High-volume Sampler Research Articles

Association between Prenatal Exposure to Air Pollutants and Newborn Thyroxine (T4) Levels

Background: Thyroid hormones play a key role in fetal and child development. Recent studies have linked prenatal exposure to atmospheric contaminants with changes in thyroid hormone levels in newborns, but the data from the few studies that have explored this issue are inconclusive. The present study aims to assess the association of total thyroxine (TT4) levels in newborns with prenatal exposure to PM2.5 and NO2. Methods: This prospective cohort study included mother-child pairs from the INMA-Gipuzkoa project. Specifically, 463 mother-child pairs with data on PM2.5 and NO2 exposure during pregnancy and TT4 levels at birth were included. PM2.5 and NO2 levels were measured by high-volume aerosol samplers and passive samplers respectively during the women’s pregnancies. TT4 levels were measured in heel-prick blood samples from infants. Data on maternal and infant covariates were gathered through questionnaires administered in the first and third trimesters of pregnancy and review of clinical records. Potential associations of PM2.5 and NO2 with TT4 levels over the entire pregnancy period and by trimesters were assessed by linear regression models. Findings: According to the results, the exposure of pregnant women to PM2.5 in the three trimesters of pregnancy was positively associated with infant TT4 level at birth (β= 0.15, 95% CI: 0.206 [0.083, 0.329], 0.119 [0.011, 0.228], 0.173 [0.058, 0.287] and 0.198 [0.091, 0.305] for the entire pregnancy, first, second and third trimesters of pregnancy, respectively). In addition, the later the exposure, the stronger the association. In contrast, no association was observed between NO2 exposure and TT4 levels. Interpretation: The results indicate that prenatal exposure to PM2.5 could lead to a thyroid function impairment in newborns. Further, they suggest that the effect of PM2.5 could be partially mediated by maternal thyroid function. Funding: This study was funded by the Carlos III Health Institute (PI06/0867), Department of Health of the Government of the Basque Country (2005111093), Gipuzkoa Regional Government (DFG06/002) and the local councils of the study area (Zumarraga, Urretxu, Legazpi, Azkoitia, Azpeitia and Beasain). Declaration of Interests: The authors have no conflicts of interest to declare. Ethics Approval Statement: The study was approved by the Ethics Committee of Donostia University Hospital (Gipuzkoa) and all mothers gave written informed consent before inclusion.

Physical and chemical properties of non-exhaust particles generated from wear between pavements and tyres

A road simulator was used to generate wear particles from the interaction between two tyre brands and a composite pavement. Particle size distributions were monitored using a scanning mobility particle sizer and an aerosol particle sizer. Continuous measurements of particle mass concentrations were also made. Collection of inhalable particles (PM10) was conducted using a high-volume sampler equipped with quartz filters, which were then analysed for organic and elemental carbon, organic constituents and elemental composition. Tyre fragments chopped into tiny chips were also subjected to detailed organic and elemental speciation. The number concentration was dominated by particles <0.5 μm, whereas most of the mass was found in particles >0.5 μm. The emission factor from wear between pavements and tyres was of the order of 2 mg km−1 veh−1. Organic carbon represented about 10% of the PM10 mass, encompassing multiple aliphatic compounds (n-alkanes, alkenes, hopanes, and steranes), PAHs, thiazols, n-alkanols, polyols, some fragrant compounds, sugars, triterpenoids, sterols, phenolic constituents, phthalate plasticisers and several types of acids, among others. The relationship between airborne particulate organic constituents and organic matter in tyre debris is discussed. The detection of compounds that have been extensively used as biomass burning tracers (e.g. retene, dehydroabietic acid and levoglucosan) in both the shredded tiny tyre chips and the wear particles from the interaction between tyres and pavement puts into question their uniqueness as markers of wood combustion. Trace and major elements accounted for about 5% of the mass of the tyre fragments but represented 15–18% of the PM10 from wear, denoting the contribution of mineral elements from the pavement. Sulphur and zinc were abundant constituents in all samples.

