PM2.5 in indoor air of a bakery: Chemical characterization and size distribution

In current literature, studies on indoor air quality mostly concern environments such as hospitals, schools and homes, and less so on spaces producing food, such as bakeries. However, small-and medium-sized bakeries are typical and very common food production spaces, mostly in Southern Italy. Considering this, the present study investigated size trends of the aerosol particles during bakery working activities and the indoor particulate matter PM2.5 chemical speciation at the same time, in order to characterize the aerosol particulate matter emissions. In particular, indoor air monitoring was performed using a silent sequential sampler and an optical particle counter monitor during 7-19 April 2013. For each daily sampling, four PM2.5 samples were collected. In each sample, OC (organic carbon), EC (elemental carbon), LG (levoglucosan) Cl- (chloride), NO2- (nitrite), NO3- (nitrate), SO42- (sulfate), C2O42- (oxalate), Na+ (sodium), NH4+ (ammonium), K+ (potassium), Mg2+ (magnesium) and Ca2+ (calcium) concentrations were determined. The main sources of particles were wood burning, the cleaning of ovens (ash removal) and the baking of bread. While levoglucosan was associated with the source wood burning, potassium in this case can be considered as a marker of the contribution of the bakery activities. This work represents the second part of indoor research activities performed in the bakery. The first part was published in Ielpo et al. (2018).