Exploratory investigation of the chemical characteristics and relative toxicity of ambient air particulates from two New Zealand cities

Toxicological effects of solvent-extracted organic matter associated with PM2.5 on human bronchial epithelial cell line NL-20

The heterogeneity and complexity of solvent-extracted organic matter associated with PM2.5 (SEOM-PM2.5) is well known; however, there is scarce information on its biological effects in human cells. This work aimed to evaluate the effect of SEOM-PM2.5 collected in northern Mexico City during the cold-dry season (November 2017) on NL-20 cells, a human bronchial epithelial cell line. The SEOM obtained accounted for 15.5% of the PM2.5 mass and contained 21 polycyclic aromatic hydrocarbons (PAHs). The cell viability decreased following exposure to SEOM-PM2.5, and there were noticeable morphological changes such as increased cell size and the presence of cytoplasmic vesicles in cells treated with 5-40 μg/mL SEOM-PM2.5. Exposure to 5 μg/mL SEOM-PM2.5 led to several alterations compared with the control cells, including the induction of double-stranded DNA breaks based (p < 0.001); nuclear fragmentation and an increased mitotic index (p < 0.05); 53BP1 staining, a marker of DNA repair by non-homologous end-joining (p < 0.001); increased BiP protein expression; and reduced ATF6, IRE1α, and PERK gene expression. Conversely, when exposed to 40 μg/mL SEOM-PM2.5, the cells showed an increase in reactive oxygen species formation (p < 0.001), BiP protein expression (p < 0.05), and PERK gene expression (p < 0.05), indicating endoplasmic reticulum stress. Our data suggest concentration-dependent toxicological effects of SEOM-PM2.5 on NL-20 cells, including genotoxicity, genomic instability, and endoplasmic reticulum stress.

Evaluation of the amelioration effect of Ganoderma formosanum extract on delaying PM2.5 damage to lung macrophages

SCOPE

Particulate matter (PM) contains toxic organic matter and heavy metals that enter the entire body through blood flow and may cause mortality. Ganoderma formosanum mycelium, a valuable traditional Chinese medicine that has been used since ancient times, contains various active ingredients that can effectively impede inflammatory responses on murine alveolar macrophages induced by PM particles.

METHODS AND RESULTS

An experimental study assessing the effect of G. formosanum mycelium extract's water fraction (WA) on PM-exposed murine alveolar macrophages using ROS measurement shows that WA reduces intracellular ROS by 12% and increases cell viability by 16% when induced by PM particles. According to RNA-Sequencing, western blotting, and real-time qPCR are conducted to analyze the metabolic pathway. The WA reduces the protein ratio in p-NF-κB/NF-κB by 18% and decreases the expression of inflammatory genes, including IL-1β by 38%, IL-6 by 29%, and TNF-α by 19%. Finally, the identification of seven types of anti-inflammatory compounds in the WA fraction is achieved through UHPLC-ESI-Orbitrap-Elite-MS/MS analysis. These compounds include anti-inflammatory compounds, namely thiamine, adenosine 5'-monophosphate, pipecolic acid, L-pyroglutamic acid, acetyl-L-carnitine, D-mannitol, and L-malic acid.

CONCLUSIONS

The study suggests that the WA has the potential to alleviate the PM -induced damage in alveolar macrophages, demonstrating its anti-inflammatory properties.

Study of summer microclimate and PM2.5 concentration in campus plant communities

Understanding the influencing effect of meteorological factors and air pollutants in the campus plot and the relationship between them is an important topic in the planning and design of campus green space. The changes of pollutant concentrations and meteorological factors in campus green space have certain patterns and specific influencing factors. In this study, we selected four sample plots in Nanjing Forestry University as the research objects, and collected various environmental parameters of the four plots on July 25, 2022. The results showed that the main influences of meteorological factors are the type of the underlying surface of the site, the degree of plant canopy density and the shade coverage area of the building. These factors mainly have a great influence on the value of temperature and humidity. The comprehensive influencing factors can be concluded that the cooling and humidifying effect of the site is ranked as follows: forest > lawn > asphalt road > concrete Square. The main influencing factors of pollutants are: illumination, wind speed, temperature and relative humidity. Among them, illumination and temperature have a negative correlation with PM2.5, wind speed and relative humidity have a positive correlation with PM2.5. Our research shows that the adjustment of campus green space factors can reduce the concentration of pollutants by changing the meteorological factors.

Contribution of water-soluble extracts to the oxidative and inflammatory effects of atmospheric aerosols: A critical review

Exposure to atmospheric particulate matter (PM) has been associated with heightened risks of lung cancer, cardiovascular and respiratory diseases. PM exposure also affects the immune system, leading to an increased susceptibility to infections, exacerbating pre-existent inflammatory and allergic lung diseases. Atmospheric PM can primarily impact human health through the generation of reactive oxygen species (ROS) that subsequently induce or exacerbate inflammation. These cytotoxic effects have been related with PM concentration, and its chemical constituents, including metals, solvent extractable organics (e.g., polycyclic aromatic hydrocarbons), and water-soluble ions. Although not receiving much attention, the fine aerosol water-soluble organic matter (WSOM) can account for a substantial portion of the overall fine PM mass and has been shown to present strong oxidative and immunomodulatory effects. Thus, the objective of this review is to provide a comprehensive analysis of the role of the water-soluble fraction of PM, with a specific focus on the contribution of the WSOM component to the cytotoxic properties of atmospheric PM. The chemical properties of the water-soluble PM fraction are briefly discussed, while emphasis is put on how PM size, composition, and temporal variations (e.g., seasonality) can impact the pro-oxidative activity, the modulation of inflammatory response, and the cytotoxicity of the water-soluble PM extracts.

