The pro-inflammatory effects of particulate matter on epithelial cells are associated with elemental composition

Review of in vitro studies evaluating respiratory toxicity of aerosols: impact of cell types, chemical composition, and atmospheric processing

In recent decades, several cell-based and acellular methods have been developed to evaluate ambient particulate matter (PM) toxicity. Although cell-based methods provide a more comprehensive assessment of PM toxicity, their results are difficult to comprehend due to the diversity in cellular endpoints, cell types, and assays and the interference of PM chemical components with some of the assays' techniques. In this review, we attempt to clarify some of these issues. We first discuss the morphological and immunological differences among various macrophage and epithelial cells, belonging to the respiratory systems of human and murine species, used in the in vitro studies evaluating PM toxicity. Then, we review the current state of knowledge on the role of different PM chemical components and the relevance of atmospheric processing and aging of aerosols in the respiratory toxicity of PM. Our review demonstrates the need to adopt more physiologically relevant cellular models such as epithelial (or endothelial) cells instead of macrophages for oxidative stress measurement. We suggest limiting macrophages for investigating other cellular responses (e.g., phagocytosis, inflammation, and DNA damage). Unlike monocultures (of macrophages and epithelial cells), which are generally used to study the direct effects of PM on a given cell type, the use of co-culture systems should be encouraged to investigate a more comprehensive effect of PM in the presence of other cells. Our review has identified two major groups of toxic PM chemical species from the existing literature, i.e., metals (Fe, Cu, Mn, Cr, Ni, and Zn) and organic compounds (PAHs, ketones, aliphatic and chlorinated hydrocarbons, and quinones). However, the relative toxicities of these species are still a matter of debate. Finally, the results of the existing studies investigating the effect of aging on PM toxicity are ambiguous, with varying results due to different cell types, different aging conditions, and the presence/absence of specific oxidants. More systematic studies are necessary to understand the role of different SOA precursors, interactions between different PM components, and aging conditions in the overall toxicity of PM. We anticipate that our review will guide future investigations by helping researchers choose appropriate cell models, resulting in a more meaningful interpretation of cell-based assays and thus ultimately leading to a better understanding of the health effects of PM exposure.

Coarse particulate matter (PM10) induce an inflammatory response through the NLRP3 activation

INTRODUCTION

PM exposure can induce inflammatory and oxidative responses; however, differences in these adverse effects have been reported depending on the chemical composition and size. Moreover, inflammatory mechanisms such as NLRP3 activation by PM10 have yet to be explored.

OBJECTIVE

To assess the impact of PM10 on cell cytotoxicity and the inflammatory response through in vitro and in vivo models.

METHODOLOGY

Peripheral blood mononuclear cells (PBMCs) from healthy donors were exposed to PM10. Cytotoxicity was determined using the LDH assay; the expression of inflammasome components and the production of pro-inflammatory cytokines were quantified through qPCR and ELISA, respectively; and the formation of ASC complexes was examined using confocal microscopy. For in vivo analysis, male C57BL6 mice were intranasally challenged with PM10 and bronchoalveolar lavage fluid was collected to determine cell counts and quantification of pro-inflammatory cytokines by ELISA. RNA was extracted from lung tissue, and the gene expression of inflammatory mediators was quantified.

RESULTS

PM10 exposure induced significant cytotoxicity at concentrations over 100 µg/mL. Moreover, PM10 enhances the gene expression and release of pro-inflammatory cytokines in PBMCs, particularly IL-1β; and induces the formation of ASC complexes in a dose-dependent manner. In vivo, PM10 exposure led to cell recruitment to the lungs, which was characterized by a significant increase in polymorphonuclear cells compared to control animals. Furthermore, PM10 induces the expression of several inflammatory response-related genes, such as NLRP3, IL-1β and IL-18, within lung tissue.

