Weekly cycle assessment of PM mass concentrations and sources, and impacts on temperature and wind speed in Southern Italy

A methodology to detect the weekly cycle impact of the particulate matter (PM), and PM sources on the nearsurface temperature and wind speed is discussed in the paper. Chemically-speciated PM10 and PM2.5 samplesare analyzed to detect the weekly cycle of both the PM mass concentrations and the PM sources identified by thePositive Matrix Factorization technique. The average percent departure (APD) of the PM mass concentrationfrom the mean value calculated for each day of the week shows that a positive (higher values during midweek)and a negative (higher values during weekend) weekly cycle characterizes the PM10 and PM2.5 mass con-centrations in Autumn-Winter (AW, September–February) and Spring-Summer (SS, March–August), respectively.The westerly transport of pollution seems to have a role on the negative PM weekly cycle found in SS. Theanalysis of the six identified aerosol sources indicates that in SS the mixed anthropogenic and the reacted dustsources likely impact the PM10 negative weekly cycle and that the mixed anthropogenic source likely impactsthe PM2.5 negative weekly cycle. The mixed anthropogenic and soil dust sources likely affect in AW the positiveweekly cycle of the PM10 mass concentration. Both sources in addition to the reacted dust source seem to affectthe PM2.5 mass concentration in AW. The APD analysis of the temperature (T) and wind speed (WS) at thesurface from measurements co-located in space and time with the PM ones reveals that the WS and T values arecharacterized by a negative weekly cycle in AW. Conversely, in SS, the WS-APD value decreases on Sunday andthe T-APD values increase in the second half of the week. These last results likely give evidence of the PM impacton the near-surface temperature and wind speed at the study site.