Search

The prevalence of wildfires continues to grow globally with exposures resulting in increased disease risk. Characterizing these health risks remains difficult due to the wide landscape of exposures that can result from different burn conditions and fuel types. This study tested the hypothesis that biomass smoke exposures from variable fuels and combustion conditions group together based on similar transcriptional response profiles, informing which wildfire-relevant exposures may be considered as a group for health risk evaluations. Mice (female CD-1) were exposed via oropharyngeal aspiration to equal mass biomass smoke condensates produced from flaming or smoldering burns of eucalyptus, peat, pine, pine needles, or red oak species. Lung transcriptomic signatures were used to calculate transcriptomic similarity scores across exposures, which informed exposure groupings. Exposures from flaming peat, flaming eucalyptus, and smoldering eucalyptus induced the greatest responses, with flaming peat grouping with the pro-inflammatory agent lipopolysaccharide. Smoldering red oak and smoldering peat induced the least transcriptomic response. Groupings paralleled pulmonary toxicity markers, though they were better substantiated by higher data dimensionality and resolution provided through -omic-based evaluation. Interestingly, groupings based on smoke chemistry signatures differed from transcriptomic/toxicity-based groupings. Wildfire-relevant exposure groupings yield insights into risk assessment strategies to ultimately protect public health.

A weighted chemical coexpression network analysis (WCCNA) was utilized to identify chemicals co-modulated to variable burning of anthropogenic materials and to link chemicals to biological responses (lung toxicity and mutagenicity). Polyaromatic hydrocarbons (PAHs) were co-modulated with increased concentrations in flaming smoke particulate matter (PM) from the burning of plastic-containing materials and showed significant association with increased neutrophil influx, cytokine levels, and mutagenicity. Inorganic elements were co-modulated with increased concentrations in flaming plywood and cardboard smoke PM and showed significant association with increased protein and albumin levels. This study shows the potential for using a computational network analysis to identify and prioritize hazardous chemical components within complex environmental mixtures and provides guidance on key chemical tracers required for intervention research to protect public health from the exposure.

Inhalation of smoke from the burning of waste materials on military bases is associated with increased incidences of cardiopulmonary diseases. This study examined the respiratory and inflammatory effects of acute inhalation exposures in mice to smoke generated by military burn pit-related materials including plywood (PW), cardboard (CB), mixed plastics (PL), and a mixture of these three materials (MX) under smoldering (0.84 MCE) and flaming (0.97 MCE) burn conditions. Mice were exposed nose-only for one hour on two consecutive days to whole or filtered smoke or clean air alone. Smoldering combustion emissions had greater concentrations of PM (∼40 mg/m3) and VOCs (∼5–12 ppmv) than flaming emissions (∼4 mg/m3 and ∼1–2 ppmv, respectively); filtered emissions had equivalent levels of VOCs with negligible PM. Breathing parameters were assessed during exposure by head-out plethysmography. All four smoldering burn pit emission types reduced breathing frequency (F) and minute volumes (MV) compared with baseline exposures to clean air, and HEPA filtration significantly reduced the effects of all smoldering materials except CB. Flaming emissions had significantly less suppression of F and MV compared with smoldering conditions. No acute effects on lung inflammatory cells, cytokines, lung injury markers, or hematology parameters were noted in smoke-exposed mice compared with air controls, likely due to reduced respiration and upper respiratory scrubbing to reduce the total deposited PM dose in this short-term exposure. Our data suggest that material and combustion type influences respiratory responses to burn pit combustion emissions. Furthermore, PM filtration provides significant protective effects only for certain material types.

Recent epidemiological findings link asthma to adverse cardiovascular responses. Yet, the precise cardiovascular impacts of asthma have been challenging to disentangle from the potential cardiovascular effects caused by asthma medication. The purpose of this study was to determine the impacts of allergic airways disease alone on cardiovascular function in an experimental model. Female Wistar rats were intranasally sensitized and then challenged once per week for 5 weeks with saline vehicle or a mixture of environmental allergens (ragweed, house dust mite, and Aspergillus fumigatus). Ventilatory and cardiovascular function, measured using double-chamber plethysmography and implantable blood pressure (BP) telemetry and cardiovascular ultrasound, respectively, were assessed before sensitization and after single and final allergen challenge. Responses to a single 0.5 ppm ozone exposure and to the cardiac arrhythmogenic agent aconitine were also assessed after final challenge. A single allergen challenge in sensitized rats increased tidal volume and specific airways resistance in response to provocation with methacholine and increased bronchoalveolar lavage fluid (BALF) eosinophils, neutrophils, lymphocytes, cytokines interleukin (IL)-4, IL-5, IL-10, IL-1β, tumor necrosis factor-α, and keratinocyte chemoattract-growth-related oncogene characteristic of allergic airways responses. Lung responses after final allergen challenge in sensitized rats were diminished, although ozone exposure increased BALF IL-6, IL-13, IL-1 β, and interferon-γ and modified ventilatory responses only in the allergen group. Final allergen challenge also increased systolic and mean arterial BP, stroke volume, cardiac output, end-diastolic volume, sensitivity to aconitine-induced cardiac arrhythmia, and cardiac gene expression with lesser effects after a single challenge. These findings demonstrate that allergic airways responses may increase cardiovascular risk in part by altering BP and myocardial function and by causing cardiac electrical instability.

Wildland fires are diminishing air quality on a seasonal and regional basis, raising concerns about respiratory health risks to the public and occupational groups. This American Thoracic Society (ATS) workshop was convened in 2019 to meet the growing health threat of wildland fire smoke. The workshop brought together a multidisciplinary group of 19 experts, including wildland fire managers, public health officials, epidemiologists, toxicologists, and pediatric and adult pulmonologists. The workshop examined the following four major topics: 1) the science of wildland fire incidence and fire management, 2) the respiratory and cardiovascular health effects of wildland fire smoke exposure, 3) communication strategies to address these health risks, and 4) actions to address wildland fire health impacts. Through formal presentations followed by group discussion, workshop participants identified top priorities for fire management, research, communication, and public policy to address health risks of wildland fires. The workshop concluded that short-term exposure to wildland smoke causes acute respiratory health effects, especially among those with asthma and chronic obstructive pulmonary disease. Research is needed to understand long-term health effects of repeated smoke exposures across fire seasons for children, adults, and highly exposed occupational groups (especially firefighters). Other research priorities include fire data collection and modeling, toxicology of different fire fuel sources, and the efficacy of health protective measures to prevent respiratory effects of smoke exposure. The workshop committee recommends a unified federal response to the growing problem of wildland fires, including investment in fire behavior and smoke air quality modeling, research on the health impacts of smoke, and development of robust clinical and public health communication tools.

The biological response of bronchial epithelial cells to particles is associated with a sequestration of cell metal by the particle surface and a subsequent disruption in host iron homeostasis. The macrophage is the cell type resident in the respiratory tract that is most likely to make initial contact with inhaled particles. We tested the postulates that (1) silica, a prototypical particle, disrupts iron homeostasis in alveolar macrophages (AMs); and (2) the altered iron homeostasis results in both an oxidative stress and pro-inflammatory effects. Human AMs (1.0 × 106/mL) demonstrated an increased import of iron following particle exposure with nonheme iron concentrations of 0.57 ± 0.03, 1.72 ± 0.09, 0.88 ± 0.09, and 3.21 ± 0.11 ppm in cells exposed for 4 h to media, 500 μM ferric ammonium citrate (FAC), 100 μg/mL silica, and both silica and FAC, respectively. Intracellular ferritin concentrations and iron release were similarly increased after AM exposure to FAC and silica. Silica increased oxidant generation by AMs measured using both dichlorofluorescein diacetate fluorescence and reduction of nitroblue tetrazolium salt. Concentrations of interleukin (IL)-1β, IL-6, IL-8, and tumor necrosis factor-α in macrophage supernatant increased following 100 μg/mL silica exposure for 24 h. Treatment of AMs with 500 μM FAC decreased both oxidant generation and cytokine release associated with silica exposure, supporting a dependence of these effects on sequestration of cell metal by the particle surface. We conclude that (1) silica exposure disrupts iron homeostasis resulting in increased import, accumulation, and release of the metal; and (2) the altered iron homeostasis following silica exposure impacts oxidant generation and pro-inflammatory effects.

