Deposition of aerosol particles on rough surfaces inside a test chamber

We investigated the deposition rate of aerosol particles (diameter between 0.03 and 5 μm) on rough surfaces of wallpapers, wall-plasters, and two types of carpets inside a test chamber. Compared to a smooth aluminum surface, the deposition rate of aerosol particles on the tested surfaces was up to 20 times depending on the surface roughness, mixing intensity, and particle size. A rough surface with a dimensionless surface roughness height k⁺ < 0.06 can be treated as a hydraulically smooth. The estimated deposition rates in this study and those predicted by a deposition model, which incorporates surface roughness, were in good agreement for coarse mode particles (diameter > 1 μm) when k⁺ < 1.04 and for ultrafine particles (diameter < 0.1 μm) when k⁺ < 0.48. The agreement between the model prediction and our estimation was better for coarse mode particles than for ultrafine particles. Deposition of aerosol particles, especially fine particles, needs more empirical investigations aiming at improving the existing models.     

Size segregated mass concentration and size distribution of near surface aerosols over a tropical Indian semi-arid station, Anantapur: Impact of long range transport

Regular measurements of size segregated as well as total mass concentration and size distribution of near surface composite aerosols, made using a ten-channel Quartz Crystal Microbalance (QCM) cascade impactor during the period of September 2007-May 2008 are used to study the aerosol characteristics in association with the synoptic meteorology. The total mass concentration varied from 59.70 ± 1.48 to 41.40 ± 1.72 μg m^− 3, out of which accumulation mode dominated by ~ 50%. On a synoptic scale, aerosol mass concentration in the accumulation (submicron) mode gradually increased from an average low value of ~ 26.92 ± 1.53 μg m^− 3 during the post monsoon season (September-November) to ~ 34.95 ± 1.32 μg m^− 3 during winter (December-February) and reaching a peak value of ~ 43.56 ± 1.42 μg m^− 3 during the summer season (March-May). On the contrary, mass concentration of aerosols in the coarse (supermicron) mode increased from ~ 9.23 ± 1.25 μg m^− 3during post monsoon season to reach a comparatively high value of ~ 25.89 ± 1.95 μg m^− 3 during dry winter months and a low value of ~ 8.07 ± 0.76 μg m^− 3 during the summer season. Effective radius, a parameter important in determining optical (scattering) properties of aerosol size distribution, varied between 0.104 ± 0.08 μm and 0.167 ± 0.06 μm with a mean value of 0.143 ± 0.01 μm. The fine mode is highly reduced during the post monsoon period and the large and coarse modes continue to remain high (replenished) so that their relative dominance increases. It can be seen that among the two parameters measured, correlation of total mass concentration with air temperature is positive (R² = 0.82) compared with relative humidity (RH) (R² = 0.75).     

Field performance evaluation of a newly developed PM₂.₅ sampler at IIT Kanpur

In order to meet the challenges of growing air pollution for a developing nation and to measure the ambient fine particles (PM_2.5, particles having aerodynamic diameter less than 2.5 μm) on routine basis an air sampler was designed, developed and evaluated in the field. The impactor removes particles greater than 2.5 μm from the air stream via impacting them onto a vacuum grease substrate and finer particles get eventually collected on a backup filter. Various impactor nozzles with conical geometry were designed based on the published theoretical design equations. A detail parametric investigation was carried out which resulted in the optimum impactor nozzle design. For this exercise, a novel dry aerosol generator was employed in addition to the well known time-of-flight instrument, APS (Aerodynamic Particle Sizer, Model 3021, TSI Inc.). The average particle losses for the impactor nozzle as well as the sampler body were below 10% and the overall pressure drop (including a backup 47 mm filter) through the PM_2.5 sampler was only 2 in. of H₂O. This developed PM_2.5 sampler operates at a flow rate of 15 LPM. Field performance of this sampler was evaluated through co-located sampling with a high volume PM_2.5 reference sampler (HVS, GEM-BLI Model 2360, Tisch Environment Instrument) within the IIT Kanpur campus. The sampling period was 10 h long and it was carried out on six different days. The entire sets of filters were analyzed gravimetrically followed by their chemical analysis for elemental and anionic analyses. The particle mass, elemental, and anionic concentrations obtained with this newly developed PM_2.5 sampler as well as those from the reference HVS sampler showed moderate to good correlation.     

