Toxicity Of PM Research Articles

In-vivo exposure of a plant model organism for the assessment of the ability of PM samples to induce oxidative stress

This study aims to propose an innovative, simple, rapid, and cost-effective method to study oxidative stress induced by PM through in-vivo exposure of the plant model organism Arabidopsis thaliana. A. thaliana seedlings were exposed to urban dust certified for its elemental content and to PM2.5 samples collected in an urban-industrial area of Northern Italy. An innovative technique for the detachment and suspension in water of the whole intact dust from membrane filters was applied to expose the model organism to both the soluble and insoluble fractions of PM2.5, which were analyzed for 34 elements by ICP-MS. Oxidative stress induced by PM on A. thaliana was assessed by light microscopic localization and UV–Vis spectrophotometric determination of superoxide anion (O2−) content on the exposed seedlings by using the nitro blue tetrazole (NBT) assay. The results showed a good efficiency and sensitivity of the method for PM mass concentrations >20 μg m−3 and an increase in O2− content in all exposed seedlings, which mainly depends on the concentration, chemical composition, and sources of the PM administered to the model organism. Particles released by biomass burning appeared to contribute more to the overall toxicity of PM. This method was found to be cost-effective and easy to apply to PM collected on membrane filters in intensive monitoring campaigns in order to obtain valuable information on the ability of PM to generate oxidative stress in living organisms.

Comparisons of physicochemical features and hepatoprotective potentials of unprocessed and processed polysaccharides from Polygonum multiflorum Thunb.

The raw and processed Polygonum multiflorum Thunb (PM) are used to treat different diseases, and PM has also been reported to have hepatotoxic effects. Moreover, mounting evidence indicates that processed PM is less toxic than raw PM. The changes in efficacy and toxicity of PM during the processing are closely related to the changes in chemical composition. Previous studies have mainly focused on the changes of anthraquinone and stilbene glycosides during process. Polysaccharides, as main components of PM, showed many pharmacological effects, but its changes in the processing has been neglected for a long time. In this study, the polysaccharides of PM in the raw (RPMPs) and processed products (PPMPs) were determined and the liver injury model induced by acetaminophen was utilized to evaluate the impact of polysaccharides on the liver. Results showed that the heteropolysaccharides RPMPs and PPMPs both comprised Man, Rha, GlcA, GalA, Glc, Ara and Xyl, but markedly differed in polysaccharide yield, molar ratio of monosaccharide composition and Mw. In vivo analysis, results showed that demonstrated that RPMPs and PPMPs both exerted hepatoprotective effects by upregulating antioxidant enzymes and repressing lipid peroxidation. It is noteworthy that the polysaccharide yield of processed PM was seven-fold higher than that of raw PM, so it is speculated that processed PM has better hepatoprotective effects at the same dose of decoction. The present work provides an important foundation for studying the polysaccharide activity of PM and further revealing the processing mechanism of PM. This study also proposed a new hypothesis that the significant increase of polysaccharide content in processed PM may be another reason that the product PM causes less liver injury.

Pollution characteristics of environmental persistent free radicals (EPFRs) and their contribution to oxidation potential in road dust in a large city in northwest China.

Environmental persistent free radicals (EPFRs) are new environmental health risk substances in the atmosphere, and their oxidative toxicity (OT) has not been strongly confirmed. In this study, the fugitive characteristics of EPFRs in road dust in a metropolitan city located in northwest China, and their potential oxidative toxicity were investigated. The results showed that the road dust contains Carbon-centered EPFRs with the mean mass concentration of (6.6±5.0) ×1017 spins/g. EPFRs in road dust are degradable and have a half-life of 4.5 years. The water insoluble (WIS) components contribute 71% to the oxidative toxicity of road dust and show a rapid toxicity generation process, while the oxidative toxicity generation rate of water-soluble dust is more stable. Based on the positive matrix factorization (PMF) model, the contribution of EPFRs-dominated factors to Total-OT and WIS-OT is 17.3% and 33.3%, respectively. The PMF model results indicated that different types of EPFRs contributed differently to the oxidative toxicity of road dust and Carbon-centered EPFRs are more likely to participate in reactive oxygen species generation. Our results highlight that the EPFRs are an important contributor to the oxidative toxicity of atmospheric particulate matter, and their oxidative toxicity is dependent on the types of free radicals. It also provides an important insight into the influence of other potentially toxic substances on the oxidative toxicity of atmospheric PM.