Heart rate assays in wild-type zebrafish embryos have been limited to analysis of one embryo per video/imaging field. Here we present for the first time a platform for high-throughput derivation of heart rate from multiple zebrafish (Danio rerio) embryos per imaging field, which is capable of quickly processing thousands of videos and ideal for multi-well platforms with multiple fish/well. This approach relies on use of 2-day post fertilization wild-type embryos, and uses only bright-field imaging, circumventing requirement for anesthesia or restraint, costly software/hardware, or fluorescently-labeled animals. Our original scripts (1) locate the heart and record pixel intensity fluctuations generated by each cardiac cycle using a robust image processing routine, and (2) process intensity data to derive heart rate. To demonstrate assay utility, we exposed embryos to the drugs epinephrine and clonidine, which increased or decreased heart rate, respectively. Exposure to organic extracts of air pollution-derived particulate matter, including diesel or biodiesel exhausts, or wood smoke, all complex environmental mixtures, decreased heart rate to varying degrees. Comparison against an established lower-throughput method indicated robust assay fidelity. As all code and executable files are publicly available, this approach may expedite cardiotoxicity screening of compounds as diverse as small molecule drugs and complex chemical mixtures.

Wildland fire emissions cause adverse cardiopulmonary outcomes, yet controlled exposure studies to characterize health impacts of specific biomass sources have been complicated by the often latent effects of air pollution. The aim of this study was to determine if postprandial responses after a high fat challenge, long used clinically to predict cardiovascular risk, would unmask latent cardiometabolic responses in rats exposed to peat smoke, a key wildland fire air pollution source. Male Wistar Kyoto rats were exposed once (1 h) to filtered air (FA), or low (0.36 mg/m3 particulate matter) or high concentrations (3.30 mg/m3) of peat smoke, generated by burning peat from an Irish bog. Rats were then fasted overnight, and then administered an oral gavage of a HF suspension (60 kcal% from fat), mimicking a HF meal, 24 h post-exposure. In one cohort, cardiac and superior mesenteric artery function were assessed using high frequency ultrasound 2 h post gavage. In a second cohort, circulating lipids and hormones, pulmonary and systemic inflammatory markers, and circulating monocyte phenotype using flow cytometry were assessed before or 2 or 6 h after gavage. HF gavage alone elicited increases in circulating lipids characteristic of postprandial responses to a HF meal. Few effects were evident after peat exposure in un-gavaged rats. By contrast, exposure to low or high peat caused several changes relative to FA-exposed rats 2 and 6 h post HF gavage including increased heart isovolumic relaxation time, decreased serum glucose and insulin, increased CD11 b/c-expressing blood monocytes, increased serum total cholesterol, alpha-1 acid glycoprotein, and alpha-2 macroglobulin (p = 0.063), decreased serum corticosterone, and increased lung gamma-glutamyl transferase. In summary, these findings demonstrate that a HF challenge reveals effects of air pollution that may otherwise be imperceptible, particularly at low exposure levels, and suggest exposure may sensitize the body to mild inflammatory triggers.

Exposure to wildfire smoke continues to be a growing threat to public health, yet the chemical components in wildfire smoke that primarily drive toxicity and associated disease are largely unknown. This study utilized a suite of computational approaches to identify groups of chemicals induced by variable biomass burn conditions that were associated with biological responses in the mouse lung, including pulmonary immune response and injury markers. Smoke condensate samples were collected and characterized, resulting in chemical distribution information for 86 constituents across ten different exposures. Mixtures-relevant statistical methods included (i) a chemical clustering and data-reduction method, weighted chemical co-expression network analysis (WCCNA), (ii) a quantile g-computation approach to address the joint effect of multiple chemicals in different groupings, and (iii) a correlation analysis to compare mixtures modeling results against individual chemical relationships. Seven chemical groups were identified using WCCNA based on co-occurrence showing both positive and negative relationships with biological responses. A group containing methoxyphenols (e.g., coniferyl aldehyde, eugenol, guaiacol, and vanillin) displayed highly significant, negative relationships with several biological esponses, including cytokines and lung injury markers. This group was further shown through quantile g-computation methods to associate with reduced biological responses. Specifically, mixtures modeling based on all chemicals excluding those in the methoxyphenol group demonstrated more significant, positive relationships with several biological responses; whereas mixtures modeling based on just those in the methoxyphenol group demonstrated significant negative relationships with several biological responses, suggesting potential protective effects. Mixtures-based analyses also identified other groups consisting of inorganic elements and ionic constituents showing positive relationships with several biological responses, including markers of inflammation. Many of the effects identified through mixtures modeling in this analysis were not captured through individual chemical analyses. Together, this study demonstrates the utility of mixtures-based approaches to identify potential drivers and inhibitors of toxicity relevant to wildfire exposures., Graphical Abstract

Wildland fires (WF) are linked to adverse health impacts related to poor air quality. The cardiovascular impacts of emissions from specific biomass sources, however, are unknown. The purpose of this study was to assess the cardiovascular impacts of a single exposure to peat smoke, a key regional WF air pollution source, and relate these to baroreceptor sensitivity and inflammation. Three-month-old male Wistar-Kyoto rats, implanted with radiotelemeters for continuous monitoring of heart rate (HR), blood pressure (BP), and spontaneous baroreflex sensitivity (BRS), were exposed once, for 1-hr, to filtered air or low (0.38 mg/m(3) PM) or high (4.04 mg/m(3)) concentrations of peat smoke. Systemic markers of inflammation and sensitivity to aconitine-induced cardiac arrhythmia, a measure of latent myocardial vulnerability, were assessed in separate cohorts of rats 24 hr after exposure. PM size (low peat = 0.4 – 0.5 microns vs. high peat = 0.8 – 1.2 microns) and proportion of organic carbon (low peat = 77% vs. high peat = 65%) varied with exposure level. Exposure to high peat and to a lesser extent low peat increased systolic and diastolic BP relative to filtered air. By contrast, only exposure to low peat elevated BRS and aconitine-induced arrhythmogenesis relative to filtered air and increased circulating levels of low-density lipoprotein cholesterol, complement components C3 and C4, angiotensin converting enzyme (ACE), and white blood cells. Taken together, exposure to peat smoke produced overt and latent cardiovascular consequences that were likely influenced by physicochemical characteristics of the smoke and associated adaptive homeostatic mechanisms.

OBJECTIVE: Previous studies have shown that air pollution exposure primes the body to heightened responses to everyday stressors of the cardiovascular system. The purpose of this study was to examine the utility of postprandial responses to a high carbohydrate oral load, a cardiometabolic stressor long used to predict cardiovascular risk, in assessing the impacts of exposure to eucalyptus smoke (ES), a contributor to wildland fire air pollution in the Western coast of the United States. MATERIALS AND METHODS: Three-month-old male Sprague Dawley rats were exposed once (1 hr) to filtered air (FA) or ES (700 μg/m(3) fine particulate matter), generated by burning eucalyptus in a tube furnace. Rats were then fasted for six hours the following morning, and subsequently administered an oral gavage of either water or a HC suspension (70 kcal% from carbohydrate), mimicking a HC meal. Two hours post gavage, cardiovascular ultrasound, cardiac pressure-volume (PV), and baroreceptor sensitivity assessments were made, and pulmonary and systemic markers assessed. RESULTS: ES inhalation alone increased serum interleukin (IL)-4 and nasal airway levels of gamma glutamyl transferase. HC gavage alone increased blood glucose, blood pressure, and serum IL-6 and IL-13 compared to water vehicle. By contrast, only ES-exposed and HC-challenged animals had increased PV loop measures of cardiac output, stroke volume, ejection fraction %, dP/dt(max), dP/dt(min), and stroke work compared to ES exposure alone and/or HC challenge alone. DISCUSSION AND CONCLUSIONS: Exposure to model wildfire air pollution modifies cardiovascular responses to HC challenge, suggesting air pollution sensitizes the body to systemic triggers.