The effect of particle size on cardiovascular disorders--the smaller the worse

Background

Previous studies observed associations between airborne particles and cardio-vascular disease. Questions, however, remain as to which size of the inhalable particles (coarse, fine, or ultrafine) exerts the most significant impact on health.

Methods

For this retrospective study, data of the total number of 23,741 emergency service calls, registered between February 2002 and January 2003 in the City of Leipzig, were analysed, identifying 5326 as being related to cardiovascular incidences. Simultaneous particle exposure was determined for the particle sizes classes < 100 nm (UFP), < 2.5 μm (PM2.5) and < 10 μm (PM10). We used a time resolution of 1 day for both parameters, emergency calls and exposure.

Results

Within the group of cardiovascular diseases, the diagnostic category of hypertensive crisis showed a significant association with particle exposure. The significant effect on hypertensive crisis was found for particles with a size of < 100 nm in diameter and starting with a lag of 2 days after exposure. No consistent influence could be observed for PM2.5 and PM10. The Odds Ratios on hypertensive crisis were significant for the particle size < 100 nm in diameter from day 2 post exposure OR = 1.06 (95%CI: 1.02-1.10, p = 0.002) up to day 7 OR = 1.05 (95%CI 1.02-1.09, p = 0.005).

Conclusion

Ultrafine particles affect cardiovascular disease adversely, particularly hypertensive crises. Their effect is significant compared with PM2.5 and PM10. It appears necessary, from a public health point of view, to consider regulating this type of particles using appropriate measurands as particle number.     

Acidic species and chloride depletion in coarse aerosol particles in the US east coast

To investigate the interactions of water-soluble acidic species associated with coarse mode aerosol particles (1.8-10 μm) and chlorine depletion, ten sets of size-segregated aerosol samples were collected by a 10-stage Micro-Orifice Uniform Deposit Impactor (MOUDI) in Newark, New Jersey on the U.S. east coast. The samples were grouped into two categories according to the air-mass back trajectories and mass ratios of sodium to magnesium and calcium: Group I was primarily impacted by marine air mass and Group II was dominated by the continental air mass. In Group I, the concentrations of coarse mode nitrate and chloride depletion showed a strong correlation (R² = 0.88). Without considering other cations, nitrate was found to account for all of the chloride depletion in coarse particles for most samples. The association of coarse mode nitrate with sea-salt particles is favored when the mass ratio of sodium to calcium is approximately equal to or greater than unity. Excess sulfate accounts for a maximum of 33% of chloride depletion in the coarse particles. Regarding chloride depletion in the different particle sizes, excess nitrate and sulfate account for 89% of the chloride depletion in the particle size range of 1.8-3.2 μm in the sample from July 13-14; all of the determined dicarboxylic acids and mono-carboxylic acids cannot compensate for the rest of the chloride depletion. In Group II, high percentages of chloride depletion were not observed. With nitrate being dominant in chlorine depletion observed at this location, N-containing species from pollution emissions may have profound impact on atmospheric composition through altering chlorine chemistry in this region.     

Particle-associated polycyclic aromatic hydrocarbons in the atmospheric environment of Zonguldak, Turkey

Airborne fine (PM(2.5)) and coarse (PM(2.5-10)) particulate matter was collected from January to December in 2007 in Zonguldak, Turkey using dichotomous Partisol 2025 sampler. Fourteen selected polycyclic aromatic hydrocarbons (PAHs) in particulate matter were determined simultaneously by high-performance liquid chromatography with fluorescence detection (HPLC-FL) and seasonal distributions were examined. The source identification of PAHs in airborne particulates was performed by principal component analysis (PCA) in combination with diagnostic ratios. The predominant PAHs determined in PM(2.5) were pyrene, fluoranthene, benzo[a]anthracene, chrysene, benzo[b]fluoranthene and benzo[a]pyrene. The total concentrations of PAHs were up to 464.0 ng m(-3) in fine and 28.0 ng m(-3) in coarse fraction in winter, whereas in summer times were up to 22.9 and 3.0 ng m(-3) respectively. Approximately 93.3% of total PAHs concentration was determined in PM(2.5) in winter and 84.0% in summer. The concentration levels of PAHs fluctuate significantly within a year with higher means and peak concentrations in the winter compared to that of summer times. Higher benzo(a)pyrene-equivalent (BaPE) concentrations of PAHs were obtained for PM(2.5) especially in winter. The results obtained from PCA in combination with diagnostic ratios revealed that coal combustion and vehicle emissions were the major pollutant sources for both PM(2.5) and PM(2.5-10) associated PAHs in studied area. Two principal components for PM(2.5) and three for PM(2.5-10) were identified and these accounted for 89.4 and 85.2% of the total variance respectively. The emissions from coal combustion were estimated to be the main source of PAHs in the ambient air particulates with contributions of 80.8% of total variance for PM(2.5) and 53.8% for PM(2.5-10).     

