Respiratory effects of exposure to diesel traffic in persons with asthma

Perinatal factors and the development of childhood asthma

BACKGROUND

Perinatal factors are suspected to have a significant impact on the development of asthma; however, sufficiently powered studies have not been performed to investigate this issue.

OBJECTIVE

To evaluate whether perinatal factors and other risk factors have an independent or combined effect on the development of asthma.

METHODS

This study involved 3,770 children (mean age 9.1 years, range 5.68-12.16 years; 51.9% boys) who were enrolled in the Elementary School Student Cohort (2009-2014) in Ulsan University Hospital (Ulsan, Korea). Subjects were divided into an asthma group (n = 514) and a non-asthma group (n = 3,256).

RESULTS

Multivariate analyses showed that early life (within first week) oxygen therapy (adjusted odds ratio [aOR] 1.864, 95% confidence interval [CI] 1.156-3.004) and breastfeeding (aOR 0.763, 95% CI 0.606-0.960) were 2 significant perinatal factors influencing the development of asthma. Environmental tobacco smoke (aOR 1.634, 95% CI 1.298-2.058) and parental allergic disease (aOR 1.882, 95% CI 1.521-2.328) also were identified as risk factors. Using subgroup analyses, combined effects on asthma development were observed between perinatal factors (early life oxygen therapy and breastfeeding) and other risk factors (vicinity to major roadway [traffic-related air pollution], environmental tobacco smoke, parental allergic disease, and atopy).

CONCLUSION

Early life oxygen therapy and breastfeeding were identified as 2 important perinatal factors influencing the development of asthma. Furthermore, these factors showed combined effects with other risk factors (environmental tobacco smoke, traffic-related air pollution, parental allergic disease, and atopy) on the development of asthma.

The Exposome and Asthma

This article on exposome and asthma focuses on the interaction of patients and their environments in various parts of their growth, development, and stages of life. Indoor and outdoor environments play a role in pathogenesis via levels and duration of exposure, with genetic susceptibility as a crucial factor that alters the initiation and trajectory of common conditions such as asthma. Knowledge of environmental exposures globally and changes that are occurring is necessary to function effectively as medical professionals and health advocates.

Impact of Air Pollution on Sedentary Behavior: A Cohort Study of Freshmen at a University in Beijing, China

Human populations worldwide have experienced substantial environmental issues in part due to air pollution, notably in China. Gaps in the scientific literature remain regarding the relationship between air pollution and sedentary behavior among young adults in China. The purpose of this study is to examine the effect of air pollution on sedentary behavior among college students living in Beijing, China. We conducted follow-up health surveys on 12,174 freshman students enrolled at Tsinghua University from 2013 to 2017. Sedentary behavior was measured using the short version of the International Physical Activity Questionnaire (IPAQ). Corresponding air pollution data measured by the Ministry of Environmental Protection of the People's Republic of China were collected to include the average hourly air quality index (AQI), PM_2.5, PM₁₀, and NO₂ (µg/m³). The data were analyzed using linear individual fixed-effect regressions. An increase in air pollution concentration of one standard deviation in AQI, PM_2.5, PM₁₀, and NO₂ was associated with an increase in weekly total hours of sedentary behavior by 7.35 (95% confidence interval (CI) = 5.89, 8.80), 6.24 (95% CI = 5.00, 7.49), 6.80 (95% CI = 5.46, 8.15), and 7.06 (95% CI = 5.65, 8.47), respectively. In the presence of air pollution, women students tended to increase their sedentary behavior more than men. Air pollution increases sedentary behavior among freshman students living in Beijing, China. Replication of this study is warranted among various populations within China.

Long-term exposure to low concentrations of air pollutants and hospitalisation for respiratory diseases: A prospective cohort study in Australia

BACKGROUND

Short- and long-term spatiotemporal variation in exposure to air pollution is associated with respiratory morbidity in areas with moderate-to-high level of air pollution, but very few studies have examined whether these associations also exist in areas with low level exposure.

OBJECTIVES

We assessed the association between spatial variation in long-term exposure to PM_2.5 and NO₂ and hospitalisation for all respiratory diseases, asthma, chronic obstructive pulmonary disease (COPD), and pneumonia, in older adults residing in Sydney, Australia, a city with low-level concentrations.

METHODS

We recorded data on hospitalisations for 100,084 participants, who were aged >45 years at entry in 2006-2009 until June 2014. Annual NO₂ and PM_2.5 concentrations were estimated for the participants' residential addresses and Cox proportional hazards regression was used to model the association between exposure to air pollutants and first episode of hospitalisation, controlling for personal and area level covariates. We further investigated the shape of the exposure-response association and potential effect modification by age, sex, education level, smoking status, and BMI.

RESULTS

NO₂ and PM_2.5 annual mean exposure estimates were 17.5 μg·m^-3 and 4.5 μg·m^-3 respectively. NO₂ and PM_2.5 was positively, although not significantly, associated with asthma. The adjusted hazard ratio for a 1 μg·m^-3 increase in PM_2.5 was 1.08, 95% confidence interval 0.89-1.30. The adjusted hazard ratio for a 5 μg·m^-3 increase in NO₂ was 1.03, 95% confidence interval 0.88-1.19. We found no positive statistically significant associations with hospitalisation for all respiratory diseases, and pneumonia while negative associations were observed with COPD.

CONCLUSIONS

We found weak positive associations of exposure to air pollution with hospitalisation for asthma while there was no evidence of an association for all respiratory diseases.

The Impact of Air Pollution on Our Epigenome: How Far Is the Evidence? (A Systematic Review)

PURPOSE OF REVIEW

This systematic review evaluated existing evidence linking air pollution exposure in humans to major epigenetic mechanisms: DNA methylation, microRNAs, long noncoding RNAs, and chromatin regulation.

RECENT FINDINGS

Eighty-two manuscripts were eligible, most of which were observational (85%), conducted in adults (66%) and based on DNA methylation (79%). Most observational studies, except panel, demonstrated modest effects of air pollution on the methylome. Panel and experimental studies revealed a relatively large number of significant methylome alterations, though based on smaller sample sizes. Particulate matter levels were positively associated in several studies with global or LINE-1 hypomethylation, a hallmark of several diseases, and with decondensed chromatin structure. Several air pollution species altered the DNA methylation clock, inducing accelerated biological aging. The causal nature of identified associations is not clear, however, especially that most originate from countries with low air pollution levels. Existing evidence, gaps, and perspectives are highlighted herein.

Impact of London's low emission zone on air quality and children's respiratory health: a sequential annual cross-sectional study

BACKGROUND

Low emission zones (LEZ) are an increasingly common, but unevaluated, intervention aimed at improving urban air quality and public health. We investigated the impact of London's LEZ on air quality and children's respiratory health.

METHODS

We did a sequential annual cross-sectional study of 2164 children aged 8-9 years attending primary schools between 2009-10 and 2013-14 in central London, UK, following the introduction of London's LEZ in February, 2008. We examined the association between modelled pollutant exposures of nitrogen oxides (including nitrogen dioxide [NO₂]) and particulate matter with a diameter of less than 2·5 μm (PM_2·5) and less than 10 μm (PM₁₀) and lung function: postbronchodilator forced expiratory volume in 1 s (FEV₁, primary outcome), forced vital capacity (FVC), and respiratory or allergic symptoms. We assigned annual exposures by each child's home and school address, as well as spatially resolved estimates for the 3 h (0600-0900 h), 24 h, and 7 days before each child's assessment, to isolate long-term from short-term effects.

FINDINGS

The percentage of children living at addresses exceeding the EU limit value for annual NO₂ (40 μg/m³) fell from 99% (444/450) in 2009 to 34% (150/441) in 2013. Over this period, we identified a reduction in NO₂ at both roadside (median -1·35 μg/m³ per year; 95% CI -2·09 to -0·61; p=0·0004) and background locations (-0·97; -1·56 to -0·38; p=0·0013), but not for PM₁₀. The effect on PM_2·5 was equivocal. We found no association between postbronchodilator FEV₁ and annual residential pollutant attributions. By contrast, FVC was inversely correlated with annual NO₂ (-0·0023 L/μg per m³; -0·0044 to -0·0002; p=0·033) and PM₁₀ (-0·0090 L/μg per m³; -0·0175 to -0·0005; p=0·038).