Evaluation of Urban Air Quality Monitoring Stations in Ulsan using Geographic Information System

To manage particulate matter (PM<sub>2.5</sub>) in Ulsan, this study evaluated the current status of the emissions and concentrations of PM<sub>2.5</sub> and the number and spatial distribution of urban air quality monitoring stations (AQMSs). The major emission sources of PM<sub>2.5</sub> in Ulsan are industrial activities (production process, manufacturing combustion, and ships), and the annual mean concentration of PM 2.5 in Ulsan is not higher than those in other large megacities. However, the toxicity of PM<sub>2.5</sub> in Ulsan seems to be high owing to the presence of hazardous air pollutants. Although the AQMSs in Ulsan have been well operated, and the number of stations is sufficient, further evaluation of the roles and spatial distribution of some of these stations is required. This study proposed the priority areas for installing new AQMSs using Geographic Information System (GIS) tools based on the population distribution and PM<sub>2.5</sub> pollution levels. The method developed in this study can be used for other cities, as well as for expanding urban areas and new downtown areas in Ulsan to assess the existing monitoring network and suggest the optimum locations of new stations.

Oxidation potential and coupling effects of the fractionated components in airborne fine particulate matter

Fine particulate matter (PM2.5) can induce the generation of reactive oxygen species (ROS) and damage human tissues. Fully understanding the generation mechanism of oxidative toxicity of PM is challenging due to the extremely complex composition. Classification methods may be helpful in understanding the ROS production mechanisms of complex PM. This study used a solvent extraction and solid phase extraction methods to separate five different components from PM2.5 includes non-extractable components that have rarely been studied before, and discussed the coupling effect and heterogeneous characteristics of oxidation activity they produced. It is found that the water-soluble component contribute about half of the PM oxidation activity, and metal ions probably contribute most of the oxidation activity. Experimental results show that oxygen molecules is the main precursor of ROS production, which depends on whether the aerosol component has catalytic conversion ability. After mixing humic-like substance (HULIS) and hydrophilic water-soluble (HP-WSM) PM, the oxidation activity increased, it is most likely to be a synergistic effect between HULIS and metal ions is dominant, but limited contribution to oxidation activity. It turns out that the non-extractable and water-insoluble components have higher oxidation activity than the water-soluble components, and the two components exhibited a more durable ability to produce 1O2. The reaction of soluble components to produce ROS is homogeneous, but it is obviously heterogeneous for these insoluble components. This study suggests that future attention should be paid to the oxidative toxicity of the non-extractable component, and that single PM component or compound cannot simply be studied independently.

Transformation of Stilbene Glucosides From Reynoutria multiflora During Processing.

The root of Reynoutria multiflora Thunb. Moldenke (RM, syn.: Polygonum multiflorum Thunb.) has been widely used in TCM clinical practice for centuries. The raw R. multiflora (RRM) should be processed before use, in order to reduce toxicity and increase efficiency. However, the content of trans-2, 3, 5, 4′-tetrahydroxystilbene-2-O-β-D-glucopyranoside (trans-THSG), which is considered to be the main medicinal ingredient, decreases in this process. In order to understand the changes of stilbene glycosides raw R. multiflora (RRM) and processed R. multiflora (PRM), a simple and effective method was developed by ultra high performance liquid chromatography tandem quadrupole/electrostatic field orbitrap high-resolution mass spectrometry (UHPLC-Q-Exactive plus orbitrap MS/MS). The content and quantity of stilbene glycosideshave undergone tremendous changes during the process. Seven parent nucleus of stilbene glycosides and 55 substituents, including 5-HMF and a series of derivatives, were identified in PM. 146 stilbene glycosides were detected in RRM, The number of detected compounds increased from 198 to 219 as the processing time increased from 4 to 32 h. Among the detected compounds, 102 stilbene glycosides may be potential new compounds. And the changing trend of the compounds can be summarized in 3 forms: gradually increased, gradually decreased, first increased and then decreased or decreased first. The content of trans-THSG was indeed decreased during processing, as it was converted into a series of derivatives through the esterification reaction with small molecular compounds. The clarification of secondary metabolite group can provide a basis for the follow-up study on the mechanism of pharmacodynamics and toxicity of PM, and for screening of relevant quality markers.