Ventilation effectiveness as an indicator of occupant exposure to particles from indoor sources

Ventilation effectiveness is an indicator of the quality of supply air distribution in ventilated rooms. It is a representation of how well a considered space is ventilated compared to a perfect air mixing condition. Depending on pollutant properties and source position relative to the airflow, ventilation effectiveness can more or less successfully be used as an indicator of air quality and human exposure. This paper presents an experimentally and numerically based study that examines the relationship between ventilation effectiveness and particle concentration in typical indoor environments. The results show that the relationship varies predominantly with airflow pattern and particle properties. Fine particles (1 μm) follow the airflow pattern more strictly than coarse particles (7 μm), and the high ventilation effectiveness indicates better removal of fine particles than coarse particles. When a ventilation system provides high mixing in the space and ventilation effectiveness is close to one, particle sizes and source location have a relatively small effect on particle concentration in the breathing zone. However, when the supply air is short circuited and large stagnation zones exist within the space, the particle concentration in the breathing zone varies with particle size, source location, and airflow pattern. Generally, the results show that for fine particles (1 μm), increase of ventilation effectiveness reduces occupant exposure; while for coarser particles (7 μm), source location and airflow around the pollutant source are the major variables that affect human exposure.     

Polycyclic aromatic hydrocarbons, elemental and organic carbon emissions from tire-wear

Tire-wear is an important source of PAHs, elemental carbon (EC) and organic carbon (OC). The emissions of these pollutants have been studied in an experimental set-up, simulating a realistic road-tire interaction (summer tire-concrete road). The large particle non-exhaust emissions (LPNE; diameter greater than 10 μm) have been evaluated over 14,500 km run of the tire. An increasing linear trend with cumulative km run was observed for emissions of PAHs and carbon. Amongst PAHs in LPNE, pyrene has been observed to be the highest (30 ± 4 mg kg^− 1) followed by benzo[ghi]perylene (17 ± 2 mg kg^− 1). Different fractions of EC-OC for tire-wear have been analyzed, and unlike exhaust emissions, EC1 was observed to be 99% of EC whereas more than 70% of the OC was the high temperature carbon (OC3 and OC4). The overall emission factors (mass tire^− 1 km^− 1) for PAHs, EC and OC from tire-wear are 378 ng tire^− 1 km^− 1, 1.46 mg tire^− 1 km^− 1 and 2.37 mg tire^− 1 km^− 1 for small cars.     

Effect of particle size on arsenic bioaccessibility in gold mine tailings of Nova Scotia

Tailings samples from the Goldenville and Montague abandoned gold mines in Nova Scotia, Canada were subjected to bioaccessibility tests to examine the effects of the choice of particle size fraction on the bioaccessibility of arsenic. The proportion of finer grains (< 150 μm) in this sample set varied from 6.0 to 66 wt.%. Samples were sieved to < 250, < 150, and < 45 μm particle size fractions. The arsenic bioaccessibility ranged from less than 1.0 to 48%, but no systematic variation was observed (p > 0.13) precluding the association of greater percent arsenic bioaccessibility with a specific particle size fraction, method or site. On the other hand, the highest bioaccessible arsenic concentrations (up to 5200 mg kg^− 1) were consistently observed in samples sieved to the < 45 μm particle size, for both the physiologically based extraction test and a glycine-buffered bioaccessibility method (in 89 and 87% of samples tested, respectively). This was due to higher total arsenic concentrations in the same particle size fraction. Grain maps obtained by X-ray absorption spectroscopy indicate that samples with the highest percent arsenic bioaccessibility contain amorphous pentavalent arsenic distributed throughout the sample as well as grains coated with pentavalent arsenic. Arsenic bioaccessibilities lower than 10% were found in samples with encapsulated arsenopyrite and some grains composed primarily of pentavalent arsenic. The < 45 μm particle size fraction appears to yield conservative (protective) estimates of the bioaccessible dose of arsenic, but wide variations exist in particle size distribution and arsenic bioaccessibility between samples. As well, sieving to < 45 μm may exclude potentially relevant particles by restricting the study to an average particle size that is smaller than the average size of particles found on human hands, and may unduly influence the resulting bioaccessibility measurements.     