INTERPRETATION

Within London's LEZ, a smaller lung volume in children was associated with higher annual air pollutant exposures. We found no evidence of a reduction in the proportion of children with small lungs over this period, despite small improvements in air quality in highly polluted urban areas during the implementation of London's LEZ. Interventions that deliver larger reductions in emissions might yield improvements in children's health.

FUNDING

National Institute for Health Research Biomedical Research Centre at Guy's and St Thomas' National Health Service (NHS) Foundation Trust and King's College London, NHS Hackney, Lee Him donation, and Felicity Wilde Charitable Trust.

Particulate matter exposure and health impacts of urban cyclists: a randomized crossover study

BACKGROUND

Cycling and other forms of active transportation provide health benefits via increased physical activity. However, direct evidence of the extent to which these benefits may be offset by exposure and intake of traffic-related air pollution is limited. The purpose of this study is to measure changes in endothelial function, measures of oxidative stress and inflammation, and lung function in healthy participants before and after cycling along a high- and low- traffic route.

METHODS

Participants (n = 38) bicycled for 1 h along a Downtown and a Residential designated bicycle route in a randomized crossover trial. Heart rate, power output, particulate matter air pollution (PM₁₀, PM_2.5, and PM₁) and particle number concentration (PNC) were measured. Lung function, endothelial function (reactive hyperemia index, RHI), C-reactive protein, interleukin-6, and 8-hydroxy-2'-deoxyguanosine were assessed within one hour pre- and post-trial.

RESULTS

Geometric mean PNC exposures and intakes were higher along the Downtown (exposure = 16,226 particles/cm³; intake = 4.54 × 10¹⁰ particles) compared to the Residential route (exposure = 9367 particles/cm³; intake = 3.13 × 10¹⁰ particles). RHI decreased following cycling along the Downtown route and increased on the Residential route; in mixed linear regression models, the (post-pre) change in RHI was 21% lower following cycling on the Downtown versus the Residential route (-0.43, 95% CI: -0.79, -0.079) but RHI decreases were not associated with measured exposure or intake of air pollutants. The differences in RHI by route were larger amongst females and older participants. No consistent associations were observed for any of the other outcome measures.

CONCLUSIONS

Although PNC exposures and intakes were higher along the Downtown route, the lack of association between air pollutant exposure or intake with RHI and other measures suggests other exposures related to cycling on the Downtown route may have been influential in the observed differences between routes in RHI.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT01708356 . Registered 16 October 2012.

Use of high-resolution metabolomics for the identification of metabolic signals associated with traffic-related air pollution

BACKGROUND

High-resolution metabolomics (HRM) is emerging as a sensitive tool for measuring environmental exposures and biological responses. The aim of this analysis is to assess the ability of high-resolution metabolomics (HRM) to reflect internal exposures to complex traffic-related air pollution mixtures.

METHODS

We used untargeted HRM profiling to characterize plasma and saliva collected from participants in the Dorm Room Inhalation to Vehicle Emission (DRIVE) study to identify metabolic pathways associated with traffic emission exposures. We measured a suite of traffic-related pollutants at multiple ambient and indoor sites at varying distances from a major highway artery for 12 weeks in 2014. In parallel, 54 students living in dormitories near (20 m) or far (1.4 km) from the highway contributed plasma and saliva samples. Untargeted HRM profiling was completed for both plasma and saliva samples; metabolite and metabolic pathway alternations were evaluated using a metabolome-wide association study (MWAS) framework with pathway analyses.

RESULTS

Weekly levels of traffic pollutants were significantly higher at the near dorm when compared to the far dorm (p < 0.05 for all pollutants). In total, 20,766 metabolic features were extracted from plasma samples and 29,013 from saliva samples. 45% of features were detected and shared in both plasma and saliva samples. 1291 unique metabolic features were significantly associated with at least one or more traffic indicator, including black carbon, carbon monoxide, nitrogen oxides and fine particulate matter (p < 0.05 for all significant features), after controlling for confounding and false discovery rate. Pathway analysis of metabolic features associated with traffic exposure indicated elicitation of inflammatory and oxidative stress related pathways, including leukotriene and vitamin E metabolism. We confirmed the chemical identities of 10 metabolites associated with traffic pollutants, including arginine, histidine, γ‑linolenic acid, and hypoxanthine.

CONCLUSIONS

Using HRM, we identified and verified biological perturbations associated with primary traffic pollutant in panel-based setting with repeated measurement. Observed response was consistent with endogenous metabolic signaling related to oxidative stress, inflammation, and nucleic acid damage and repair. Collectively, the current findings provide support for the use of untargeted HRM in the development of metabolic biomarkers of traffic pollution exposure and response.

Short-term transcriptome and microRNAs responses to exposure to different air pollutants in two population studies

Diesel vehicle emissions are the major source of genotoxic compounds in ambient air from urban areas. These pollutants are linked to risks of cardiovascular diseases, lung cancer, respiratory infections and adverse neurological effects. Biological events associated with exposure to some air pollutants are widely unknown but applying omics techniques may help to identify the molecular processes that link exposure to disease risk. Most data on health risks are related to long-term exposure, so the aim of this study is to investigate the impact of short-term exposure (two hours) to air pollutants on the blood transcriptome and microRNA expression levels. We analyzed transcriptomics and microRNA expression using microarray technology on blood samples from volunteers participating in studies in London, the Oxford Street cohort, and, in Barcelona, the TAPAS cohort. Personal exposure levels measurements of particulate matter (PM₁₀, PM_2.5), ultrafine particles (UFPC), nitrogen oxides (NO₂, NO and NOx), black carbon (BC) and carbon oxides (CO and CO₂) were registered for each volunteer. Associations between air pollutant levels and gene/microRNA expression were evaluated using multivariate normal models (MVN). MVN-models identified compound-specific expression of blood cell genes and microRNAs associated with air pollution despite the low exposure levels, the short exposure periods and the relatively small-sized cohorts. Hsa-miR-197-3p, hsa-miR-29a-3p, hsa-miR-15a-5p, hsa-miR-16-5p and hsa-miR-92a-3p are found significantly expressed in association with exposures. These microRNAs target also relevant transcripts, indicating their potential relevance in the research of omics-biomarkers responding to air pollution. Furthermore, these microRNAs are also known to be associated with diseases previously linked to air pollution exposure including several cancers such lung cancer and Alzheimer's disease. In conclusion, we identified in this study promising compound-specific mRNA and microRNA biomarkers after two hours of exposure to low levels of air pollutants during two hours that suggest increased cancer risks.

Association between the Ratio of FEV₁ to FVC and the Exposure Level to Air Pollution in Neversmoking Adult Refractory Asthmatics Using Data Clustered by Patient in the Soonchunhyang Asthma Cohort Database

Using real-world cases, asthma-related clinical data were clustered by patient; 5% of all asthmatics were found to have refractory asthma (RA) with a relatively low lung function (forced expiratory volume in 1 s/forced vital capacity (FEV₁/FVC) less than 80%). Using a multilevel study design for clustered spirometry data observed between 2005 and 2014, we evaluated the association between changes in the ratio of FEV₁ to FVC and variations in acute exposure to air pollution. We analyzed 2310 episodes of RA from 214 neversmoking patients. In spring, a 1 µg/m³ increase in concentration of particles ≤10 μm (PM10) on Lag 1 significantly reduced the ratio by 0.4% (95% confidence interval (CI): 0.1⁻0.7%) after adjusting for sex, age, body mass index (BMI), and total Immunoglobulin E (IgE) level. Unit (ppb) increase in SO₂ concentration on Lag 3 and 4 in fall and on Lag 6 in winter significantly reduced the ratio by 2 to 3% (p < 0.05). We found that acute exposure to PM10 in spring or SO₂ in fall or winter were positively associated with lung function drop indicating necessity of control strategies of target air pollutant source by season to protect susceptible population.

