Serum cytokine levels related to exposure to volatile organic compounds and PM2.5 in dwellings and workplaces in French farmers - a mechanism to explain nonsmoking COPD

On the dose-response association of fine and ultrafine particles in an urban atmosphere: toxicological outcomes on bronchial cells at realistic doses of exposure at the Air Liquid Interface

Air pollution and particulate matter (PM) are the leading environmental cause of death worldwide. Exposure limits have lowered to increase the protection of human health; accordingly, it becomes increasingly important to understand the toxicological mechanisms on cellular models at low airborne PM concentrations which are relevant for actual human exposure. The use of air liquid interface (ALI) models, which mimic the interaction between airborne pollutants and lung epithelia, is also gaining importance in inhalation toxicological studies. This study reports the effects of ALI direct exposure of bronchial epithelial cells BEAS-2B to ambient PM1 (i.e. particles with aerodynamic diameter lower than 1 μm). Gene expression (HMOX, Cxcl-8, ATM, Gadd45-a and NQO1), interleukin (IL)-8 release, and DNA damage (Comet assay) were evaluated after 24 h of exposure. We report the dose-response curves of the selected toxicological outcomes, together with the concentration-response association and we show that the two curves differ for specific responses highlighting that concentration-response association may be not relevant for understanding toxicological outcomes. Noteworthy, we show that pro-oxidant effects may be driven by the deposition of freshly emitted particles, regardless of the airborne PM1 mass concentration. Furthermore, we show that reference airborne PM1 metrics, namely airborne mass concentration, may not always reflect the toxicological process triggered by the aerosol. These findings underscore the importance of considering different aerosol metrics to assess the toxicological potency of fine and ultrafine particles. To better protect human health additional metrics should be defined, than account for the properties of the entire aerosol mixture including specific as particle size (i.e. particles with aerodynamic diameter lower than 20 nm), the relevant aerosol sources (e.g., traffic combustion, secondary organic aerosol …) as well as their atmospheric processing (freshly emitted vs aged ones).

NMR-based metabolomics for investigating urinary profiles of metal carpentry workers exposed to welding fumes and volatile organic compounds

Introduction

Metal carpentry includes a wide range of work activities such as welding and cutting metallic components, use of solvents and paints. Therefore, the employees in these types of activities are mainly exposed to welding fumes and volatile organic solvents. Here, we present an NMR-based metabolomic approach for assessing urinary profiles of workers in the same company that are exposed to two different risk factors.

Methods

The study enrolled 40 male subjects exposed to welding fumes, 13 male subjects exposed to volatile organic compounds of a metal carpentry company, and 24 healthy volunteers. All samples were collected, in the middle of the working week at fast. Thirty-five urinary metabolites belonging to different chemical classes such as amino acids, organic acids and amines were identified and quantified. Results were processed by multivariate statistical analysis for identifying significant metabolites for each working group examined, compared to controls.

Results

Workers exposed to welding fumes displayed urinary increase in glutamine, tyrosine, taurine, creatine, methylguanidine and pseudouridine associated to oxidative impairment, while workers exposed to volatile organic compounds showed higher urinary levels of branched chain aminoacids.

Conclusion

Our work identified specific urinary profile related to each occupational exposure, even if it is below the threshold limit values.

The role of liver enzymes in the association between ozone exposure and diabetes risk: a cross-sectional study of Zhuang adults in China

Background: Growing evidence has demonstrated the role of ambient air pollutants in driving diabetes incidence. However, epidemiological evidence linking ozone (O3) exposure to diabetes risk has been scarcely studied in Zhuang adults in China. We aimed to investigate the associations of long-term exposure to O3 with diabetes prevalence and fasting plasma glucose (FPG) and estimate the mediating role of liver enzymes in Zhuang adults. Methods: We recruited 13 843 ethnic minority adults during 2018-2019 based on a cross-sectional study covering nine districts/counties in Guangxi. Generalized linear mixed models were implemented to estimate the relationships between O3 exposure and diabetes prevalence and FPG. Mediation effect models were constructed to investigate the roles of liver enzymes in the associations of O3 exposure with diabetes prevalence and FPG. Subgroup analyses were conducted to identify potential effect modifications. Results: Long-term exposure to O3 was positively associated with diabetes prevalence and FPG levels in Zhuang adults, with an excess risk of 7.32% (95% confidence interval [CI]: 2.56%, 12.30%) and an increase of 0.047 mmol L-1 (95% CI: 0.032, 0.063) for diabetes prevalence and FPG levels, respectively, for each interquartile range (IQR, 1.18 μg m-3) increment in O3 concentrations. Alanine aminotransferase (ALT) significantly mediated 8.10% and 29.89% of the associations of O3 with FPG and diabetes prevalence, respectively, and the corresponding mediation proportions of alkaline phosphatase (ALP) were 8.48% and 30.00%. Greater adverse effects were observed in females, obese subjects, people with a low education level, rural residents, non-clean fuel users, and people with a history of stroke and hypertension in the associations of O3 exposure with diabetes prevalence and/or FPG levels (all P values for interaction < 0.05). Conclusion: Long-term exposure to O3 is related to an increased risk of diabetes, which is partially mediated by liver enzymes in Chinese Zhuang adults. Promoting clean air policies and reducing exposure to environmental pollutants should be a priority for public health policies geared toward preventing diabetes.