CONCLUSION

Briefly, PM10 exposure reduced the viability of primary cells and triggered an inflammatory response, involving NLRP3 inflammasome activation and the subsequent production of IL-1β. Moreover, PM10 induces the recruitment of cells to the lung and the expression of multiple cytokines; this phenomenon could contribute to epithelial damage and, thus to the development and exacerbation of respiratory diseases such as viral infections.

Characterization of elements, PAHs, AhR-activity and pro-inflammatory responses of road tunnel-derived particulate matter in human hepatocyte-like and bronchial epithelial cells

The aims were to characterize the content of elements and polycyclic aromatic hydrocarbons (PAHs) in size-separated particulate matter (PM) sampled in a road tunnel, estimate the contribution of PAHs to the toxic potential, and measure the pro-inflammatory potential of PM samples and extracts with increasing polarity. Several elements/metals previously associated with cytokine responses were found. Based on PAHs levels and published PAHs potency, the calculated mutagenic and carcinogenic activities of size-separated samples were somewhat lower for coarse than fine and ultrafine PM. The AhR-activity of the corresponding PM extracts measured in an AhR-luciferase reporter model (human hepatocytes) were more similar. The highest AhR-activity was found in the neutral (parent and alkylated PAHs) and polar (oxy-PAHs) fractions, while the semi-polar fractions (mono-nitrated-PAHs) had only weak activity. The neutral and polar aromatic fractions from coarse and fine PM were also found to induce higher pro-inflammatory responses and CYP1A1 expression in human bronchial epithelial cells (HBEC3-KT) than the semi-polar fractions. Fine PM induced higher pro-inflammatory responses than coarse PM. AhR-inhibition reduced cytokine responses induced by parent PM and extracts of both size fractions. Contributors to the toxic potentials include PAHs and oxy-PAHs, but substantial contributions from other organic compounds and/or metals are likely.

Oxidative potential and in vitro toxicity of particles generated by pyrotechnic smokes in human small airway epithelial cells

Pyrotechnic smokes are widely used in civilian and military applications. The major issue arise from the release of particles after smoke combustion but the health risks related to their exposure are poorly documented whereas toxicity of airborne particles on the respiratory target are very well known. Therefore, this study aimed to explore the in vitro toxicity of the particle fraction of different pyrotechnic smokes. Particles from a red signalling smoke (RSS), an hexachloroethane-based obscuring smoke (HC-OS) and an anti-intrusion smoke (AIS) were collected from the cloud. RSS particles displayed the highest organic fraction (quinones and polycyclic aromatic hydrocarbons) of the three samples characterized. AIS particles contained K and cholesterol derivatives. HC-OS particles were mainly metallic with very high concentrations of Al, Fe and Ca. Intrinsic oxidative potential of smoke particles was measured with two assays. Depletions of DTT by RSS particles was greater than depletion obtained with AIS and HC-OS particles but depletion of acid ascorbic (AA) was only observed with HC-OS particles. In vitro toxicity was assessed by exposing human small airway epithelial cells (SAEC) to various concentrations of particles. After 24 h of exposure, cell viability was not affected but significant modifications of mRNA expression of antioxidant (SOD-1 and -2, catalase, HO-1, NQO-1) and inflammatory markers (IL-6, IL-8, TNF-α) were observed and were dependent on smoke type. Particles rich in metal, such as HC-OS, induced a greatest depletion of AA and a greatest inflammatory response, whereas particles rich in organic compounds, such as RSS, induced a greatest DTT depletion and a greatest antioxidant response. In conclusion, the three smoke particles have an intrinsic oxidative potential and triggered a cell adaptive response. Our study improved the knowledge of particle toxicity of pyrotechnic smokes and scientific approach developed here could be used to study other type of particles.