Characteristics of peak concentrations of black carbon encountered by elementary school children

The objectives of this study were to examine characteristics of peak concentrations, including frequency, duration, and relative magnitude, and estimate its contributions to overall daily exposure to BC by activity and microenvironment. We assessed daily personal exposures from August 2015 to January 2016 (75.2% of weekdays and 24.8% of weekend days; 64.1% of school days and 35.9% of holidays) among forty 10-12 years old children living in the Seoul metropolitan area. These children were equipped with a microaethalometer (BC monitor) and recorded a time-activity diary. Pre-administrated questionnaires and follow-up interviews also provided information on children's time-activity patterns. Owing to the absence of a generally accepted threshold, peaks were alternatively defined as BC concentrations higher TWA, the 95th percentile, and the 99th percentile. Peak concentrations made substantial contributions to total daily exposure to BC (peaks ≥ TWA: 60%, peaks ≥95th-percentile: 19%, and peaks ≥99th-percentile: 6%). Average peak levels higher than TWA and the 95th percentile differed significantly by activity and ME. Transportation and cooking led to frequent peak occurrences which disproportionately contributed to daily integrated exposure relative to time spent in these activities. Walking was characterized by occasional brief but high-magnitude peaks exceeding the 99th percentile, which produced the most intense potential dose (0.09% of daily time spent on walking accounted for 1.6% of daily potential dose). It might be attributed to encounters with high emissions sources such as passing/idling vehicles and environmental tobacco smoke. Trips by diesel vehicle produced frequently occurring and long-duration peaks above the 95th percentile that contributed 2% to total daily exposure (corresponding time: 0.3%). Charbroiling meat incurred sustained peaks as intense as those in trips by diesel vehicles. Peaks during commuting showed relatively high exposure intensity on weekdays, possibly because of increased surrounding traffic volume on these days, while those during cooking accounted for a more elevated residential contribution to daily integrated exposure.

Frequency of heavy vehicle traffic and association with DNA methylation at age 18 years in a subset of the Isle of Wight birth cohort

Assessment of changes in DNA methylation (DNA-m) has the potential to identify adverse environmental exposures. To examine DNA-m among a subset of participants (n = 369) in the Isle of Wight birth cohort who reported variable near resident traffic frequencies. We used self-reported frequencies of heavy vehicles passing by the homes of study subjects as a proxy measure for TRAP, which were: never, seldom, 10 per day, 1-9 per hour and >10 per hour. Methylation of cytosine-phosphate-guanine (CpG) dinucleotide sequences in the DNA was assessed from blood samples collected at age 18 years (n = 369) in the F1 generation. We conducted an epigenome wide association study to examine CpGs related to the frequency of heavy vehicles passing by subjects' homes, and employed multiple linear regression models to assess potential associations. We repeated some of these analysis in the F2 generation (n = 140). Thirty-five CpG sites were associated with heavy vehicular traffic. After adjusting for confounders, we found 23 CpGs that were more methylated, and 11 CpGs that were less methylated with increasing heavy vehicular traffic frequency among all subjects. In the F2 generation, 2 of 31 CpGs were associated with traffic frequencies and the direction of the effect was the same as in the F1 subset while differential methylation of 7 of 31 CpG sites correlated with gene expression. Our findings reveal differences in DNA-m in participants who reported higher heavy vehicular traffic frequencies when compared to participants who reported lower frequencies.

Short-term effects of airport-associated ultrafine particle exposure on lung function and inflammation in adults with asthma

BACKGROUND

Exposure to ultrafine particles (UFP, particles with aerodynamic diameter < 100 nm) is associated with reduced lung function and airway inflammation in individuals with asthma. Recently, elevated UFP number concentrations (PN) from aircraft landing and takeoff activity were identified downwind of the Los Angeles International Airport (LAX) but little is known about the health impacts of airport-related UFP exposure.

METHODS

We conducted a randomized crossover study of 22 non-smoking adults with mild to moderate asthma in Nov-Dec 2014 and May-Jul 2015 to investigate short-term effects of exposure to LAX airport-related UFPs. Participants conducted scripted, mild walking activity on two occasions in public parks inside (exposure) and outside (control) of the high UFP zone. Spirometry, multiple flow exhaled nitric oxide, and circulating inflammatory cytokines were measured before and after exposure. Personal UFP PN and lung deposited surface area (LDSA) and stationary UFP PN, black carbon (BC), particle-bound PAHs (PB-PAH), ozone (O3), carbon dioxide (CO2) and particulate matter (PM2.5) mass were measured. Source apportionment analysis was conducted to distinguish aircraft from roadway traffic related UFP sources. Health models investigated within-subject changes in outcomes as a function of pollutants and source factors.

RESULTS

A high two-hour walking period average contrast of ~34,000 particles·cm-3 was achieved with mean (std) PN concentrations of 53,342 (25,529) and 19,557 (11,131) particles·cm-3 and mean (std) particle size of 28.7 (9.5) and 33.2 (11.5) at the exposure and control site, respectively. Principal components analysis differentiated airport UFPs (PN), roadway traffic (BC, PB-PAH), PM mass (PM2.5, PM10), and secondary photochemistry (O3) sources. A standard deviation increase in the 'Airport UFPs' factor was significantly associated with IL-6, a circulating marker of inflammation (single-pollutant model: 0.21, 95% CI = 0.08-0.34; multi-pollutant model: 0.18, 0.04-0.32). The 'Traffic' factor was significantly associated with lower Forced Expiratory Volume in 1 s (FEV1) (single-pollutant model: -1.52, -2.28 to -0.77) and elevated sTNFrII (single-pollutant model: 36.47; 6.03-66.91; multi-pollutant model: 64.38; 6.30-122.46). No consistent associations were observed with exhaled nitric oxide.

CONCLUSIONS

To our knowledge, our study is the first to demonstrate increased acute systemic inflammation following exposure to airport-related UFPs. Health effects associated with roadway traffic exposure were distinct. This study emphasizes the importance of multi-pollutant measurements and modeling techniques to disentangle sources of UFPs contributing to the complex urban air pollution mixture and to evaluate population health risks.

Inhalational exposure to particulate matter air pollution alters the composition of the gut microbiome

Recent studies suggest an association between particulate matter (PM) air pollution and gastrointestinal (GI) disease. In addition to direct deposition, PM can be indirectly deposited in oropharynx via mucociliary clearance and upon swallowing of saliva and mucus. Within the GI tract, PM may alter the GI epithelium and gut microbiome. Our goal was to determine the effect of PM on gut microbiota in a murine model of PM exposure via inhalation. C57BL/6 mice were exposed via inhalation to either concentrated ambient particles or filtered air for 8-h per day, 5-days a week, for a total of 3-weeks. At exposure's end, GI tract tissues and feces were harvested, and gut microbiota was analyzed. Alpha-diversity was modestly altered with increased richness in PM-exposed mice compared to air-exposed mice in some parts of the GI tract. Most importantly, PM-induced alterations in the microbiota were very apparent in beta-diversity comparisons throughout the GI tract and appeared to increase from the proximal to distal parts. Changes in some genera suggest that distinct bacteria may have the capacity to bloom with PM exposure. Exposure to PM alters the microbiota throughout the GI tract which maybe a potential mechanism that explains PM induced inflammation in the GI tract.

Outdoor air pollution and cystic fibrosis

Outdoor air pollution is increasingly identified as a contributor to respiratory and cardiovascular disease. Pro-inflammatory particles and gases are inhaled deep into the lungs, and are associated with impaired lung growth and exacerbations of chronic respiratory diseases. The magnitude of these effects are of interest to patients and families, and have been assessed in studies specific to CF. Using systematic review methodology, we sought to collate these studies in order to summarise the known effects of air pollution in cystic fibrosis, and to present information on decreasing personal air pollution exposures.