Unlocking the secrets: Volatile Organic Compounds (VOCs) and their devastating effects on lung cancer

Lung cancer (LCs) is still a serious health problem globally, with many incidences attributed to environmental triggers such as Volatile Organic Compounds (VOCs). VOCs are a broad class of compounds that can be released via various sources, including industrial operations, automobile emissions, and indoor air pollution. VOC exposure has been linked to an elevated risk of lung cancer via multiple routes. These chemicals can be chemically converted into hazardous intermediate molecules, resulting in DNA damage and genetic alterations. VOCs can also cause oxidative stress, inflammation, and a breakdown in the cellular protective antioxidant framework, all of which contribute to the growth of lung cancer. Moreover, VOCs have been reported to alter critical biological reactions such as cell growth, apoptosis, and angiogenesis, leading to tumor development and metastasis. Epidemiological investigations have found a link between certain VOCs and a higher probability of LCs. Benzene, formaldehyde, and polycyclic aromatic hydrocarbons (PAHs) are some of the most well-researched VOCs, with comprehensive data confirming their cancer-causing potential. Nevertheless, the possible health concerns linked with many more VOCs and their combined use remain unknown, necessitating further research. Identifying the toxicological consequences of VOCs in LCs is critical for establishing focused preventative tactics and therapeutic strategies. Better legislation and monitoring mechanisms can limit VOC contamination in occupational and environmental contexts, possibly reducing the prevalence of LCs. Developing VOC exposure indicators and analyzing their associations with genetic susceptibility characteristics may also aid in early identification and targeted therapies.

Serum metabolome responses induced by long-term inoculation of suspended PM2.5 in chicken

The adverse effects of exposure to fine particulate matter (PM2.5) on body health have attracted global public attention. However, there is limited research on PM2.5 in animal houses. Numerous studies have indicated that long-term exposure to high levels of PM2.5 can cause damage to multiple systems in animals. Poultry houses are one of the primary sources of PM2.5 emissions. However, there is limited research on the effects of PM2.5 exposure on poultry organisms. This study analyzed the histopathological changes in the lung tissue of poultry under PM2.5 exposure conditions. It used the LC-MS method to analyze the alterations in the serum metabolomic profile of poultry. This study confirmed that long-term exposure to high levels of PM2.5 had significantly reduced the growth performance of poultry. Histopathological slides of the lung tissue in chickens exposed to long-term retention of PM2.5 clearly showed significant damage. Furthermore, the serum metabolome analysis revealed significant changes in the serum metabolic profile of chickens exposed to long-term PM2.5 exposure. Specifically, there were notable alterations in the Glycerophospholipid metabolism, Steroid hormone biosynthesis, and Phenylalanine, tyrosine, and tryptophan biosynthesis pathways.

Evaluation of genotoxicity, oxidative stress and immune parameters of auto-paint workers

The automotive industry is a very wide area from the manufacturing of the pieces of the engine, the body, plastics to the assembly of the car. There is a chemical risk at different stages of production because of the requirement of the use of many corrosive and irritant chemicals such as paints, adhesives, acids, and bases. The aim of the study was to determine the genotoxicity, oxidative stress and immune parameters of automotive paint workers in Ankara, Türkiye. DNA damage of workers mainly responsible from the painting of the automotives were evaluated using the alkaline comet assay and the levels of some oxidative stress and immune biomarkers were also investigated. Increased lymphocyte DNA damage and also higher 8-hydroxy-2'-deoxyguanosine (8-OHdG) and malondialdehyde (MDA) levels were observed while decreased glutathione (GSH), glutathione peroxidase (GPx), and glutathione reductase (GR) levels were found in the workers compared to their controls There were no significant differences between the study groups in the levels of interleukin (IL)- 1beta, IL-17, IL-23, Clara cell secretory protein (CC16), tumor necrosis factor-alpha (TNF-alpha), catalase (CAT), and superoxide dismutase (SOD). The results show that occupational exposure to chemicals in automotive industry may cause DNA damage in workers due to oxidative stress.