Lung cancer associated with combustion particles and fine particulate matter (PM2.5) - The roles of polycyclic aromatic hydrocarbons (PAHs) and the aryl hydrocarbon receptor (AhR)

Air pollution is the leading cause of lung cancer after tobacco smoking, contributing to 20% of all lung cancer deaths. Increased risk associated with living near trafficked roads, occupational exposure to diesel exhaust, indoor coal combustion and cigarette smoking, suggest that combustion components in ambient fine particulate matter (PM2.5), such as polycyclic aromatic hydrocarbons (PAHs), may be central drivers of lung cancer. Activation of the aryl hydrocarbon receptor (AhR) induces expression of xenobiotic-metabolizing enzymes (XMEs) and increase PAH metabolism, formation of reactive metabolites, oxidative stress, DNA damage and mutagenesis. Lung cancer tissues from smokers and workers exposed to high combustion PM levels contain mutagenic signatures derived from PAHs. However, recent findings suggest that ambient air PM2.5 exposure primarily induces lung cancer development through tumor promotion of cells harboring naturally acquired oncogenic mutations, thus lacking typical PAH-induced mutations. On this background, we discuss the role of AhR and PAHs in lung cancer development caused by air pollution focusing on the tumor promoting properties including metabolism, immune system, cell proliferation and survival, tumor microenvironment, cell-to-cell communication, tumor growth and metastasis. We suggest that the dichotomy in lung cancer patterns observed between smoking and outdoor air PM2.5 represent the two ends of a dose-response continuum of combustion PM exposure, where tumor promotion in the peripheral lung appears to be the driving factor at the relatively low-dose exposures from ambient air PM2.5, whereas genotoxicity in the central airways becomes increasingly more important at the higher combustion PM levels encountered through smoking and occupational exposure.

Exposure to real-ambient particulate matter induced vascular hypertrophy through activation of PDGFRβ

BACKGROUND

Vascular toxicity induced by particulate matter (PM) exposure exacerbates the onset and development of cardiovascular diseases; however, its detailed mechanism remains unclear. Platelet-derived growth factor receptor β (PDGFRβ) acts as a mitogen for vascular smooth muscle cells (VSMCs) and is therefore essential for normal vasoformation. However, the potential effects of PDGFRβ on VSMCs in PM-induced vascular toxicity have not yet been elucidated.

METHODS

To reveal the potential roles of PDGFRβ signalling in vascular toxicity, individually ventilated cage (IVC)-based real-ambient PM exposure system mouse models and PDGFRβ overexpression mouse models were established in vivo, along with in vitro VSMCs models.

RESULTS

Vascular hypertrophy was observed following PM-induced PDGFRβ activation in C57/B6 mice, and the regulation of hypertrophy-related genes led to vascular wall thickening. Enhanced PDGFRβ expression in VSMCs aggravated PM-induced smooth muscle hypertrophy, which was attenuated by inhibiting the PDGFRβ and janus kinase 2 /signal transducer and activator of transcription 3 (JAK2/STAT3) pathways.

CONCLUSION

Our study identified the PDGFRβ gene as a potential biomarker of PM-induced vascular toxicity. PDGFRβ induced hypertrophic effects through the activation of the JAK2/STAT3 pathway, which may be a biological target for the vascular toxic effects caused by PM exposure.

Coconut Oil Alleviates the Oxidative Stress-Mediated Inflammatory Response via Regulating the MAPK Pathway in Particulate Matter-Stimulated Alveolar Macrophages

Exposure to particulate matter (PM) is related to various respiratory diseases, and this affects the respiratory immune system. Alveolar macrophages (AMs), which are defenders against pathogens, play a key role in respiratory inflammation through cytokine production and cellular interactions. Coconut oil demonstrates antioxidant and anti-inflammatory properties, and it is consumed worldwide for improved health. However, reports on the protective effects of coconut oil on the PM-induced respiratory immune system, especially in AMs, are limited. In this study, we generated artificial PM (APM) with a diameter approximately of 30 nm by controlling the temperature, and compared its cytotoxicity with diesel exhaust particles (DEP). We also investigated the antioxidant and anti-inflammatory effects of coconut oil in APM− and DEP−stimulated AMs, and the underlying molecular mechanisms. Our results showed that APM and DEP had high cytotoxicity in a dose-dependent manner in AMs. In particular, APM or DEP at 100 μg/mL significantly decreased cell viability (p < 0.05) and significantly increased oxidative stress markers such as reactive oxygen species (p < 0.01); the GSSH/GSH ratio (p < 0.01); and cytokine production, such as tumor necrosis factor-α (p < 0.001), interleukin (IL)-1β (p < 0.001), and IL-6 (p < 0.001). The expression of the genes for chemokine (C-X-C motif) ligand-1 (p < 0.05) and monocyte chemoattractant protein-1 (p < 0.001); and the proteins toll-like receptor (TLR) 4 (p < 0.01), mitogen-activated protein kinase (MAPK), and c-Jun N-terminal kinase (p < 0.001), p38 (p < 0.001); and extracellular receptor-activated kinase (p < 0.001), were also upregulated by PM. These parameters were reversed upon treatment with coconut oil in APM− or DEP−stimulated AMs. In conclusion, coconut oil can reduce APM− or DEP−induced inflammation by regulating the TLR4/MAPK pathway in AMs, and it may protect against adverse respiratory effects caused by PM exposure.

The oxidative and neurotoxic potentials of the ambient PM2.5 extracts: The efficient multi-solvent extraction method

The health effects of ambient air particulate matter with a diameter of ≤2.5 μm (PM_2.5) on the central nervous system are well known and the induced oxidative stress has been shown as their main neuropathologic outcome. Ambient air PM_2.5 sampling methods mostly use air sampler systems that collect PM_2.5 on filters, which is followed by a PM_2.5 extraction approach. Inefficient extraction may lead to compositional bias and unreal interpretation of the results. This study aimed to compare our proposed multi-solvent extraction (MSE) approach for PM_2.5 extraction with a conventional aqueous extraction (AqE) method using the analysis of oxidative effects and cytotoxicity in the human neuroblastoma SH-SY5Y cell line. Ambient PM_2.5 samples were collected from an urban traffic location in Tehran city, the capital of Iran, using a high-volume sampler. The developed MSE method was proved to have superior advantages over the AqE method including an increased extraction efficiency (as much as 96 against 48% for PM_ms and PM_aq, respectively), and decreased artifacts and compositional biases. Ambient PM_2.5, besides PM_ms and PM_aq were analyzed for water-soluble ions, metals, and major elements. Dithiothreitol, ascorbic acid, lipid peroxidation, and cell viability assays on SH-SY5Y cells represented the significantly higher oxidative potential for PM_ms compared to PM_aq. The increased cytotoxicity may occur because of the increased oxidative potential of PM_ms and possibly is associated with higher efficiency of the MSE over the AqE method for removal of total redox-active PM components.

PM2.5 promoted lipid accumulation in macrophage via inhibiting JAK2/STAT3 signaling pathways and aggravating the inflammatory reaction

BACKGROUND

Abnormal lipid accumulation in macrophages may lead to macrophages foaming, which is the most important pathological process of atherosclerosis. Atmospheric PM_2.5 could enter the blood circulation and further affect the lipid metabolism of macrophages. But the underlying mechanism is not unclear. This study was undertaken to clarify the effect of PM_2.5 on lipid metabolism in macrophages, and to explore the role of inflammatory reaction and JAK2/STAT3 signaling pathway in this process.