Optimization of a thermal desorption-gas chromatography/mass spectrometry method for characterization of semi-volatile organic compounds in high time resolved PM2.5

Organic aerosol (OA) is an important fraction of fine particulate matter. Most primary OA emissions comprise semivolatile organic compounds (SVOCs) that are reactive and may partition into particle and vapor phases. Collection of SVOCs in the particle phase at high time resolution reduces positive and negative artifacts, but requires sensitive analytical techniques for chemical characterization. In this work, we investigated the effect of thermal desorption-gas chromatography/mass spectrometry (TD-GC-MS) analytical variables on 16 polycyclic aromatic hydrocarbons (PAHs) and 29 n-alkanes. Analytical responses of target compounds were mostly influenced by trap desorption time and GC column pressure. The optimal TD-GC-MS trap desorption conditions were 350 °C for 10 min at GC constant pressure mode of 17 psi. Good linearity (R2 > 0.99) was observed for all target analytes (with the exception of 6 ring PAHs and C35–C39n-alkanes). Method detection limits were 0.038–0.157 ng m−3 and 0.028–0.355 ng m−3 for PAHs and n-alkanes, respectively. The optimized method was tested on PM2.5 samples collected with the high-volume sampling technique at high temporal resolution of 2 h. Analysis of a sample, followed by analysis of a blank, did not show carryover. The optimized TD-GC-MS method showed the capability to resolve diurnal variations of target analytes in high time resolved PM2.5. Using TD-GC-MS for analysis of high time resolved PM2.5 will contribute to the improvement of source apportionment, emission inventories, and global chemistry-climate models.

Health risk assessment of polycyclic aromatic hydrocarbons (PAHs) adsorbed in PM2.5 and PM10 in a region of Arequipa, Peru.

The concentrations of PM2.5 and PM10, as well as those of the PAHs bound to these particles, were quantified at four sites in the region of Arequipa, Peru, during the year 2018. These samples were collected with high volume samplers, and the concentrations of the PAHs were quantified by liquid chromatography (HPLC). The values found for PM2.5 and PM10 at all the sampling sites in Arequipa exceeded the norms established in Peru (50 μg m-3 annual average value for PM10 and 25 μg m-3 annual average value for PM2.5), with the industrial site presenting the highest values of particulate matter (PM10 max = 235.1 μg m-3; PM2.5 max = 218.4 μg m-3). With respect to seasonality, in the cold season (winter), the concentration of particles was higher compared to the other seasons. Concerning the PAHs, it was found that these had the highest concentrations at the industrial site, followed by the site with high vehicular traffic, with both these sites differing significantly from the rural sites. In addition, at the industrial and high traffic sites, there was a predominance of PAHs with 5 and 6 rings, whereas at the rural sites, PAHs with fewer rings predominated. Finally, the calculated values of lifetime lung cancer risk also revealed a difference between sites with marked emission sources, where irrigation was considered moderate, and the rural sites, where irrigation was considered low. This demonstrated that people living at sites with mobile sources and/or industries had a higher cancer risk compared to the inhabitants of rural sites.

Temporal variation of atmospheric 7Be and 210Pb concentrations and their activity size distributions at Astana, Kazakhstan in Central Asia

Atmospheric concentrations of 7Be and 210Pb obtained by a high-volume air sampler with a cascade impactor were measured from September 2016 to November 2017 in Astana, Kazakhstan. The levels and seasonal variations of atmospheric 7Be and 210Pb concentrations were investigated together with their activity size distributions. Typical seasonal variability was observed with higher concentrations of 7Be occurring in the warm summer and that of 210Pb towards the cold winter. These trends may be attributed to the increased vertical mixing within the troposphere during the warm summer season and the frequent inversion conditions of the surface layers during the cold winter season.

Mass concentrations and lung cancer risk assessment of PAHs bound to PM1 aerosol in six industrial, urban and rural areas in the Czech Republic, Central Europe