Distribution of the solvent-extractable organic compounds in fine (PM1) and coarse (PM1-10) particles in urban, industrial and forest atmospheres of Northern Algeria

The distribution of the solvent-extractable organic components in the fine (PM₁) and coarse (PM_1-10) fractions of airborne particulate was studied for the first time in Algeria. That was done during October 2006 concurrently in a big industrial district, a busy urban area, and a forest national park located in Algiers, Boumerdes, Blida, respectively, which are the three biggest provinces of Northern Algeria. Most of the organic matter identified in both particle size ranges consisted of n-alkanes and n-alkanoic acids, with minor contributions coming from polycyclic aromatic hydrocarbons (PAHs), nitrated polycyclic aromatic hydrocarbons (NPAHs), oxygenated PAHs, and other polar compounds (e.g., caffeine and nicotine). The potential emission sources of airborne contaminants were reconciled by combining the values of n-alkane carbon preference index (CPI) and selected diagnostic ratios of PAHs, calculated in both size ranges. The mean cumulative concentrations of PAHs reached 3.032 ng m^− 3 at the Boumerdes site, urban, 80% of which (i.e. 2.246 ng m^− 3) in the PM₁ fraction, 6.462 ng m^− 3 at Rouiba-Réghaia, industrial district, (5.135 ng m^− 3 or 80% in PM₁), and 0.512 ng m^− 3 at Chréa, forested mountains (0.370 ng m^− 3 or 72% in PM₁). Similar patterns were shown by all organic groups, which resulted overall enriched in the fine particles at the three sites. Carcinogenic and mutagenic potencies associated to PAHs were evaluated by multiplying the concentrations of “toxic” compounds times the corresponding potency factors normalized vs. benzo(a)pyrene (BaP), and were found to be both acceptable.     

Spatial and temporal distribution of polycyclic aromatic hydrocarbons (PAHs) in the atmosphere of Xiamen, China

An intensive sampling program was conducted from October 2008 to September 2009 at the five different environmental sites in Xiamen, Fujian Province, to study the spatial and temporal characteristics of Polycyclic Aromatic Hydrocarbons (PAHs) in the gaseous and particulate phase, respectively. The PAHs concentrations at different sites were quite distinct during four seasons. The average concentrations of PAHs in winter were about 8.4 times higher than those in spring, and the concentrations of background were 0.56 times lower than those of industrial area. In addition, the higher temperature in summer affected the particle/gas partitioning of PAHs and led to the higher concentrations of gaseous PAHs. Diagnostic ratios of PAHs, which were employed to indicate the primary sources of PAHs in Xiamen, showed that the traffic vehicle exhaust was the largest contributor and the primary source for PAHs in Xiamen, especially in urban area; while the stationary combustion processes, such as petrochemical factories and power plants, were mainly responsible for PAHs sources in the industrial areas. The health risk of PAHs in the particulate phase was higher than those of the gaseous phase at the five sampling sites. The average toxic equivalent (BaP_eq) of the benzo[a]pyrene values for PAHs were 0.14, 0.32, 1.38 and 3.59 ng m^− 3 in spring, summer, autumn and winter, respectively. Furthermore, the results of average BaP_eq in all four seasons indicated that the health risks of particulate PAHs were higher than those of the gaseous PAHs at different sampling sites.     

Transport of polycyclic aromatic hydrocarbons and pesticides during snowmelt within an urban watershed

During snowmelt events in urban watersheds large amounts of organic contaminants are mobilized, potentially affecting the quality of surface and groundwater resources. The transport of polycyclic aromatic hydrocarbons (PAHs) and two pesticides in the highly urbanized Highland Creek watershed within the city of Toronto, Canada, was investigated by sampling river water during two snowmelt periods. The dissolved and the particulate fractions were separately extracted and analyzed. While during normal flow conditions levels of the sum of nine PAHs including phenanthrene, anthracene, fluoranthene, pyrene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, indeno(1,2,3-c,d)pyrene, and benzo(ghi)perylene ranged between 18 and 45 ng/L, concentrations at the onset of melting varied from 550 to 4500 ng/L. Considering enhanced stream discharge rates during snowmelt the contaminant flux in the river increased by three orders of magnitude. The intensity of the melt event largely determined the extent of the PAH concentration increase in the river. The relatively water soluble pesticides chlorothalonil and lindane (γ-HCH) also tended to appear early during melting. Their enrichment in river water may be influenced by the thickness of the snow pack at the onset of melting, and the mode of melt water ablation from the snow pack to the stream, i.e. whether it occurs by overland or sub-surface flow.     