Developmental toxicity induced by particulate matter (PM2.5) in zebrafish (Danio rerio) model.

Contemporary research in epidemiology has found that being exposed to air pollution at an early stage of life has associations with both acute and chronic conditions of the multi-organs. Nevertheless, the reasons for this have yet to be fully explained. Because of this there is a need for a robust investigation into the damaging toxic influence of diesel particulate matter (PM2.5) on living organisms. This study is aimed to investigate the developmental toxicity of PM2.5 by using zebrafish (Danio rerio) embryo/larvae as a disease model and to understand the toxicity effects of PM2.5 on ecological environment more thoroughly. This research demonstrates that being exposed to PM2.5 leads to a significant increase in mortality, effective developmental morphology, reductions in hatching rates and lower heart rates in zebrafish. Additionally, it leads to increases in the length of string heart, area of pericardium, and apoptosis, reduces the number of normal intersegmental vessels (ISVs) and motor neurons in the trunk region and liver formation defects in zebrafish embryos. Investigation employing a scanning electron microscope demonstrates that being exposed to PM2.5 leads to damage in zebrafish larvae skin cell layers. Histological analysis demonstrates that when these larvae are treated with PM2.5 then abnormalities occur in the neurons, liver, heart, gills, brain, and eyes, and remarkable increase in in the cellular/subcellular levels of organelle dissolution. These findings are useful to help us understand the pathophysiological influence of being exposed to PM2.5 on the multi-organ defects of zebrafish. More research into which particular elements that make up diesel pollution contribute to this toxicity is needed so that the dangers to development can be further analysed.

Source Apportionment and Toxicity of PM in Urban, Sub-Urban, and Rural Air Quality Network Stations in Catalonia

Air quality indicators, i.e., PM10, NO2, O3, benzo[a]pyrene, and several organic tracer compounds were evaluated in an urban traffic station, a sub-urban background station, and a rural background station of the air quality network in Catalonia (Spain) from summer to winter 2019. The main sources that contribute to the organic aerosol and PM toxicity were determined. Traffic-related air pollution dominated the air quality in the urban traffic station, while biomass burning in winter and secondary organic aerosol (SOA) in summer impact the air quality in the sub-urban and rural background stations. Health risk assessment for chronic exposure over the past decade, using WHO air quality standards, showed that NO2, PM10 and benzo[a]pyrene from traffic emissions pose an unacceptable risk to the human population in the urban traffic station. PM10 and benzo[a]pyrene from biomass burning were unacceptably high in the sub-urban and rural background stations. Toxicity tests of the PM extracts with epithelial lung cells showed higher toxicity in wintertime samples in the sub-urban and rural stations, compared to the urban traffic station. These results require different mitigation strategies for urban and rural sites in order to improve the air quality. In urban areas, traffic emissions are still dominating the air quality, despite improvements in the last years, and may directly be responsible for part of the SOA and O3 levels in sub-urban and rural areas. In these later areas, air pollution from local biomass burning emissions are dominating the air quality, essentially in the colder period of the year.

In vitro toxicity of indoor and outdoor PM10 from residential wood combustion

Particulate matter with aerodynamic diameter < 10 μm (PM10) was collected, indoors and outdoors, when wood burning appliances (open fireplace and woodstove) were in operation. The PM10 ecotoxicity was assessed with the Vibrio fischeri bioluminescence inhibition assay, while the cytotoxicity was evaluated by the WST-8 and lactate dehydrogenase (LDH) release assays using A549 cells. Extracts of PM10-bound polycyclic aromatic hydrocarbons (PAH) were tested for their mutagenicity through the TA98 and TA100 Ames test. The bioluminescent inhibition assay revealed that indoor particles released from the fireplace were the most toxic. Indoors, the reduction in A549 cell metabolic activity was over two times higher for the fireplace in comparison with the woodstove (32 ± 3.2% and 72 ± 7.6% at the highest dose, respectively). Indoor particles from the fireplace were found to induce greater cytotoxicity than the corresponding outdoor samples. Combined WST-8 and LDH results suggest that PM10 exposure induce apoptotic cell death pathway in which the cell membrane integrity is maintained. Indoor and outdoor samples lacked direct and indirect mutagenic activity in any of the tester strains. For indoor-generated PM10, organic carbon and PAH were significantly correlated with cell viability and bioluminescence reduction, suggesting a role of organic compounds in toxicity.