Are In Vitro Cytotoxicity Assessments of Environmental Samples Useful for Characterizing the Risk of Exposure to Multiple Contaminants at the Workplace? A Systematic Review

In some occupational environments risk characterization is challenging or impossible to achieve due to the presence of multiple pollutants and contaminants. Thus, in vitro testing using the most relevant cell lines will provide information concerning health effects due to the co-exposure to multiple stressors. The aim of this review article is to identify studies where the cytotoxicity assessment was performed in environmental samples, as well as to describe the main outputs and challenges regarding risk characterization and management. This study is based on a study of the available information/data on cytotoxicity assessment performed on environmental samples following the PRISMA methodology. Different cell lines were used depending on the environment assessed and exposure routes implicated. The A549 alveolar epithelial cell line was applied in four studies for occupational exposure in the waste sorting industry and for outdoor environments; lymphocytes were used in two studies for occupational and outdoor environments; swine kidney cells were used in three studies performed in the waste industry and hepatocellular/Hep G2 in one study in the waste industry. Cytotoxicity assessments in environmental samples should have a more prominent role due to their contribution for identifying and better understanding the associations between co-exposure to environmental contaminants and adverse human health effects as a prioritization for risk management.

Revisiting Total Particle Number Measurements for Vehicle Exhaust Regulations

Road transport significantly contributes to air pollution in cities. Emission regulations have led to significantly reduced emissions in modern vehicles. Particle emissions are controlled by a particulate matter (PM) mass and a solid particle number (SPN) limit. There are concerns that the SPN limit does not effectively control all relevant particulate species and there are instances of semi-volatile particle emissions that are order of magnitudes higher than the SPN emission levels. This overview discusses whether a new metric (total particles, i.e., solids and volatiles) should be introduced for the effective regulation of vehicle emissions. Initially, it summarizes recent findings on the contribution of road transport to particle number concentration levels in cities. Then, both solid and total particle emission levels from modern vehicles are presented and the adverse health effects of solid and volatile particles are briefly discussed. Finally, the open issues regarding an appropriate methodology (sampling and instrumentation) in order to achieve representative and reproducible results are summarized. The main finding of this overview is that, even though total particle sampling and quantification is feasible, details for its realization in a regulatory context are lacking. It is important to define the methodology details (sampling and dilution, measurement instrumentation, relevant sizes, etc.) and conduct inter-laboratory exercises to determine the reproducibility of a proposed method. It is also necessary to monitor the vehicle emissions according to the new method to understand current and possible future levels. With better understanding of the instances of formation of nucleation mode particles it will be possible to identify its culprits (e.g., fuel, lubricant, combustion, or aftertreatment operation). Then the appropriate solutions can be enforced and the right decisions can be taken on the need for new regulatory initiatives, for example the addition of total particles in the tailpipe, decrease of specific organic precursors, better control of inorganic precursors (e.g., NH3, SOx), or revision of fuel and lubricant specifications.

Airborne particulate matter induces oxidative damage, DNA adduct formation and alterations in DNA repair pathways

Air pollution, which includes particulate matter (PM), is classified in group 1 as a carcinogen to humans by the International Agency for Research in Cancer. Specifically, PM exposure has been associated with lung cancer in patients living in highly polluted cities. The precise mechanism by which PM is linked to cancer has not been completely described, and the genotoxicity induced by PM exposure plays a relevant role in cell damage. In this review, we aimed to analyze the types of DNA damage and alterations in DNA repair pathways induced by PM exposure, from both epidemiological and toxicological studies, to comprehend the contribution of PM exposure to carcinogenesis. Scientific evidence supports that PM exposure mainly causes oxidative stress by reactive oxygen species (ROS) and the formation of DNA adducts, specifically by polycyclic aromatic hydrocarbons (PAH). PM exposure also induces double-strand breaks (DSBs) and deregulates the expression of some proteins in DNA repair pathways, precisely, base and nucleotide excision repairs and homologous repair. Furthermore, specific polymorphisms of DNA repair genes could lead to an adverse response in subjects exposed to PM. Nevertheless, information about the effects of PM on DNA repair pathways is still limited, and it has not been possible to conclude which pathways are the most affected by exposure to PM or if DNA damage is repaired properly. Therefore, deepening the study of genotoxic damage and alterations of DNA repair pathways is needed for a more precise understanding of the carcinogenic mechanism of PM.