Effects of different laying periods on airborne bacterial diversity and antibiotic resistance genes in layer hen houses

Poultry farms are a complex environment for close contact between humans and animals. Accumulating evidence has indicated that pathogens and drug resistance genes in chicken houses may pose a serious threat to public health and economic concerns. However, insufficient knowledge of the indoor aerosol microbiome and resistome profiles of layer hen houses hampers the understanding of their health effects. Environmental surveillance of antibiotic resistance may contribute to a better understanding and management of the human exposure risk of bioaerosols under the environmental conditions of chicken houses. In addition, the chicken house has a long operation cycle, and the bacterial diversity and antibiotic resistance genes of aerosols in different periods may be different. In this study, air samples were collected from 18 chicken houses on three farms, including the early laying period (EL), peak laying period (PL), and late laying period (LL). 16S rRNA gene sequencing and metagenomics were used to study the composition of the bacteria and resistome in aerosols of layer hen houses and the results showed that they varied with laying period. The highest alpha diversity of bacteria was observed in PL bioaerosols. The dominant bacterial phyla included Firmicutes, Bacteroidetes and Proteobacteria. Three potential pathogenic bacterial genera (Bacteroides, Corynebacterium and Fusobacterium) were found. The most abundant ARG type was aminoglycosides in all laying periods. In total, 22 possible ARG host genera were detected. ARG subtypes and abundance were both higher in LL. Network analysis also showed higher co-occurrence patterns between the bacteria and resistome in bioaerosols. The laying period plays an important role in the bacterial community and resistome in layer house aerosols.

Short-term effects of the toxic component of traffic-related air pollution (TRAP) on lung function in healthy adults using a powered air purifying respirator (PAPR)

Short-term exposure to traffic-related air pollution (TRAP) are associated with reduced lung function. However, TRAP is a mixture of various gaseous pollutants and particulate matter (PM), and therefore it is unknown that which components of TRAP are responsible for the respiratory toxicity. Using a powered air-purifying respirator (PAPR), we conducted a randomized, double-blind, crossover trial in which 40 adults were exposed to TRAP for 2 h at the sidewalk of a busy road. During the exposure, the participants wore the PAPR fitted with a PM filter, a PM and volatile organic compounds (VOCs) filter, or a sham filter (no filtration, Sham mode). The participants were blinded to the type of filter in their PAPR, and experienced three exposures, once for each intervention mode in random order. We measured two lung function measures (forced expiratory volume in 1 s [FEV1] and forced vital capacity [FVC]) and an airway inflammation marker (fraction of exhaled nitric oxide [FE_NO]) before and immediately after each exposure, and further measured them at different time periods after exposure. We applied linear mixed effect models to estimate the effects of the interventions on the changes of lung function from baseline values after controlling for other covariates. Compared to baseline, exposing to TRAP decreased FEV1 and FVC, and increased FEV1/FVC and FE_NO in all three intervention modes. The mixed models showed that with the sham mode as reference, lung function and airway inflammation post exposure were significantly improved by filtering both PM and VOCs, but marginally affected by filtering only PM. In conclusion, the VOCs component of TRAP is responsible for the reduction in lung function caused by short-term exposure to TRAP. However, the result needs to be interpreted cautiously before further verified by laboratory experiment using purely isolated component(s) of TRAP.

Acute effects of ambient non-methane hydrocarbons on cardiorespiratory hospitalizations: A multicity time-series study in Taiwan

BACKGROUND

Few environmental epidemiological studies and no large multicity studies have evaluated the acute short-term health effects of ambient non-methane hydrocarbons (NMHC), the essential precursors of ground-level ozone and secondary organic aerosol formation.

OBJECTIVE

We conducted this multicity time-series study in Taiwan to evaluate the association between airborne NMHC exposure and cardiorespiratory hospital admissions.

METHODS

We collected the daily mean concentrations of NMHC, fine particulate matter (PM2.5), ozone (O3), weather conditions, and daily hospital admission count for cardiorespiratory diseases between 2014 and 2017 from eight major cities of Taiwan. We applied an over-dispersed generalized additive Poisson model (GAM) with adjustment for temporal trends, seasonal variations, weather conditions, and calendar effects to compute the effect estimate for each city. Then we conducted a random-effects meta-analysis to pool the eight city-specific effect estimates to obtain the overall associations of NMHC exposure on lag0 day with hospital admissions for respiratory and circulatory diseases, respectively.

RESULTS

On average, a 0.1-ppm increase of lag0 NMHC demonstrated an overall 0.9% (95% CI: 0.4-1.3%) and 0.8% (95% CI: 0.4-1.2%) increment of hospital admissions for respiratory and circulatory diseases, respectively. Further analyses with adjustment for PM2.5 and O3 in the multi-pollutant model or sensitivity analyses with restricting the NMHC monitoring from the general stations only confirmed the robustness of the association between ambient NMHC exposure and cardiorespiratory hospitalizations.

CONCLUSION

Our findings provide robust evidence of higher cardiorespiratory hospitalizations in association with acute exposure to ambient NMHC in eight major cities of Taiwan.