The daily concentrations of 15 polycyclic aromatic hydrocarbons (PAHs) in PM1 aerosol samples, including 7 carcinogenic PAHs, were determined in six urban/rural areas in the Czech Republic in winter seasons between 2013 and 2017. The PM1 aerosol was collected on quartz fibre filters using high-volume samplers for 24 h and PAHs were analysed by GC-MS. The highest concentrations of PAHs were found in the industrial city Ostrava (60.8 ng m−3), which is one of the most polluted areas in the Czech Republic, while the lowest concentrations were obtained in the small town Čelákovice (11.7 ng m−3) and in the background rural area Košetice (12.3 ng m−3). Carcinogenic PAHs formed 43.9%–57.8% of total analysed PAHs.The toxic equivalence factors for individual PAHs adopted from literature and two unit risks (Cal-EPA and WHO) were used for the evaluation of carcinogenic risk of PAHs exposure. The inhalation cancer risk models assume a lifetime exposure (70 years), whereas our measurement was realized for a relatively short duration in winters where concentrations of PAHs are usually high. The average of PAHs concentrations will be lower for the whole year resulting in lower lung cancer risk values. The calculated lifetime lung cancer risk of PAHs exposure for the measured winter periods suggested 1545 cases per 1 million people in Ostrava (industrial area), 192–456 cases per 1 million people in other four investigated cities/towns and 182 cases per 1 million people in Košetice (rural area). The calculated lifetime lung cancer risk values are related only to ambient concentrations of PAHs in atmospheric aerosols. Nevertheless, other factors can influence and increase the lung cancer risk, e.g., occupation, smoking, indoor emissions of coal/wood combustion in stoves or genetic factors of individuals. Our results can also be underestimated due to the determination of PAHs only in PM1 aerosol.

Estimation of PM10 Levels and Sources in Air Quality Networks by Digital Analysis of Smartphone Camera Images Taken from Samples Deposited on Filters.

This paper explores the performance of smartphone cameras as low-cost and easily accessible tools to provide information about the levels and origin of particulate matter (PM) in ambient air. We tested the concept by digital analysis of the images of daily PM10 (particles with diameters 10 µm and smaller) samples captured on glass fibre filters by high-volume aerosol samplers at urban and rural locations belonging to the air quality monitoring network of Extremadura (Spain) for one year. The images were taken by placing the filters inside a box designed to maintain controlled and reproducible light conditions. Digital image analysis was carried out by a mobile colour-sensing application using red, green, blue/hue, saturation, value/hue, saturation, luminance (RGB/HSV/HSL) parameters, that were processed through statistical procedures, directly or transformed to greyscale. The results of the study show that digital image analysis of the filters can roughly estimate the concentration of PM10 within an air quality network, based on a significant linear correlation between the concentration of PM10 measured by an official gravimetric method and the colour parameters of the filters’ images, with better results in the case of the saturation parameter (SHSV). The methodology based on digital analysis can discriminate urban and rural sampling locations affected by different local particle-emitting sources and is also able to identify the presence of remote sources such as Saharan dust outbreaks in both urban and rural locations. The proposed methodology can be considered as a useful complement to the aerosol sampling equipment of air quality network field units for a quick estimation of PM10 in the ambient air, through a simple, accessible and low-cost procedure, with further miniaturization potential.

Fate of the organophosphate insecticide, chlorpyrifos, in leaves, soil, and air following application.

A field study was conducted to further our understanding about the fate and transport of the organophosphate insecticide, chlorpyrifos, and its degradation product, chlorpyrifos oxon. Leaf, soil and air sampling was conducted for 21 days after chlorpyrifos application to a field of purple tansy (Phacelia tanacetifolia). Air samples were collected using a high-volume air sampler (HVAS) and seven battery-operated medium-volume active air samplers placed around the field and on a 500-m transect extending away from the field. Chlorpyrifos was detected every day of the sampling period in all matrices, with concentrations decreasing rapidly after application. Chlorpyrifos oxon was only detected in air samples collected with the HVAS during the first three days after application. Wind direction played a significant role in controlling the measured air concentrations in near-field samples. The SCREEN3 model and chlorpyrifos' Characteristic Travel Distance (CTD) were used to predict modelled chlorpyrifos concentrations in air along the transect. The concentration trend predicted by the SCREEN3 model was similar to that of measured concentrations whereas CTD-modelled concentrations decreased at a significantly slower rate, indicating that downwind chlorpyrifos concentrations in air were primarily controlled by air dispersion. The SCREEN3-predicted chlorpyrifos concentrations were >5 times higher than measured concentrations, indicating that simple approaches for calculating accurate pesticide volatilization fluxes from agricultural fields are still needed. Finally, we found that measured concentrations in air on Days 0-2 at locations up to 500 m from the field were at levels considered concerning for human health.