Characterizing the Chemical Profile of Incidental Ultrafine Particles for Toxicity Assessment Using an Aerosol Concentrator

Incidental ultrafine particles (UFPs) constitute a key pollutant in industrial workplaces. However, characterizing their chemical properties for exposure and toxicity assessments still remains a challenge. In this work, the performance of an aerosol concentrator (Versatile Aerosol Concentration Enrichment System, VACES) was assessed to simultaneously sample UFPs on filter substrates (for chemical analysis) and as liquid suspensions (for toxicity assessment), in a high UFP concentration scenario. An industrial case study was selected where metal-containing UFPs were emitted during thermal spraying of ceramic coatings. Results evidenced the comparability of the VACES system with online monitors in terms of UFP particle mass (for concentrations up to 95 µg UFP/m3) and between filters and liquid suspensions, in terms of particle composition (for concentrations up to 1000 µg/m3). This supports the applicability of this tool for UFP collection in view of chemical and toxicological characterization for incidental UFPs. In the industrial setting evaluated, results showed that the spraying temperature was a driver of fractionation of metals between UF (<0.2 µm) and fine (0.2-2.5 µm) particles. Potentially health hazardous metals (Ni, Cr) were enriched in UFPs and depleted in the fine particle fraction. Metals vaporized at high temperatures and concentrated in the UF fraction through nucleation processes. Results evidenced the need to understand incidental particle formation mechanisms due to their direct implications on particle composition and, thus, exposure. It is advisable that personal exposure and subsequent risk assessments in occupational settings should include dedicated metrics to monitor UFPs (especially, incidental).

Adverse effects of prenatal exposure to residential dust on post-natal brain development

BACKGROUND

Previous studies have shown an association between prenatal exposure to particulate matter (PM) and adverse brain development. However, it is unclear whether gestational exposure to community-sampled residential PM has an impact on the developing brain.

OBJECTIVES

We aimed to test whether in utero exposure to PM from residential roof spaces (ceiling voids) alters critical foetal neurodevelopmental processes.

METHODS

Pregnant C57BL/6 mice were intranasally exposed to 100 μg of roof space particles (~5 mg kg^-1) in 50 μl of saline, or saline alone under light methoxyflurane anaesthesia, throughout mid-to-late gestation. At 2 weeks post-natal age, pups were sacrificed and assessed for body and brain growth. The brain tissue was collected and examined for a range of neurodevelopmental markers for synaptogenesis, synaptic plasticity, gliogenic events and myelination by immunohistochemistry.

RESULTS

Gestational exposure to roof space PM reduced post-natal body and brain weights. There was no significant effect of roof space PM exposure on synaptogenesis, synaptic plasticity or astrocyte density. However, PM exposure caused increased myelin load in the white matter and elevated microglial density which was dependent on the PM sample. These effects were found to be consistent between male and female mice.

CONCLUSIONS

Our data suggest that exposure to residential roof space PM during pregnancy impairs somatic growth and causes neuropathological changes in the developing brain.

Differential inflammatory and toxic effects in-vitro of wood smoke and traffic-related particulate matter from Sydney, Australia

BACKGROUND

It is well known that PM_2.5 generated by traffic or burning wood is pro-inflammatory and induces various adverse health outcomes in humans. In Sydney, New South Wales, Australia, the main anthropogenic contributors to particulate matter (PM) air pollution are wood combustion heaters, on-road vehicles, and coal-fired power stations. However, the relative toxicity of these local sources has not to date been investigated.

METHOD

PM_2.5 was collected on filters from the same sampling site in Liverpool, one suburb of Sydney. According to the positive matrix factorisation and collection season, filters were representative of either day with high traffic-related air pollution (TRAP), wood smoke, or both TRAP and woodsmoke (mixed air pollution). The elemental composition of the PM was assessed by accelerator-based ion beam analysis techniques (i.e. PIXE & PIGE) and size by Dynamic Light Scattering. Toxicity and inflammation were assessed in-vitro in human bronchial epithelial cells by measuring interleukin-6 (IL-6), interleukin-8 (IL-8) release, and MTT.