Air pollution and resistance to inhaled glucocorticoids: Evidence, mechanisms and gaps to fill

Substantial evidence indicates that cigarette smoke exposure induces resistance to glucocorticoids, the primary maintenance medication in asthma treatment. Modest evidence also suggests that air pollution may reduce the effectiveness of these critical medications. Cigarette smoke, which has clear parallels with air pollution, has been shown to induce glucocorticoid resistance in asthma and it has been speculated that air pollution may have similar effects. However, the literature on an association of air pollution with glucocorticoid resistance is modest to date. In this review, we detail the evidence for, and against, the effects of air pollution on glucocorticoid effectiveness, focusing on results from epidemiology and controlled human exposure studies. Epidemiological studies indicate a correlation between increased air pollution exposure and worse asthma symptoms. But these studies also show a mix of beneficial and harmful effects of glucocorticoids on spirometry and asthma symptoms, perhaps due to confounding influences, or the induction of glucocorticoid resistance. We describe mechanisms that may contribute to reductions in glucocorticoid responsiveness following air pollution exposure, including changes to phosphorylation or oxidation of the glucocorticoid receptor, repression by cytokines, or inflammatory pathways, and epigenetic effects. Possible interactions between air pollution and respiratory infections are also briefly discussed. Finally, we detail a number of therapies that may boost glucocorticoid effectiveness or reverse resistance in the presence of air pollution, and comment on the beneficial effects of engineering controls, such as air filtration and asthma action plans. We also call attention to the benefits of improved clean air policy on asthma. This review highlights numerous gaps in our knowledge of the interactions between air pollution and glucocorticoids to encourage further research in this area with a view to reducing the harm caused to those with airways disease.

Errors associated with the use of roadside monitoring in the estimation of acute traffic pollutant-related health effects

Near-road monitoring creates opportunities to provide direct measurement on traffic-related air pollutants and to better understand the changing near-road environment. However, how such observations represent traffic-related air pollution exposures for estimating adverse health effect in epidemiologic studies remains unknown. A better understanding of potential exposure measurement error when utilizing near-road measurement is needed for the design and interpretation of the many observational studies linking traffic pollution and adverse health. The Dorm Room Inhalation to Vehicle Emission (DRIVE) study conducted near-road measurements of several single traffic indicators at six indoor and outdoor sites ranging from 0.01 to 2.3 km away from a heavily-trafficked (average annual daily traffic over 350,000) highway artery between September 2014 to January 2015. We examined spatiotemporal variability trends and assessed the potential for bias and errors when using a roadside monitor as a primary traffic pollution exposure surrogate, in lieu of more spatially-refined, proximal exposure indicators. Pollutant levels measured during DRIVE showed a low impact of this highway hotspot source. Primary pollutant species, including NO, CO, and BC declined to near background levels by 20-30 m from the highway source. Patterns of correlation among the sites also varied by pollutant and time of day. NO₂, specifically, exhibited spatial trends that differed from other single-pollutant primary traffic indicators. This finding provides some indication of limitations in the use of NO₂ as a primary traffic exposure indicator in panel-based health effect studies. Interestingly, roadside monitoring of NO, CO, and BC tended to be more strongly correlated with sites, both near and far from the road, during morning rush hour periods, and more weakly correlated during other periods of the day. We found pronounced attenuation of observed changes in health effects when using measured pollutant from the near-road monitor as a surrogate for true exposure, and the magnitude varied substantially over the course of the day. Caution should be taken when using near-road monitoring network observations, alone, to investigate health effects of traffic pollutants.

The impact of acute air pollution fluctuations on bronchiectasis pulmonary exacerbation: a case-crossover analysis

In bronchiectasis, exacerbations are believed to be triggered by infectious agents, but often no pathogen can be identified. We hypothesised that acute air pollution exposure may be associated with bronchiectasis exacerbations.

We combined a case-crossover design with distributed lag models in an observational record linkage study. Patients were recruited from a specialist bronchiectasis clinic at Ninewells Hospital, Dundee, UK.

We recruited 432 patients with clinically confirmed bronchiectasis, as diagnosed by high-resolution computed tomography. After excluding days with missing air pollution data, the final model for particles with a 50% cut-off aerodynamic diameter of 10 µm (PM10) was based on 6741 exacerbations from 430 patients and for nitrogen dioxide (NO2) it included 6248 exacerbations from 426 patients. For each 10 µg·m−³ increase in PM10 and NO2, the risk of having an exacerbation that same day increased significantly by 4.5% (95% CI 0.9–8.3) and 3.2% (95% CI 0.7–5.8) respectively. The overall (lag zero to four) increase in risk of exacerbation for a 10 μg·m−3 increase in air pollutant concentration was 11.2% (95% CI 6.0–16.8) for PM10 and 4.7% (95% CI 0.1–9.5) for NO2. Subanalysis showed higher relative risks during spring (PM10 1.198 (95% CI 1.102–1.303), NO2 1.146 (95% CI 1.035–1.268)) and summer (PM10 2.142 (95% CI 1.785–2.570), NO2 1.352 (95% CI 1.140–1.602)) when outdoor air pollution exposure would be expected to be highest.

In conclusion, acute air pollution fluctuations are associated with increased exacerbation risk in bronchiectasis.

A Muscarinic Antagonist Reduces Airway Inflammation and Bronchoconstriction Induced by Ambient Particulate Matter in a Mouse Model of Asthma

Ambient particulate matter (PM) can increase airway inflammation and induce bronchoconstriction in asthma. This study aimed to investigate the effect of tiotropium bromide, a long-acting muscarinic antagonist, on airway inflammation and bronchoconstriction induced by ambient PM in a mouse model of asthma. We compared the effect of tiotropium bromide to that of fluticasone propionate and formoterol fumarate. BALB/c mice were sensitized to ovalbumin (OVA) via the airways and then administered tiotropium bromide, fluticasone propionate, or formoterol fumarate. Mice were also sensitized to ambient PM via intranasal instillation. Differential leukocyte counts and the concentrations of interferon (IFN)-γ, interleukin (IL)-5, IL-6, IL-13, and keratinocyte-derived chemokine (KC/CXCL1) were measured in bronchoalveolar lavage fluid (BALF). Diacron-reactive oxygen metabolites (dROMs) were measured in the serum. Airway resistance and airway inflammation were evaluated in lung tissue 24 h after the OVA challenge. Ambient PM markedly increased neutrophilic airway inflammation in mice with OVA-induced asthma. Tiotropium bromide improved bronchoconstriction, and reduced neutrophil numbers, decreased the concentrations of IL-5, IL-6, IL-13, and KC/CXCL1 in BALF. However, tiotropium bromide did not decrease the levels of dROMs increased by ambient PM. Though eosinophilic airway inflammation was reduced with fluticasone propionate, neutrophilic airway inflammation was unaffected. Bronchoconstriction was improved with formoterol fumarate, but not with fluticasone propionate. In conclusion, tiotropium bromide reduced bronchoconstriction, subsequently leading to reduced neutrophilic airway inflammation induced by ambient PM.

Source-specific pollution exposure and associations with pulmonary response in the Atlanta Commuters Exposure Studies

Concentrations of traffic-related air pollutants are frequently higher within commuting vehicles than in ambient air. Pollutants found within vehicles may include those generated by tailpipe exhaust, brake wear, and road dust sources, as well as pollutants from in-cabin sources. Source-specific pollution, compared to total pollution, may represent regulation targets that can better protect human health. We estimated source-specific pollution exposures and corresponding pulmonary response in a panel study of commuters. We used constrained positive matrix factorization to estimate source-specific pollution factors and, subsequently, mixed effects models to estimate associations between source-specific pollution and pulmonary response. We identified four pollution factors that we named: crustal, primary tailpipe traffic, non-tailpipe traffic, and secondary. Among asthmatic subjects (N = 48), interquartile range increases in crustal and secondary pollution were associated with changes in lung function of -1.33% (95% confidence interval (CI): -2.45, -0.22) and -2.19% (95% CI: -3.46, -0.92) relative to baseline, respectively. Among non-asthmatic subjects (N = 51), non-tailpipe pollution was associated with pulmonary response only at 2.5 h post-commute. We found no significant associations between pulmonary response and primary tailpipe pollution. Health effects associated with traffic-related pollution may vary by source, and therefore some traffic pollution sources may require targeted interventions to protect health.