Levels, spatial distribution, and source identification of airborne environmentally persistent free radicals from tree leaves

Environmentally persistent free radicals (EPFRs) are receiving increasing concern due to their toxicity and ubiquity in the environment. To avoid restrictions imposed when using a high-volume active sampler, this study uses tree leaves to act as passive samplers to investigate the spatial distribution characteristics and sources of airborne EPFRs. Tree leaf samples were collected from 120 sites in five areas around China (each approximately 4 km × 4 km). EPFR concentrations in particles (<2 μm) on the surface of 110 leaf samples were detected, ranging from 7.5 × 1016 to 4.5 × 1019 spins/g. For the 10 N.D. samples, they were all collected from areas inaccessible by vehicles. The g-values of EPFRs on 68% leaf samples were larger than 2.004, suggesting the electron localized on the oxygen atom, and they were consistent with the road dust sample (g-value: 2.0042). Significant positive correlation was found between concentrations of elemental carbon (tracer of vehicle emissions) and EPFRs. Spatial distribution mapping showed that EPFR levels in various land uses differed noticeably. Although previous work has linked atmospheric EPFRs to waste incineration, the evidence in this study suggests that vehicle emissions, especially from heavy-duty vehicles, are the main sources. While waste incinerators with low emissions or effective dust-control devices might not be an important EPFR contributor. According to our estimation, over 90% of the EPFRs deposited on tree leaves might be attributed to automotive exhaust emissions, as a synergistic effect of primary exhausts and degradation of aromatic compounds in road dust. With adding the trapping agent into the particle samples (<2 μm), signals of hydroxyl radicals were observed. This indicates that EPFRs collected from this phytosampling method can lead to the release of reactive oxygen species (ROS) once they are inhaled by human beings. Thus, this study helps highlight EPFR “hotspots” for potential health risk identification.

Derivation of flow rate and calibration method for high-volume air samplers

Abstract. Sampling the atmosphere to analyze contaminants is different from other environmental matrices because measuring the volume of air collected requires a mechanical flow-through device to draw the air and measure its flow rate. The device used must have the capability of concentrating the analytes of interest onto a different substrate because the volumes of air needed are often on the order of hundreds of cubic meters. The use of high-volume air samplers has grown since 1967, when recommended limits of a large number of organic contaminants in air were developed. Equations used for calculating the air flow through the device over time have similarly been developed. However, the complete derivation of those equations has never appeared in the scientific literature. Here a thorough derivation of those equations is provided with definitions of the mechanical systems that are used in the process, along with the method of calibrating and calculating air flow.

Molecular Composition and Source Apportionment of Fine Organic Aerosols in Autumn in Changchun

Organic aerosols have attracted increasing attention recently due to their significant contribution to fine particles (PM2.5) and their complex components and sources. In this study, a total of 40 PM2.5 samples were collected simultaneously with high-volume samplers in Changchun from 16th Oct to 29th Nov 2016. Organic carbon (OC), elemental carbon (EC), non-polar organic compounds including n-alkanes, polycyclic aromatic hydrocarbons (PAHs), and hopanes, and levoglucosan in atmospheric fine particles were analyzed. The main sources of organic aerosols were identified by molecular markers, diagnostic ratios, and a principal component analysis-multiple liner regression (PCA-MLR) model. The results showed that the average mass concentration of PM2.5 was (79.0±55.7) μg·m-3, and the averaged OC and EC mass concentrations were (20.7±15.6) μg·m-3 and (2.2±1.1) μg·m-3, which accounted for 26.2% and 2.8% of PM2.5, respectively. The total average concentration of the tested non-polar organic compounds was (186.3±104.5) ng·m-3 and, in descending order, this was composed of n-alkane (101.3±67.0) ng·m-3, polycyclic aromatic hydrocarbons (81.4±46.0) ng·m-3, hopanes (3.8±1.9) ng·m-3. The PCA-MLR model results showed that the relative contributions of the main sources of organic aerosols were coal combustion (47.0%), biomass burning (42.6%), and traffic emission (10.4%).

Anionic Surfactants and Traffic Related Emission from an Urban Area of Perak, Malaysia.