METHOD

Macrophages derived from THP-1 cells were exposed to PM_2.5 (0,100,200,400 μg/mL) for 6 h and 12 h. STAT3 agonist ColivelinTFA is used to specifically excite STAT3. The survival rate of macrophages was detected by CCK-8. The lipid levels in macrophages were detected by colorimetry. The levels of inflammatory factors secreted by macrophages were detected by ELISA. Q-PCR was used to detect the mRNA expression levels, and Western Blot was used to detect the protein expression levels of JAK2/STAT3 pathway genes.

RESULT

The survival rate of macrophages was reduced by PM_2.5, and the levels of TG, T-CHO and LDL-C of macrophages exposed to PM_2.5 were increased. PM_2.5 led to the increasing level of IL-6 and the decreasing level of IL-4, and the JAK2/STAT3 signaling pathway was inhibited by PM_2.5. Colivelin TFA significantly decreased the increasing levels of TG, T-CHO and LDL-C levels, and increased the decreasing mRNA levels of IL-4, and LPL induced by PM_2.5 (p < 0.05).

DISCUSSION

PM_2.5 could cause the lipid accumulation of macrophages by inhibiting the JAK2/STAT3 signaling pathway, and inflammatory responses may be involved in this process.

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.

Characteristics and toxicological effects of commuter exposure to black carbon and metal components of fine particles (PM2.5) in Hong Kong

Epidemiological studies have demonstrated significant associations between traffic-related air pollution and adverse health outcomes. Personal exposure to fine particles (PM_2.5) in transport microenvironments and their toxicological properties remain to be investigated. Commuter exposures were investigated in public transport systems (including the buses and Mass Transit Railway (MTR)) along two sampling routes in Hong Kong. Real-time sampling for PM_2.5 and black carbon (BC), along with integrated PM_2.5 sampling, were performed during the warm and cold season of 2016-2017, respectively. Commuter exposure to BC during 3-hour commuting time exhibited a wider range, from 3.4 to 4.6 μg/m³ on the bus and 5.5 to 8.7 μg/m³ in MTR cabin (p < .05). PM_2.5 mass and major chemical constituents (including organic carbon (OC), elemental carbon (EC), and metals) were analyzed. Cytotoxicity, including cellular reactive oxygen species (ROS) production, was determined in addition to acellular ROS generation. PM_2.5 treatment promoted the ROS generation in a concentration-dependent manner. Consistent diurnal variations were observed for commuter exposure to BC and PM_2.5 components, along with cellular and acellular ROS generation, which marked with two peaks during the morning (08:00-11:00) and evening rush hours (17:30-20:30). Commuter exposures in the MTR system were characterized by higher levels of PM_2.5 and elemental components (e.g., Ca, Cr, Fe, Zn, Ba) compared to riding the bus, along with higher cellular and acellular ROS production (p < .01). These metals were attributed to different sources: rail tracks, wheels, brakes, and crustal origin. Weak to moderate associations were shown for the analyzed transition metals with PM_2.5-induced cell viability and cellular ROS. Multiple linear regression analysis revealed that Ni, Zn, Mn, Fe, Ti, and Co attributed to cytotoxicity and ROS generation. These findings underscore the importance of commuter exposures and their toxic effects, urging effective mitigating strategies to protect human health.

Chemical composition and in vitro aryl hydrocarbon receptor-mediated activity of atmospheric particulate matter at an urban, agricultural and industrial site in North Africa (Bizerte, Tunisia)

As recognized risk factor to pose a health threat to humans and wildlife globally, atmospheric particulate matter (PM) were collected from a North African coastal city (Bizerte, Tunisia) for one year, and were characterized for their chemical compositions, including mercury (Hg_PM), as well as organic contaminants (polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs)), organic carbon (OC) and organic nitrogen (ON), determined in a previous study. Then, we applied an in vitro reporter gene assay (DR-CALUX) to detect and quantify the dioxin-like activity of PM-associated organic contaminants. Results showed that average Hg_PM concentration over the entire sampling period was found to be 13.4 ± 12 pg m^-3. Seasonal variation in the Hg_PM concentration was observed with lower values in spring and summer and higher values in winter and autumn due to the variation of meteorological conditions together with the emission sources. Principal component analysis suggested that fossil fuel combustion and a nearby cement factory were the dominant anthropogenic Hg_PM sources. Aryl hydrocarbon receptor (AhR)-mediated activities were observed in all organic extracts of atmospheric PM from Bizerte city (388.3-1543.6 fg m^-3), and shows significant positive correlations with all PM-associated organic contaminants. A significant proportion of dioxin-like activity of PM was related to PAHs. The dioxin-like activity followed the same trend as PM-associated organic contaminants, with higher dioxin-like activity in the cold season than in the warm season, indicating the advantage and utility of the use of bioassays in risk assessment of complex environmental samples.

Emission factors and composition of PM2.5 from laboratory combustion of five Western Australian vegetation types

This study investigated the emission of PM₁₀ and PM_2.5 (particulates with diameters of less than 10 µm and 2.5 µm, respectively) and the chemical composition of PM_2.5 from laboratory combustion of five Australian vegetation types (three grasslands, a woodland and a forest). A mix of plants representative of Banksia (woodland) and Jarrah (forest) and three types of grasses (Spinifex - Triodia basedowii; Kimberley grass - Sehima nervosum and Heteropogon contortus; and an invasive grass (Veldt) - Ehrharta calycina) were burnt in 9 combustion conditions comprised of 3 fuel moisture levels (dry, moist, wet) and 3 air flow rates (no, low and high flow). PM (particulate matter) samples were collected onto filters and measured using gravimetric analysis. PM_2.5 was then extracted and analyzed for water-soluble metals and polycyclic aromatic hydrocarbons (PAH) concentrations. The largest proportion of PM₁₀ (98%) from vegetation fires was PM_2.5. Banksia yielded the highest PM_2.5 emission factor (EF), followed by Jarrah and Spinifex. Veldt grass combustion generated significantly higher emissions of PM_2.5 compared with the other two grass types. High moisture contents and flow rates resulted in larger emissions of PM_2.5. A strong correlation (R² = 0.84) was observed between the EF for PM_2.5 and combustion efficiency, suggesting higher PM emission with lower combustion efficiencies. Potassium and sodium were the most abundant PM_2.5-bound water soluble metals, accounting for more than 97% of the total mass of metals analyzed. PAHs were found in significant concentrations, including the carcinogenic benzo(a)pyrene. Pyrene and fluoranthene were the most abundant PAHs detected, accounting for nearly 40% mass of the total PAHs. Indeno(1,2,3-cd)pyrene and benzo(g,h,i)perylene ratio (IND/IND + BghiP) appeared to be produced in a diagnostic ratio that indicated that the PAHs were derived from vegetation fires rather than other sources of emissions. The EF for PM_2.5 and its chemical composition (water-soluble metals and PAHs) were strongly influenced by the type of vegetation burned. The results presented in this study could be useful in predicting the risks of human health effects on firefighters and the public who may be exposed to regular bushfires in Australia.

