Organic, elemental and inorganic carbon in particulate matter of six urban environments in Europe

[摘要] A series of 7-week sampling campaigns were conducted in urban backgroundsites of six European cities as follows: Duisburg (autumn), Prague (winter),Amsterdam (winter), Helsinki (spring), Barcelona (spring) and Athens(summer). The campaigns were scheduled to include seasons of local publichealth concern due to high particulate concentrations or findings inpreviously conducted epidemiological studies. Aerosol samples were collectedin parallel with two identical virtual impactors that divide air particlesinto fine (PM_2.5) and coarse (PM_2.5-10) size ranges. From thecollected filter samples, elemental (EC) and organic (OC) carbon contentswere analysed with a thermal-optical carbon analyser (TOA); total Ca, Ti,Fe, Si, Al and K by energy dispersive X-ray fluorescence (ED-XRF); As, Cu,Ni, V, and Zn by inductively coupled plasma mass spectrometry (ICP/MS);Ca²⁺, succinate, malonate and oxalate by ion chromatography (IC); andthe sum of levoglucosan+galactosan+mannosan (∑MA) by liquidchromatography mass spectrometry (LC/MS). The campaign means of PM_2.5and PM_2.5-10 were 8.3-29.6 µg m^-3 and 5.4-28.7 µg m^-3,respectively. The contribution of particulate organic matter (POM)to PM_2.5 ranged from 21% in Barcelona to 54% in Prague, whilethat to PM_2.5-10 ranged from 10% in Barcelona to 27% in Prague.The contribution of EC was higher to PM_2.5 (5-9%) than toPM_2.5-10 (1-6%) in all the six campaigns. Carbonate (C(CO₃),that interferes with the TOA analysis, was detected in PM_2.5-10 ofAthens and Barcelona but not elsewhere. It was subtracted from the OC by asimple integration method that was validated. The CaCO₃ accounted for55% and 11% of PM_2.5-10 in Athens and Barcelona, respectively. Itwas anticipated that combustion emissions from vehicle engines affected thePOM content in PM_2.5 of all the six sampling campaigns, but acomparison of mass concentration ratios of the selected inorganic andorganic tracers of common sources of organic material to POM suggested alsointeresting differences in source dominance during the campaign periods:Prague (biomass and coal combustion), Barcelona (fuel oil combustion,secondary photochemical organics) and Athens (secondary photochemicalorganics). The on-going toxicological studies will clarify the healthsignificance of these findings.

[学科分类] 大气科学