RESULTS

Mixed air pollution (TRAP/wood smoke) PM had more nanometer (nm) sized PM than the other two groups. Using an in-vitro model of the lungs, the mixed air pollution PM was the most toxic, whereas the PM from woodsmoke induced greater IL-6 release than TRAP PM. There was no difference in the induction of IL-8 between the three sources of PM.

CONCLUSION

Marked differences occur in the cellular response to PM from different sources, with differences in both toxicity and inflammation.

No association between pyrite content and lung cell responses to coal particles

There has been an increase in the identification of cases of coal workers’ pneumoconiosis (CWP) in recent years around the world. While there are a range of possible explanations for this, studies have implicated the pyrite content of coal as a key determinant of CWP risk. However, experimental studies to support this link are limited. The aim of this study was to assess the association between the pyrite content, and subsequent release of bioavailable iron, in coal particles and the response of lung cells involved in the pathogenesis of CWP (epithelial cells, macrophages and fibroblasts). Using real-world Australian coal samples, we found no evidence of an association between the pyrite content of the coal and the magnitude of the detrimental cell response. We did find evidence of an increase in IL-8 production by epithelial cells with increasing bioavailable iron (p = 0.01), however, this was not linked to the pyrite content of the coal (p = 0.75) and we did not see any evidence of a positive association in the other cell types. Given the lack of association between the pyrite content of real-world coal particles and lung cell cytotoxicity (epithelial cells and macrophages), inflammatory cytokine production (epithelial cells, macrophages and fibroblasts), and cell proliferation (fibroblasts) our data do not support the use of coal pyrite content as a predictor of CWP risk.

Reactive oxygen species production and inflammatory effects of ambient PM2.5 -associated metals on human lung epithelial A549 cells "one year-long study": The Delhi chapter

The fine particulate matter (PM_2.5) was collected at academic campus of Indian Institute of Technology, Delhi, India from January-December 2017. The PM_2.5 samples were analysed for carcinogenic (Cd, Cr, As, Ni, and Pb) and non-carcinogenic (V, Cu, Zn, Fe) trace metals and their elicited effects on carcinoma epithelial cell line A549. Toxicological testing was done with ELISA kit. Same analyses were repeated for standard reference material (NIST-1648a) represents urban particulate matter. The student-t test and spearman correlation were used for data analysis. The seasonality in PM_2.5 mass concentration and chemical composition showed effect on biological outcomes. The PM_2.5 in post-monsoon and winter had higher amount of trace metals compared to mass collected in pre-monsoon and monsoon. Following the trend in PM mass concentration significantly (p < 0.5) lower cell viability was observed in post-monsoon and winter compared to other two seasons. NIST UPM 1648(a) samples always had higher cytotoxicity compared to ambient PM_2.5 Delhi sample. Strong association of Chromium, Nickel, Cadmium, and Zinc was observed with cell viability and reactive oxygen species (ROS) production. In winter IL-6, IL-8 production were 2.8 and 3 times higher than values observed in post-monsoon and 53 and 9 times higher than control. In winter season trace metals As, Cu, Fe, in pre-monsoon Cr, Ni, As, Pb, V, and Fe, in post-monsoon Cd and V strongly correlated with ROS generation. ROS production in winter and pre-monsoon seasons found to be 2.6 and 1.3 times higher than extremely polluted post-monsoon season which had 2 to 3 times higher PM_2.5 concentration compared to winter and pre-monsoon. The result clearly indicated that the presence of Fe in winter and pre-monsoon seasons catalysed the ROS production, probably OH˙ radical caused high cytokines production which influenced the cell viability reduction, while in post-monsoon PM majorly composed of Pb, As, Fe and Cu and affected by photochemical smog formation showed significant association between ROS production with cell viability. Overall, in Delhi most toxic seasons for respiratory system are winter and post-monsoon and safest season is monsoon.