Oxidative potential of ambient fine particulate matter for ranking of emission sources: an insight for emissions reductions

In Delhi, the capital of India, fine particulate matter (PM2.5) poses alarming challenges to human health and well-being. The majority of air pollution studies are focused on measurements of concentrations and composition of atmospheric particulate matter and gaseous species. However, a more useful insight is the actual impact on human health due to air pollution—and how this varies with pollutant abundance and pollutant source. Toxic potential measures the intrinsic/extrinsic toxicity of PM. Source apportionment studies are required to determine dominant sources contributing to PM toxic potential. Thus, health hazardous emission sources could be targeted first to reduce the air pollution levels in the region.

Caracterização e Avaliação da Toxicidade de MP10 Presentes na Área Urbana de Catalão – GO Associados a Parâmetros Climatológicos

This work presents concentration variation, characterization and evaluation of in vitro toxicity of PM 10 μm particulate material (PM10) collected at two sites in the urban area of Catalao-GO. Sampling was carried out during the period from 08/05/17 to 03/28/18. PM10 concentration measurement were in accordance with CONAMA legislation. X-ray fluorescence spectrometry identifies the mainly presence of iron and small amount phosphorus and sulfur, characteristic the PM10 as a result of soil re-suspension, vehicular emission and emissions from industrial sources. The toxicity study using PM10 as hazards particles did not show the inhibit bacterial growth.

UPLC/MS/MS-Based Metabolomics Study of the Hepatotoxicity and Nephrotoxicity in Rats Induced by Polygonum multiflorum Thunb.

Polygonum multiflorum Thunb. (PM) is one of the most frequently used natural products in China. Its hepatotoxicity has been proven and reported. However, chronic PM toxicity is a dynamic process, and a few studies have reported the long-term hepatotoxic mechanism of PM or its nephrotoxicity. To elucidate the mechanism of hepatotoxicity and nephrotoxicity induced by PM after different administration times, different samples from rats were systematically investigated by traditional biochemical analysis, histopathological observation, and nontargeted metabolomics. The concentrations of direct bilirubin (DBIL) at 4 weeks and total bile acid, DBIL, uric acid, and blood urea nitrogen at 8 weeks were significantly increased in the treatment group compared with those in the control group. Approximately, 12 metabolites and 24 proteins were considered as unique toxic biomarkers and targets. Metabolic pathway analysis showed that the primary pathways disrupted by PM were phenylalanine and tyrosine metabolism, which resulted in liver injury, accompanied by chronic kidney injury. As the administration time increased, the toxicity of PM gradually affected vitamin B6, bile acid, and bilirubin metabolism, leading to aggravated liver injury, abnormal biochemical indicators, and marked nephrotoxicity. Our results suggest that the hepatotoxicity and nephrotoxicity caused by PM are both dynamic processes that affect different metabolic pathways at different administration times, which indicated that PM-induced liver and kidney injury should be treated differently in the clinic according to the degree of injury.

Seasonal effects of ambient PM2.5 on the cardiovascular system of hyperlipidemic mice