Previous studies have shown that air pollution exposure primes the body to heightened responses to everyday stressors of the cardiovascular system. The purpose of this study was to examine the utility of postprandial responses to a high carbohydrate oral load, a cardiometabolic stressor long used to predict cardiovascular risk, in assessing the impacts of exposure to eucalyptus smoke (ES), a contributor to wildland fire air pollution in the Western coast of the United States. Three-month-old male Sprague Dawley rats were exposed once (1 h) to filtered air (FA) or ES (700 µg/m3 fine particulate matter), generated by burning eucalyptus in a tube furnace. Rats were then fasted for six hours the following morning, and subsequently administered an oral gavage of either water or a HC suspension (70 kcal% from carbohydrate), mimicking a HC meal. Two hours post gavage, cardiovascular ultrasound, cardiac pressure–volume (PV), and baroreceptor sensitivity assessments were made, and pulmonary and systemic markers assessed. ES inhalation alone increased serum interleukin (IL)-4 and nasal airway levels of gamma glutamyl transferase. HC gavage alone increased blood glucose, blood pressure, and serum IL-6 and IL-13 compared to water vehicle. By contrast, only ES-exposed and HC-challenged animals had increased PV loop measures of cardiac output, ejection fraction %, dP/dtmax, dP/dtmin, and stroke work compared to ES exposure alone and/or HC challenge alone. Exposure to a model wildfire air pollution source modifies cardiovascular responses to HC challenge, suggesting air pollution sensitizes the body to systemic triggers.

Background There is an urgent need to provide access to cleaner end user energy technologies for the nearly 40% of the world's population who currently depend on rudimentary cooking and heating systems. Advanced cookstoves (CS) are designed to cut emissions and solid-fuel consumption, thus reducing adverse human health and environmental impacts. Study premise We hypothesized that, compared to a traditional (Tier 0) three-stone (3-S) fire, acute inhalation of solid-fuel emissions from advanced natural-draft (ND; Tier 2) or forced-draft (FD; Tier 3) stoves would reduce exposure biomarkers and lessen pulmonary and innate immune system health effects in exposed mice. Results Across two simulated cooking cycles (duration ~ 3 h), emitted particulate mass concentrations were reduced 80% and 62% by FD and ND stoves, respectively, compared to the 3-S fire; with corresponding decreases in particles visible within murine alveolar macrophages. Emitted carbon monoxide was reduced ~ 90% and ~ 60%, respectively. Only 3-S-fire-exposed mice had increased carboxyhemoglobin levels. Emitted volatile organic compounds were FD ≪ 3-S-fire ≤ ND stove; increased expression of genes involved in xenobiotic metabolism (COX-2, NQO1, CYP1a1) was detected only in ND- and 3-S-fire-exposed mice. Diminished macrophage phagocytosis was observed in the ND group. Lung glutathione was significantly depleted across all CS groups, however the FD group had the most severe, ongoing oxidative stress. Conclusions These results are consistent with reports associating exposure to solid fuel stove emissions with modulation of the innate immune system and increased susceptibility to infection. Lower respiratory infections continue to be a leading cause of death in low-income economies. Notably, 3-S-fire-exposed mice were the only group to develop acute lung injury, possibly because they inhaled the highest concentrations of hazardous air toxicants (e.g., 1,3-butadiene, toluene, benzene, acrolein) in association with the greatest number of particles, and particles with the highest % organic carbon. However, no Tier 0–3 ranked CS group was without some untoward health effect indicating that access to still cleaner, ideally renewable, energy technologies for cooking and heating is warranted.

Air pollution is a diverse and dynamic mixture of gaseous and particulate matter, limiting our understanding of associated adverse health outcomes. The biological effects of two simulated smog atmospheres (SA) with different compositions but similar air quality health indexes were compared in a non-obese diabetic rat model (Goto-Kakizaki, GK) and three mouse immune models (house dust mite (HDM) allergy, antibody response to heat-killed pneumococcus, and resistance to influenza A infection). In GK rats, both SA-PM (high particulate matter) and SA-O(3) (high ozone) decreased cholesterol levels immediately after a 4-hour exposure, whereas only SA-O(3) increased airflow limitation. Airway responsiveness to methacholine was increased in HDM-allergic mice compared with non-allergic mice, but exposure to SA-PM or SA-O(3) did not significantly alter responsiveness. Exposure to SA-PM did not affect the IgM response to pneumococcus, and SA-O(3) did not affect virus titers, although inflammatory cytokine levels were decreased in mice infected at the end of a 7-day exposure. Collectively, acute SA exposures produced limited health effects in animal models of metabolic and immune diseases. Effects of SA-O(3) tended to be greater than those of SA-PM, suggesting that gas-phase components in photochemically-derived multipollutant mixtures may be of greater concern than secondary organic aerosol PM.

The production of photochemical atmospheres under controlled conditions in an irradiation chamber permits the manipulation of parameters that influence the resulting air-pollutant chemistry and potential biological effects. To date, no studies have examined how contrasting atmospheres with a similar Air Quality Health Index (AQHI), but with differing ratios of criteria air pollutants, might differentially affect health end points. Here, we produced two atmospheres with similar AQHIs based on the final concentrations of ozone, nitrogen dioxide, and particulate matter (PM(2.5)). One simulated atmosphere (SA-PM) generated from irradiation of ∼23 ppmC gasoline, 5 ppmC α-pinene, 529 ppb NO, and 3 μg m(−3) (NH(4))(2)SO(4)resulted in an average of 55 μg m(−3) PM(2.5), 643 ppb NO(2), and 430 ppb O(3) (AQHI of 99.8). Chemical The other atmosphere (SA-O(3)) generated from 8 ppmC gasoline, 5 ppmC isoprene, 874 ppb NO, and 2 μg m(−3) (NH(4))(2)SO(4)resulted in an average of 55 μg m(−3) PM(2.5), 643 ppb NO(2), and 430 ppb O(3) (AQHI of 99.8). Chemical speciation by gas chromatography showed that photo-oxidation degraded the organic precursors and promoted the de novo formation of secondary reaction products such as formaldehyde and acrolein. Further work in accompanying papers describe toxicological outcomes from the two distinct photochemical atmospheres.

Early life nutritional deficiencies can lead to increased cardiovascular susceptibility to environmental exposures. Thus, the purpose of this study was to examine the effect of early life persistent vitamin D deficiency (VDD) on the cardiopulmonary response to a particulate matter-enhanced photochemical smog. Mice were fed a VDD or normal diet (ND) after weaning. At 17 weeks of age, mice were implanted with radiotelemeters to monitor electrocardiogram, heart rate (HR), and heart rate variability (HRV). Ventilatory function was measured throughout the diet before and after smog exposure using whole-body plethysmography. VDD mice had lower HR, increased HRV, and decreased tidal volume compared with ND. Regardless of diet, HR decreased during air exposure; this response was blunted by smog in ND mice and to a lesser degree in VDD. When compared with ND, VDD increased HRV during air exposure and more so with smog. However, smog only increased cardiac arrhythmias in ND mice. This study demonstrates that VDD alters the cardiopulmonary response to smog, highlighting the possible influence of nutritional factors in determining responses to air pollution. The mechanism of how VDD induces these effects is currently unknown, but modifiable factors should be considered when performing risk assessment of complex air pollution atmospheres.

