A 6-month air sampling survey was conducted at 26 sites across the African continent with the aim to establish baseline information on contamination of ambient air with persistent organic pollutants (POPs) as a reference for future monitoring programs in the region. Sampling sites included continental, rural and urban backgrounds, agricultural and industrial sites as well as waste and obsolete pesticide dumps. Concentrations of polycyclic aromatic hydrocarbons, polychlorinated dibenzo-p-dioxins and furans, polychlorinated biphenyls and organochlorine pesticides were low at most of the rural background sites, but they raise some concern in big cities. The large temporal variability in the pesticide concentrations suggested seasonal application of gamma-HCHs and endosulfans; levels of p,p'-DDT were often much higher than those of p,p'-DDE and indicated recent application of DDT.
This study reports on the first complex data set of emission factors (EFs) of selected pollutants from combustion of five fuel types (lignite, bituminous coal, spruce, beech, and maize) in six different domestic heating appliances of various combustion designs. The effect of fuel as well as the effect of boiler type was studied. In total, 46 combustion runs were performed, during which numerous EFs were measured, including the EFs of particulate matter (PM), carbon monoxide, polyaromatic hydrocarbons (PAH), hexachlorobenzene (HxCBz), polychlorinated dibenzo-p-dioxins and furans (PCDD/F), etc. The highest EFs of nonchlorinated pollutants were measured for old-type boilers with over-fire and under-fire designs and with manual stoking and natural draft. Emissions of the above-mentioned pollutants from modern-type boilers (automatic, downdraft) were 10 times lower or more. The decisive factor for emission rate of nonchlorinated pollutants was the type of appliance; the type of fuel plays only a minor role. Emissions of chlorinated pollutants were proportional mainly to the chlorine content in fuel, but the type of appliance also influenced the rate of emissions significantly. Surprisingly, higher EFs of PCDD/F from combustion of chlorinated bituminous coal were observed for modern-type boilers (downdraft, automatic) than for old-type ones. On the other hand, when bituminous coal was burned, higher emissions of HxCBz were found for old-type boilers than for modern-type ones.
Spatial and temporal variation of vapor-and particle-phase polycyclic aromatic hydrocarbons (PAHs) was determined in six urban and sub-urban locations in Kaunas, Lithuania during heating and non heating seasons. Two different sampling methodologies were used: passive (based on semipermeable membrane device, SPMD) and active (based on collection on filter and sorption). Sixteen priority PAHs as well as methylated PAHs were quantified in the collected samples. The sampled total amount of 16 PAHs investigated in SPMDs ranged from 10-138 ng/day outdoors, from 5-59 ng/day indoors during the winter sampling campaign. In summer these amounts varied from 11-19 ng/day outdoors and from 19-27 ng/day indoors. The total concentrations of vapor and particle-phase PAH in winter in actively taken samples varied from 49-286 ng/m 3 outdoors and from 28-83 ng/m 3 indoors. Seasonal differences as well as the influence of the fuel burning for domestic heating purposes on the PAH concentration outdoors were well reflected by the data obtained using the SPMD methodology.
Summary. Effect of column bleed on trueness of determination of trace levels of dibenzofuranes (PCDD/F) and biphenyls (PCB) by gas chromatography-high-resolution mass spectrometry (GC-HRMS) was studied. As a result of extensive bleed of an arylenesiloxane capillary column, fluctuations of abundance ratios of monitored ions were observed, making exact determination of target analytes impossible. These effects were observed on food samples as well as on pure standard mixtures. The column bleed affected the abundance ratios of PCDD/F and PCB within the range of 13-328 pg of target analyte/mL, and higher levels of analytes remained intact. An analysis of diluted calibration mixtures is recommended as a tool for detection of column bleed.
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