ABSTRACTPeople in polluted communities are often exposed to both PM and ozone (O3), albeit not always simultaneously; an important question is whether exposure to particles with seasonal compositional differences can influence biological outcomes. We addressed this question using a mouse model of cardiovascular disease by contrasting the health outcomes of exposures to particles formed or aged during periods of relatively high photochemical activity (i.e. spring/summer), which has increased ambient O3 concentrations, with outcomes of exposures to fall/winter particles which are associated with lower O3 concentrations. Electrocardiographs (ECGs) and blood pressures (BPs) were acquired following exposures to concentrated ambient particles (CAPs). ECGs were analyzed to changes in specific waveform parameters and changes in heart rate variability (HRV). Exposures elicited several types of waveform abnormalities that were associated with seasonal differences in particle constituents. Alterations in R-R interval and P-R interval were seen following exposure to summer CAPs but not fall CAPs and differential responses were seen in the corrected Q-T interval following the two seasonal exposures. Measures of HRV increased after exposure to summer CAPs compared to air-exposed controls but not following the winter CAPs exposure. There were chemical differences with respect to the organic constituents in ambient particles between summer and fall aerosol. The oxygen to carbon ratios (O:C) were generally higher in the spring and summer than in the fall, consistent with seasonal differences in atmospheric photochemical activity. Seasonal differences in atmospheric photochemical activity can modify ambient aerosol composition and can alter biological responses in the cardiovascular system. The results from this study confirm that ambient photochemical activity can alter the toxicity of ambient PM. Regional and seasonal differences in PM2.5 composition should be important considerations when evaluating the effects of PM exposure on cardiovascular health.Implications: Particles formed during periods of high photochemical activity (e.g. spring/summer) elicit more adverse cardiovascular health effects than particles formed during periods of low photochemical activity (e.g. fall/winter). Seasonal differences in atmospheric photochemical activity modified ambient aerosol composition and worsened cardiovascular responses. These results can inform regulatory agencies and may help design air quality regulations for PM2.5 that consider seasonal and regional variations.

Toxicity of fine and quasi-ultrafine particles: Focus on the effects of organic extractable and non-extractable matter fractions.

To date no study has been able to clearly attribute the observed toxicological effects of atmospheric particles (PM) to a specific class of components. The toxicity of both the organic extractable matter (OEM2.5-0.3) and non-extractable matter (NEM2.5-0.3) of fine particles (PM2.5-0.3) was compared to that of PM2.5-0.3 in its entirety on normal human epithelial bronchial BEAS-2B cells in culture. The specific effect of the quasi-ultrafine fraction (PM0.3) was assessed, by comparing the responses of cells exposed to the PM2.5-0.3 and PM0.3 organic extractable matter, OEM2.5-0.3 and OEM0.3 respectively. Chemically, PAH, O-PAH, and N-PAH were respectively 43, 17, and 4 times more concentrated in PM0.3 than in PM2.5-0.3, suggesting thereby a predominant influence of anthropogenic activities and combustion sources. BEAS-2B cells exposed to PM2.5-0.3, NEM2.5-0.3, EOM2.5-0.3 and OEM0.3 lead to different profiles of expression of selected genes and proteins involved in the metabolic activation of PAH, O-PAH, and N-PAH, and in the genotoxicity pathways. Specifically, OEM0.3 was the most inducer for phase I and phase II enzymes implicated in the metabolic activation of PAH (AHR, AHRR, ARNT, CYP1A1, CYP1B1, EPHX-1, GSTA-4) thereby producing the highest DNA damage, felt by ATR and, thereafter, a cascade of protein phosphorylation (CHK1/CHK2/MDM2) closely related to the cell cycle arrest (P21 and P53 induction). This study underlined the crucial role played by the organic chemicals present in PM0.3. These results should be considered in any future study looking for the main chemical determinants responsible for the toxicity of ambient fine PM.

Cardiovascular effects of airborne particulate matter: A review of rodent model studies.

In recent year, animal models have been growingly used to increase our knowledge about the toxicity of PM and underlying mechanisms leading to cardiovascular diseases. In this article, we review the current state of knowledge and findings of studies investigating the cardiovascular effects of PM in rats and mice. The six main areas covered in this review include: I) nature of particulate matter and toxicity mechanisms, II) systemic inflammation, III) heart rate and heart rate variability, IV) histopathological effects, V) atherosclerosis, VI) thrombosis, and VI) myocardial infarction. This review showed that animal model studies have been successful to bring new insights into the mechanisms underlying PM-induced cardiovascular diseases. However, there are some areas that the exact mechanisms are still unclear. In conclusion, investigating the cardiovascular effects of PM invivo or interpreting the results should attempt to justify the role of different PM compositions, which may vastly affect the overall cytotoxicity of particles.