Size distribution of particulate polycyclic aromatic hydrocarbons in fresh combustion smoke and ambient air: A review

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in the atmosphere and they mostly stem from the imperfect combustion of fossil fuels and biofuels. PAHs are inherently associated with homogenous fine particles or distributed to different-sized particles during the aging of air masses. PAHs carried by fine particles undergo a long-range transport to remote areas while those adsorbed on coarse particles have a shorter lifetime in ambient air. More importantly, PAHs with higher molecular weights tend to be bound with finer particles and can deeply enter the lungs, posing severe health risks to humans. Thus, the environmental fate and health effects of particulate PAHs are strongly size-dependent. This review summarizes the size distributions of particulate PAHs freshly emitted from combustion sources as well as the distribution patterns of PAHs in ambient particles. It was found that PAHs from stationary sources are primarily bound to fine particles, which are slightly larger than particles to which PAHs from mobile sources are bound. In ambient air, particulate PAHs are distributed in larger size modes than those in the combustion fume, and the particle size decreases with PAH molecular weight increasing. The relevant mechanisms and influencing factors of particle size distribution changes are illustrated in this article, which are essentially attributed to combustion and ambient temperature as well as the physical and chemical properties of PAHs. Overall, the study on the particle size distribution of PAHs will contribute for a full understanding of the origin, atmospheric behaviors and health effects of particulate PAHs.

Methylation at cg05575921 of a smoking-related gene (AHRR) in non-smoking Taiwanese adults residing in areas with different PM2.5 concentrations

BACKGROUND

DNA methylation is associated with cancer, metabolic, neurological, and autoimmune disorders. Hypomethylation of aryl hydrocarbon receptor repressor (AHRR) especially at cg05575921 is associated with smoking and lung cancer. Studies on the association between AHRR methylation at cg05575921 and sources of polycyclic aromatic hydrocarbon (PAH) other than smoking are limited. The aim of our study was to assess the pattern of blood DNA methylation at cg05575921 in non-smoking Taiwanese adults living in areas with different PM_2.5 levels.

METHODS

Data on blood DNA methylation, smoking, and residence were retrieved from the Taiwan Biobank dataset (2008-2015). Current and former smokers, as well as individuals with incomplete information were excluded from the current study. The final analysis included 708 participants (279 men and 429 women) aged 30-70 years. PM_2.5 levels have been shown to increase as one moves from the northern through central towards southern Taiwan. Based on this trend, the study areas were categorized into northern, north-central, central, and southern regions.

RESULTS

Living in PM_2.5 areas was associated with lower methylation levels: compared with the northern area (reference area), living in north-central, central, and southern areas was associated with lower methylation levels at cg05575921. However, only methylation levels in those living in central and southern areas were significant (β = - 0.01003, P = 0.009 and β = - 0.01480, P < 0.001, respectively. Even though methylation levels in those living in the north-central area were not statistically significant, the test for linear trend was significant (P < 0.001). When PM_2.5 was included in the regression model, a unit increase in PM_2.5 was associated with 0.00115 (P < 0.001) lower cg05575921 methylation levels.

CONCLUSION

Living in PM_2.5 areas was inversely associated with blood AHRR methylation levels at cg05575921. The methylation levels were lowest in participants residing in southern followed by central and north-central areas. Moreover, when PM_2.5 was included in the regression model, it was inversely associated with methylation levels at cg05575921. Blood methylation at cg05575921 (AHRR) in non-smokers might indicate different exposures to PM_2.5 and lung cancer which is a PM_2.5-related disease.

Effects of Different Components of PM2.5 on the Expression Levels of NF-κB Family Gene mRNA and Inflammatory Molecules in Human Macrophage

Background: Studies have found that exposure to fine particulate matter with sizes below 2.5 µm (PM2.5) might cause inflammation response via the NF-κB pathway. To date, only a few studies have focused on the toxicity of different components of PM2.5. We aimed to explore the effects of PM2.5 with different components on the expression levels of NF-κB family gene mRNA and inflammatory molecules in human macrophages. Methods: Human monocytic cell line THP-1-derived macrophages were exposed to water-soluble (W-PM2.5), fat-soluble (F-PM2.5), and insoluble (I-PM2.5) PM2.5. The cell survival rate was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The levels of inflammatory molecules were determined by enzyme-linked immunosorbent assay (ELISA), and the relative mRNA levels of the NF-κB family gene were determined by real time PCR. Results: PM2.5 could decrease the cell viability. After exposure to W-PM2.5, the levels of interleukins (IL)-1β and IL-12 p70 significantly increased. After exposure to F-PM2.5, the levels of IL-12 p70 significantly increased. The levels of IL-12 p70 and TNF-α after exposure to I-PM2.5 were significantly higher than that in W- and F-PM2.5 treatment groups. The levels of IL-8, C reactive protein (CRP), and cyclooxygenase (COX)-2 increased only after exposure to I-PM2.5. F-PM2.5 increased the mRNA levels of NF-κB genes, especially NF-κB1 and RelA. Conclusions: PM2.5 can decrease the cell survival rate and up-regulate the expression of NF-κB family gene mRNA and inflammatory molecules. The main toxic components of PM2.5 related to inflammatory response in macrophages were the I-PM2.5.

