Seasonal variation of PCDD/Fs in the metropolis of Istanbul,Turkey

Atmospheric concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) compounds were investigated at three different regions of Istanbul which reflect urban, urban/industrial, and sub-urban characteristics. Air samples were collected simultaneously for both gaseous and particulate phases using high volume samplers on monthly time intervals from May 2011 to October 2012. The highest concentrations (3,056 fg/m³ and 156 fg I-TEQ/m³) were observed at the sampling site that reflects traffic, residential, and industrial emission source characteristics, while the lowest concentrations (829 fg/m³ and 38 fg I-TEQ/m³) were observed at the sampling point which is far away from centrum and reflects sub-urban characteristics. Concentrations of PCDD congeners were, in general, found to be higher than PCDF congeners, and OCDD, 1,2,3,4,6,7,8-HpCDD/F, and OCDF congeners were recorded to be the most abundant congeners. Winter season concentrations were also found to be higher especially in particulate phase. As a result, combustion processes such as motor vehicles and residential heating equipment were thought to be the principal sources of emissions of PCDD/F compounds when both congener profiles and seasonal variations are considered. Basic statistical evaluation of the data resembled high degree of inverse correlations between PCDD/F concentrations and UV and solar radiation.     

Tributyltin distribution and producing androgenic activity in water,sediment, and fish muscle

This study investigated the concentrations of Tributyltin (TBT) in water, sediment, and fish muscle samples taken from Kaohsiung Harbor and Kaoping River estuary, Taiwan. TBT concentrations in water and sediment samples ranged from less than 18.5 to 34.1 ng Sn L^?1 and from 2.44 to 29.7 ng Sn g^?1 weight per weight (w/w), respectively. Concentrations in the TBT‐contaminated fish muscle samples ranged from 10.8 to 79.6 ng Sn g^?1 w/w. The TBT concentrations in fish muscle were higher than those in water and sediment samples. The fish muscle/water TBT bioconcentration factor (BCF) ranged from 590 to 3363 L kg^?1. Additionally, the water samples were assessed for androgenic activity with an MCF7‐AR1 human breast cancer cell line. The androgenic activity ranged from 0.94 to 3.1 ng‐dihydrotestosterone per litre water (ng‐DHT L^?1). Higher concentrations of TBT in water and sediment samples occurred in the dry season, but the androgenic activity had higher values in the rainy season.     

Heavy metals and Pb isotopic composition of aerosols in urban and suburban areas of Hong Kong and Guangzhou,South China—Evidence of the long-range transport of air contaminants

Rapid urbanization and industrialization in South China has placed great strain on the environment and on human health. In the present study, the total suspended particulate matter (TSP) in the urban and suburban areas of Hong Kong and Guangzhou, the two largest urban centres in South China, was sampled from December 2003 to January 2005. The samples were analysed for the concentrations of major elements (Al, Fe, Mg and Mn) and trace metals (Cd, Cr, Cu, Pb, V and Zn), and for Pb isotopic composition. Elevated concentrations of metals, especially Cd, Pb, V and Zn, were observed in the urban and suburban areas of Guangzhou, showing significant atmospheric trace element pollution. Distinct seasonal patterns were observed in the heavy metal concentrations of aerosols in Hong Kong, with higher metal concentrations during the winter monsoon period, and lower concentrations during summertime. The seasonal variations in the metal concentrations of the aerosols in Guangzhou were less distinct, suggesting the dominance of local sources of pollution around the city. The Pb isotopic composition in the aerosols of Hong Kong had higher ²⁰⁶Pb/²⁰⁷Pb and ²⁰⁸Pb/²⁰⁷Pb ratios in winter, showing the influence of Pb from the northern inland areas of China and the Pearl River Delta (PRD) region, and lower ²⁰⁶Pb/²⁰⁷Pb and ²⁰⁸Pb/²⁰⁷Pb ratios in summer, indicating the influence of Pb from the South Asian region and from marine sources. The back trajectory analysis showed that the enrichment of heavy metals in Hong Kong and Guangzhou was closely associated with the air mass from the north and northeast that originated from northern China, reflecting the long-range transport of heavy metal contaminants from the northern inland areas of China to the South China coast.     