Particulate-bound polycyclic aromatic hydrocarbons in naturally ventilated multi-storey residential buildings of Singapore: Vertical distribution and potential health risks

The main objective of the study is to quantify the polycyclic aromatic hydrocarbons (PAHs) concentration levels (US EPA priority components) in fine traffic-generated particles (PM_2.5) at various heights of typical multi-storey public housing buildings located in close proximity, i.e. within 30 m and along a busy major expressway in Singapore. The secondary objective is to estimate the potential health risks associated with inhalation exposure, based on the toxic equivalency factors (TEFs) at the various floors of these buildings. Two typical public housing buildings, both naturally ventilated residential apartment blocks, of point block configuration (22-storey) and slab block configuration (16-storey) were selected for the study. Particulate samples were collected for chemical analysis at three representative floors: the lower, the mid, and the upper floors of the buildings. Key meteorological parameters such as wind speed, wind direction, ambient temperature, and relative humidity were also measured at the representative floors. All samples were analyzed for the 16 PAH priority pollutants listed by US EPA. The vertical PAH distribution profile varies with height of building depending on the type of block configuration. The total mean concentrations of particulate PAHs for point and slab blocks are 3.32±1.76 ng/m³ (0.56–7.2 ng/m³) and 6.0±1.88 ng/m³ (3.19–10.26 ng/m³), respectively. For the point block, the highest mean total PAH concentration occurred at the mid floor followed by the upper floor. The lower floor had the least mean total PAH concentration. For the slab block, the highest mean total PAH concentration occurred at the lower floor and remained almost constant up to the mid floor and thereafter gradually decreased from mid floor to upper floor of the building. These results suggest that the building configuration influences the vertical distribution of particulate PAHs. The dominant particulate PAHs measured at the point block are naphthalene, acenaphthylene, benzo(b)fluoranthene, and benzo(g,h,i)perylene while those for the slab block, the main particulate PAHs are naphthalene, phenanthrene, fluoranthene, and benzo(g,h,i)perylene. The Bpe/Ind ratio for both blocks ranged from 0.92±0.2 to 1.63±0.6 indicating particulate PAHs are contributed by a mixture of both diesel and petrol engine type of vehicles, with diesel engine vehicles contributing a higher percentage of particulate PAHs to the different floor levels of both buildings. The total BaP_eq concentrations for point and slab blocks are 1.06±0.64 ng/m³ (0.14–2.45 ng/m³) and 0.94±1.22 ng/m³ (0.10–4.59 ng/m³), respectively. The total BaP equivalency results showed the potential health risk to cancer due to inhalation exposure is of concern for residents living in both blocks since the total BaP_eq concentrations for both blocks were very close to, or slightly exceeded the maximum permissible risk level of 1 ng/m³ of benzo(a)pyrene.     

Composition and particle size of superparamagnetic corrosion products in tap water

Chemical analyses, magnetization, Mössbauer spectrum, and x-ray diffraction measurements were made on solids removed from tap water by means of membrane filters. The taps from which this water was obtained had previously been unused for prolonged periods of time. When these taps were reactivated and water was first drawn, it was observed that the quantity of coarse solids in the water gradually decreased with flow, while at the same time the quantity of fine solids gradually increased. The magnetization, Mössbauer spectra, and x-ray diffraction patterns of the solids showed the presence of a significant number of superparamagnetic particles of magnetite. In the temperature range of our measurements (77 K < T < 300 K), paramagnetic iron-based species, particularly lepidocrocite, were also present in the solids. Contaminants such as Pb, Cu, and As were observed to be present in significant amounts, and it is shown that these are adsorbed to the magnetic nanoparticles. It was observed that almost all of the solid particles could be removed by means of 5-μm filters. This removal process can be explained by means of a model which assumes that initial deposition of coarse aggregates of corrosion products on the filters forms a coating, rich in extremely fine iron oxides. The coating has a high capacity for sorption of very small individual particles.     