Mass spectrometry-based metabolomics reveals the mechanism of ambient fine particulate matter and its components on energy metabolic reprogramming in BEAS-2B cells

Exposure to airborne fine particulate matter (PM_2.5) is associated with various adverse effects. However, the molecular mechanism involved in PM_2.5-elicited energy metabolic reprogramming and the toxic chemical determinants within PM_2.5 are not well elucidated. In this study, nontargeted and targeted metabolomics research were conducted to investigate the overall metabolic changes and relevant toxicological pathways caused by Taiyuan winter total PM_2.5 and its water soluble and organic soluble fractions in human lung bronchial epithelial cells (BEAS-2B). The results showed that significant metabolome alterations in BEAS-2B cells were observed after the exposure of total PM_2.5 and its organic soluble fraction. Purine metabolism, arginine and proline metabolism, glutathione (GSH) metabolism, tricarboxylic acid (TCA) cycle and glycolysis were mainly affected. Along with a significant increase of reactive oxygen species (ROS), malondialdehyde (MDA), nitric oxide (NO) and pro-inflammatory cytokines (TNF-α, IL-6 and IL-1β), obvious metabolic phenotype remodeling from oxidative phosphorylation to glycolysis was found in BEAS-2B cells treated with total PM_2.5 and its organic soluble fraction. Compared with water soluble fraction, organic soluble fraction was found to play the dominant role in PM_2.5 toxicity. Our study provided novel insights into the mechanism of PM_2.5-elicited toxicity.

Seasonal variations in the oxidative stress and inflammatory potential of PM2.5 in Tehran using an alveolar macrophage model; The role of chemical composition and sources

The current study was designed to assess the association between temporal variations in urban PM_2.5 chemical composition, sources, and the oxidative stress and inflammatory response in an alveolar macrophage (AM) model. A year-long sampling campaign collected PM_2.5 samples at the Sharif University in Tehran, Iran. PM-induced reactive oxygen species (ROS) production was measured both with an acellular dithiothreitol consumption assay (DTT-ROS; ranged from 2.1 to 9.3 nmoles min^-1 m^-3) and an in vitro macrophage-mediated ROS production assay (AM-ROS; ranged from 125 to 1213 μg Zymosan equivalents m^-3). The production of tumor necrosis factor alpha (TNF-α; ranged from ~60 to 518 pg TNF-α m^-3) was quantified as a marker of the inflammatory potential of the PM. PM-induced DTT-ROS and AM-ROS were substantially higher for the colder months' PM (1.5-fold & 3-fold, respectively) compared with warm season. Vehicular emission tracers, aliphatic diacids, and hopanes exhibited moderate correlation with ROS measures. TNF-α secretion exhibited a markedly different pattern than ROS activity with a 2-fold increase in the warm months compared to the rest of the year. Gasoline vehicles and residual oil combustion were moderately associated with both ROS measures (R ≥ 0.67, p < 0.05), while diesel vehicles exhibited a strong correlation with secreted TNF-α in the cold season (R = 0.89, p < 0.05). mRNA expression of fourteen genes including antioxidant response and pro-inflammatory markers were found to be differentially modulated in our AM model. HMOX1, an antioxidant response gene, was up-regulated throughout the year. Pro-inflammatory genes (e.g. TNF-α and IL1β) were down-regulated in the cold season and displayed moderate to weak correlation with crustal elements (R > 0.5, p < 0.05). AM-ROS activity showed an inverse relationship with genes including SOD2, TNF, IL1β and IL6 (R ≥ -0.66, p < 0.01). Our findings indicate that Tehran's PM_2.5 has the potential to induce oxidative stress and inflammation responses in vitro. In the current study, these responses included NRF2, NF-κB and MAPK pathways.

In Vitro and In Vivo Experimental Studies of PM2.5 on Disease Progression

Air pollution is a very critical issue worldwide, particularly in developing countries. Particulate matter (PM) is a type of air pollution that comprises a heterogeneous mixture of different particle sizes and chemical compositions. There are various sources of fine PM (PM2.5), and the components may also have different effects on people. The pathogenesis of PM2.5 in several diseases remains to be clarified. There is a long history of epidemiological research on PM2.5 in several diseases. Numerous studies show that PM2.5 can induce a variety of chronic diseases, such as respiratory system damage, cardiovascular dysfunction, and diabetes mellitus. However, the epidemiological evidence associated with potential mechanisms in the progression of diseases need to be proved precisely through in vitro and in vivo investigations. Suggested mechanisms of PM2.5 that lead to adverse effects and chronic diseases include increasing oxidative stress, inflammatory responses, and genotoxicity. The aim of this review is to provide a brief overview of in vitro and in vivo experimental studies of PM2.5 in the progression of various diseases from the last decade. The summarized research results could provide clear information about the mechanisms and progression of PM2.5-induced disease.

Rosiglitazone inhibits PM2.5-induced cytotoxicity in human lung epithelial A549 cells

Background

Exposure to fine particulate matter <2.5 µm in diameter (PM2.5) leads to global adverse health effects, including increases in morbidity and mortality of respiratory diseases. PM2.5 increases production of reactive oxygen species (ROS) in the lung, which further lead to oxidative stress, cell apoptosis and cell death. According to results of previous studies, oxidative stress and subsequent cell apoptosis can be reduced by peroxisome proliferator-activated receptor gamma (PPARγ) in various cell types, however, its role in oxidative stress-related cell apoptosis caused by PM2.5 in respiratory systems is unclear.

Methods

Human lung alveolar epithelial A549 cells were exposed to PM2.5 with or without rosiglitazone (an agonist of PPARγ) treatment. Cellular apoptosis and intracellular oxidative stress were determined by flow cytometry based on FITC Annexin V and DCFH-DA fluorescence, respectively. Western blot was conducted to determine the expression of Bax, Bcl2, PPARγ, P-ERK1/2, ERK1/2, P-STAT3, and STAT3.

Results

PPARγ was downregulated in PM2.5-treated A549 cells, and application of rosiglitazone reduced PM2.5-mediated ROS generation and cell apoptosis. In addition, our results indicated that rosiglitazone treatment suppressed PM2.5-induced ERK1/2 and STAT3 activation.

Conclusions

Collectively, these data suggested that rosiglitazone protects against PM2.5-induced ROS production and cell apoptosis and represses activation of ERK1/2 and STAT3 signaling in A549 cells. Our results indicated that rosiglitazone is a potential therapeutic agent for PM2.5-induced lung diseases.

Ambient endotoxin in PM10 and association with inflammatory activity, air pollutants, and meteorology, in Chitwan, Nepal

BACKGROUND

Endotoxin associated with ambient PM (particulate matter) has been linked to adverse respiratory symptoms, but there have been few studies of ambient endotoxin and its association with co-pollutants and inflammation.