Biomarkers for the adverse effects on respiratory system health associated with atmospheric particulate matter exposure

Large amounts of epidemiological evidence have confirmed the atmospheric particulate matter (PM_2.5) exposure was positively correlated with the morbidity and mortality of respiratory diseases. Nevertheless, its pathogenesis remains incompletely understood, probably resulting from the activation of oxidative stress, inflammation, altered genetic and epigenetic modifications in the lung upon PM_2.5 exposure. Currently, biomarker investigations have been widely used in epidemiological and toxicological studies, which may help in understanding the biologic mechanisms underlying PM_2.5-elicited adverse health outcomes. Here, the emerging biomarkers to indicate PM_2.5-respiratory system interactions were summarized, primarily related to oxidative stress (ROS, MDA, GSH, etc.), inflammation (Interleukins, FE_NO, CC16, etc.), DNA damage (8-OHdG, γH2AX, OGG1) and also epigenetic modulation (DNA methylation, histone modification, microRNAs). The identified biomarkers shed light on PM_2.5-elicited inflammation, fibrogenesis and carcinogenesis, thus may favor more precise interventions in public health. It is worth noting that some inconsistent findings may possibly relate to the inter-study differentials in the airborne PM_2.5 sample, exposure mode and targeted subjects, as well as methodological issues. Further research, particularly by -omics technique to identify novel, specific biomarkers, is warranted to illuminate the causal relationship between PM_2.5 pollution and deleterious lung outcomes.

Inflammation-associated pulmonary microbiome and metabolome changes in broilers exposed to particulate matter in broiler houses

The particulate matter (PM) in livestock houses, one of the primary sources of atmospheric PM, is not only detrimental to the respiratory health of animals and farmworkers but also poses a threat to the public environment and public health and warrants increased attention. In this study, we investigated the variation in the pulmonary microbiome and metabolome in broiler chickens exposed to PM collected from a broiler house. We examined the pulmonary microbiome and metabolome in broilers, observing that PM induced a visible change in α and β diversity. A total of 66 differential genera, including unclassified_f_Ruminococcaceae and Campylobacter, were associated with pulmonary inflammation. Untargeted metabolomics was utilised to identify 63 differential metabolites induced by PM and correlated with differential bacteria. We observed that PM resulted in injury of the broiler lung and disruption of the microbial community, as well as causing changes in the observed metabolites. These results imply that perturbations to the microbiome and metabolome may play pivotal roles in the mechanism underlying PM-induced broiler lung damage.

Epidemiological evidence relating risk factors to chronic obstructive pulmonary disease in China: A systematic review and meta-analysis

BACKGROUND

Chronic obstructive pulmonary disease (COPD), the most common chronic respiratory disease worldwide, not only leads to the decline of pulmonary function and quality of life consecutively, but also has become a major economic burden on individuals, families, and society in China. The purpose of this meta-analysis was to explore the risk factors for developing COPD in the Chinese population that resides in China and to provide a theoretical basis for the early prevention of COPD.

METHODS

A total of 2457 cross-sectional, case-control, and cohort studies published related to risk factors for COPD in China were searched. Based on the inclusion and exclusion criteria, 20 articles were selected. Stata 11.0 was used for meta-analysis. After merging the data, the pooled effect and 95% confidence intervals (CIs) were calculated to assess the association between risk factors and COPD. Heterogeneity between studies was assessed using I2 and Cochran's Q tests. Begg's test was used to assess publication bias.

RESULTS

Exposure to particulate matter less than 2.5 μm in diameter (PM2.5) (pooled effect = 1.73; 95%CI: 1.16~2.58; P <0.01), smoking history (pooled effect = 2.58; 95%CI: 2.00~3.32; P <0.01), passive smoking history (pooled effect = 1.39; 95%CI: 1.03~1.87; P = 0.03), male sex(pooled effect = 1.70; 95%CI: 1.31~2.22; P <0.01), body mass index (BMI) <18.5 kg/m2 (pooled effect = 1.73; 95%CI: 1.32~2.25; P <0.01), exposure to biomass burning emissions (pooled effect = 1.65; 95%CI: 1.32~2.06; P <0.01), childhood respiratory infections (pooled effect = 3.44; 95%CI: 1.33~8.90; P = 0.01), residence (pooled effect = 1.24; 95%CI: 1.09~1.42; P <0.01), and a family history of respiratory diseases (pooled effect = 2.04; 95%CI: 1.53~2.71; P <0.01) were risk factors for COPD in the Chinese population.

CONCLUSION

Early prevention of COPD could be accomplished by quitting smoking, reducing exposure to air pollutants and biomass burning emissions, maintaining body mass index between 18.5 kg/m2 and 28 kg/m2, protecting children from respiratory infections, adopting active treatments to children with respiratory diseases, and conducting regular screening for those with family history of respiratory diseases.