Emission characteristics of polycyclic aromatic hydrocarbons from combustion of different residential coals in North China

Emission properties of polycyclic aromatic hydrocarbons (PAHs) from combustion of six residential coals in North China were investigated. The results indicated that, the total emission factors (EFs) for 15 PAH species in gaseous and particulate phases ranged from 52.8 to 1434.8 mg/kg with a decreasing sequence of local bituminous coals and anthracite coals, and honeycomb briquettes were largely dependent on the raw coals used to produce them. Particulate phase, dominated by median or high molecular weight components, made a major contribution (68.8% - 76.5%) to the total EFs for bituminous coals, while gaseous phase with principal low molecular weight species accounted for most (86.3% - 97.9%) of the total EFs for anthracite coals. The phase partitioning of PAH emission for honeycomb briquettes was similarly dependent on the crude coals. The total EFs, phase partitioning and component profiles of emitted PAHs were mainly influenced by the inner components of the studied coals. Burning mode and flue number on household coal-stoves also affected the emission characteristics by means of the oxygen supply. A sum of seven carcinogenic PAHs, benzo(a)pyrene(BaP)-equivalent carcinogenic power and total toxicity potency expressed in 2,3,7,8-tetrachlorodibenzo-dioxin(TCDD) toxic equivalence exhibited that bituminous coals and produced honeycomb briquettes had remarkably elevated values. Fluoranthene, benzo(b)fluoranthene, benzo(k)fluoranthene, chrysene and indeno(1,2,3-cd)pyrene from anthracite coals showed higher levels of BaP-based toxic equivalent factor, though the other toxicity indices were rather low for this type of coal.     

Biodegradation of polycyclic aromatic hydrocarbons by Sphingomonas sp. enhanced by water-extractable organic matter from manure compost

The effectiveness of in-situ bioremediation of polycyclic aromatic hydrocarbons (PAHs) may be inhibited by their low aqueous solubility and strong absorption to soil constituents. The aim of this research was to evaluate the effect of water-extractable organic matter (WEOM) from manure compost on the biodegradation of various PAHs. The aqueous solubilities of PAHs including phenanthrene, pyrene and benzo[a]pyrene under different concentrations of WEOM from cow manure compost were initially evaluated. The contribution of WEOM on the degradation of PAHs by Sphingomonas sp. was then investigated. Dissolution results confirmed the ability of WEOM to increase the apparent solubility of the 3PAHs. Time course of biodegradation also revealed its positive contribution to their removal. For example, the degradation of pyrene was 118% higher in the presence of 1000 mg-C L^− 1 WEOM as compared to the mineral salt medium (MSM) alone after 48 h incubation. In addition, degradation was 12% higher with WEOM than with Glucose-Ammonium nitrate despite the more than 6 times higher cell concentration in the latter. WEOM from other manure composts such as chicken and pig were found to have the same effect. Finally, additional tests confirmed that high molecular weight WEOM (> 1000 Da) contributed mainly to solubility and biodegradation enhancements. On the basis of these results, the increase in apparent solubility of PAHs in WEOM solutions may have a significant impact on their biodegradation. It is postulated that the application of WEOM-rich manure composts may be extended in the in-situ bioremediation of PAHs-polluted soil.     

Exposure of children to airborne particulate matter of different size fractions during indoor physical education at school

Although moderate regular aerobic exercise is recommended for good health, adverse health consequences may be incurred by people who exercise in areas with high ambient pollution, such as in the centres of large cities with dense traffic. The exposure of children during exercise is of special concern because of their higher sensitivity to air pollutants. The size-segregated mass concentration of particulate matter was measured in a naturally ventilated elementary school gym during eight campaigns, seven to ten days long, from November 2005 through August 2006 in a central part of Prague (Czech Republic). The air was sampled using a five-stage cascade impactor. The indoor concentrations of PM_2.5 recorded in the gym exceeded the WHO recommended 24-hour limit of 25 μg m⁻³ in 50% of the days measured. The average 24-h concentrations of PM_2.5 (24.03 μg m⁻³) in the studied school room did not differ much from those obtained from the nearest fixed site monitor (25.47 μg m⁻³) and the indoor and ambient concentrations were closely correlated (correlation coefficient 0.91), suggesting a high outdoor-to-indoor penetration rate. The coarse indoor fraction concentration (PM_2.5–10) was associated with the number of exercising pupils (correlation coefficient 0.77), indicating that human activity is its main source. Considering the high pulmonary ventilation rate of exercising children and high outdoor particulate matter concentrations, the levels of both coarse and fine aerosols may represent a potential health risk for sensitive individuals during their physical education performed in naturally ventilated gyms in urban areas with high traffic intensity.     