Inputs and distributions of synthetic musk fragrances in an estuarine and coastal environment; a case study

Synthetic musks are ubiquitous contaminants in the environment. Compartmental distributions (dissolved, suspended particle associated and sedimentary) of the compounds throughout an axial estuarine transect and in coastal waters are reported. High concentrations of Galaxolide^® (HHCB) and Tonalide^® (AHTN) (987-2098 ng/L and 55-159 ng/L, respectively) were encountered in final effluent samples from sewage treatment plants (STPs) discharging into the Tamar and Plym Estuaries (UK), with lower concentrations of Celestolide^® (ADBI) (4-13 ng/L), Phantolide^® (AHMI) (6-9 ng/L), musk xylene (MX) (4-7 ng/L) and musk ketone (MK) (18-30 ng/L). Rapid dilution from the outfalls is demonstrated with resulting concentrations of HHCB spanning from 5 to 30 ng/L and those for AHTN from 3 to 15 ng/L. The other musks were generally not detected in the estuarine and coastal waters. The suspended particulate matter (SPM) and sedimentary profiles and compositions (HHCB:AHTN ratios) generally reflect the distribution in the water column with highest concentrations adjacent to sewage outfalls.     

Seasonal variations of particle-associated nitrosamines by gas chromatography–mass spectrometry in the atmospheric environment of Zonguldak, Turkey

A gas chromatography–mass spectrometry method has been proposed for the determination of low-level mutagenic and carcinogenic nitrosamines in particulate matter. The method includes the collection of particulate matters (PM_2.5 and PM₁₀) using a dichotomous Partisol 2025 sampler and extraction of the compounds from aqueous solution with dichloromethane/2-propanol after sonication with a slightly basic water solution prior to their GC-MS analysis in electron impact mode. The obtained recoveries of nitrosamines ranged from 92.4 to 99.2 %, and the precision of this method, as indicated by the relative standard deviations, was within the range of 0.95–2.46?%. The detection limits obtained from calculations using the GC-MS results based on S/N?=?3 were found within the range from 4 to 22 pg/m³. The predominant nitrosamines determined in particulate matter were N-nitrosodimethylamine, N-nitrosodiethylamine, N-nitrosodibutylamine and N-nitrosomorpholine. Furthermore, N-mono- and dinitrosopiperazine and N-nitrosoethylbutylamine were also determined. N-dinitrosopiperazine was detected in PM_2.5 samples at the highest concentrations of up to 22.85 ng/m³ and in PM_2.5–10 samples at concentrations up to 7.60 ng/m³ in winter, whereas it was found in PM_2.5 samples up to 5.15 ng/m³ and in PM_2.5–10 samples up to 3.12 ng/m³ in summer. The total concentrations of nitrosamines were up to 161.4 ng/m³ in fine and 53.90 ng/m³ in coarse fractions in winter, whereas in summer were up to 35.24 and 12.60 ng/m³, respectively. The concentration levels of nitrosamines fluctuated significantly within a year, with higher means and peak concentrations in the winter compared to that in the summertime. The seasonal variations of particle-associated nitrosamine concentrations were investigated together with their relationships with meteorological parameters using Pearson’s correlation analysis in the winter and summer periods. Analysis of variance was used to determine which concentrations of nitrosamines were statistically different from one another and, together with meteorological parameters and discriminant analysis, was used to classify the particle samples by particle size according to seasons. The classification results of the particle samples in different seasons were very satisfactory, allowing 99.5 % of cases to be correctly grouped.     

Radioactive isotopes in atmospheric aerosols over Russia and the Sea of Japan following nuclear accident at Fukushima Nr. 1 Daiichi Nuclear Power Station in March 2011