Toxicological impact of organic ultrafine particles (UFPs) in human bronchial epithelial BEAS-2B cells at air-liquid interface

Air pollution has significant health effects worldwide, and airborne particles play a significant role in these effects. Ultrafine particles (UFPs) have an aerodynamic diameter of 0.1 μm or less, can penetrate deep into the respiratory tree, and are more toxic due to their large specific surface area, which should adsorb organic compounds. The aim of this study is to show the toxicological effects of UFPs with high organic content at low dose on BEAS-2B cells through at air-liquid interface (ALI) exposure using a Vitrocell® technology and a miniCAST (Combustion Aerosol Standard) generator. In conjunction with this approach, chemical analysis of particles and gas phase was performed to evaluate the presence of polycyclic aromatic hydrocarbons (PAHs). Chemical analyses confirmed the presence of PAHs in UFPs. With this experimental setup, exposure of the BEAS-2B cells induced neither cytotoxicity nor mitochondrial dysfunction. However, an increase of oxidative stress was observed, as assessed through Nrf2, NQO1, HO-1, CuZnSOD, MnSOD, and Catalase gene expression, together with significant induction of genes related to xenobiotic metabolism CYP1A1 and CYP1B1. Negative regulation of inflammatory genes expression (IL-6 and IL-8) was present three hours after the exposition to the UFPs. Taken together, this experimental approach, using repeatable conditions, should help to clarify the mechanisms by which organic UFPs induce toxicological effects.

Estimating Occupational Exposure to VOCs, SVOCs, Particles and Participant Survey Reported Symptoms in Central Thailand Rice Farmers Using Multiple Sampling Techniques

Thailand is known for its agricultural productivity and rice exportation. Most farms use small machines and manual labor, creating potential exposure to multiple health hazards. A cross-sectional study was conducted to measure pollutants liberated during preparation, pesticide application, and harvesting. Thirty rice farmers, mostly males from 41 to 50 years old, participated. The participant survey data showed that 53.3% of the respondents spent >2 h per crop on preparation, <1 h on pesticide application, and about 1-2 h harvesting; 86.7% of the respondents maintained and stored mechanical applicators at home, suggesting possible after-work exposures. Gloves, fabric masks, boots, and hats were worn during all activities, and >90% wore long sleeved shirts and pants. VOCs and SVOCs were collected using charcoal tubes and solid phase micro sample extraction (SPME). An analysis of the charcoal and SPME samplers found that 30 compounds were detected overall and that 10 were in both the charcoal tubes and SPME samplers. The chemicals most often detected were 1, 1, 1 Trichloro ethane and xylene. Additionally, farmers experienced the highest exposure to particulates during harvesting. These results demonstrated that farmers experience multiple exposures while farming and that risk communication with education or training programs may mitigate exposure.

Association of cardiorespiratory hospital admissions with ambient volatile organic compounds: Evidence from a time-series study in Taipei, Taiwan

As important precursors of ozone and secondary organic aerosols, the harmful impact of exposure to ambient volatile organic compounds (VOCs) is of public health interest. However, few studies have investigated the health risks of numerous individual VOC species. This study linked the daily concentrations of 54 C2-C11 VOC species monitored from the Wanhua Photochemical Assessment Monitoring Station and hospital admissions for cardiorespiratory diseases in Taipei, Taiwan, from the National Health Insurance Research Database. A standard time-series approach entailing a series of sensitivity analyses was applied to investigate the short-term health risks of exposure to VOC subgroups and species. Consistent associations of all VOC subgroups and main species with chronic obstructive pulmonary disease (COPD) hospitalizations were demonstrated. In addition, associations of the C5-C6 alkanes, C2-C3 alkenes, toluene, and xylene with asthma hospitalizations were found, as were associations of aromatic hydrocarbons with hospitalizations for heart failure. An interquartile range increase in total VOC exposure at lag0 day (102.6 parts per billion carbon) was associated with increments of 1.84% (95% confidence interval: 0.54%-3.15%), 1.65% (0.71%-2.60%), and 1.21% (0.36%-2.07%) in hospitalizations for asthma, COPD, and heart failure, respectively. The effect estimates were robust with data excluding extreme values, the second pollutant adjustment for PM_2.5 and O₃, and the Bonferroni correction. The associations of ambient VOC exposure with cardiorespiratory hospitalizations in Taipei serve as a reference for VOC regulations and ozone control strategies.

Assessing PM2.5-associated risk of hospitalization for COPD: an application of daily excessive concentration hours

Existing PM2.5-morbidity studies using daily mean concentration as exposure metric may fail to capture intra-day variations of PM2.5 concentrations, resulting in underestimated health impacts to some extent. This study introduced a novel indicator, daily excessive concentration hours (DECH), defined as sums of per-hourly excessive concentrations of PM2.5 against a specific threshold within a day. PM2.5 DECHs were separately calculated as daily concentration-hours >8, 10, 15, 20, and 25 μg/m3 (abbreviations: DECH-8, DECH-10, DECH-15, DECH-20, and DECH-25). We adopted a time-stratified case-crossover design with conditional logistic regression models to compare risks of hospitalizations for chronic obstructive pulmonary disease (COPD) associated with PM2.5 mean and DECHs in Shenzhen, China. We observed highly comparable PM2.5-COPD associations using exposure metrics of daily mean and DECHs with above-defined thresholds. For instance, PM2.5 mean and DECHs showed similar increases in risks of COPD hospitalization for an interquartile range rise in exposure, with odds ratio estimates of 1.26 (95% confidence interval: 1.06-1.50) for PM2.5 mean, 1.24 (1.05-1.46) for DECH-10 and 1.21 (1.06-1.39) for DECH-25, respectively. Findings remained robust after further adjusting for gaseous pollutants (e.g., SO2, NO2, CO, and O3) and meteorologic factors (e.g., wind speed and air pressure). Our study strengthened the evidence that DECHs could come be as a novel exposure metric in health risk assessments associated with short-term exposure to ambient PM2.5.