Ultrafine Particle Exposure Reveals the Importance of FOXO1/Notch Activation Complex for Vascular Regeneration

AIMS

Redox active ultrafine particles (UFP, d < 0.2 μm) promote vascular oxidative stress and atherosclerosis. Notch signaling is intimately involved in vascular homeostasis, in which forkhead box O1 (FOXO1) acts as a co-activator of the Notch activation complex. We elucidated the importance of FOXO1/Notch transcriptional activation complex to restore vascular regeneration after UFP exposure.

RESULTS

In a zebrafish model of tail injury and repair, transgenic Tg(fli1:GFP) embryos developed vascular regeneration at 3 days post amputation (dpa), whereas UFP exposure impaired regeneration (p < 0.05, n = 20 for control, n = 28 for UFP). UFP dose dependently reduced Notch reporter activity and Notch signaling-related genes (Dll4, JAG1, JAG2, Notch1b, Hey2, Hes1; p < 0.05, n = 3). In the transgenic Tg(tp1:GFP; flk1:mCherry) embryos, UFP attenuated endothelial Notch activity at the amputation site (p < 0.05 vs. wild type [WT], n = 20). A disintegrin and metalloproteinase domain-containing protein 10 (ADAM10) inhibitor or dominant negative (DN)-Notch1b messenger RNA (mRNA) disrupted the vascular network, whereas notch intracellular cytoplasmic domain (NICD) mRNA restored the vascular network (p < 0.05 vs. WT, n = 20). UFP reduced FOXO1 expression, but not Master-mind like 1 (MAML1) or NICD (p < 0.05, n = 3). Immunoprecipitation and immunofluorescence demonstrated that UFP attenuated FOXO1-mediated NICD pull-down and FOXO1/NICD co-localization, respectively (p < 0.05, n = 3). Although FOXO1 morpholino oligonucleotides (MOs) attenuated Notch activity, FOXO1 mRNA reversed UFP-mediated reduction in Notch activity to restore vascular regeneration and blood flow (p < 0.05 vs. WT, n = 5). Innovation and Conclusion: Our findings indicate the importance of the FOXO1/Notch activation complex to restore vascular regeneration after exposure to the redox active UFP. Antioxid. Redox Signal. 28, 1209-1223.

Urban particulate matter in air pollution penetrates into the barrier-disrupted skin and produces ROS-dependent cutaneous inflammatory response in vivo

BACKGROUND

Particulate matter (PM) is an integral part of air pollution, which is a mixture of particles suspended in the air. Recently, it has been reported that PM is associated with increased risks of skin diseases, especially atopic dermatitis in children. However, it is unclear if PM directly goes into the skin and what mechanisms are involved in response to PM.

OBJECTIVE

To see whether PM could penetrate into the barrier-disrupted skin, produce reactive oxygen species (ROS), and elicit an inflammatory response.

METHODS

We collected PMs during a winter in Seoul and used cultured keratinocytes for in vitro study and tape-stripped BALB/c mice for in vivo study.

RESULTS

Keratinocyte cytotoxicity increased in a dose-dependent manner by PM treatment. IL-8 and MMP-1 mRNA expression and protein levels were significantly increased compared to control by qPCR and ELISA, respectively. Cellular ROS production was increased by PM treatment, and antioxidant N-acetyl cysteine pretreatment prevented induction of inflammatory cytokines IL-8 and MMP-1. In PM-treated keratinocytes, electron-dense subcellular particles were observed by transmission electron microscopy. PM was observed inside hair follicles in both intact and barrier-disrupted skin in vivo. Additionally, intercellular penetration of PM was seen in the barrier-disrupted skin. Repeated PM application induced epidermal thickening and dermal inflammation with neutrophil infiltration. Finally, N-acetyl cysteine could ameliorate skin inflammation induced by PM application.

CONCLUSION

PM penetrates into the barrier-disrupted skin, causing inflammation, demonstrating detrimental effects in the skin.

Effects of personal air pollution exposure on asthma symptoms, lung function and airway inflammation

BACKGROUND

There is evidence that air pollution increases the risk of asthma hospitalizations and healthcare utilization, but the effects on day-to-day asthma control are not fully understood.

OBJECTIVE

We undertook a prospective single-centre panel study to test the hypothesis that personal air pollution exposure is associated with asthma symptoms, lung function and airway inflammation.

METHODS

Thirty-two patients with a clinical diagnosis of asthma were provided with a personal air pollution monitor (Cairclip NO₂ /O₃ ) which was kept on or around their person throughout the 12-week follow-up period. Ambient levels of NO₂ and particulate matter were modelled based upon satellite imaging data. Directly measured ozone, NO₂ and particulate matter levels were obtained from a monitoring station in central Leicester. Participants made daily electronic records of asthma symptoms, peak expiratory flow and exhaled nitric oxide. Spirometry and asthma symptom questionnaires were completed at fortnightly study visits. Data were analysed using linear mixed effects models and cross-correlation.

RESULTS

Cairclip exposure data were of good quality with clear evidence of diurnal variability and a missing data rate of approximately 20%. We were unable to detect consistent relationships between personal air pollution exposure and clinical outcomes in the group as a whole. In an exploratory subgroup analysis, total oxidant exposure was associated with increased daytime symptoms in women but not men.

CONCLUSIONS AND CLINICAL RELEVANCE

We did not find compelling evidence that air pollution exposure impacts on day-to-day clinical control in an unselected asthma population, but further studies are required in larger populations with higher exposure levels. Women may be more susceptible than men to the effects of air pollution, an observation which requires confirmation in future studies.

Role of sputum biomarkers in the management of asthma

PURPOSE OF REVIEW

Airway inflammation is considered to be a cardinal feature of asthma. However, the type of airway inflammation is heterogeneous and airway inflammation may even be absent. Biomarkers may help to identify the inflammatory phenotype or endotype, especially now the time has come that targeted therapies enter daily practice.

RECENT FINDINGS

Sputum biomarkers have increased our insights into the different inflammatory asthma phenotypes, their response to treatment and their association with progression of disease. New endotypes of type 2 driven inflammation were identified using a multidimensional approach. A specific mast cell subtype has been linked with type 2 driven inflammation and response to inhaled corticosteroids. Advances have been made with regard to sputum cytokine analysis and might also help to guide future treatment of severe asthma.

SUMMARY

Identifying the target population for biological therapies will not be possible without the use of biomarkers. Optimized, easy-to-apply, automated methods for sputum analysis (cellular content or soluble markers) need to be developed for implementation of sputum biomarkers in daily clinical practice.

Estimated individual inhaled dose of fine particles and indicators of lung function: A pilot study among Chinese young adults

Fine particle (PM_2.5)-related lung damage has been reported in most studies regarding environmental or personal PM_2.5 concentrations. To assess effects of personal PM_2.5 exposures on lung function, we recruited 20 postgraduate students and estimated the individual doses of inhaled PM_2.5 based on their microenvironmetal PM_2.5 concentrations, time-activity patterns and refereed inhalation rates. During the period of seven consecutive days in each of the four seasons, we repeatedly measured the daily lung function parameters and airway inflammation makers such as fractional exhaled nitric oxide (FeNO) as well as systemic inflammation markers including interleukin-1β on the final day. The high individual dose (median (IQR)) of inhaled PM_2.5 was 957 (948) μg/day. We observed a maximum FeNO increase (9.1% (95%CI: 2.2-15.5)) at lag 0 day, a maximum decrease of maximum voluntary ventilation (11.8% (95% CI: 4.6-19.0)) at lag 5 day and a maximum interleukin-1β increase (103% (95% CI: 47-159)) at lag 2 day for an interquartile range increase in the individual dose of inhaled PM_2.5 during the four seasons. Short-term exposure to PM_2.5 assessed by the individual dose of inhaled PM_2.5 was associated with higher airway and systemic inflammation and reduced lung function. Further studies are needed to understand better underlying mechanisms of lung damage following acute exposure to PM_2.5.