Inflammatory responses of urban air PM modulated by chemical composition and different air quality situations in Nanjing, China

The health risks of air pollutants and ambient particulate matter (PM) are widely known. PM composition and toxicity have shown substantial spatiotemporal variability. Yet, the connections between PM composition and toxicological and health effects are vaguely understood. This is a crucial gap in knowledge that needs to be addressed in order to establish air quality guidelines and limit values that consider the chemical composition of PM instead of the current assumption of equal toxicity per inhaled dose. Here, we demonstrate further evidence for varying toxicological effects of urban PM at equal mass concentrations, and estimate how PM composition and emission source characteristics influenced this variation. We exposed a co-culture model mimicking alveolar epithelial cells and macrophages with size-segregated urban ambient PM collected before, during, and after the Nanjing Youth Olympic Games 2014. We measured the release of a set of cytokines, cell cycle alterations, and genotoxicity, and assessed the spatiotemporal variations in these responses by factorial multiple regression analysis. Additionally, we investigated how a previously identified set of emission sources and chemical components affected these variations by mixed model analysis. PM-exposure induced cytokine signaling, most notably by inducing dose-dependent increases of macrophage-regulating GM-CSF and proinflammatory TNFα, IL-6, and IL-1β concentrations, modest dose-dependent increase for cytoprotective VEGF-A, but very low to no responses for anti-inflammatory IL-10 and immunoregulatory IFNγ, respectively. We observed substantial differences in proinflammatory cytokine production depending on PM sampling period, location, and time of day. The proinflammatory response correlated positively with cell cycle arrest in G1/G0 phase and loss of cellular metabolic activity. Furthermore, PM_0.2 caused dose-dependent increases in sub-G1/G0 cells, suggesting increased DNA degradation and apoptosis. Variations in traffic and oil/fuel combustion emissions contributed substantially to the observed spatiotemporal variations of toxicological responses.

Seasonally varied cytotoxicity of organic components in PM2.5 from urban and industrial areas of a Chinese megacity

The atmospheric fine particulate matters (PM_2.5) induce significant negative effects on human health, such as in the form of oxidative stress and pro-inflammatory response. Organic pollutants are important harmful and toxic compositions in PM_2.5, risks of which usually show temporal and spatial variations. To investigate the toxic effects of airborne organic pollutants on human lung epithelial cells A549, the PM_2.5 samples were collected monthly from both urban and industrial areas during a whole year in Nanjing, eastern China. After exposure to organic components extracted from these PM_2.5, the cell viability, lactate dehydrogenase content, oxidative stress index level and inflammatory factor expression level were measured. Supported by the concentrations of polycyclic aromatic hydrocarbons (PAHs) and n-alkanes, results showed that, organic components of PM_2.5 from cold season (winter and spring) typically influenced cell membrane, cell oxidation and inflammatory damage, while the urban samples of warm season (summer and autumn) impacted cell viability more prominently. Spatially, the toxicity of samples from industrial sources was generally stronger than that from urban source, but urban samples induced much stronger damage to cell membranes than industrial one. The correlations between the PAHs, n-alkanes contents and toxicity parameters indicated that, the airborne organic components derived from motor vehicle exhaust and coal combustion were possibly the key toxic sources.

The association of PM2.5 with airway innate antimicrobial activities of salivary agglutinin and surfactant protein D

Fine particulate matter ≤2.5 μm (PM_2.5) is a prominent global public health risk factor that can cause respiratory infection by downregulating the amounts of antimicrobial proteins and peptides (AMPs). Both salivary agglutinin (SAG) and surfactant protein D (SPD) are important AMPs in respiratory mucosal fluid, providing protection against airway pathogen invasion and infection by inducing microbial aggregation and enhancing pathogen clearance. However, the relationship between PM_2.5 and these AMPs is unclear. To better understand the relationship between PM_2.5 and airway innate immune defenses, we review the respiratory antimicrobial activities of SAG and SPD, as well as the adverse effects of PM_2.5 on airway innate antimicrobial defense. We speculate there exists a dual effect between PM_2.5 and respiratory antimicrobial activity, which means that PM_2.5 suppresses respiratory antimicrobial activity through downregulating airway AMPs, while airway AMPs accelerate PM_2.5 clearance by inducing PM_2.5 microbial aggregation. We propose further research on the relationship between PM_2.5 and these AMPs.