Artificial radionuclides, such as iodine-131 (¹³¹I), cesium-134 (¹³⁴Cs), and cesium-137 (¹³⁷Cs), as well as natural isotopes of beryllium-7 (⁷Be) and potassium-40 (⁴⁰K) have been registered in atmospheric aerosols over Vladivostok selected from 11 March to 17 June 2011. Additionally, ¹³⁴Cs and ¹³⁷Cs were detected in atmospheric aerosols over Tomsk selected from 16 March to 17 June 2011. Artificial radionuclides were also discovered in atmospheric wet depositions sampled in Vladivostok from 3 to 17 May 2011. Moreover, these radionuclides have been registered in atmospheric aerosols over the sea surface of the Sea of Japan selected from 3 to 31 May 2011 during an expedition of the “Nadezhda” sailing ship. From 18 March to 15 April, an increase in concentrations of atmospheric aerosols over Vladivostok from 108.8 to 321.5 μg/m³ has been registered. It was accompanied by increased activity concentrations of ¹³⁴Cs, ¹³⁷Cs, and the ¹³¹I. During the period from 18 March to 15 April, activity concentrations of ¹³⁷Cs and ¹³⁴Cs in atmospheric aerosols increased 100 times compared with the minimum detectable concentration (MDC) level and peaked in the weekly sample gathered from 8 to 15 April (145.0 and 105.3 μBq/m³, respectively). Variability of concentrations of natural isotopes of ⁷Be and ⁴⁰K was not greater than 1 order of magnitude throughout the sampling period. Maximal values of ¹³⁷Cs and ¹³⁴Cs concentrations (1,281.5?±?141 and 384.4?±?42.3 μBq/m³, respectively) in Tomsk were reached in samples taken from 1 to 2 April. For the atmospheric aerosol samples from the Sea of Japan, the largest concentration of ¹³¹I (392.3?±?215.7 μBq/m³) was detected from 13 to 19 May, while all other samples had much lower concentration values. Synoptic analysis of back trajectories movement of air masses showed that the radioactive cloud came to Vladivostok from the regions of Siberia and northeastern part of China. Synoptic analysis for Tomsk showed that during the period of maximal activity concentrations (1–9 April), air masses were arriving from the European part of Russia and north of Kazakhstan.     

Identification and source apportionment of polycyclic aromatic hydrocarbons in ambient air particulate matter of Riyadh, Saudi Arabia

In an effort to assess the occurrence and sources of polycyclic aromatic hydrocarbons (PAHs) in the ambient air of Riyadh, Saudi Arabia, PM₁₀ samples were collected during December 2010. Diagnostic PAH concentration ratios were used as a tool to identify and characterize the PAH sources. The results reflect high PM₁₀ and PAH concentrations (particulate matter (PM)?=?270–1,270 μg/m³). The corresponding average PAH concentrations were in the range of 18?±?8 to 1,003?±?597 ng/m³ and the total concentrations (total PAHs (TPAHs) of 17 compounds) varied from 1,383 to 13,470 ng/m³ with an average of 5,871?±?2,830 ng/m³. The detection and quantification limits were 1–3 and 1–10 ng/ml, respectively, with a recovery range of 42–80 %. The ratio of the sum of the concentrations of the nine major non-alkylated compounds to the total (CPAHs/TPAHs) was 0.87?±?0.10, and other ratios were determined to apportion the PM sources. The PAHs found are characteristic for emissions from traffic with diesel being a predominant source.     

Significant geographic gradients in particulate sulfate over Japan determined from multiple-site measurements and a chemical transport model: Impacts of transboundary pollution from the Asian continent

We found a significant geographic gradient (longitudinal and latitudinal) in the sulfate (SO₄^2?) concentrations measured at multiple sites over the East Asian Pacific Rim region. Furthermore, the observed gradient was well reproduced by a regional chemical transport model. The observed and modeled SO₄^2? concentrations were higher at the sites closer to the Asian continent. The concentrations of SO₄^2? from China as calculated by the model also showed the fundamental features of the longitudinal/latitudinal gradient. The proportional contribution of Chinese SO₄^2? to the total in Japan throughout the year was above 50–70% in the control case, using data for Chinese sulfur dioxide (SO₂) emission from the Regional Emission Inventory in Asia (40–60% in the low Chinese emissions case, using Chinese SO₂ emissions data from the State Environmental Protection Administration of China), with a winter maximum of approximately 65–80%, although the actual concentrations of SO₄^2? from China were highest in summer. The multiple-site measurements and the model analysis strongly suggest that the SO₄^2? concentrations in Japan were influenced by the outflow from the Asian continent, and this influence was greatest in the areas closer to the Asian continent. In contrast, we found no longitudinal/latitudinal gradient in SO₂ concentrations; instead SO₂ concentrations were significantly correlated with local SO₂ emissions. Our results show that large amounts of particulate sulfate are transported over long distances from the East Asian Pacific Rim region, and consequently the SO₄^2? concentrations in Japan are controlled by the transboundary outflow from the Asian continent.     