VITROCELL® systems permit cell exposures at the air–liquid interface (ALI); however, there are inconsistent methodologies in the literature for their operation. Some studies find that exposure to air (vehicle control) induced cytotoxicity relative to incubator controls; others do not mention if any cytotoxicity was encountered. We sought to test whether temperature and relative humidity (temp/RH) influence cytotoxicity with an unmodified (conditions A & B) and modified (condition C) VITROCELL® 6 CF with temp/RH controls to permit conditioning of the sampled air-flow. We exposed BEAS-2B cells for 1 h to air and measured viability (WST-1 cell proliferation assay) and lactate dehydrogenase (LDH) release 6 h post-exposure. Relative to controls, cells exposed to air at (A) 22 °C and 18% RH had a 47.9% ± 3.2% (p 75% RH showed no changes in cell viability and no increase in LDH release. Furthermore, cells exposed to air at 37 °C and >75% RH 24 h post-exposure showed no changes in viability or LDH release relative to incubator controls. Thus, reductions in cell viability were induced under conditions used typically in the literature (conditions A & B). However, our modifications (condition C) overcome this shortcoming by preventing cell desiccation; regulating temp/RH is essential for conducting adequate ALI exposures.

The Cleveland airshed comprises a complex mixture of industrial source emissions that contribute to periods of non-attainment for fine particulate matter (PM2.5) and are associated with increased adverse health outcomes in the exposed population. Specific PM sources responsible for health effects however are not fully understood. Size-fractionated PM (coarse, fine, and ultrafine) samples were collected using a ChemVol sampler at an urban site (G.T. Craig (GTC)) and rural site (Chippewa Lake (CLM)) from July 2009 to June 2010, and then chemically analyzed. The resulting speciated PM data were apportioned by EPA positive matrix factorization to identify emission sources for each size fraction and location. For comparisons with the ChemVol results, PM samples were also collected with sequential dichotomous and passive samplers, and evaluated for source contributions to each sampling site. The ChemVol results showed that annual average concentrations of PM, elemental carbon, and inorganic elements in the coarse fraction at GTC were ∼2, ∼7, and ∼3 times higher than those at CLM, respectively, while the smaller size fractions at both sites showed similar annual average concentrations. Seasonal variations of secondary aerosols (e.g., high NO3− level in winter and high SO42− level in summer) were observed at both sites. Source apportionment results demonstrated that the PM samples at GTC and CLM were enriched with local industrial sources (e.g., steel plant and coal-fired power plant) but their contributions were influenced by meteorological conditions and the emission source's operation conditions. Taken together the year-long PM collection and data analysis provides valuable insights into the characteristics and sources of PM impacting the Cleveland airshed in both the urban center and the rural upwind background locations. These data will be used to classify the PM samples for toxicology studies to determine which PM sources, species, and size fractions are of greatest health concern.

Acute and chronic exposures to biomass wildfire smoke pose significant health risks to firefighters and impacted communities. Susceptible populations such as asthmatics may be particularly sensitive to wildfire effects. We examined pulmonary responses to biomass smoke generated from combustion of peat, oak, or eucalyptus in control and house dust mite (HDM)-allergic mice. Mice were exposed 1 hour/day for 2 consecutive days to emissions from each fuel type under smoldering or flaming conditions (~40 or ~3.3 mg PM/m(3), respectively) while maintaining comparable CO levels (~60–120 ppm). Control and allergic mice reduced breathing frequency during exposure to all biomass emissions compared with pre-exposure to clean air. Smoldering eucalyptus and oak, but not peat, further reduced frequency compared to flaming conditions in control and allergic groups, while also reducing minute volume and peak inspiratory flow in control mice. Several biochemical and cellular markers of lung injury and inflammation were suppressed by all biomass emission types in both HDM-allergic and control mice. Control mice exposed to flaming eucalyptus at different PM concentrations (C) and times (T) with the same C×T product had a greater decrease in breathing frequency with high concentration acute exposure compared with lower concentration episodic exposure. This decrease was ameliorated by PM HEPA filtration, indicating that the respiratory changes were partially mediated by biomass smoke particles. These data show that exposure to smoldering eucalyptus or oak smoke inhibits respiratory responses to a greater degree than peat smoke. Anti-inflammatory effects of CO may possibly contribute to smoke-induced suppression of allergic inflammatory responses.

The characteristics of wildland fire smoke exposures which initiate or exacerbate cardiopulmonary conditions are unclear. We previously reported that, on a mass basis, lung toxicity associated with particulate matter (PM) from flaming smoke aspirated into mouse lungs is greater than smoldering PM. In this study, we developed a computer-controlled inhalation system which can precisely control complex biomass smoke emissions from different combustion conditions. This system was used to examine the toxicity of inhaled biomass smoke from peat, eucalyptus, and oak fuels generated under smoldering and flaming phases with emissions set to the same approximate concentration of carbon monoxide (CO) for each exposure (60–110 ppm), resulting in PM levels of ~ 4 mg/m3 for flaming and ~ 40 mg/m3 for smoldering conditions. Mice were exposed by inhalation 1 h/day for 2 days, and assessed for lung toxicity at 4 and 24 h after the final exposure. Peat (flaming and smoldering) and eucalyptus (smoldering) smoke elicited significant inflammation (neutrophil influx) in mouse lungs at 4 h with the peat (flaming) smoke causing even greater lung inflammation at 24-h post-exposure. A significant alteration in ventilatory timing was also observed in mice exposed to the peat (flaming) and eucalyptus (flaming and smoldering) smoke immediately after each day of exposure. No responses were seen for exposures to similar concentrations of flaming or smoldering oak smoke. The lung toxicity potencies (neutrophil influx per PM mass) agreed well between the inhalation and previously reported aspiration studies, demonstrating that although flaming smoke contains much less PM mass than smoldering smoke, it is more toxic on a mass basis than smoldering smoke exposure, and that fuel type is also a controlling factor.

Exposure to coarse particulate matter (PM) is associated with lung inflammation and exacerbation of respiratory symptoms in sensitive populations, but the degree to which specific emission sources contribute to these effects is unclear. We examined whether coarse PM samples enriched with diverse sources differentially exacerbate allergic airway responses. Coarse PM was collected weekly (7/2009-6/2010) from urban (G.T. Craig [GTC]) and rural (Chippewa Lake Monitor [CLM]) sites in the Cleveland, Ohio area. Source apportionment results were used to pool GTC filter PM extracts into five samples dominated by traffic, coal, steel (two samples), or road salt sources. Five CLM samples were prepared from corresponding weeks. Control non-allergic and house dust mite (HDM)-allergic Balb/cJ mice were exposed by oropharyngeal aspiration to 100 μg coarse GTC or CLM, control filter extract, or saline only, and responses were examined 2 d after PM exposures. In allergic mice, CLM traffic, CLM road salt and all GTC samples except steel-1 significantly increased airway responsiveness to methacholine (MCh) compared with control treatments. In non-allergic mice, CLM traffic, CLM steel-2 and all GTC samples except coal significantly increased bronchoalveolar lavage fluid (BALF) neutrophils, while only CLM traffic PM increased eosinophils in allergic mice. In non-allergic mice, CLM coal PM increased BALF interleukin (IL)-13 and GTC steel-1 PM increased TNF-α levels. These results demonstrate that equal masses of GTC and CLM coarse PM enriched with a variety of sources exacerbate allergic airway disease. Greater PM concentrations at the urban GTC site signify a greater potential for human health effects.