The human circulating miRNome reflects multiple organ disease risks in association with short-term exposure to traffic-related air pollution

Traffic-related air pollution is a complex mixture of particulate matter (PM) and gaseous pollutants, such as nitrogen dioxide (NO2). PM exposure contributes to the pathogenesis of many diseases including several types of cancer, as well as pulmonary, cardiovascular and neurodegenerative diseases. Also exposure to NO2 has been related to increased cardiovascular mortality. In search of an early diagnostic biomarker for improved air pollution-associated health risk assessment, recent human studies have shown that certain circulating miRNAs are altered upon exposure to traffic-related air pollutants. Here, we present for the first time a global analysis of the circulating miRNA genome in an experimental cross-over study of a human population exposed to traffic-related air pollution. By utilizing next-generation sequencing technology and detailed real-time exposure measurements we identified 54 circulating miRNAs to be dose- and pollutant species-dependently associated with PM10, PM2.5, black carbon, ultrafine particles and NO2 already after 2 h of exposure. Bioinformatics analysis suggests that these circulating miRNAs actually reflect the adverse consequences of traffic pollution-induced toxicity in target tissues including the lung, heart, kidney and brain. This study shows the strong potential of circulating miRNAs as novel biomarkers for environmental health risk assessment.

Low Dose Carbon Black Nanoparticle Exposure Does Not Aggravate Allergic Airway Inflammation in Mice Irrespective of the Presence of Surface Polycyclic Aromatic Hydrocarbons

Exposure to exogenous noxae, such as particulate matter, can trigger acute aggravations of allergic asthma—a chronic inflammatory airway disease. We tested whether Carbon Black nanoparticles (CBNP) with or without surface polycyclic aromatic hydrocarbons (PAH) aggravate an established allergic airway inflammation in mice. In an ovalbumin mouse model, Printex^®90 (P90), P90 coated with benzo[a]pyrene (P90-BaP) or 9-nitroanthracene (P90-9NA), or acetylene soot exhibiting a mixture of surface PAH (AS-PAH) was administered twice (70 µL, 100 µg/mL) during an established allergic airway inflammation. We analyzed the immune cell numbers and chemokine/cytokine profiles in bronchoalveolar lavages, the mRNA expressions of markers for PAH metabolism (Cyp1a1, 1b1), oxidative stress (HO-1, Gr, Gpx-3), inflammation (KC, Mcp-1, IL-6, IL-13, IL-17a), mucin synthesis (Muc5ac, Muc5b), the histology of mucus-producing goblet cells, ciliary beat frequency (CBF), and the particle transport speed. CBNP had a comparable primary particle size, hydrodynamic diameter, and ζ-potential, but differed in the specific surface area (P90 > P90-BaP = P90-9NA = AS-PAH) and surface chemistry. None of the CBNP tested increased any parameter related to inflammation. The unmodified P90, however, decreased the tracheal CBF, decreased the Muc5b in intrapulmonary airways, but increased the tracheal Muc5ac. Our results demonstrated that irrespective of the surface PAH, a low dose of CBNP does not acutely aggravate an established allergic airway inflammation in mice.

Biomarkers of Human Cardiopulmonary Response After Short-Term Exposures to Medical Laser-Generated Particulate Matter From Simulated Procedures: A Pilot Study

OBJECTIVE

We conducted an exposure chamber study in humans using a simulated clinical procedure lasing porcine tissue to demonstrate evidence of effects of exposure to laser-generated particulate matter (LGPM).

METHODS

We measured pre- and post-exposure changes in exhaled nitric oxide (eNO), spirometry, heart rate variability (HRV), and blood markers of inflammation in five volunteers.

RESULTS

Change in pre- and post-exposure measurements of eNO and spirometry was unremarkable. Neutrophil and lymphocyte counts increased and fibrinogen levels decreased in four of the five subjects. Measures of HRV showed decreases in the standard deviation of normal between beat intervals and sequential 5-minute intervals.

CONCLUSION

These data represent the first evidence of human physiologic response to LGPM exposure. Further exploration of coagulation effects and HRV is warranted.

Exercise-Induced Bronchoconstriction: Background, Prevalence, and Sport Considerations

The transient airway narrowing that occurs as a result of exercise is defined as exercise-induced bronchoconstriction (EIB). The prevalence of EIB has been reported to be up to 90% in asthmatic patients, reflecting the level of disease control. However, EIB may develop even in subjects without clinical asthma, particularly in children, athletes, patients with atopy or rhinitis, and following respiratory infections. The intensity, duration, and type of training have been associated with the occurrence of EIB. In athletes, EIB seems to be only partly reversible, and exercise seems to be a causative factor of airway inflammation and symptoms.

Occupational exposure to diesel engine exhaust and serum cytokine levels

The International Agency for Research on Cancer has classified diesel engine exhaust (DEE) as a human lung carcinogen. Given that inflammation is suspected to be an important underlying mechanism of lung carcinogenesis, we evaluated the relationship between DEE exposure and the inflammatory response using data from a cross-sectional molecular epidemiology study of 41 diesel engine testing workers and 46 unexposed controls. Repeated personal exposure measurements of PM_2.5 and other DEE constituents were taken for the diesel engine testing workers before blood collection. Serum levels of six inflammatory biomarkers including interleukin (IL)-1, IL-6, IL-8, tumor necrosis factor (TNF)-α, macrophage inflammatory protein (MIP)-1β, and monocyte chemotactic protein (MCP)-1 were analyzed in all subjects. Compared to unexposed controls, concentrations of MIP-1β were significantly reduced by ∼37% in DEE exposed workers (P < 0.001) and showed a strong decreasing trend with increasing PM_2.5 concentrations in all subjects (P_trend  < 0.001) as well as in exposed subjects only (P_trend  = 0.001). Levels of IL-8 and MIP-1β were significantly lower in workers in the highest exposure tertile of PM_2.5 (>397 µg/m³ ) compared to unexposed controls. Further, significant inverse exposure-response relationships for IL-8 and MCP-1 were also found in relation to increasing PM_2.5 levels among the DEE exposed workers. Given that IL-8, MIP-1β, and MCP-1 are chemokines that play important roles in recruitment of immunocompetent cells for immune defense and tumor cell clearance, the observed lower levels of these markers with increasing PM_2.5 exposure may provide insight into the mechanism by which DEE promotes lung cancer. Environ. Mol. Mutagen. 59:144-150, 2018. © 2017 Wiley Periodicals, Inc.

Relationship Between Air Quality and Outdoor Exercise Behavior in China: a Novel Mobile-Based Study

PURPOSE

Based on data collected from an exercise app, the study aims to provide empirical evidence on the relationship between air quality and patterns of outdoor exercise in China.

METHODS

Objective outdoor exercise data spanning 160 days were collected from 153 users of an exercise app, Tulipsport in China. Each exercise mode (running, biking, and walking, respectively) was organized into five air quality categories based on Air Quality Index (AQI): excellent, good, mild pollution, moderate pollution, and serious pollution. Key parameters of each app user were calculated and analyzed: the total number of exercise bouts, the average duration, and the average distance of each exercise mode in each air quality category.

RESULTS

Multivariate analyses of variance indicate that the users were less likely to participate in outdoor running, biking, and walking (F = 24.16, p < .01, Wilk's Λ = 0.64) as levels of air pollution increased. However, there is no difference in terms of average distance and duration of exercise across different air pollution categories.