城市垃圾焚烧渗沥液中Ca2+对厌氧EGSB处理效果的影响简

研究了城市生活垃圾焚烧厂渗沥液中Ca²⁺对厌氧颗粒污泥膨胀床反应器（EGSB）处理效果的影响,并采用静态实验方法考察了Ca²⁺对厌氧颗粒污泥产甲烷活性的影响。实验结果表明,进水COD为17 000 mg/L的条件下,当Ca²⁺浓度低于6 000 mg/L时,EGSB对COD去除率达93%以上;当Ca²⁺浓度高于6 000 mg/L时,COD去除率随运行时间明显下降,并在污泥中形成大量沉淀。静态实验结果表明,废水中低浓度Ca²⁺促进了厌氧颗粒污泥的产甲烷活性,但高浓度Ca²⁺明显抑制了其产甲烷活性,这是导致高Ca²⁺浓度条件下EGSB对COD去除率降低的主要原因。研究表明,颗粒污泥产甲烷活性恢复程度随Ca²⁺浓度增加而减弱。     

Polychlorinated dibenzo-p-dioxins (PCDDs) and furans (PCDFs) in urban air and deposition in the United Kingdom

Polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) have been monitored in air and deposition at four UK urban sites (London, Cardiff, Manchester and Stevenage) since the beginning of 1991; data from the first 2 years are presented here. Median Σ2,3,7,8-substituted PCDD/F concentrations in air were 3.2, 4.0, 3.5 and 2.6 pg/m³ respectively for London, Cardiff, Manchester and Stevenage. Median Σ2,3,7,8-substituted PCDD/F deposition fluxes were 1.5 ng/m²/day in London, 1.4 ng/m²/day in Cardiff and Manchester and 0.79 ng/m²/day in Stevenage. Seasonal variations in the PCDD/F concentrations were observed at all sites for both air and deposition, with concentrations/fluxes generally elevated during the winter.     

Polycyclic aromatic hydrocarbons in indoor and outdoor air in Turkey: Estimations of sources and exposure

The aim of the current study was to measure polycyclic aromatic hydrocarbons (PAHs) in eight indoor (In both kitchen and living room) air sampling locations using a passive sampling method for collection. Passive outdoor air samples were also collected from 3 of the same sampling locations as the indoor air sampling sites. Sampling was conducted in three seasons. The summer season, when windows are generally open, was between 18th July and 01st September, 2014; the autumn and winter seasons, when windows are mostly closed, was between 18^th October and 01^st December, 2014, and 01^st December, 2014, and 18^th January, 2015, respectively.

Average PAH concentrations in summer were 22 ± 21 ng/m³ and 17 ± 12 ng/m³ in the living room and kitchen, respectively, whereas living room and kitchen average PAH concentrations were 23 ± 16 ng/m³ and 20 ± 9 ng/m³, respectively, in autumn and 23 ± 13 ng/m³ and 23 ± 24 ng/m³, respectively, in winter. Outdoor air PAH concentrations in summer, autumn and winter were 7 ± 0.4 ng/m³, 22 ± 13 ng/m³ and 209 ± 33 ng/m³, respectively. An increase in outdoor PAH concentrations was measured in winter compared to the concentrations in summer and autumn, which paralleled the lower outdoor air temperature. However, PAH concentrations in the indoor environment vary according to the household characteristics and personal habits.     

Estimates of community exposure and health risk to sulfur dioxide from power plant emissions using short-term mobile and stationary ambient air monitoring