Anionic surfactants are one of the pollutants derived from particulate matter (PM) and adversely affect the health of living organisms. In this study, the compositions of surfactants extracted from PM and vehicle soot collected in an urban area were investigated. A high-volume air sampler was used to collect PM sample at urban area based on coarse (> 1.5µm) and fine (< 1.5µm) mode particles. Meanwhile, the vehicle soot was collected randomly from the exhaust pipe of various types of diesel and petrol vehicles using a soft brush during dry days. The concentration of anionic surfactants, such as Methylene Blue Active Substances (MBAS), was determined by the colorimetric method using UV-Vis Spectrophotometer. Morphological properties of the PM and exhaust soot sample was studied using field-emission scanning electron microscope. Results revealed that the MBAS concentration was dominated by fine mode particles (6.03 ± 3.97µmolg-1), whereas heavy-duty vehicles, such as buses, demonstrated the highest surfactant concentration with an average value of 0.340 ± 0.180µmolg-1. The structure of collected PM for all samples mostly appeared to be an irregular shape with the size range of ultrafine particles (0.05-0.2µm). The emission of surfactants from diesel and petrol vehicles, especially at urban areas, should be a major concern, because they could negatively affect human health and the environment.

Evaluation of the factor of enrichment of atmospheric particulate matter in the Campus of UFMG, Belo Horizonte

The particulate matter present in the atmospheric air of large cities is one of the pollutants that causes great environmental risks. Due to their composition of solids and liquids varying in size, shape, composition and origin, they have an impact on the health of the exposed population, agriculture, forests and acidification of lakes. In this scenario, the present work had as objective to evaluate the concentration of the 10-micrometer particulate matter, commonly called PM10, and the elementary concentrations in air filters whose sampling was carried out at the Campus of the Federal University of Minas Gerais. For this, a high-volume sampler was used to collect the particulate matter. The elementary concentration of the particulate matter was determined via neutron activation analysis, method k0. Applying the enrichment factor technique, the influence of anthropogenic sources at the sampled site was investigated. The results showed anthropogenic interferences of zinc, sodium, chromium and iron and a geogenic impoverishment of cobalt.

Predictors of personal exposure to black carbon among women in southern semi-rural Mozambique

Sub-Saharan Africa (SSA) has the highest proportion of people using unclean fuels for household energy, which can result in products of incomplete combustion that are damaging for health. Black carbon (BC) is a useful marker of inefficient combustion-related particles; however, ambient air quality data and temporal patterns of personal exposure to BC in SSA are scarce. We measured ambient elemental carbon (EC), comparable to BC, and personal exposure to BC in women of childbearing age from a semi-rural area of southern Mozambique. We measured ambient EC over one year (2014–2015) using a high-volume sampler and an off-line thermo-optical-transmission method. We simultaneously measured 5-min resolved 24-h personal BC using a portable MicroAeth (AE51) in 202 women. We used backwards stepwise linear regression to identify predictors of log-transformed 24-h mean and peak (90th percentile) personal BC exposure. We analyzed data from 187 non-smoking women aged 16–46 years. While daily mean ambient EC reached moderate levels (0.9 μg/m3, Standard Deviation, SD: 0.6 μg/m3), daily mean personal BC reached high levels (15 μg/m3, SD: 19 μg/m3). Daily patterns of personal exposure revealed a peak between 6 and 7 pm (>35 μg/m3), attributable to kerosene-based lighting. Key determinants of mean and peak personal exposure to BC were lighting source, kitchen type, ambient EC levels, and temperature. This study highlights the important contribution of lighting sources to personal exposure to combustion particles in populations that lack access to clean household energy.

Buoyant microbubbles as alternatives or adjuncts to magnetic bead methods for high-purity cell isolation

Abstract Widely used in immunologic applications, magnetic bead systems have significant limitations including cumbersome workflows, generation of high-shear and high-compressive forces during routine use, and limited performance in low and high volume samples. Buoyancy-activated cell sorting (BACS) overcomes these issues by using low-density microbubbles in lieu of magnets and iron beads to perform isolation. Here we report methods for three common uses: removal of extraneous RBCs prior to FACS, isolation of high-purity B lymphocytes from murine spleens, and improvement of a magnetic NK separation system by jointly applying BACS to remove contaminating NKT cells. RBC removal from leukopheresis-derived PBMC was performed with anti-CD235a-conjugated microbubbles. B cell isolation was performed with streptavidin microbubbles and a negative selection cocktail of biotinylated anti-murine antibodies. NK cell isolation was performed on PBMC using Miltenyi human CD56 MicroBeads and an additional purification step using streptavidin microbubbles and an anti-CD3 antibody. Each experiment used Akadeum microbubbles and a one-minute trituration to combine microbubbles with cell suspensions. RBC microbubbles provided 98.3 ± 1.0% removal of RBCs with 11.3 ± 0.9% nonspecific binding. B cells isolated with microbubbles were 91.8 ± 2.8% pure with a yield of 94.2 ± 4.3%. NK purification with magnetic microparticles produced 80.5 ± 0.7% purity. Additional purification with microbubbles increased purity to 90.8 ± 1.3%. Microbubbles are a flexible and simpler alternative to magnetic cell isolation systems, delivering comparable performance and, when used in conjunction with magnetic beads, superior purity.