Epidemiology studies over the past five decades have provided convincing evidence that exposure to air pollution is associated with multiple adverse health outcomes, including increased mortality. Air pollution is a complex mixture of particles, vapors and gases emitted from natural and anthropogenic sources as well as formed through photochemical transformation processes. In metropolitan areas, air pollutants from combustion emissions feature a blend of emitted particles, oxides of carbon, sulfur and nitrogen, volatile organic compounds, and secondary reaction products, such as ozone, nitrogen dioxide, and secondary organic aerosols. Because many of the primary and transformed pollutants track together, their relative contributions to health outcomes are difficult to disentangle. Aside from the criteria pollutants ozone and nitrogen dioxide and some of the simpler aldehydes (e.g. formaldehyde and acrolein), other products from photochemical processes are a particularly vexing class of chemicals to investigate since they comprise a dynamic ill-defined complex mixture in both particulate and gas phases. The purpose of this review was to describe and compare health effects of freshly emitted versus oxidatively or photochemically aged air pollutants. In some cases, (e.g. single volatile organic compounds) photochemical transformation resulted in marked enhancements in toxicity through formation of both known and unidentified reaction products, while in other examples (e.g. aging of automobile emissions) the potentiation of effect was variable. The variation in experimental design, aging system employed, concentration and type of starting agent, and toxicity endpoints make comparisons between different studies exceedingly difficult. A more systematic approach with a greater emphasis on higher throughput screening and computational toxicology is needed to fully answer under what conditions oxidatively- or photochemically-transformed pollutants elicit greater health effects than primary emissions.

Canola (or rapeseed) oil and waste vegetable oil (WVO) are used commonly to make biodiesel fuels composed completely from these oils (B100) or as blends with petroleum diesel (B0). However, no studies have reported the mutagenic potencies of the particulate matter with diameter ≤2.5 μm (PM(2.5)) or the mutagenicity emission factors, such as revertants/MJ(thermal) (rev/MJ(th)) for these biodiesel emissions. Using strains TA98 and TA100 with the Salmonella (Ames) mutagenicity assay, we determined these metrics for organic extracts of PM(2.5) of emissions from biodiesel containing 5% soy oil (soy B5); 5, 20, 50, and 100% canola (canola B5, B20, B50, B100), and 100% waste vegetable oil (WVO B100). The mutagenic potencies (rev/mg PM(2.5)) of the canola B100 and WVO B100 emissions were generally greater than those of B0, whereas the mutagenicity emission factors (rev/MJ(th), rev/kg fuel, and rev/m(3)) were less, reflecting the lower PM emissions of the biodiesels relative to B0. Nearly all the rev/mg PM(2.5) and rev/MJ(th) values were greater in TA98 with S9 than without S9, indicating a relatively greater role for polycyclic aromatic hydrocarbons, which require S9, than nitroarenes, which do not. In TA100 −S9, the rev/mg PM(2.5) and rev/MJ(th) for the biodiesels were generally ≥ to those of B0, indicating that most of these biodiesels produced more direct-acting, base-substitution mutagenic activity than did B0. For B100 biodiesels and petroleum diesel, the rev/MJ(th) in TA98 +S9 ranked: petroleum diesel > canola > WVO > soy. The diesel emissions generally had rev/MJ(th) values orders of magnitude higher than those of large utility-scale combustors (natural gas, coal, oil, or wood) but orders of magnitude lower than those of inefficient open burning (e.g., residential wood fireplaces). These comparative data of the potential health effects of a variety of biodiesel fuels will help inform the life-cycle assessment and use of biodiesel fuels.

The health effects of individual criteria air pollutants have been well investigated. However, little is known about the health effects of air pollutant mixtures that more realistically represent environmental exposures. The present study was designed to evaluate the cardiac effects of inhaled simulated smog atmospheres (SA) generated from the photochemistry of either gasoline and isoprene (SA-G) or isoprene (SA-Is) in mice. Four-month-old female mice were exposed for 4 h to filtered air (FA), SA-G, or SA-Is. Immediately and 20 h after exposure, cardiac responses were assessed with a Langendorff preparation using a protocol consisting of 20 min of global ischemia followed by 2 h of reperfusion. Cardiac function was measured by index of left-ventricular developed pressure (LVDP) and cardiac contractility (dP/dt) before ischemia. Pre-ischemic LVDP was lower in mice immediately after SA-Is exposure (52.2 ± 5.7 cm H2O compared to 83.9 ± 7.4 cm H2O after FA exposure; p = 0.008) and 20 h after SA-G exposure (54.0 ± 12.7 cm H2O compared to 79.3 ± 7.4 cm H2O after FA exposure; p = 0.047). Pre-ischemic left ventricular contraction dP/dtmax was lower in mice immediately after SA-Is exposure (2025 ± 169 cm H2O/sec compared to 3044 ± 219 cm H2O/sec after FA exposure; p

No study has evaluated the mutagenicity of atmospheres with a calculated air quality health index (AQHI). Thus, we generated in a UV-light-containing reaction chamber two simulated atmospheres (SAs) with similar AQHIs but different proportions of criteria pollutants and evaluated them for mutagenicity in three Salmonella strains at the air-agar interface. We continuously injected into the chamber gasoline, nitric oxide, and ammonium sulfate, as well as either α-pinene to produce SA-PM, which had a high concentration of particulate matter (PM): 119 ppb ozone (O(3)), 321 ppb NO(2), and 1007 μg/m(3) PM(2.5); or isoprene to produce SA-O(3), which had a high ozone (O(3)) concentration: 415 ppb O(3), 633 ppb NO(2), and 55 μg/m(3) PM(2.5). Neither PM(2.5) extracts, NO(2), or O(3) alone, nor non-photo-oxidized mixtures were mutagenic or cytotoxic. Both photo-oxidized atmospheres were largely direct-acting base-substitution mutagens with similar mutagenic potencies in TA100 and TA104. The mutagenic potencies [(revertants/h)/(mgC/m(3))] of SA-PM (4.3 ± 0.4) and SA-O(3) (9.5 ± 1.3) in TA100 were significantly different (P < 0.0001), but the mutation spectra were not (P = 0.16), being ~54% C → T and ~46% C → A. Thus, the AQHI may have some predictive value for the mutagenicity of the gas phase of air.

INTRODUCTION –: Exposure to air pollution is linked to adverse cardiovascular events, even in healthy individuals without underlying disease. Yet, it is clear that the severity of this effect depends on the composition of the air pollution mixture, which can vary quite significantly from one place to another. Therefore, this study was conducted to compare the cardiac effects of particulate matter (PM)-enhanced and ozone(O(3))-enhanced smog atmospheres in mice. We hypothesized that O(3)-enhanced smog would cause greater cardiac dysfunction than PM-enhanced smog due to the higher concentrations of irritant gases. METHODS –: Conscious unrestrained radiotelemetered mice were exposed once whole-body to either PM- (SA-PM) or ozone-enhanced (SA-O(3)) smog, or filtered air (FA) for four hours. Heart rate (HR) and electrocardiogram (ECG) were recorded continuously before, during and after exposure, and ventilatory function was assessed using a whole-body plethysmograph immediately and 24hrs after exposure. RESULTS –: Exposure to SA-PM significantly increased HR when compared to both FA and SA-O(3). Both smog atmospheres increased heart rate variability (HRV) and neither caused any changes in ventilation after exposure. However, normalization of the responses to PM concentration revealed that SA-O(3) was far more potent in increasing HRV and causing ventilatory changes than SA-PM. Furthermore, only SA-O(3) caused a significant increase in the number of cardiac arrhythmias. In contrast, there were no differences in any of the parameters between SA-PM and SA-O(3) when the responses were normalized to total or gas-phase only hydrocarbons. CONCLUSIONS –: The results of this study demonstrate that even a single exposure to a complex smog mixture causes acute cardiac effects in mice. Although the generalized physiological responses of the PM- and O(3)-rich smog are similar, the latter is more potent in causing electrical disturbances and breathing changes potentially due to the effects of irritant gases which dominated the mixture. Thus, even though the effects of PM are probably more significant in the long-term, acute cardiac effects appear to be determined by the gases.