To estimate plausible health effects associated with peak sulfur dioxide (SO₂) levels from three coal-fired power plants in the Baltimore, Maryland, area, air monitoring was conducted between June and September 2013. Historically, the summer months are periods when emissions are highest. Monitoring included a 5-day mobile and a subsequent 61-day stationary monitoring study. In the stationary monitoring study, equipment was set up at four sites where models predicted and mobile monitoring data measured the highest average concentrations of SO₂. Continuous monitors recorded ambient concentrations each minute. The 1-min data were used to calculate 5-min and 1-hr moving averages for comparison with concentrations from clinical studies that elicited lung function decrement and respiratory symptoms among asthmatics. Maximum daily 5-min moving average concentrations from the mobile monitoring study ranged from 70 to 84 ppb (183–220 µg/m³), and maximum daily 1-hr moving average concentrations from the mobile monitoring study ranged from 15 to 24 ppb (39–63 µg/m³). Maximum 5-min moving average concentrations from stationary monitoring ranged from 39 to 229 ppb (102–600 µg/m³), and maximum daily 1-hr average concentrations ranged from 15 to 134 ppb (40–351 µg/m³). Estimated exposure concentrations measured in the vicinity of monitors were below the lowest levels that have demonstrated respiratory symptoms in human clinical studies for healthy exercising asthmatics. Based on 5-min and 1-hr monitoring, the exposure levels of SO₂ in the vicinity of the C.P. Crane, Brandon Shores, and H.A. Wagner power plants were not likely to elicit respiratory symptoms in healthy asthmatics.

Implications: Mobile and stationary air monitoring for SO₂ were conducted to quantify short-term exposure risk, to the surrounding community, from peak emissions of three coal-fired power plants in the Baltimore area. Concentrations were typically low, with only a few 5-min averages higher than levels indicated during clinical trials to induce changes in lung capacity for healthy asthmatics engaged in exercise outdoors.     

Comparisons of ambient air particulates concentrations (TSP,PM2.5) and dry depositions during smog and non-smog periods at Luliao,Shalu District sampling site

The concentrations of ambient total suspended particulates (TSP) and PM_2.5, and the dry depositions at a sample site at Luliao Junior High School (Luliao) in central Taiwan were measured during smog and non-smog days between December 2017 and July 2018. The results are compared to those obtained during non-smog periods in the years 2015–2017. The mean TSP and PM_2.5 concentrations and dry deposition flux were 72.41?±?26.40, 41.88?±?23.51?μg/m³, and 797.57?±?731.46?μg/m² min, respectively, on the smog days. The mean TSP and PM_2.5 concentrations and dry deposition flux on the non-smog days were 56.39?±?18.08, 34.81?±?12.59?μg/m³ and 468.93?±?600.57?μg/m² min, respectively. The mean TSP concentration in the smog period was 28% greater than that in the non-smog period, and the mean PM_2.5 concentration was 20% higher. The mean dry deposition flux in the smog period was 70% higher than that in the non-smog period at Luliao. The PM_2.5 concentrations exceeded the standards set by the Taiwan EPA (35?μg/m³ daily, and 15?μg/m³ annually). Therefore, the TSP and PM_2.5 concentrations and dry deposition must be reduced in central Taiwan on smog days. In addition, atmospheric TSP and PM_2.5 concentrations at various sampling sites were compared, and those herein were not higher than those measured in other countries. Finally, apart from the local traffic emissions, during smog periods, the other pollution source originated from the transportation process of traffic pollutants emitted in the northwest side of Taiwan.     

The impact of production type and region on polychlorinated biphenyl (PCB), polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/F) concentrations in Canadian chicken egg yolks

Chicken eggs from five different production types (conventional, omega-3 enriched, free range, organic and free run) were collected, when available, from three regions (west, central and east) of Canada to determine persistent organic pollutant (POP) concentrations. Total polychlorinated biphenyl (PCB) concentrations (∑37 congeners) in yolks from the eggs ranged from 0.162 ng g⁻¹ lipid to 24.8 ng g⁻¹ lipid (median 1.25 ng g⁻¹ lipid) while the concentration of the sum of the 6 indicator PCBs ranged from 0.100 ng g⁻¹ lipid to 9.33 ng g⁻¹ lipid (median 0.495 ng g⁻¹ lipid). Total polychlorinated dibenzo-p-dioxin/dibenzofuran (PCDD/F) concentrations ranged from 2.37 pg g⁻¹ lipid to 382 pg g⁻¹ lipid (median 9.53 pg g⁻¹ lipid). The 2005 WHO toxic equivalency (TEQ) ranged from 0.089 pg TEQ_{PCDD/F+dioxin-like[DL]-PCB} g⁻¹ lipid to 12.8 pg TEQ_{PCDD/F+DL-PCB} g⁻¹ lipid (median 0.342 pg TEQ_{PCDD/F+DL-PCB} g⁻¹ lipid). PCB and PCDD/F concentrations were significantly different (p < 0.001) in egg yolks from different regions of collection. In contrast to observations in Europe, PCB and PCDD/F concentrations in Canadian egg yolks were not impacted solely by the production type (e.g., conventional, free range, organic, etc.) used to maintain the laying chickens. Additionally, only one Canadian free range yolk from western Canada (12.8 pg TEQ_{PCDD/F+DL-PCB} g⁻¹ lipid) exceeded the European toxic equivalent concentration limits for eggs (5 pg TEQ_{PCDD/F+DL-PCB} g⁻¹ lipid). This differs from observations in Europe where free range/home produced eggs frequently have higher POP concentrations than eggs from other production types. Median PCB dietary intake estimates based on consumption of eggs were less than 10 ng d⁻¹ while median PCDD/F intakes were less than 45 pg d⁻¹.     