Environmental and Genetic Factors in the Pathogenesis of COPD in the Road-Working Population

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a typical heterogeneous condition caused by environmental and genetic risk factors.

OBJECTIVES

We investigated extrinsic (environmental) and intrinsic (genetic) factors contributing to the development of COPD in a nonsmoker road-working population in Northeast China.

METHOD

The target population was divided into a COPD group and an exposed control group. Another healthy nonroad working nonsmoker control group was also included for environmental factor comparison. Peripheral blood was collected and analyzed using inductively coupled plasma mass spectrometry for inorganic elements of PM2.5, and microarray, rt-PCR, and Multiplex ELISA for genetic factors.

RESULTS

Forty-three COPD road workers, thirty-nine non-COPD road workers, and 52 age and gender-matched healthy nonroad workers were enrolled. There were significantly higher levels in all 24 inorganic elements in the COPD group compared with the healthy control group except potassium and manganese, while the majority of inorganic elements were similar between the COPD group and the exposed control group except in aluminum and cobalt. There were 39 genes showing significant differences between the COPD group and the exposed control group. Collagen, type XV, alpha 1 (COL15A1), Meis homeobox 1 (MEIS1), carbonyl reductase 3 (CBR3), and amine oxidase, copper containing 3 (AOC3) were confirmed by rt-PCR to be differentially expressed. Their correlations with blood cytokines were also evaluated.

CONCLUSIONS

Aluminum might contribute to the development of COPD in the road-working population. CBR3 and AOC3 seem expressed in different patterns than previously reported, evidenced by their correlation with proinflammatory and anti-inflammatory cytokines.

A Narrative Review of Occupational Air Pollution and Respiratory Health in Farmworkers

The agricultural crop sector in the United States depends on migrant, seasonal, and immigrant farmworkers. As an ethnic minority group in the U.S. with little access to health care and a high level of poverty, farmworkers face a combination of adverse living and workplace conditions, such as exposure to high levels of air pollution, that can place them at a higher risk for adverse health outcomes including respiratory infections. This narrative review summarizes peer-reviewed original epidemiology research articles (2000-2020) focused on respirable dust exposures in the workplace and respiratory illnesses among farmworkers. We found studies (n = 12) that assessed both air pollution and respiratory illnesses in farmworkers. Results showed that various air pollutants and respiratory illnesses have been assessed using appropriate methods (e.g., personal filter samplers and spirometry) and a consistent pattern of increased respiratory illness in relation to agricultural dust exposure. There were several gaps in the literature; most notably, no study coupled occupational air exposure and respiratory infection among migrant, seasonal and immigrant farmworkers in the United States. This review provides an important update to the literature regarding recent epidemiological findings on the links between occupational air pollution exposures and respiratory health among vulnerable farmworker populations.

Emerging role of mitochondria in airborne particulate matter-induced immunotoxicity

The immune system is one of the primary targets of airborne particulate matter. Recent evidence suggests that mitochondria lie at the center of particulate matter-induced immunotoxicity. Particulate matter can directly interact with mitochondrial components (proteins, lipids, and nucleic acids) and impairs the vital mitochondrial processes including redox mechanisms, fusion-fission, autophagy, and metabolic pathways. These disturbances impede different mitochondrial functions including ATP production, which acts as an important platform to regulate immunity and inflammatory responses. Moreover, the mitochondrial DNA released into the cytosol or in the extracellular milieu acts as a danger-associated molecular pattern and triggers the signaling pathways, involving cGAS-STING, TLR9, and NLRP3. In the present review, we discuss the emerging role of mitochondria in airborne particulate matter-induced immunotoxicity and its myriad biological consequences in health and disease.

Direct and Oxidative DNA Damage in a Group of Painters Exposed to VOCs: Dose - Response Relationship

Volatile organic compounds (VOCs) are present in several working activities. This work is aimed at comparing oxidative stress and DNA damage biomarkers to specific VOCs in the occupational exposure of painters. Dose-response relationships between biomarkers of oxidative stress and of dose were studied. Unmetabolized VOCs and their urinary metabolites were analyzed. Urinary Methylhyppuric acids (MHIPPs, xylenes metabolite), Phenylglyoxylic and Mandelic acid (PGA, MA ethylbenzene metabolites), S-Benzylmercapturic acid (SBMA, toluene metabolite), and S-Phenylmercapturic acid (SPMA, benzene metabolite) were quantified at the end of work-shift. Oxidative stress was determined by: urinary excretion of 8-oxodGuo, 8-oxoGua and 8-oxoGuo and direct/oxidative DNA damage in blood by Fpg-Comet assay. Multivariate linear regression models were used to assess statistical significance of the association between dose and effect biomarkers. The regressions were studied with and without the effect of hOGG1 and XRCC1 gene polymorphisms. Statistically significant associations were found between MHIPPs and both 8-oxoGuo and oxidative DNA damage effect biomarkers measured with the Comet assay. Oxidative DNA damage results significantly associated with airborne xylenes and toluene, whilst 8-oxodGuo was significantly related to urinary xylenes and toluene. Direct DNA damage was significantly associated to SBMA. XRCC1 wild-type gene polymorphism was significantly associated with lower oxidative and total DNA damage with respect to heterozygous and mutant genotypes. The interpretation of the results requires some caution, as the different VOCs are all simultaneously present in the mixture and correlated among them.