Brine Shrimp Toxicity of Essential Oils from Musa spp.

Essential oils of seven Musa spp.’s fruits namely, Musa acuminata colla ‘gros michel’ (PE), Musa acuminata colla ‘lakatan’ (PB), Musa acuminata colla ‘sucrier’ (PM), Musa acuminata × balbisiana ‘horn plantain’ (PT), Musa acuminata × balbisiana colla ‘saba’ (PN), Musa acuminata colla 'inarnibal' (PO) and Musa acuminata colla ‘red’ (PJ) were extracted by hydrodistillation method using Clevenger apparatus. The essential oils were analysed using GC-FID and identified using Kovat Indeces compared with published information. PE gave the highest yields of oils compared to the other species with yield of 0.43% and 0.28% for its peels and flesh, respectively. The most abundant groups present in most of the essential oils are ester and alcohol groups. The brine shrimp toxicity of PT, PM, PN and PO essential oils were tested and showed toxicity against brine shrimp in dose dependent manner. It can be concluded that the essential oils showed some biological activities which may be a potent medicine in curing tumor. This study implies that the presence of ester and alcohol groups are a good marker for the biological activities of plants. Further studies should focus on the potential of the essential oils of Musa spp. as an antitumor medicine.

Impact of intervention of biomass cookstove technologies and kitchen characteristics on indoor air quality and human exposure in rural settings of India

This study investigates the impact of increased levels of indoor air pollution (IAP) caused due to biomass burning in the rural households of Northern India. A comparative assessment of the impact of traditional cookstoves (TCS) and improved cookstoves (ICS) coupled with the characteristics of kitchen was conducted to estimate the PM (PM10, PM2.5, PM1), CO/CO2 concentrations in the micro-environments of kitchen and living area of the households. The study incorporated both extensive and intensive real-time indoor air quality (IAQ) monitoring during the two cooking sessions of the day. The pollutant concentrations were reported in terms of 24-h as well as 8-h (cooking hours including morning and evening meal) averages. Influence of the three types of kitchen characteristics, i.e., enclosed, semi-enclosed and open was also comprehensively analyzed to measure its impact on the IAQ. In addition to this, the IAQ was further used to evaluate the particle size distribution (PSD), respiratory tract deposition and exposure index to assess its impact on health status of the exposed group including women involved in cooking practices. The results of the study highlighted that deployment of ICS would help in improving the IAQ of the kitchen area by resulting in reducing the concentrations of PM10, PM2.5, PM1 and CO by 21–62%, 20–80%, 24–87% and 19–93%, respectively. It was also highlighted that the kitchen characteristics significantly influence the accumulation of air pollutants, demonstrated by the results that the IAQ being worst in the case of enclosed kitchen, resulted in the highest exposure index values. Multivariate regression models to predict PM1 concentration were also developed for three kitchen categories for both TCS and ICS. Thus, the current study concludes that usage of ICS coupled with efficient designing of the kitchen can improve the overall IAQ of the household along with immense health benefits. Overall, the study emphasized the need of more comprehensive studies to fully assess the association of household air pollution (HAP) and health of individual in the rural settings by considering the toxicity of PM.

Chemical characterization of fine and ultrafine PM, direct and indirect genotoxicity of PM and their organic extracts on pulmonary cells

Particulate matter in ambient air constitutes a complex mixture of fine and ultrafine particles composed of various chemical compounds including metals, ions, and organics. A multidisciplinary approach was developed by studying physico-chemical characteristics and mechanisms involved in the toxicity of particulate atmospheric pollution. PM0.3–2.5 and PM2.5 including ultrafine particles were sampled in Dunkerque, a French industrialized seaside city. PM samples were characterized from a chemical and toxicological point of view. Physico-chemical characterization evidenced that PM2.5 comes from several sources: natural ones, such as soil resuspension and marine sea-salt emissions, as well as anthropogenic ones, such as shipping traffic, road traffic, and industrial activities. Human BEAS-2B lung cells were exposed to PM0.3–2.5, or to the Extractable Organic Matter (EOM) of PM0.3–2.5 and PM2.5. These exposures induced several mechanisms of action implied in the genotoxicity, such as oxidative DNA adducts and DNA Damage Response. The toxicity of PM-EOM was higher for the sample including the ultrafine fraction (PM2.5) containing also higher concentrations of polycyclic aromatic hydrocarbons. These results evidenced the major role of organic compounds in the toxicity of PM.