Chemical Characteristics of Fine Particulate Matter in Poland in Relation with Data from Selected Rural and Urban Background Stations in Europe

Air pollution by particulate matter (PM) is recognized as a one of the most important environmental issue. A particular attention is being paid to fine PM fraction (PM2.5, PM1.0) due to its detrimental impact on human health and long-term persistence in the air. Presented work is an in-depth bibliometric study on the concentrations and chemical composition of PM2.5 among 27 rural and 38 urban/urban background stations dispersed across the Europe. Obtained results indicate that the chemical composition of PM2.5, in terms of mass concentrations and percentage contribution of main chemical constituents, is relatively different in various parts of Europe. Urban and urban background stations are typically characterized by higher share of total carbon (TC) in PM2.5, compared to rural background sites, mostly pronounced during the heating periods. The share of the secondary inorganic aerosol (SIA) is typically higher at rural background stations, especially in North-Western Europe. In general, the relative contribution of SIA in PM2.5 mass, both at rural and urban background stations, showed more or less pronounced seasonal variation, opposite to Polish measurement sites. Moreover, Poland stands out from the majority of the European stations by strong dominance of total carbon over secondary inorganic aerosol.

A cost-effective technique for generating preservable biomass smoke extract and measuring its effect on cell receptor expression in human bronchial epithelial cells

Nearly half of the world’s population uses biomass fuel for the purposes of cooking and heating. Smoke derived from biomass increases the risk of the development of lung diseases, including pneumonia, chronic obstructive pulmonary disease, airway tract infections, and lung cancer. Despite the evidence linking biomass smoke exposure to pulmonary disease, only a small number of experimental studies have been conducted on the impact of biomass smoke on airway epithelial cells. This is in part due to the lack of a standard and easily accessible procedure for the preparation of biomass smoke. Here, we describe a cost-effective and reproducible method for the generation of different smoke extracts, in particular, cow dung smoke extract (CDSE) and wood smoke extract (WSE) for use in a range of biological applications. We examined the effect of the biomass smoke extracts on human bronchial epithelial cell expression of a known responder to cigarette smoke exposure (CSE), the platelet-activating factor receptor (PAFR). Similar to the treatment with CSE, we observed a dose-dependent increase in PAFR expression on human airway epithelial cells that were exposed to CDSE and WSE. This method provides biomass smoke in a re-usable form for cell and molecular bioscience studies on the pathogenesis of chronic lung disease.

Did Fine Particulate Matter from the Summer 2016 Landscape Fires in Tasmania Increase Emergency Ambulance Dispatches? A Case Crossover Analysis

During summer in early 2016, over 70 landscape fires in Tasmania (Australia) caused several severe episodes of fire smoke across the island state. To assess the health impact of the fire smoke, a case crossover analysis was performed, which measured the association between increased concentrations of PM2.5 and emergency ambulance dispatches (EAD) from 1 January to 31 March 2016. Control days were matched by latitude and longitude, day of the week and calendar month. Exposure data were obtained from air quality monitoring stations at lag times of 1–48 h and for the 24-h mean on the same day and 1-day lag. Positive associations were observed between an increase of 10 µg/m3 in PM2.5 and EAD for stroke on the same day (OR 1.10, 95% CI 1.02–1.19) and at 1-day lag (OR 1.10, 95% CI 1.02–1.18). Furthermore, there were non-significant increases in breathing problems (OR 1.04, 95% CI 1.00–1.08) and diabetic problems (OR 1.11, 95% CI 0.99–1.22) at 1-day lag. The EAD for all causes were not increased. These findings will be used for ambulance service planning and public health risk communication in future landscape fire events.