Gender differences in respiratory health outcomes among farming cohorts around the globe: findings from the AGRICOH consortium

Purpose: Respiratory hazards of farming have been identified for centuries, with little focus on gender differences. We used data from the AGRICOH consortium, a collective of prospective cohorts of agricultural workers, to assess respiratory disease prevalence among adults in 18 cohorts representing over 200,000 farmers, farm workers, and their spouses from six continents.Methods: Cohorts collected data between 1992 and 2016 and ranged in size from 200 to >128,000 individuals; 44% of participants were female. Farming practices varied from subsistence farming to large-scale industrial agriculture. All cohorts provided respiratory outcome information for their cohort based on their study definitions. The majority of outcomes were based on self-report using standard respiratory questionnaires; the greatest variability in assessment methods was associated with chronic obstructive pulmonary disease (COPD).Results: For all three respiratory symptoms (cough, phlegm, and wheeze), the median prevalence in men was higher than in women, with the greatest difference for phlegm (17% vs. 10%). For asthma, women had a higher prevalence (7.8% vs 6.5%), with the difference associated with allergic asthma. The relative proportion of allergic asthma varied among cohorts. In two of eight cohorts for women and two of seven cohorts for men, allergic asthma was more common than non-allergic asthma.Conclusions: These findings indicate that respiratory outcomes are common among farmers around the world despite differences in agricultural production. As women in the general population are at higher risk of asthma, exploring gender differences in occupational studies is critical for a deeper understanding of respiratory disease among agricultural workers.

Seasonal variations of microbial assemblage in fine particulate matter from a nursery pig house

The microorganisms contained in PM_2.5 from livestock houses can spread over long distances through airborne transmission. As such, the potential bacterial pathogens and fungal allergens within can pose a formidable threat to nearby residents' health and the overall environment. However, little is known about the microbial assemblage contained in PM_2.5 from pig houses. In this study, 16S and 18S rRNA gene sequencing was employed to analyze the bacterial and fungal assemblage contained in PM_2.5 from a nursery pig house across four seasons, respectively. The results showed that alpha diversity was higher in summer and autumn compared to the spring and winter. The bacterial and fungal assemblage varied according to season. At the phylum level, the dominant bacteria and fungi were Firmicutes and Basidiomycota, respectively, across the four seasons. At the genus level, a total of five potential bacterial pathogen and 20 potential fungal allergen genera were identified across the samples. The most abundant bacterial pathogen and fungal allergen genera were observed in summer and autumn, respectively, but neither had a significant correlation with PM_2.5 concentration. Moreover, microbial diversity and the relative abundance of fungal allergen genera were positively correlated with temperature and relative humidity. It can be concluded that microbial diversity and assemblage varied significantly among the seasons in a nursery pig house, and this can be useful in exploring the potential risks of PM_2.5 from pig houses across all four seasons.

Indoor exposure to particulate matter and volatile organic compounds in dwellings and workplaces and respiratory health in French farmers

Introduction

Few investigations have related objective assessments of indoor air pollutants to respiratory health in farmers, in spite of the many rural environmental hazards to which they are exposed. Chemical air pollution has been particularly neglected.

Objective

We investigated the relationships of indoor exposure to particulate matter (PM) and volatile organic compounds (VOCs) to respiratory health in farmers.

Methods

Nineteen VOCs (5 families) and PM (from ultrafine to total suspended particles (TSP)) were objectively assessed in dwellings and workplaces in 109 French farmers during a week. To take into account multiple exposures, scores of exposure were computed for total VOCs and VOCs families. Individuals filled a standardized questionnaire and underwent spirometry with bronchodilation test.

Results

On average, VOCs concentrations were higher in dwellings than in workplaces. The reverse was observed for PM. When considering the mean concentrations of air pollutants for the whole farm (dwellings + workplaces), asthma (9.3%) was positively associated with elevated exposure to benzene (adjusted odds-ratio (ORa) = 6.64, 95%CI: 1.56–28.27), trichloroethylene (4.80, 1.00–23.30) and halogenated hydrocarbons score (2.9, 95% 1.3–6.8). Early airway obstruction (FEF_25–75 < 80%, with normal FEV₁ and FVC and FEV/FVC ≥ 70%) (29.8%) was related to elevated exposure to 2-butoxyetylacetate (11.49, 1.55–85.37) and glycol ethers score (2.0; 1.0–4.1) in the whole farm and to PM_2.5 (ORa = 5.26, 95% CI: 1.09–25.28) in the granary/stable. The risk of Chronic Obstructive Pulmonary Diseases (FEV/FVC < 70%) (COPD) (4.26%) was found to be larger with elevated exposure to aldehydes (OR = 3.95, 1.09–14.26).