Black Carbon Aerosol at McMurdo Station,Antarctica

ABSTRACT

Aerosol light absorption as black carbon (BC) was measured from November 19, 1995, to February 6, 1996, at a location 0.65 km downwind of the center of McMurdo Station on the Antarctic coast. The results show a bimo-dal frequency distribution of BC concentrations. Approximately 65% of the measurements were found in a mode at a low range of concentrations centered at ~20 ng/m³. These concentrations are higher than those found at other remote Antarctic locations and probably represent contamination from the station. The remaining measurements were in a high-concentration mode (BC ~300 ng/m³), indicating direct impact of local emissions from combustion activities at the station. High values of BC were associated with winds from the direction of the station, and the BC flux showed a clear directionality. Maximum BC concentrations occurred between 7:00 and 11:00 a.m. The "polluted" mode accounted for more than 80% of the BC frequency-weighted impact at this location.     

In situ measurement of isoprene in the marine air and surface seawater from the western North Pacific

Isoprene (2-methyl-1,3-butadiene) was measured on board of R/V Mirai for eight air samples and 14 seawater samples collected in the western North Pacific during ACE-Asia campaign (from 18 to 26 May 2001). The measurements were conducted in situ using a cryo-focus/gas chromatography/mass spectrometry (Cryo/GC/MS). Concentrations of isoprene ranged from 7.2 to 110 parts-per-trillion (pptv) in the marine air, and ranged from below 12 to 94 pmol l⁻¹ in the seawater. Based on these results, sea-to-air fluxes of isoprene were calculated to be 184 and 300 nmol m⁻² day⁻¹ for two samples, and the upper limits of the fluxes were also calculated to be from 32 to 300 nmol m⁻² day⁻¹. Atmospheric isoprene concentrations cannot be explained only by the flux from the seawater. Thus, the concentrations of isoprene in the marine air in western North Pacific should be significantly affected by terrestrial vegetational emission and subsequent long-range atmospheric transport of isoprene.     

Polycyclic aromatic hydrocarbons in sediments,pore water and the amphipod Pontoporeia hoyi from Lake Michigan

Polycyclic aromatic hydrocarbon (PAH) concentrations were measured in Pontoporeia hoyi, the most abundant benthic organism in Lake Michigan, and in its associated sediment/pore water matrix. Individual PAH concentrations ranged from 10 ppb to 1 ppm in three sedimentary environments having different levels of organic carbon. Pore water concentrations appeared to be independent of sediment concentrations. P. hoyi bioconcentration factors ranged from approximately 10⁴ to 10⁵ for seven analyzed PAHs. A major fraction of the phenanthrene, fluoranthene and pyrene in P. hoyi appears to come from sediments and pore water, while chrysene and BaP are primarily obtained from water.     

Atmospheric trace element concentrations in total suspended particles near Paris,France