APPLICATION OF AN AUTOMATED IDENTIFICATION AND QUANTIFICATION SYSTEM WITH A GC/MS DATABASE (AIQS-DB) FOR SIMULTANEOUS ANALYSIS OF PHTHALATE ESTERS AND STEROLS IN AIR PARTICLES

The aim of this study is to apply an automated identification and quantification system with a GC-MS database (AIQS-DB) for simultaneous analysis of phthalate esters (PAEs) and sterols in air particles. Air particles samples were collected on the roof of building located by the side of a busy street with heavy traffic load (Pham Van Dong street) (AP1) and in a highly populated residential area (Phu Do town) (AP2). At each sampling location, day and night samples were collected separately (around 10 h for each sample) continuously 6 d using a Kimoto high-volume air sampler. Air particle samples were then extracted by dichloromethane and determined and quantified by GC/MS instrument with the AIQS-DB. Analytical results of 12 PAEs and 13 sterols in air particles samples showed that five out of 12 PAEs and seven out of 13 sterols were detected. Di(2-ethylhexyl)phthalate (DEHP), di-n-butyl phthalate (DBP) and di-iso-butyl phthalate (DiBP) concentrations were highest, contributed 94% of the total detected phthalates concentration. Cholesterol and beta-sitosterol were detected in all the samples and accounted more than 70% of the total detected sterols concentration at Phu Do town. This is the first study on the application of AIQS-GC for simultaneous determination of PAE and sterols in the air particle, especially results obtained from this study provides new important information about the level and occurrence of sterol in air in Vietnam.

Time-resolved spread of antibiotic resistance genes in highly polluted air

Antibiotic resistance genes (ARGs) have emerged as a global health concern. A large volume of work has already been devoted to ARGs in aquatic ecosystems. However, ARG dispersal patterns in air remain to be largely unknown despite of its greater role in transmission. This work aims to investigate time-resolved airborne spread of ARGs and their corresponding subtype bacterial carriers in highly polluted air. Time-resolved air samples (20 m3 each with three samples) were collected using a high volume sampler (1 m3/min) every 4 h continuously (both day and night) during low (14–93 μg/m3) and high PM2.5 (36–205 μg/m3) pollution times (over 6 days with a total of 69 air samples) in Beijing. All air samples were subjected to 16S rRNA sequence analysis for 39 ARG subtypes. Pure culturable bacterial isolates from Beijing and Shijiazhuang were Sanger sequenced for species identification and also subjected to high throughput ARG subtype detection. ARG and its subtype relative abundances in the air were observed to differ greatly (up to 3 folds for abundance) both day and night, and the blaTEM gene was found to lead the ARG abundance. For an early morning time, the multi-drug resistant NDM-1 gene was detected up to 30% of total ARG abundance in highly polluted air. Identified as a major NDM-1 and vanB gene carrier, Bacillus halotolerans were also shown to disseminate more ARG subtypes. On another front, tnpA and intI1 were shown to vary greatly in abundance, while the sul3 gene was found widespread among the culturable Bacillus isolates in the air. Principal component analysis (PCA) showed different gene co-occurrence networks for different PM2.5 pollution episodes, e.g., tnpA and intI1 for gene transfer and integration, respectively, were found more abundant for the high PM2.5 pollution episode. This study highlights a serious yet previously unidentified public health threat from time-resolved airborne spread of ARGs. Further work is urgently warranted to track the sources of ARGs for their optimized control during high PM2.5 pollution episodes.