Conclusion

Indoor chemical air pollution is detrimental to farmers’ respiratory health. More epidemiological investigations with detailed exposure assessments and clinical measures of respiratory effects are needed in rural settings to corroborate these findings.

Fine-particulate matter aggravates cigarette smoke extract-induced airway inflammation via Wnt5a-ERK pathway in COPD

Background

Exposure to environmental particulate matter (PM) ≤2.5 μm in diameter (PM_2.5) and smoking are common contributors to COPD, and pertinent research implicates both factors in pulmonary inflammation. Using in vivo mouse and in vitro human cellular models, we investigated the joint impact of PM_2.5 pollution, and cigarette smoke (CS) in mice or cigarette-smoke extract (CSE) in cells on COPD inflammation, and explored potential mechanisms.

Methods

Tissue changes in lungs of C57BL/6 mice exposed to PM_2.5 and CS were studied by light microscopy, H&E, immunochemistry, and immunofluorescence-stained sections. Levels of inflammatory factors induced by PM_2.5/CS in mice and PM_2.5/CSE in 16HBE cells were also monitored by quantitative reverse-transcription (qRT)-PCR and ELISA. Expression of genes related to the Wnt5a-signaling pathway was assessed at transcriptional and protein levels using immunofluorescence, qRT-PCR, and Western blotting.

Results

Inflammatory response to combined exposure of PM_2.5 and CS or CSE in mouse and 16HBE cells surpassed responses incited separately. Although separate PM_2.5 and CS/CSE exposure upregulated the expression of Wnt5a (a member of the Wnt-secreted glycoprotein family), combined PM_2.5 and CS/CSE exposure produced a steeper rise in Wnt5a levels. Use of a Wnt5a antagonist (BOX5) successfully blocked related inflammatory effects. ERK phosphorylation appeared to mediate the effects of Wnt5a in the COPD model, promoting PM_2.5 aggravation of CS/CSE-induced airway inflammation.

Conclusion

Our findings suggest that combined PM_2.5 and CS/CSE exposure induce airway inflammation and Wnt5a expression in vivo in mice and in vitro in 16HBE cells. Furthermore, PM_2.5 seems to aggravate CS/CSE-induced inflammation via the Wnt5a–ERK pathway in the context of COPD.

COPD rat model is more susceptible to cold stress and PM2.5 exposure and the underlying mechanism

The purpose of this study is to verify the hypothesis that chronic obstructive pulmonary disease (COPD) model rat is more susceptible to cold stress and fine particulate matter (PM_2.5) exposure than the healthy rat, and explore the related mechanism. COPD rat model, established with cigarette smoke and lipopolysaccharide intratracheal instillation, were exposed to cold stress (0 °C) and PM_2.5 (0, 3.2, 12.8 mg/ml). After that, the levels of superoxide dismutase, inducible nitric oxide synthase (iNOS), tumor necrosis factor alpha (TNF-α), monocyte chemotactic protein 1 (MCP-1) and angiotensin Ⅱ (Ang-Ⅱ) in lung were measured, as well as the expression levels of lung 8-hydroxy-2-deoxyguanosine (8-OHdG), nuclear factor kappa B (NF-κB), heme-oxygenase-1 (HO-1) and nuclear factor erythroid-2-related factor 2 (Nrf2). There were significant positive relationships between PM_2.5 and lung level of iNOS, TNF-α, MCP-1 and Ang-Ⅱ, lung function and pathologic damage in COPD rats. The HO-1, NF-κB and 8-OHdG were found highly expressed in COPD rat lung, particularly at the higher PM_2.5 dose of cold stress groups, while Nrf2 was found declined. Thus, COPD rats may be more susceptible to cold stress and PM_2.5 exposure. Cold stress may aggravate PM_2.5-induced toxic effects in the lung of COPD rats through increasing Ang-Ⅱ/NF-κB signaling pathway and suppressing Nrf2 signaling pathway.

Serum Periostin Is Negatively Correlated With Exposure to Formaldehyde and Volatile Organic Compounds in Children

Epidemiological studies have shown that exposure to tobacco smoke causing irritation and inflammation in the airways tends to reduce serum periostin concentrations in adults. We now investigate prospective cross-sectional study on 135 Korean students aged 7 years in the first grade who were participating in the Seongnam Atopy Project for Children's Happiness 2016 (SAP₂₀₁₆) cohort. To the best of our knowledge, this is the first study to show significant inverse correlations between serum periostin concentration and exposure to xylene and formaldehyde in children. Our findings suggested the need for caution in using the serum periostin level as a marker for allergic diseases, since exposure to volatile organic compounds and formaldehyde may confound the interpretation of these results.