Priority pollutants in surface waters and settleable particles within a densely urbanised area: Case study of Paris (France)

Implementation of the European Water Framework Directive 2000/60/EC (WFD) requires Member States to expand their collective knowledge of priority pollutants (PPs) within receiving waters. To achieve this objective, information on the occurrence of PPs in surface waters and, more specifically, within densely urbanised areas needs to be collected. This study has therefore been designed to provide information on both PP occurrence and concentration build-up along a heavily urbanised transect of the Seine River in the Paris region (France). A large range of PPs were observed in settleable particles and, to a lesser extent, in the waters surveyed. In surface waters, a total of 18 PPs, including 15 priority hazardous substances?, were indeed detected, yet concentrations rarely exceeded the limit of quantification. In fact, only diuron?, DEHP?, fluoranthene and para-tert-octylphenol? are observed on a frequent basis, with concentrations ranging from < 0.01 to 1.0 µg l^− 1. As regards the Environmental Quality Standards (EQS), 10 substances or groups of substances were found in surface waters to exhibit concentrations above the annual average value, while only the benzo(a)pyrene? concentration exceed the maximum allowable level. As for the Canadian Sediment Quality Guidelines, settleable particles collected in the Seine River appear to be heavily contaminated since most samples contain PP levels above the guideline values (18 PPs) and, in many cases, above the probable effect levels (15 PPs), which underscores that the levels of metals, PAHs and PCBs in settleable particles constitute a potential risk to freshwater organisms.     

Removal of probable human carcinogenic polycyclic aromatic hydrocarbons from contaminated water using molecularly imprinted polymer

A molecularly imprinted polymer (MIP) adsorbent for carcinogenic polycyclic aromatic hydrocarbons (PAHs) was prepared using a non-covalent templating technique. MIP particles sized from 2 to 5 μm were synthesized in acetonitrile by using six PAHs mix as a template, methacrylic acid as the functional monomer, and ethylene glycol dimethacrylate as the cross-linker. When compared with the non-imprinted polymer (NIP), the MIP showed an excellent affinity towards PAHs in aqueous solution with binding capacity (B_max) of 687 μg g⁻¹MIP, imprinting effect of 6, and a dissociation constant of 24 μM. The MIP exhibited significant binding affinity towards PAHs even in the presence of environmental parameters such as dissolved organic matter (COD) and total dissolved inorganic solids (TDS), suggesting that this material may be appropriate for removal of carcinogenic PAHs. The feasibility of removing PAHs from water by the MIP demonstrated using groundwater spiked with PAHs. In addition, the MIP reusability without any deterioration in performance was demonstrated at least ten repeated cycles.     

Levels, chemical composition and sources of fine aerosol particles (PM1) in an area of the Mediterranean basin

Daily samples of fine aerosol particles (i.e., PM1, aerosol particles with an aerodynamic diameter less than 1.0 μm) were collected in Tito Scalo — Southern Italy — from April 2006 to March 2007. Measurements were performed by means of a low-volume gravimetric sampler, and each PM1 sample was analyzed by means of Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) or Atomic Absorption Spectrometry (GFAAS and FAAS) techniques in order to determine its content in fourteen trace elements (Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Ti and Zn). During the period examined, PM1 daily concentrations ranged between 0.3 µg m^− 3 and 55 µg m^− 3 with a mean value of 8 µg m^-3, a standard deviation of 7 µg m^− 3 and a median value of 6 µg m^− 3. As far as PM1 chemical composition is concerned, the mean values of the trace element concentrations decreased in the following order: Ca > Fe > Al > Na > K > Cr > Mg > Pb > Ni ≈ Ti ≈ Zn > Cd ≈ Cu > Mn. Principal Component Analysis (PCA) allowed the identification of three probable PM1 sources: industrial emissions, traffic and re-suspension of soil dust. Moreover, the results of a procedure applied to study the potential long-range transport contribution to PM1 chemical composition, showed that trace element concentrations do not seem to be affected by air mass origin and path. This was probably due to the strong impact of the local emission sources and the lack of the concentration measurements of some important elements and compounds that could better reveal the long-range transport influence on PM1 measurements at ground level.