CONCLUSIONS

People's participation in outdoor exercise is impeded by air pollution severity, but they stick to their exercise routines once exercise is initiated. Although people should protect themselves from health damages caused by exercising under pollution, the decreases in physical activity associated with air pollution may also pose an indirect risk to public health. The interactive relationship between air quality, exercise, and health warrants more empirical and interdisciplinary explorations.

Cys34 Adductomes Differ between Patients with Chronic Lung or Heart Disease and Healthy Controls in Central London

Oxidative stress generates reactive species that modify proteins, deplete antioxidant defenses, and contribute to chronic obstructive pulmonary disease (COPD) and ischemic heart disease (IHD). To determine whether protein modifications differ between COPD or IHD patients and healthy subjects, we performed untargeted analysis of adducts at the Cys34 locus of human serum albumin (HSA). Biospecimens were obtained from nonsmoking participants from London, U.K., including healthy subjects (n = 20) and patients with COPD (n = 20) or IHD (n = 10). Serum samples were digested with trypsin and analyzed by liquid chromatography-high resolution mass spectrometry. Effects of air pollution on adduct levels were also investigated based on estimated residential exposures to PM_2.5, O₃ and NO₂. For the 39 adducts with sufficient data, levels were essentially identical in blood samples collected from the same subjects on two consecutive days, consistent with the 28 day residence time of HSA. Multivariate linear regression revealed 21 significant associations, mainly with the underlying diseases but also with air-pollution exposures (p-value < 0.05). Interestingly, most of the associations indicated that adduct levels decreased with the presence of disease or increased pollutant concentrations. Negative associations of COPD and IHD with the Cys34 disulfide of glutathione and two Cys34 sulfoxidations, were consistent with previous results from smoking and nonsmoking volunteers and nonsmoking women exposed to indoor combustion of coal and wood.

EXPOsOMICS: final policy workshop and stakeholder consultation

The final meeting of the EXPOsOMICS project “Final Policy Workshop and Stakeholder Consultation” took place 28–29 March 2017 to present the main results of the project and discuss their implications both for future research and for regulatory and policy activities. This paper summarizes presentations and discussions at the meeting related with the main results and advances in exposome research achieved through the EXPOsOMICS project; on other parallel research initiatives on the study of the exposome in Europe and in the United States and their complementarity to EXPOsOMICS; lessons learned from these early studies on the exposome and how they may shape the future of research on environmental exposure assessment; and finally the broader implications of exposome research for risk assessment and policy development on environmental exposures. The main results of EXPOsOMICS in relation to studies of the external exposome and internal exposome in relation to both air pollution and water contaminants were presented as well as new technologies for environmental health research (adductomics) and advances in statistical methods. Although exposome research strengthens the scientific basis for policy development, there is a need in terms of showing added value for public health to: improve communication of research results to non-scientific audiences; target research to the broader landscape of societal challenges; and draw applicable conclusions. Priorities for future work include the development and standardization of methodologies and technologies for assessing the external and internal exposome, improved data sharing and integration, and the demonstration of the added value of exposome science over conventional approaches in answering priority policy questions.

Indoor particulate pollution in fitness centres with emphasis on ultrafine particles

Fitness centres (FC) represent a unique indoor microenvironment. Exercising on regular basis provides countless health benefits and improves overall well-being, but if these facilities have poor indoor air quality, the respective exercisers might be subjected to some adverse risks. Considering the limited existent data, this work aimed to evaluate particulate pollution (PM_10, PM_2.5, and ultrafine particles - UFP) in indoor air of FC and to estimate the respective risks for occupants (both staff and exercising subjects). Sampling was conducted during 40 consecutive days of May-June 2014 in general fitness areas, studios and classrooms (for group activities) of four different fitness centres (FC1-FC4) situated within Oporto metropolitan area, Portugal. The results showed that across the four FC, PM₁₀ ranged between 5 and 1080 μg m^-3 with median concentrations (15-43 μg m^-3) fulfilling the limit (50 μg m^-3) of Portuguese legislation in all FC. PM_2.5 (medians 5-37 μg m^-3; range 5-777 μg m^-3) exceeded thresholds of 25 μg m^-3 at some FC, indicating potential risks for the respective occupants; naturally ventilated FC exhibited significantly higher PM ranges (p < 0.05). Similarly, UFPs (range 0.5-88.6 × 10³ # cm^-3) median concentrations were higher (2-3 times) at FC without controlled ventilation systems. UFP were approximately twice higher (p < 0.05) during the occupied periods (mean of 9.7 × 10³vs. 4.8 × 10³ # cm^-3) with larger temporal variations of UFP levels observed in general fitness areas than in classrooms and studios. Cardio activities (conducted in studios and classrooms) led to approximately twice the UFPs intakes than other types of exercising. These results indicate that even short-term physical activity (or more specifically its intensity) might strongly influence the daily inhalation dose. Finally, women exhibited 1.2 times higher UFPs intake than men thus suggesting the need for future gender-specific studies assessing UFP exposure.

Respiratory and cardiovascular responses to walking down a traffic-polluted road compared with walking in a traffic-free area in participants aged 60 years and older with chronic lung or heart disease and age-matched healthy controls: a randomised, crossover study

BACKGROUND

Long-term exposure to pollution can lead to an increase in the rate of decline of lung function, especially in older individuals and in those with chronic obstructive pulmonary disease (COPD), whereas shorter-term exposure at higher pollution levels has been implicated in causing excess deaths from ischaemic heart disease and exacerbations of COPD. We aimed to assess the effects on respiratory and cardiovascular responses of walking down a busy street with high levels of pollution compared with walking in a traffic-free area with lower pollution levels in older adults.

METHODS

In this randomised, crossover study, we recruited men and women aged 60 years and older with angiographically proven stable ischaemic heart disease or stage 2 Global initiative for Obstructive Lung Disease (GOLD) COPD who had been clinically stable for 6 months, and age-matched healthy volunteers. Individuals with ischaemic heart disease or COPD were recruited from existing databases or outpatient respiratory and cardiology clinics at the Royal Brompton & Harefield NHS Foundation Trust and age-matched healthy volunteers using advertising and existing databases. All participants had abstained from smoking for at least 12 months and medications were taken as recommended by participants' doctors during the study. Participants were randomly assigned by drawing numbered disks at random from a bag to do a 2 h walk either along a commercial street in London (Oxford Street) or in an urban park (Hyde Park). Baseline measurements of participants were taken before the walk in the hospital laboratory. During each walk session, black carbon, particulate matter (PM) concentrations, ultrafine particles, and nitrogen dioxide (NO₂) concentrations were measured.

FINDINGS

Between October, 2012, and June, 2014, we screened 135 participants, of whom 40 healthy volunteers, 40 individuals with COPD, and 39 with ischaemic heart disease were recruited. Concentrations of black carbon, NO₂, PM₁₀, PM_2.5, and ultrafine particles were higher on Oxford Street than in Hyde Park. Participants with COPD reported more cough (odds ratio [OR] 1·95, 95% CI 0·96-3·95; p<0·1), sputum (3·15, 1·39-7·13; p<0·05), shortness of breath (1·86, 0·97-3·57; p<0·1), and wheeze (4·00, 1·52-10·50; p<0·05) after walking down Oxford Street compared with Hyde Park. In all participants, irrespective of their disease status, walking in Hyde Park led to an increase in lung function (forced expiratory volume in the first second [FEV₁] and forced vital capacity [FVC]) and a decrease in pulse wave velocity (PWV) and augmentation index up to 26 h after the walk. By contrast, these beneficial responses were attenuated after walking on Oxford Street. In participants with COPD, a reduction in FEV₁ and FVC, and an increase in R5-20 were associated with an increase in during-walk exposure to NO₂, ultrafine particles and PM_2.5, and an increase in PWV and augmentation index with NO₂ and ultrafine particles. In healthy volunteers, PWV and augmentation index were associated both with black carbon and ultrafine particles.