Exposure to wildland fire-related particulate matter (PM) causes adverse health outcomes. However, the direct links between cardiopulmonary health effects of wildland fire air pollution and specific biomass sources remain unclear. The purpose of this study was to investigate cardiopulmonary responses in rats following exposure to PM extracts collected from peat fire smoke. We hypothesized that peat smoke PM exposure would dose-dependently alter cardiopulmonary function. Male Sprague-Dawley rats (n = 8/group) were exposed to 35 μg (Lo PM) or 350 μg (Hi PM) of peat smoke PM extracts suspended in 200 μL of saline, or 200 μL of saline alone (Vehicle) via oropharyngeal aspiration (OA). We evaluated ventilatory effects of exposure immediately after OA in whole-body plethysmographs for 12 minutes. Ventilatory expiration times were the lowest in Hi PM exposed subjects at 6 minutes into recovery (p=0.01 vs. Lo PM, p=0.08 vs. Vehicle) and resolved shortly afterwards. The next day, we evaluated cardiovascular function in the same subjects via cardiac ultrasound under isoflurane anesthesia. Compared to Vehicle, Hi PM had 45% higher end systolic volume (p = 0.03) and 17% higher pulmonary artery blood flow acceleration/ejection time ratios, and both endpoints expressed significant increasing linear trends by dose (p = 0.01 and 0.02, respectively). In addition, linear trend analyses across doses (Vehicle, Lo PM, and Hi PM) detected an increase for end diastolic volume and decreases for ejection fraction and fractional shortening. These data suggest that exposure to peat smoke emissions modulates regulation of ventricular ejection and filling volumes, which could be related to altered blood flow in the pulmonary circulation. Moreover, early airway responses to peat smoke PM may point to irritant/autonomic mechanisms as potential drivers of later cardiovascular responses.

Background: The increasing size and frequency of wildland fires are leading to greater potential for cardiopulmonary disease and cancer in exposed populations; however, little is known about how the types of fuel and combustion phases affect these adverse outcomes. Objectives: We evaluated the mutagenicity and lung toxicity of particulate matter (PM) from flaming vs. smoldering phases of five biomass fuels, and compared results by equal mass or emission factors (EFs) derived from amount of fuel consumed. Methods: A quartz-tube furnace coupled to a multistage cryotrap was employed to collect smoke condensate from flaming and smoldering combustion of red oak, peat, pine needles, pine, and eucalyptus. Samples were analyzed chemically and assessed for acute lung toxicity in mice and mutagenicity in Salmonella. Results: The average combustion efficiency was 73 and 98% for the smoldering and flaming phases, respectively. On an equal mass basis, PM from eucalyptus and peat burned under flaming conditions induced significant lung toxicity potencies (neutrophil/mass of PM) compared to smoldering PM, whereas high levels of mutagenicity potencies were observed for flaming pine and peat PM compared to smoldering PM. When effects were adjusted for EF, the smoldering eucalyptus PM had the highest lung toxicity EF (neutrophil/mass of fuel burned), whereas smoldering pine and pine needles had the highest mutagenicity EF. These latter values were approximately 5, 10, and 30 times greater than those reported for open burning of agricultural plastic, woodburning cookstoves, and some municipal waste combustors, respectively. Conclusions: PM from different fuels and combustion phases have appreciable differences in lung toxic and mutagenic potency, and on a mass basis, flaming samples are more active, whereas smoldering samples have greater effect when EFs are taken into account. Knowledge of the differential toxicity of biomass emissions will contribute to more accurate hazard assessment of biomass smoke exposures. https://doi.org/10.1289/EHP2200

Exposure to fine particulate matter (PM) air pollution causes adverse cardiopulmonary outcomes. Yet, the limited capacity to readily identify contributing PM sources and associated PM constituents in any given ambient air shed impedes risk assessment efforts. The health effects of PM have been attributed in part to its capacity to elicit irritant responses. A variety of chemicals trigger irritant behavior responses in zebrafish that can be easily measured. The purposes of this study were to examine the utility of zebrafish locomotor responses in the toxicity assessment of fine PM and its chemical fractions and uncover mechanisms of action. Locomotor responses were recorded in 6-day-old zebrafish exposed for 60 min in the dark at 26 °C to the extractable organic matter of a compressor-generated diesel exhaust PM (C-DEP) and 4 of its fractions (F1-F4) containing varying chemical classes of increasing polarity. The role of the transient receptor potential (TRP) cation channel TRPA1, a chemical sensor in mammals and zebrafish, in locomotor responses to C-DEP, was also examined. Acrolein, an environmental irritant and known activator of TRPA1, and all extracts induced concentration-dependent locomotor responses whose potencies ranked as follows: polar F3 > weakly polar F2 > C-DEP > highly polar F4 > nonpolar F1, indicating that polar and weakly polar fractions that included nitro- and oxy-polyaromatic hydrocarbons (PAHs), drove C-DEP responses. Irritant potencies in fish positively correlated with mutagenic potencies of the same extracts in strains of Salmonella sensitive to nitro- and oxy-PAHs, further implicating these chemical classes in the zebrafish responses to C-DEP. Pharmacologic inhibition of TRPA1 blocked locomotor responses to acrolein and the extracts. Taken together, these data indicate that the zebrafish locomotor assay may help expedite toxicity screening of fine PM sources, identify causal chemical classes, and uncover plausible biological mechanisms.

Biodiesel made from the transesterification of plant- and animal-derived oils is an important alternative fuel source for diesel engines. Although numerous studies have reported health effects associated with petroleum diesel emissions, information on biodiesel emissions are more limited. To this end, a program at the U.S. EPA assessed health effects of biodiesel emissions in rodent inhalation models. Commercially obtained soybean biodiesel (B100) and a 20% blend with petroleum diesel (B20) were compared to pure petroleum diesel (B0). Rats and mice were exposed independently for 4 h/day, 5 days/week for up to 6 weeks. Exposures were controlled by dilution air to obtain low (50 µg/m(3)), medium (150 µg/m(3)) and high (500 µg/m(3)) diesel particulate mass (PM) concentrations, and compared to filtered air. This article provides details on facilities, fuels, operating conditions, emission factors and physico-chemical characteristics of the emissions used for inhalation exposures and in vitro studies. Initial engine exhaust PM concentrations for the B100 fuel (19.7 ± 0.7 mg/m(3)) were 30% lower than those of the B0 fuel (28.0 ± 1.5 mg/m(3)). When emissions were diluted with air to control equivalent PM mass concentrations, B0 exposures had higher CO and slightly lower NO concentrations than B100. Organic/elemental carbon ratios and oxygenated methyl esters and organic acids were higher for the B100 than B0. Both the B0 and B100 fuels produced unimodal-accumulation mode particle-size distributions, with B0 producing lower concentrations of slightly larger particles. Subsequent papers in this series will describe the effects of these atmospheres on cardiopulmonary responses and in vitro genotoxicity studies.

Modifications to a VITROCELL exposure system were required to mitigate cytotoxicity caused by the absence of temperature and humidity control.

As a result of the challenge of recent dust storms to public health, we tested the postulate that desert dust collected in the southwestern United States imparts a biological effect in respiratory epithelial cells and an animal model. Two samples of surface sediment were collected from separate dust sources in northeastern Arizona. Analysis of the PM20 fraction demonstrated that the majority of both dust samples were quartz and clay minerals (total SiO₂ of 52 and 57%). Using respiratory epithelial and monocytic cell lines, the two desert dusts increased oxidant generation, measured by Amplex Red fluorescence, along with carbon black (a control particle), silica, and NIST 1649 (an ambient air pollution particle). Cell oxidant generation was greatest following exposures to silica and the desert dusts. Similarly, changes in RNA for superoxide dismutase-1, heme oxygenase-1, and cyclooxygenase-2 were also greatest after silica and the desert dusts supporting an oxidative stress after cell exposure. Silica, desert dusts, and the ambient air pollution particle NIST 1649 demonstrated a capacity to activate the p38 and ERK1/2 pathways and release pro-inflammatory mediators. Mice, instilled with the same particles, showed the greatest lavage concentrations of pro-inflammatory mediators, neutrophils, and lung injury following silica and desert dusts. We conclude that, comparable to other particles, desert dusts have a capacity to (1) influence oxidative stress and release of pro-inflammatory mediators in respiratory epithelial cells and (2) provoke an inflammatory injury in the lower respiratory tract of an animal model. The biological effects of desert dusts approximated those of silica.