OBJECTIVES

Our aim was to measure endotoxin associated with ambient PM₁₀ (particulate matter with aerodynamic diameter<10μm) in summer 2016 at four locations in Chitwan, Nepal, and investigate its association with meteorology, co-pollutants, and inflammatory activity.

METHODS

PM₁₀ concentrations were recorded and filter paper samples were collected using E-samplers; PM_1, PM_2.5, black carbon (BC), methane (CH₄), and carbon monoxide (CO) were also measured. The Limulus amebocyte lysate (LAL) assay was used for endotoxin quantification and the nuclear factor kappa B (NFκB) activation assay to assess inflammatory activity.

RESULTS

The mean concentration of PM₁₀ at the different locations ranged from 136 to 189μg/m³, and of endotoxin from 0.29 to 0.53EU/m³. Pollutant presence was positively correlated with endotoxin. Apart from relative humidity, meteorological variations had no significant impact on endotoxin concentration. NF-κB activity was negatively correlated with endotoxin concentration.

CONCLUSIONS

To the best of our knowledge, this study provides the first measurements of ambient endotoxin associated with PM₁₀ in Nepal. Endotoxin and co-pollutants were positively associated indicating a similar source. Endotoxin was negatively correlated with inflammatory activity as a result of a time-limited forest fire event during the sampling period. Studies of co-pollutants suggested that the higher levels of endotoxin related to biomass burning were accompanied by increased levels of anti-inflammatory agents, which suppressed the endotoxin inflammatory effect.

In vitro assessment of the toxicity of bushfire emissions: A review

Bushfires produce many toxic pollutants and the smoke has been shown to have negative effects on human health, especially to the respiratory system. Bushfires are predicted to increase in size and frequency, leading to a greater incidence of smoke and impacts. While there are many epidemiological studies of the potential impact on populations, there are few studies using in vitro methods to investigate the biological effects of bushfire emissions to better understand its toxicity and significance. This review focused on the literature pertaining to in vitro toxicity testing to determine the state of knowledge on current methods and findings on the impacts of bushfire smoke. There was a considerable variation in the experimental conditions, outcomes and test concentrations used by researchers using in vitro methods. Of the studies reviewed, most reported adverse impacts of particulate matter (PM) on cytotoxic and genotoxic responses. Studies on whole smoke were rare. Finer primary particulates from bushfire smoke were generally found to be more toxic than the coarse particulates and the toxicological endpoints of bushfire PM different to ambient PM. However the variation in study designs and experimental conditions made comparisons difficult. This review highlights the need for standard protocols to enable appropriate comparisons between studies to be undertaken including the assessment of physiologically relevant outcomes. Further work is essential to establish the effect of burning different vegetation types and combustion conditions on the toxicity of bushfire emissions to better inform both health and response agencies on the significance of smoke from bushfires.

Industrial PM2.5 cause pulmonary adverse effect through RhoA/ROCK pathway

According to the Chinese Ministry of Health, industrial pollution-induced health impacts have been the leading cause of death in China. While industrial fine particulate matter (PM_2.5) is associated with adverse health effects, the major action mechanisms of different compositions of PM_2.5 are currently unclear. In this study, we treated normal human lung epithelial BEAS-2B cells with industrial organic and water-soluble PM_2.5 extracts under daily alveolar deposition dose to elucidate the molecular mechanisms underlying adverse pulmonary effects induced by PM_2.5, including oxidative damage, inflammatory response, lung epithelial barrier dysfunction, and the recruitment of macrophages. We found that water-soluble PM_2.5 extracts caused more severe cytotoxic effects on BEAS-2B cells compared with that of organic extracts. Both organic and water-soluble PM_2.5 extracts induced activation of the RhoA/ROCK pathway. Inflammatory response, epithelial barrier dysfunction, and the activation of NF-кB caused by both PM_2.5 extracts were attenuated by ROCK inhibitor Y-27632. This indicated that both PM_2.5 extracts could cause damage to epithelial cells through RhoA/ROCK-dependent NF-кB activation. Furthermore, the upregulation of macrophage adhesion induced by both PM_2.5 extracts was also attenuated by Y-27632 in a co-culture model of macrophages and the epithelial cells. Therefore, our results support that industrial PM_2.5 extracts-induced activation of the RhoA/ROCK-dependent NF-кB pathway induces pulmonary adverse effect. Thus, pharmacological inhibition of ROCK activation might have therapeutic potential in preventing lung disease associated with PM_2.5.

Toxicity Research of PM2.5 Compositions In Vitro

According to the published literature, we surmise that particulate matter (PM) concentration, individually, may be less important than components in explaining health effects. PM_2.5 (aerodynamic diameter < 2.5 μm) had similar cytotoxicity (e.g., cell viability reduction, oxidative damage, inflammatory effects and genetic toxicity) on different types of cells. The studies of cells are readily available for detailed mechanistic investigations, which is more appropriate for learning and comparing the mechanism caused by single or mixed ingredients coating a carbon core. No review exists that holistically examines the evidence from all components-based in vitro studies. We reviewed published studies that focus on the cytotoxicity of normal PM_2.5. Those studies suggested that the toxicity of mixed compositions differs greatly from the single ingredients in mixed components and the target cells. The cytotoxic responses caused by PM_2.5 components have not shown a consistent association with clear, specific health effects. The results may be beneficial for providing new targets for drugs for the treatment of PM_2.5-related diseases.

Association of IL-6 with PM2.5 Components: Importance of Characterizing Filter-Based PM2.5 Following Extraction

Filter-based toxicology studies are conducted to establish the biological plausibility of the well-established health impacts associated with fine particulate matter (PM_2.5) exposure. Ambient PM_2.5 collected on filters is extracted into solution for toxicology applications, but frequently, characterization is nonexistent or only performed on filter-based PM_2.5, without consideration of compositional differences that occur during the extraction processes. To date, the impact of making associations to measured components in ambient instead of extracted PM_2.5 has not been investigated. Filter-based PM_2.5 was collected at locations (n = 5) and detailed characterization of both ambient and extracted PM_2.5 was performed. Alveolar macrophages (AMJ2-C11) were exposed (3, 24, and 48 h) to PM_2.5 and the pro-inflammatory cytokine interleukin (IL)-6 was measured. IL-6 release differed significantly between PM_2.5 collected from different locations; surprisingly, IL-6 release was highest following treatment with PM_2.5 from the lowest ambient concentration location. IL-6 was negatively correlated with the sum of ambient metals analyzed, as well as with concentrations of specific constituents which have been previously associated with respiratory health effects. However, positive correlations of IL-6 with extracted concentrations indicated that the negative associations between IL-6 and ambient concentrations do not accurately represent the relationship between inflammation and PM_2.5 exposure. Additionally, seven organic compounds had significant associations with IL-6 release when considering ambient concentrations, but they were not detected in the extracted solution. Basing inflammatory associations on ambient concentrations that are not necessarily representative of in vitro exposures creates misleading results; this study highlights the importance of characterizing extraction solutions to conduct accurate health impact research.

