Indoor and outdoor concentration of PM2.5 vanadium, nickel, and sulphur in three Mediterranean areas

Abstract

Pollutants in particulate matter (PM) are associated with respiratory disorders. Data on indoor concentration of elemental chemical pollutants in highly polluted areas is scanty. In the context of RESPIRA Project, we evaluated both outdoor and indoor concentrations of air pollutants in the Mediterranean area. Gravimetric samples of PM with aerodynamic diameter<2.5 µm were collected on Teflon filters. Concentration of ICP-MS extracted component was measured in 84 sites of South of Sicily (41 in Gela, close to a petrochemical complex, 43 in rural area) and 54 in Malta. Similarly. Indoor measures were performed in 73 houses in Sicily (35 in Gela, 38 in rural area) and in 46 of Malta. Outdoor Vanadium (V) concentrations (median and interquartile range, ng/m3) were: 1.77 (0.60-4.30) in Malta, 1.51 (0.72-2.89) in Gela, and 0.29 (0.11-0.69) in Rural Area (p<.0001); Nickel (Ni): 1.37 (0.65-2.74), 0.82 (0.45-1.37), and 0.29 (0.17-0.55, p<.0001); Sulphur (S) 210 (73-683), 705 (334-1,078), 203 (148-384, p=.0004). Home Indoor V concentrations were 1.34 (0.38-6.70) in Malta, 1.03 (0.44-2.04) in Gela, and 0.16 (0.10-0.44) in Rural Area (p<.0001); Ni: 1.10 (0.52-3.35), 0.61 (0.40-1.16), and 0.28 (0.19-0.35, p<.0001); S: 324 (71-728), 662 (379-1,090), and 257 (187-437, p=.0007). Outdoor/indoor relationships for the investigated elements were tested. V: R2=.665, p<.0001. Ni: R2=.750, p<.0001. S: R2=.587, p<.0001. In conclusion, significantly higher indoor concentration of atmospheric pollutants exist in highly polluted areas. These, in absence of indoor sources, depend on outdoor concentrations