Background: The cardiopulmonary effects of the individual criteria air pollutants have been well investigated, but little is known about the cardiopulmonary effects of inhaled multipollutant mixtures that more realistically represent environmental exposures. Objectives: We assessed the cardiopulmonary effects of exposure to photochemically altered particle-free multipollutant mixtures. Methods: We exposed mice to filtered air (FA), multipollutant mixtures, or ozone (O3) for 4 hr in a photochemical reaction chamber. Eight hours after exposure, we assessed cardiac responses using a Langendorff preparation in a protocol consisting of 20 min of global ischemia followed by 2 hr of reperfusion. Cardiac function was assessed by measuring the index of left-ventricular developed pressure (LVDP) and contractility (dP/dt) before ischemia. On reperfusion after ischemia, recovery of postischemic LVDP and size of infarct were examined. We used bronchoalveolar lavage (BAL) cell counts to assess lung inflammation. Results: Exposure to the multipollutant mixtures decreased LVDP, baseline rate of left ventricular contraction (dP/dtmaximum), and baseline rate of left ventricular relaxation (dP/dtminimum) compared with exposure to FA. Exposure to O3 also decreased heart rate and dP/dtminimum. Time to ischemic contracture was prolonged in the multipollutant-mixture group relative to that in the FA group. Mice in the multipollutant-mixture group had better recovery of postischemic LVDP and smaller infarct size. Exposure to multipollutant mixtures and to O3 exposure increased numbers of macrophages in the BAL fluid. Conclusions: Exposure to photochemically altered urban air pollution appears to affect cardiac mechanics in isolated perfused hearts. Inhalation of acute multipollutant mixtures decreases LVDP and cardiac contractility in isolated non-ischemic murine hearts, prolongs ischemic contracture, increases postischemic recovery of LVDP, and reduces infarct size. Citation: McIntosh-Kastrinsky R, Diaz-Sanchez D, Sexton KG, Jania CM, Zavala J, Tilley SL, Jaspers I, Gilmour MI, Devlin RB, Cascio WE, Tong H. 2013. Photochemically altered air pollution mixtures and contractile parameters in isolated murine hearts before and after ischemia. Environ Health Perspect 121:1344–1348; http://dx.doi.org/10.1289/ehp.1306609

Several types of diesel exhaust particles (DEPs) have been used for toxicology studies, including a highorganic automobile DEP (A-DEP) from Japan, and a low-organic forklift DEP developed by the National Institute of Standards and Technology (N-DEP). However, these DEPs were not characterized extensively for chemical composition or sub-fractionated and tested extensively for mutagenicity. We collected a compressor-generated DEP (C-DEP) and characterized it by conducting bioassay-directed fractionation of the extractable organics in Salmonella and correlating the results by hierarchical clustering with the concentrations of 32 polycyclic aromatic hydrocarbons (PAHs). Relative to A- and N-DEP, the mutagenic potency of C-DEP was intermediate in TA100 1S9 (PAH mutagenicity) but was lowest in TA98 – S9 (nitroarene mutagenicity). More than 50% of the mass of the extractable organics of C-DEP eluted in the nonpolar fraction 1, and only -20% eluted in the moderately polar Fractions 2 and 3. However, most of the mutagenicity eluted in Fractions 2 and 3, similar to A-DEP but different from N-DEP. HPLC-derived mutagrams of 62 sub-fractions per fraction confirmed that most of the mutagenicity was due to moderately polar compounds. The diagnostic strains identified a strong role for PAHs, nitroarenes, aromatic amines, and oxy-PAHs in the mutagenicity of C-DEP. Hierarchical clustering confirmed the importance of oxy-PAHs but not that of nitroarenes. To our knowledge this is the first use of hierarchical clustering to correlate chemical composition with the mutagenicity of a complex mixture. The chemical analysis and mutagenicity of C-DEP described here makes C-DEP suitable for additional toxicological studies.

Over the past decade, soy biodiesel (BD) has become a first alternative energy source that is economically viable and meets requirements of the Clean Air Act. Due to lower mass emissions and reduced hazardous compounds compared to diesel combustion emissions (CE), BD exposure is proposed to produce fewer adverse health effects. However, considering the broad use of BD and its blends in different industries, this assertion needs to be supported and validated by mechanistic and toxicological data. Here, adverse effects were compared in lungs and liver of BALB/cJ mice after inhalation exposure (0, 50, 150, or 500 μg/m3; 4 h/d, 5 d/wk, for 4 wk) to CE from 100% biodiesel (B100) and diesel (D100). Compared to D100, B100 CE produced a significant accumulation of oxidatively modified proteins (carbonyls), an increase in 4-hydroxynonenal (4-HNE), a reduction of protein thiols, a depletion of antioxidant gluthatione (GSH), a dose-related rise in the levels of biomarkers of tissue damage (lactate dehydrogenase, LDH) in lungs, and inflammation (myeloperoxidase, MPO) in both lungs and liver. Significant differences in the levels of inflammatory cytokines interleukin (IL)-6, IL-10, IL-12p70, monocyte chemoattractant protein (MCP)-1, interferon (IFN) γ, and tumor necrosis factor (TNF)-α were detected in lungs and liver upon B100 and D100 CE exposures. Overall, the tissue damage, oxidative stress, inflammation, and cytokine response were more pronounced in mice exposed to BD CE. Further studies are required to understand what combustion products in BD CE accelerate oxidative and inflammatory responses.

Epidemiological studies have linked exposure to ambient particulate matter (PM) with increased asthmatic symptoms. Diesel exhaust particles (DEP) are a predominant source of vehicle derived ambient PM, and experimental studies have demonstrated that they may have adjuvant potential when given with an antigen. We previously compared 3 DEP samples: N-DEP, A-DEP, and C-DEP in a murine ovalbumin (OVA) mucosal sensitization model and reported the adjuvant activity to be: C-DEP ≍ A-DEP > N-DEP. The present study analyzed gene expression changes from the lungs of these mice. Transcription profiling demonstrated that all the DEP samples altered cytokine and toll-like receptor pathways regardless of type, with or without antigen sensitization. Further analysis of DEP exposure with OVA showed that all DEP treatments altered networks involved in immune and inflammatory responses. The A- and C-DEP/OVA treatments induced differential expression of apoptosis pathways in association with stronger adjuvant responses, while expression of cell cycle control and DNA damage pathways were also altered in the C-DEP/OVA treatment. This comprehensive approach using gene expression analysis to examine changes at a pathway level provides detailed information on events occurring in the lung after DEP exposure, and confirms that the most bioactive sample induced many more individual genes and changes in immunoregulatory and homeostatic pathways.

Emerging evidence suggests environmental chemical exposures during critical windows of development may contribute to the escalating prevalence of obesity. We tested the hypothesis that prenatal air pollution exposure would predispose the offspring to weight gain in adulthood. Pregnant mice were exposed to filtered air (FA) or diesel exhaust (DE) on embryonic days (E) 9-17. Prenatal DE induced a significant fetal brain cytokine response at E18 (46-390% over FA). As adults, offspring were fed either a low-fat diet (LFD) or high-fat diet (HFD) for 6 wk. Adult DE male offspring weighed 12% more and were 35% less active than FA male offspring at baseline, whereas there were no differences in females. Following HFD, DE males gained weight at the same rate as FA males, whereas DE females gained 340% more weight than FA females. DE-HFD males had 450% higher endpoint insulin levels than FA-HFD males, and all males on HFD showed decreased activity and increased anxiety, whereas females showed no differences. Finally, both DE males and females fed HFD showed increased microglial activation (30-66%) within several brain regions. Thus, prenatal air pollution exposure can "program" offspring for increased susceptibility to diet-induced weight gain and neuroinflammation in adulthood in a sex-specific manner.