Toxicity assessment of atmospheric particulate matter in the Mediterranean and Black Seas open waters

Atmospheric deposition of particulate matter (PM) is recognized as a relevant input vector for toxic compounds, such as polycyclic aromatic hydrocarbons (PAHs), into the marine environment. In this work we aimed to analyse the biological activity and potential adverse effects of PM constituents to aquatic organisms. Organic extracts of atmospheric PM samples from different sub-basins of the Mediterranean and Black Seas were screened using different toxicological tests. A yeast-based assay (AhR-RYA) revealed that dioxin-like activity correlated with the concentration of total PAHs in the PM samples, as well as with their predicted toxic equivalent values (TEQs). Although the zebrafish embryotoxicity test (the ZET assay) showed no major phenotypical adverse effects, up-regulation of mRNA expression of cyp1a, fos and development-related genes (previously described as related to PM toxicity) was observed in exposed embryos when compared to controls. Results showed that mRNA patterns of the studied genes followed a similar geographic distribution to both PAH content and dioxin-like activity of the corresponding extracts. The analysis also showed a distinct geographical pattern of activation of pancreatic markers previously related to airborne pollution, probably indicating a different subset of uncharacterized particle-bound toxicants. We propose the combination of the bioassays tested in the present study to be applied to future research with autochthonous species to assess exposure and potential toxic effects of ambient PM. The present study emphasizes the need for more in-depth studies into the toxic burden of atmospheric PM on aquatic ecosystems, in order to improve future regulatory guidelines.

Mutagenicity profile of atmospheric particulate matter in a small urban center subjected to airborne emission from vehicle traffic and sugar cane burning

Atmospheric particulate matter (PM) is genotoxic and recently was classified as carcinogenic to humans by the International Agency for Research on Cancer. PM chemical composition varies depending on source and atmospheric conditions. The Salmonella/microsome assay is the most used mutagenicity test and can identify the major chemical classes responsible for observed mutagenicity. The objective of this work was to characterize the mutagenicity of PM samples from a countryside city, Limeira, Brazil, which is influenced by heavy traffic and sugar cane biomass burning. Six samples of total PM were collected. Air mass backward trajectories were calculated. Organic extracts were assayed using the Salmonella/microsome microsuspension mutagenicity assay using TA98, YG1041, and TA1538, with and without metabolic activation (S9). YG1041 was the most sensitive strain and mutagenicity reached 9,700 revertants per m(3) without metabolic activation. Potency for TA1538 was higher than TA98, indicating that this strain should be considered in air mutagenicity studies. The increased response to YG1041 relative to TA98, and the decreased response with S9, suggests that nitroaromatics are the major contributors. Limeira is among the most mutagenic cities in the world. High mutagenicity in Limeira seems to occur when the air mass from the area of sugarcane production is mixed with air from the region impacted by anthropogenic activities such as traffic. An increase in the formation of nitro-polycyclic aromatic hydrocarbons may result from longer contact time between the aromatic compounds and the atmosphere with high NOx and ozone concentration, although more studies are required to confirm this hypothesis.

Characterization of ambient and extracted PM2.5 collected on filters for toxicology applications

Research on the health effects of fine particulate matter (PM2.5) frequently disregards the differences in particle composition between that measured on an ambient filter versus that measured in the corresponding extraction solution used for toxicological testing. This study presents a novel method for characterizing the differences, in metallic and organic species, between the ambient samples and the corresponding extracted solutions through characterization of extracted PM2.5 suspended on filters. Removal efficiency was found to be 98.0 ± 1.4% when measured using pre- and post-removal filter weights, however, this efficiency was significantly reduced to 80.2 ± 0.8% when measured based on particle mass in the extraction solution. Furthermore, only 47.2 ± 22.3% of metals and 24.8 ± 14.5% of organics measured on the ambient filter were found in the extraction solution. Individual metallic and organic components were extracted with varying efficiency, with many organics being lost entirely during extraction. Finally, extraction efficiencies of specific PM2.5 components were inversely correlated with total mass. This study details a method to assess compositional alterations resulting from extraction of PM2.5 from filters, emphasizing the need for standardized procedures that maintain compositional integrity of ambient samples for use in toxicology studies of PM2.5.

Toxicity of atmospheric particle-bound PAHs: an environmental perspective

Atmospheric polycyclic aromatic hydrocarbons (PAHs) are environmental pollutants that represent a risk not only to humans, but to all living organisms. High-molecular weight PAHs are more toxic than lighter relatives, and also have a higher tendency to bind onto air particles (i.e., particle matter, PM). PM is a major constituent of air pollution. Adequate assessment of the biological impact of PM requires the analysis, not only of the effects on human health, but also on the environment. Since the aquatic systems work as a natural sink to these air pollutants, assessing the effects of particle-bound PAHs on aquatic organisms may further characterize its potential aquatic toxicity, also providing simple and low-cost alternative assays to investigate PM biological effects in vivo. We review the current scientific literature, addressing the atmospheric PAHs fate, transformation and deposition, pertinent particle-bound PAHs toxicity data, and the potential aquatic toxic burden. Conceptual and experimental procedures that could improve future investigations and risk assessments are also considered.

Composition and effects of inhalable size fractions of atmospheric aerosols in the polluted atmosphere. Part II. In vitro biological potencies

Exposure to particulate matter (PM) in ambient air has been shown to lead to adverse health consequences. Six size fractions of PM with aerodynamic diameter smaller than 10μm (PM10) and gas phase were collected at six localities with different major pollution sources. Extracts of samples were assessed for AhR-mediated toxicity, (anti-)estrogenicity, (anti-)androgenicity and genotoxicity. The biological responses were interpreted relative to chemical characterization. Historically, for regulatory purposes, evaluation of air pollution was based mainly on assessment of the sum of PM10. In the case of AhR-mediated activity, PM1 was responsible for more than 75% of the activity of the particulate fraction from all localities. The assessed effects were correlated with concentrations of polycyclic aromatic hydrocarbons (PAH), organic carbon content and specific surface area of the PM. A significant proportion of biologically active chemicals seems to be present in the gas phase of air. The results suggest that an average daily exposure based just on the concentrations of contaminants contained in PM10, as regulated in EU legislation so far, is not a sufficient indicator of contaminants in air particulates and adoption of standards more similar to other countries and inclusion of other parameters besides mass should be considered.