The genotoxicity of organic extracts from particulate truck emissions produced at various engine operating modes using diesel or biodiesel (B100) fuel: A pilot study

An analysis of the toxic effects of emissions should reflect real traffic conditions. The exhaust emissions of particulate matter from diesel engines strongly depend on their operating conditions, with low-speed, low-load "urban creep" conditions, common for truck traffic in heavily congested urban areas, being one of the worst. We aimed to detect the genotoxicity of organic extracts from particulate matter in the exhaust of the diesel engine Zetor 1505 running on diesel and biodiesel (B100) fuels at characteristic modes of extended "urban creep", typical for transit truck traffic in Prague, comparing the first 5 min of idling with extended (20–80 min) idling, full load after idle, "stabilized" full load, and 30% load. The diluted exhaust was sampled with high volume samplers on glass fiber fluorocarbon coated filters. The filters were extracted with dichloromethane and DNA damage was analyzed in A549 cells using comet assay, with the inclusion of formamidopyrimidine DNA glycosylase (FPG) and endonuclease III (ENDOIII) to recognize oxidized DNA bases. The cells were exposed to extractable organic matter (EOM) for 4 and 24 h at non-cytotoxic dose corresponding to 0.001 m3 of undiluted exhaust gas per ml cell media. At the 4 h exposure interval, all samples from B100 and diesel emissions induced DNA damage. EOM from the extended idle engine mode exerted the strongest genotoxic effect for both fuels. Twenty hours later, the cells exposed to diesel EOM exhibited a further increase of DNA strand breaks compared to the preceding interval. In contrast, DNA damage seemed to be fully repaired in cells treated with EOM derived from biodiesel B100. The preliminary results suggest that (i) diesel emissions are more genotoxic than the emissions from B100, (ii) biodiesel induced DNA lesions are repaired within 24 h.

Prediction of short and medium term PM10 concentration using artificial neural networks

Purpose There has been a growing concern about air quality because in recent years, industrial and vehicle emissions have resulted in unsatisfactory human health conditions. There is an urgent need for the measurements and estimations of particulate pollutants levels, especially in urban areas. As a contribution to this issue, the purpose of this paper is to use data from measured concentrations of particulate matter and meteorological conditions for the predictions of PM10. Design/methodology/approach The procedure included daily data collection of current PM10 concentrations for the city of São Carlos-SP, Brazil. These data series enabled to use an estimator based on artificial neural networks. Data sets were collected using the high-volume sampler equipment (VFA-MP10) in the period ranging from 1997 to 2006 and from 2014 to 2015. The predictive models were created using statistics from meteorological data. The models were developed using two neural network architectures, namely, perceptron multilayer (MLP) and non-linear autoregressive exogenous (NARX) inputs network. Findings It was observed that, over time, there was a decrease in the PM10 concentration rates. This is due to the implementation of more strict environmental laws and the development of less polluting technologies. The model NARX that used as input layer the climatic variables and the PM10 of the previous day presented the highest average absolute error. However, the NARX model presented the fastest convergence compared with the MLP network. Originality/value The presentation of a given PM10 concentration of the previous day improved the performance of the predictive models. This paper brings contributions with the NARX model applications.

Airborne PM10 and lead concentrations at selected traffic junctions in Khyber Pakhtunkhwa, Pakistan: Implications for human health

The airborne particulates pollution is a serious concern due to its adverse health impacts. This study was carried out to assess the PM10 mass concentration and PM10-bound lead (Pb) at two major traffic junctions in Charsadda and Upper Dir Districts of Khyber Pakhtunkhwa (KP), Pakistan. A high-volume Reference Ambient Air Sampler (RAAS) was used to collect PM10 samples (n = 30) on glass fiber filters from April 2017 to September 2017. The PM10 mass was determined by gravimetric analysis weighing each filter disc before and after sampling. The PM10-bound Pb concentrations were determined using graphite furnace atomic absorption spectroscopy after filters acid digestion. Health risks of PM10-bound Pb were evaluated numerically by hazard quotient (HQ) and hazard index (HI). The PM10 mass (24 h mean) was 4.6 times higher than the WHO guideline value for air quality. Likewise, the PM10-bound Pb was 1.3 times higher than the WHO guideline value. Mean PM10 concentrations were 254 ± 67 μg/m3 and 208 ± 85 μg/m3 and mean PM10-bound Pb concentrations were 709 ± 206 ng/m3 and 638 ± 231 ng/m3 at the traffic junctions in Charsadda and Upper Dir Districts respectively. The mean HI values were less than 1 for the exposed adults and children indicating that health effects are unlikely to occur in the exposed population. Measures should be taken to monitor the airborne PM10 on regular basis and reduce its emissions into the air.