Biodiesel and biodiesel-blend fuels offer a renewable alternative to petroleum diesel, but few data are available concerning the carcinogenic potential of biodiesel exhausts.We compared the formation of covalent DNA adducts by the in vitro metabolic activation of organic extracts of diesel-exhaust particles (DEP) from petroleum diesel and soy biodiesel and correlated DNA adduct levels and mutagenicity in Salmonella TA100.We examined two different DEP from petroleum diesel (C-DEP and B0), one from soy bean oil biodiesel (B100) and one from combustion of a blend of 20% B100 and 80% B0 (B20) for in vitro DNA adduct-forming potential under oxidative or nitroreductive conditions in the presence of calf thymus DNA as well as in vivo in Salmonella TA100. The modified DNA was hydrolyzed and analyzed by (32)P-postlabeling using either butanol extraction or nuclease P1 pre-enrichment.Multiple DNA adducts were produced with chromatographic mobilities consistent with PAH and nitro-PAH adducts. The types and quantities of DNA adducts produced by the two independent petroleum diesel DEP were similar, with both polycyclic aromatic hydrocarbon (PAH)- and nitro-PAH-derived adducts formed. Relative potencies for S9-mediated DNA adduct formation, either per mass of particulate or per MJ(th) energy consumed were B100 B0 B20.Soy biodiesel emissions induced DNA damage in the form of presumptive PAH and nitro-PAH DNA adducts that correlated with mutagenicity in Salmonella. B20 is the soy biodiesel used most commonly in the US, and it produced the lowest DNA adduct-emission factor, ∼50% that of petroleum diesel.

Context: Soy biodiesel is the predominant biodiesel in the USA, but there is little understanding of the classes of chemicals responsible for the mutagenicity of its emissions. Objective: We determined some of the chemical classes responsible for the mutagenicity of the particulate matter (PM) of the emissions from petroleum diesel (B0) and biodiesel containing increasing concentrations of soy methyl esters (B20, B50, and B100). Materials and methods: We subjected organic extracts of the PM to bioassay-directed fractionation by sequential elution on silica gel with solvents of increasing polarity to produce four fractions per fuel. We injected these onto high performance liquid chromatography to produce 62 sub-fractions per fraction based on chemical polarity and evaluated all fractions and sub-fractions for mutagenicity in Salmonella. We correlated the results with the concentrations of 32 polycyclic aromatic hydrocarbons (PAHs) in the fractions. Results: The mutagenicity-emission factors of the fractions generally decreased with increasing concentrations of soy in the fuel. Despite the different chemical compositions of the fuels, the extractable organics of all four emissions had similar features: ∼60% of the mass was nonpolar, non-mutagenic compounds; most of the PAHs were polar; and most of the mutagenicity was due to weakly polar and polar compounds. Some of the mutagenicity of B20 was due to highly polar compounds. Conclusions: The PM from soy biodiesel emissions was less mutagenic than that from petroleum diesel, and this reduction was associated with reduced concentrations of various weakly polar, polar, and highly polar mutagens, including PAHs, aromatic amines, nitroarenes, and oxy-PAHs.

Diesel exhaust (DE) has been shown to increase the risk of cardiac arrhythmias. Although biodiesel has been proposed as a "safer" alternative to diesel, it is still uncertain whether it actually poses less threat.We hypothesized that exposure to pure or 20% soy biodiesel exhaust (BDE) would cause less sensitivity to aconitine-induced arrhythmia than DE in rats.Spontaneously hypertensive (SH) rats implanted with radiotelemeters were exposed once or for 5 d (4 h) to either 50 mg/m(3) (low), 150 mg/m(3) (medium), or 500 mg/m(3) (high) of DE (B0), 20% (B20) or 100% (B100) soy biodiesel exhaust. Arrhythmogenesis was assessed 24 h later by continuous infusion of aconitine, an arrhythmogenic drug, while heart rate (HR), and electrocardiogram (ECG) were monitored.Rats exposed once or for 5 d to low, medium, or high B0 developed arrhythmia at significantly lower doses of aconitine than controls, whereas rats exposed to B20 were only consistently sensitive after 5 d of the high concentration. B100 caused mild arrhythmia sensitivity at the low concentration, only after 5 d of exposure at the medium concentration and after either a single or 5 d at the high concentration.These data demonstrate that exposure to B20 causes less sensitivity to arrhythmia than B0 and B100. This diminished effect may be due to lower irritant components such as acrolein and nitrogen oxides. Thus, in terms of cardiac health, B20 may be a safer option than both of the pure forms.

Increased use of renewable energy sources raise concerns about health effects of new emissions. We analyzed relative cardiopulmonary health effects of exhausts from (1) 100% soy biofuel (B100), (2) 20% soy biofuel + 80% low sulfur petroleum diesel (B20), and (3) 100% petroleum diesel (B0) in rats. Normotensive Wistar–Kyoto (WKY) and spontaneously hypertensive rats were exposed to these three exhausts at 0, 50, 150 and 500 μg/m3, 4 h/day for 2 days or 4 weeks (5 days/week). In addition, WKY rats were exposed for 1 day and responses were analyzed 0 h, 1 day or 4 days later for time-course assessment. Hematological parameters, in vitro platelet aggregation, bronchoalveolar lavage fluid (BALF) markers of pulmonary injury and inflammation, ex vivo aortic ring constriction, heart and aorta mRNA markers of vasoconstriction, thrombosis and atherogenesis were analyzed. The presence of pigmented macrophages in the lung alveoli was clearly evident with all three exhausts without apparent pathology. Overall, exposure to all three exhausts produced only modest effects in most endpoints analyzed in both strains. BALF γ-glutamyl transferase (GGT) activity was the most consistent marker and was increased in both strains, primarily with B0 (B0 > B100 > B20). This increase was associated with only modest increases in BALF neutrophils. Small and very acute increases occurred in aorta mRNA markers of vasoconstriction and thrombosis with B100 but not B0 in WKY rats. Our comparative evaluations show modest cardiovascular and pulmonary effects at low concentrations of all exhausts: B0 causing more pulmonary injury and B100 more acute vascular effects. BALF GGT activity could serve as a sensitive biomarker of inhaled pollutants.

Engineered carbon nanotubes are being developed for a wide range of industrial and medical applications. Because of their unique properties, nanotubes can impose potentially toxic effects, particularly if they have been modified to express functionally reactive chemical groups on their surface. The present study was designed to evaluate whether acid functionalization (AF) enhanced the cardiopulmonary toxicity of single-walled carbon nanotubes (SWCNT) as well as control carbon black particles. Mice were exposed by oropharyngeal aspiration to 10 or 40 microg of saline-suspended single-walled carbon nanotubes (SWCNTs), acid-functionalized SWCNTs (AF-SWCNTs), ultrafine carbon black (UFCB), AF-UFCB, or 2 microg LPS. 24 hours later, pulmonary inflammatory responses and cardiac effects were assessed by bronchoalveolar lavage and isolated cardiac perfusion respectively, and compared to saline or LPS-instilled animals. Additional mice were assessed for histological changes in lung and heart. Instillation of 40 microg of AF-SWCNTs, UFCB and AF-UFCB increased percentage of pulmonary neutrophils. No significant effects were observed at the lower particle concentration. Sporadic clumps of particles from each treatment group were observed in the small airways and interstitial areas of the lungs according to particle dose. Patches of cellular infiltration and edema in both the small airways and in the interstitium were also observed in the high dose group. Isolated perfused hearts from mice exposed to 40 microg of AF-SWCNTs had significantly lower cardiac functional recovery, greater infarct size, and higher coronary flow rate than other particle-exposed animals and controls, and also exhibited signs of focal cardiac myofiber degeneration. No particles were detected in heart tissue under light microscopy. This study indicates that while acid functionalization increases the pulmonary toxicity of both UFCB and SWCNTs, this treatment caused cardiac effects only with the AF-carbon nanotubes. Further experiments are needed to understand the physico-chemical processes involved in this phenomenon.