Proinflammatory effects and oxidative stress within human bronchial epithelial cells exposed to atmospheric particulate matter (PM(2.5) and PM(>2.5)) collected from Cotonou, Benin

After particulate matter (PM) collection in Cotonou (Benin), a complete physicochemical characterization of PM2.5 and PM>2.5 was led. Then, their adverse health effects were evaluated by using in vitro culture of human lung cells. BEAS-2B (bronchial epithelial cells) were intoxicated during short-term exposure at increasing PM concentrations (1.5-96 μg/cm(2)) to determine global cytotoxicity. Hence, cells were exposed to 3 and 12 μg/cm(2) to investigate the potential biological imbalance generated by PM toxicity. Our findings showed the ability of both PM to induce oxidative stress and to cause inflammatory cytokines/chemokines gene expression and secretion. Furthermore, PM were able to induce gene expression of enzymes involved in the xenobiotic metabolism pathway. Strong correlations between gene expression of metabolizing enzymes, proinflammatory responses and cell cycle alteration were found, as well as between proinflammatory responses and cell viability. Stress oxidant parameters were highly correlated with expression and protein secretion of inflammatory mediators.

Toxic assessment of urban atmospheric particle-bound PAHs: relevance of composition and particle size in Barcelona (Spain)

Zebrafish embryotoxicity and dioxin-like activity levels were tested for particulate air samples from an urban background site in Barcelona (Spain). Samples were collected during 14 months, and maximal values for both biological activities corresponded to samples collected during late autumn months, correlating with elevated PAH levels. Vehicle and combustion emissions appeared as the potentially most toxic sources, whereas total PM mass and mineral content appeared to be poor predictors of the biological activity of the samples. Samples simultaneously collected at different particle size cut-offs (10, 2.5, and 1 μm) did not differ significantly in dioxin-like PAH levels and biological activity, indicating that the sub-micron particle fraction (PM1) concentrated essentially all observed toxicity. Our results support the need for a tighter control on sub-micron particle emissions and show that total PM mass and, particularly, PM10, may not fully characterize the toxic potential of air samples.

In vitro tests to assess toxic effects of airborne PM(10) samples. Correlation with metals and chlorinated dioxins and furans

Inhalation is an important exposure pathway to airborne pollutants such as heavy metals, polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and particulate matter. Chronic exposure to those chemicals, which form part of complex environmental mixtures, may mean important human health risks. In the present study, the suitability of different in vitro tests to evaluate the toxic effects of air PM(10) pollutants is investigated. In addition, it is also assessed how to distinguish the contribution of chemical pollutants to toxicity. Sixty-three air samples were collected in various areas of Catalonia (Spain), and the levels of ecotoxicity, cytotoxicity and genotoxicity were evaluated. Aqueous acidic extractions of quartz fiber filters, where PM(10) had been retained, were performed. The photo-luminescent bacteria Vibrio fischeri (Microtox®) bioassay was performed to assess ecotoxicity. Moreover, MTT and Comet Assays, both using human lung epithelial cells A549 as target cells, were applied to assess the cytotoxicity and genotoxicity of air samples, respectively. The results show that Microtox® is an excellent screening test to perform a first evaluation of air quality, as it presented a significant correlation with chemical contaminants, contrasting with MTT Assay. Although none of the samples exhibited genotoxicity, a high correlation was found between this in vitro test and carcinogenic agents. Urban samples from traffic-impacted areas would be significantly more toxic. Finally, environmental temperature was identified as a key parameter, as higher values of ecotoxicity were found in winter.

Mutagenicity of particulate matter fractions in areas under the impact of urban and industrial activities

Organisms in the environment are exposed to a mixture of pollutants. Therefore the purpose of this study was to analyze the mutagenicity of organic and inorganic responses in two fractions of particulates (TSP and PM2.5) and extracts (organic and aqueous). The mutagenicity of organic and aqueous particulate matter extracts from urban-industrial and urban-residential areas was evaluated by Salmonella/microsome assay, through the microsuspension method, using strain TA98 with and without liver metabolization. Additionally, strains YG1021 and YG1024 (nitro-sensitive) were used for organic extracts. Aqueous extracts presented negative responses for mutagenesis and cytotoxicity was detected in 50% of the samples. In these extracts the presence of potential bioavailable metals was identified. All organic extracts presented mutagens with a higher potential associated with PM2.5. This study presents a first characterization of PM2.5 in Brazil, through the Salmonella/microsome assay. The evaluation strategy detected the anthropic influence of groups of compounds characteristically found in urban and industrial areas, even in samples with PM values in accordance with quality standards. Thus, the use of a genotoxic approach in areas under different anthropic influences will favor the adoption of preventive measures in the health/environment relation.

Effect based monitoring of seasonal ambient air exposures in Australia sampled by PUF passive air samplers

There has been relatively little bioanalytical effect based monitoring conducted using samples derived from polyurethane foam (PUF) passive air samplers. Combining these techniques may provide a more convenient and cost effective means of monitoring the potential for biological effects resulting from exposure to complex mixtures in a range of scenarios. Seasonal polycyclic aromatic hydrocarbon (PAH) levels were monitored at sites around Australia using direct chemical analysis. In addition, both indirect acting genotoxicity (umuC assay) and aryl hydrocarbon receptor (AhR) activity (chemically activated fluorescent gene expression [CAFLUX assay]), which are effects potentially relevant to subsequent carcinogenesis for these compounds, were measured. The levels of PAHs as well as genotoxicity and AhR activity were all higher in winter compared to summer and for sites in urban capital cities compared to other locations. Statistically significant relationships were found between the levels of PAHs and both genotoxicity and AhR activity. The dominant contributors to the total AhR activity, were found to be for compounds which are not resistant to H(2)SO(4)/silica gel treatment and were relatively rapidly metabolised that is consistent with a PAH type response. Relative potency estimates for individual PAHs determined for the first time on the CAFLUX assay were used to estimate the proportion of total AhR activity (≤ 3.0%) accounted by PAHs monitored. Observed responses are thus largely due to non-quantified AhR active compounds.