Source identification, apportionment and toxicity of indoor and outdoor PM2.5 airborne particulates in a region characterised by wood burning.

The occurrence of airborne particulate matter has been flagged as "of concern" in several megacities, especially in Asia. Selected Chilean regions have similar problems as wood burning is the major source of heating in homes. This concern has led to mitigation measures restricting the burning of wood at periods when the particulate matter smaller than 2.5 μm (PM2.5) concentrations are predicted to be high. This work investigates the linkage between indoor and outdoor particle concentrations, determines their source through the polyaromatic hydrocarbon (PAH) signature and investigates the efficacy of the current management practice of burning restrictions. The PM2.5 fraction was collected at 12 different properties with coincident indoor and outdoor sampling using a low-volume active sampler for 24 hours. Indoor concentrations of PM2.5 ranged from 6 to 194 μg m(-3) with a mean of 72 μg m(-3) and corresponding outdoor concentrations ranged from 5 to 367 μg m(-3) with a mean of 85 μg m(-3) over the winter periods of 2014 and 2015; the Chilean national permitted maximum in outdoor air is 50 μg m(-3) in 24 hours. Higher concentrations were measured when the outdoor air temperature was lower. The PAHs were analysed on the PM2.5 fraction; the indoor concentrations ranged from 2 to 291 ng m(-3) with a mean of 51 ng m(-3) compared to an outdoor concentration between 3 and 365 ng m(-3) with a mean of 71 ng m(-3). Multivariate statistical analysis of the PAH profiles using principal components analysis (PCA) and polytopic vector analysis (PVA) identified wood burning, static and mobile diesel emissions and kerosene combustion as the major contributors to the particulate matter. When converted to toxicity equivalents (BaP-TEQ), the highest toxicity arising from PAHs in the indoor air was associated with a property that used a "leaky" combined wood stove and heater and also used a wood-fired brazier for local heating. In outdoor air, there was a relationship between the housing density and the BaP-TEQ, such that denser housing had higher BaP-TEQ values. The restrictions in wood burning on selected days may have had a measureable effect on the PM2.5 concentrations in that region but the effects were small and only present for the day of the restriction.

Toxicological effects of indoor PM10 in urban primary schools in Barcelona, Spain

Background. The BREATHE project, funded by the EU and led by CREAL in Spain, has conducted a campaign measuring aerosols in primary schools in Barcelona. Monitoring sites were separated into high and low-pollution areas with the primary aim of recognizing if differences in air pollutants affect the neurological system of children and their behaviour at school. Aims. Within BREATHE the CECAT sub-project is considering the toxicological aspect of the problem by investigating the toxicity of PM looking at its ability to induce a systemic oxidative stress which damages cells and DNA molecules. Methods. A total of 20 schools were sampled (10 with high traffic density and 10 with low). The sampling took place inside the classrooms for 4 consecutive days at 2 different times a year (winter/summer 2012) to take into account the changes of air pollutants in different climatic conditions. To determine particle oxidative capacity, PM10 in the classrooms was collected using an Airborne Sample Analysis Platform system (ASAP; Model 2800 Thermo) on PUF substrates (sample flow-rate 200 l/min). The genotoxicity, inflammatory potential and cytotoxicity of the PM10 samples are being elucidated using 3 complementary biological assays: Plasmid Scission Assay (PSA) – genotoxicity; DCFH ROS Assay - potential pro-inflammatory; F-actin polymerisation Assay – cytotoxicity. Results. PSA results show the PM dose able to damage 50% of a plasmid DNA molecule (TD50 values), an indication of the ability of the PM sample to exert potential oxidative stress. The TD50 values obtained so far reveal wide variations, although most values are higher than those for outdoor air, implying that PM in indoor air is causing less damage. There does not appear to be an obvious link between TD50 values and concentrations of NO2 and Black Carbon. The full toxicological dataset, including DCFH and ROS F-actin polymerisation assays will be presented at the conference.