To evaluate today’s trace element atmospheric concentrations in large urban areas, an atmospheric survey was carried out for 18 months, from March 2002 to September 2003, in Saclay, nearby Paris. The total suspended particulate matter (TSP) was collected continuously on quartz fibre filters. The TSP contents were determined for 36 elements (including Ag, Bi, Mo and Sb) using two analytical methods: Instrumental Neutron Activation Analysis (INAA) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The measured concentrations were in agreement within the uncertainties with the certified values for the polycarbonate reference material filter SRM-2783 (National Institute for Standard Technology NIST, USA). The measured concentrations were significantly lower than the recommended atmospheric concentrations. In 2003, the Pb atmospheric level at Saclay was 15 ng/m³, compared to the 500 ng/m³ guideline level and to the 200 ng/m³ observed value in 1994. The typical urban background TSP values of 1–2, 0.2–1, 4–6, 10–30 and 3–5 ng/m³ for As, Co, Cr, Cu and Sb, respectively, were inferred from this study and were compared with the literature data. The typical urban background TSP concentrations could not be realised for Cd, Pb and Zn, since these air concentrations are highly influenced by local features. The Zn concentrations and Zn/Pb ratio observed in Saclay represented a characteristic fingerprint of the exceptionally large extent of zinc-made roofs in Paris and its suburbs. The traffic-related origin of Ba, Cr, Cu, Pb and Sb was demonstrated, while the atmospheric source(s) of Ag was not identified.     

Authors’ Reply

ABSTRACT

Exposures of occupants in school buses to on-road vehicle emissions, including emissions from the bus itself, can be substantially greater than those in outdoor settings. A dual tracer method was developed and applied to two school buses in Seattle in 2005 to quantify in-cabin fine particulate matter (PM_2.5) concentrations attributable to the buses' diesel engine tailpipe (DPM_tp) and crankcase vent (PM_ck) emissions. The new method avoids the problem of differentiating bus emissions from chemically identical emissions of other vehicles by using a fuel-based organometallic iridium tracer for engine exhaust and by adding deuterated hexatriacontane to engine oil. Source testing results showed consistent PM:tracer ratios for the primary tracer for each type of emissions. Comparisons of the PM:tracer ratios indicated that there was a small amount of unburned lubricating oil emitted from the tailpipe; however, virtually no diesel fuel combustion products were found in the crankcase emissions. For the limited testing conducted here, although PM_ck emission rates (averages of 0.028 and 0.099 g/km for the two buses) were lower than those from the tailpipe (0.18 and 0.14 g/km), in-cabin PM_ck concentrations averaging 6.8 μg/m³ were higher than DPM_tp (0.91 μg/m³ average). In-cabin DPM_tp and PM_ck concentrations were significantly higher with bus windows closed (1.4 and 12 μg/m³, respectively) as compared with open (0.44 and 1.3 μg/m³, respectively). For comparison, average closed- and open-window in-cabin total PM_2.5 concentrations were 26 and 12 μg/m³, respectively. Despite the relatively short in-cabin sampling times, very high sensitivities were achieved, with detection limits of 0.002 μg/m³ for DPM_tp and 0.05 μg/m³ for PM_ck.

IMPLICATIONS PM_2.5 measurements in two Seattle school buses showed average concentrations of 26 and 12 μg/m³ with windows closed and open, respectively. Virtually all PM_2.5 was car bonaceous. Tracer measurements showed that bus self-pollution contributed approximately 50% of total PM_2.5 concentrations with windows closed and 15% with windows open, with over three-quarters of these contributions attributed to crankcase emissions. Maintaining ventilation in buses clearly reduces total PM_2.5 exposures and that from the buses' own emissions. The dual tracer method now offers researchers a new technique for explicit identification of single source contributions in settings with multiple sources of carbonaceous emissions.     

Particulate and Nicotine Sampling in Public Facilities and Offices

Abstract

The purpose of this study was to characterize and measure indoor air quality in public facilities and office buildings. The pollutants of interest were particulate matter smaller than 2.5 μm in diameter, PM-2.5, and environmental tobacco smoke (ETS). Integrated PM- 2.5 samples were taken on Teflon membrane filters using Harvard Aerosol Impactors as a pre-size selector. Filters were analyzed by gravimetric analysis. Nicotine, which was used as a marker for ETS, was collected on sodium-bisulfate-impregnated, glass-fiber filters and was analyzed by gas chromatography. Twenty-one structures were monitored in Metropolitan Boston. Measured particle concentrations ranged from 6.0 μg/m³ to about 550 μg/m³. Nicotine concentrations were as high as 26 μg/m³ in a designated smoking room. Real-time measurements were also taken using two types of nephelometers; a Handheld Aerosol Monitor (HAM) and a Miniature Real-Time Aerosol Monitor (MINIRAM). Short-term field measurements with these instruments correlated better with the integrated PM-2.5 concentrations in smoking locations than with concentrations in non-smoking areas.