\text{PM}}\) and EF\({}_{\text{F}}\) can be observed. Firstly, a continuously decreasing tendency is more evident. This is due to the fact that the abatement efficiency for fluorine compounds depends on different variables; the emission of this pollutant can be handled by finer regulation on the concentration of calcium hydroxide inside the filters or by employing higher quality clays, which contain lower amounts of fluorine impurities. For this reason,continuous efforts are spent on the achievement of decreasing levels for this emission factor. Secondly, the values obtained during the whole timespan for the three production classes are comparable as these specific pollutant emissions are entirely ascribed to the firing stage. Lastly, the comparison with the Italian BAT and EU Ecolabel limit values (0.6 and 0.2 g/m\({}^{2}\) respectively) confirms the vast efforts made by the Italian ceramic industry over the years in the management of fluorine emissions within the European context.