INTERPRETATION

Short-term exposure to traffic pollution prevents the beneficial cardiopulmonary effects of walking in people with COPD, ischaemic heart disease, and those free from chronic cardiopulmonary diseases. Medication use might reduce the adverse effects of air pollution in individuals with ischaemic heart disease. Policies should aim to control ambient levels of air pollution along busy streets in view of these negative health effects.

FUNDING

British Heart Foundation.

Inhaled diesel exhaust alters the allergen-induced bronchial secretome in humans

Diesel exhaust (DE) is a paradigm for traffic-related air pollution. Human adaptation to DE is poorly understood and currently based on oversimplified models. DE promotes allergic responses, but protein expression changes mediated by this interaction have not been systematically investigated. The aim of this study was to define the effect of inhaled DE on allergen-induced proteins in the lung.

We performed a randomised and blinded controlled human crossover exposure study. Participants inhaled filtered air or DE; thereafter, contralateral lung segments were challenged with allergen or saline. Using label-free quantitative proteomics, we comprehensively defined DE-mediated alteration of allergen-driven secreted proteins (secretome) in bronchoalveolar lavage. We further examined expression of proteins selected from the secretome data in independent validation experiments using Western blots, ELISA and immunohistochemistry.

We identified protein changes unique to co-exposure (DE+allergen), undetected with mono-exposures (DE or allergen alone). Validation studies confirmed that specific proteins (e.g.the antimicrobial peptide cystatin-SA) were significantly enhanced with DE+allergen compared to either mono-exposure.

This study demonstrates that common environmental co-exposures can uniquely alter protein responses in the lungs, illuminating biology that mono-exposures cannot. This study highlights the value of complex humanin vivomodels in detailing airway responses to inhaled pollution.

Effects of ambient particulate matter on aerobic exercise performance

Background/Objective

Wintertime thermal inversions in narrow mountain valleys create a ceiling effect, increasing concentration of small particulate matter (PM_2.5). Despite potential health risks, many people continue to exercise outdoors in thermal inversions. This study measured the effects of ambient PM_2.5 exposure associated with a typical thermal inversion on exercise performance, pulmonary function, and biological markers of inflammation.

Methods

Healthy, active adults (5 males, 11 females) performed two cycle ergometer time trials outdoors in a counterbalanced design: 1) low ambient PM_2.5 concentrations (<12 μg/m³), and 2) an air quality index (AQI) ranking of “yellow.” Variables of interest were exercise performance, exhaled nitric oxide (eNO), c-reactive protein (CRP), forced vital capacity (FVC), and forced expiratory volume in 1 s (FEV₁).

Results

Despite a significant difference in mean PM_2.5 concentration of 9.3 ± 3.0 μg/m³ between trials (p < .001), there was no significant difference (p = .424) in the distance covered during low PM_2.5 conditions (9.9 ± 1.7 km) compared to high PM_2.5 conditions (10.1 ± 1.5 km). There were no clinically significant differences across time or between trials for eNO, CRP, FVC, or FEV₁. Additionally, there were no dose-response relationships (p > .05) for PM_2.5 concentration and the measured variables.

Conclusion

An acute bout of vigorous exercise during an AQI of “yellow” did not diminish exercise performance in healthy adults, nor did it have a negative effect on pulmonary function or biological health markers. These variables might not be sensitive to small changes from acute, mild PM_2.5 exposure.

Asthma disease as cause of admission to hospitals due to exposure to ambient oxidants in Mashhad, Iran

Nowadays, asthma is one of the most common chronic respiratory diseases, worldwide. Many reports have emphasized the correlation between the short-term exposure to the ambient air pollutants and acute respiratory diseases, especially among children with asthmatic symptoms. The aim of this study was to evaluate the relationship between the exposure to three atmospheric antioxidants (NO₂, SO₂, and O₃) and hospital admission due to asthmatic disease (HAAD) in the city of Mashhad, Iran. The concentrations of atmospheric antioxidants were obtained from the real-time monitoring stations located in the city. The collected data were employed for developing predictive models in the AirQ software. In order to investigate the association between short-term exposure to air pollutants and HAAD, the study participants were categorized into two age groups: less than 15 and from 15 to 64 years old. The results indicated that in people less than 15 years increase in NO₂ (attributable proportion (AP) = 3.775%, 95% CI 0.897-6.883%), SO₂ (AP = 3.649%, 95% CI 1.295-5.937%), and O₃ (AP = 0.554%,95% CI 0.00-3.321) results in increase in HAAD. While for those aged between 15 and 64 years, the AP was 4.192% (95% CI 0.450-7.662%) for NO₂; 0.0% (95% CI 0.00-1.687%) for SO₂; and 0.236% (95% CI 0.00-1.216%) for O₃. The number of asthmatic cases who were less than 15 years admitted to the hospitals during the study period was higher than that of those within the age groups between 15 and 64 years as a consequence of exposure to NO₂ (101 vs. 75), SO₂ (98 vs. 0), and O₃ (15 vs. 3), respectively. To the best of our knowledge, the AirQ model has not been applied before to estimate the effect of atmospheric antioxidant exposure on hospital admission because of asthma disease. Eventually, this model is proposed to be applicable for other cities around the world.

Mechanistic insight into the impact of nanomaterials on asthma and allergic airway disease

Asthma is a chronic respiratory disease known for its high susceptibility to environmental exposure. Inadvertent inhalation of engineered or incidental nanomaterials is a concern for human health, particularly for those with underlying disease susceptibility. In this review we provide a comprehensive analysis of those studies focussed on safety assessment of different nanomaterials and their unique characteristics on asthma and allergic airway disease. These include in vivo and in vitro approaches as well as human and population studies. The weight of evidence presented supports a modifying role for nanomaterial exposure on established asthma as well as the development of the condition. Due to the variability in modelling approaches, nanomaterial characterisation and endpoints used for assessment in these studies, there is insufficient information for how one may assign relative hazard potential to individual nanoscale properties. New developments including the adoption of standardised models and focussed in vitro and in silico approaches have the potential to more reliably identify properties of concern through comparative analysis across robust and select testing systems. Importantly, key to refinement and choice of the most appropriate testing systems is a more complete understanding of how these materials may influence disease at the cellular and molecular level. Detailed mechanistic insight also brings with it opportunities to build important population and exposure susceptibilities into models. Ultimately, such approaches have the potential to more clearly extrapolate relevant toxicological information, which can be used to improve nanomaterial safety assessment for human disease susceptibility.

Clinical, functional and inflammatory characteristics in patients with paucigranulocytic stable asthma: Comparison with different sputum phenotypes

BACKGROUND

According to induced sputum cell count, four different asthma phenotypes have been recognized (eosinophilic, neutrophilic, mixed and paucigranulocytic). The aim of this study was to detect functional and inflammatory characteristics of patients with paucigranulocytic asthma.

METHODS

A total of 240 asthmatic patients were categorized into the four phenotypes according to cell counts in induced sputum. All patients underwent pulmonary function tests, and measurement of fraction of exhaled nitric oxide (FeNO). The levels of IL-8, IL-13 and eosinophilic cationic protein (ECP) were also measured in sputum supernatant. Treatment, asthma control and the presence of severe refractory asthma (SRA) were also recorded.

RESULTS

Patients were categorized into the four phenotypes as follows: eosinophilic (40%), mixed (6.7%), neutrophilic (5.4%) and paucigranulocytic (47.9%). Although asthma control test did not differ between groups (P=.288), patients with paucigranulocytic asthma had better lung function (FEV₁ % pred) [median (IQR): 71.5 (59.0-88.75) vs 69.0 (59.0-77.6) vs 68.0 (60.0-85.5) vs 80.5 (69.7-95.0), P=.009] for eosinophilic, mixed, neutrophilic and paucigranulocytic asthma, respectively, P=.009). SRA occurred more frequently in the eosinophilic and mixed phenotype (41.6% and 43.7%, respectively) and less frequently in the neutrophilic and paucigranulocytic phenotype (25% and 21.7%, respectively, P=.01). FeNO, ECP and IL-8 were all low in the paucigranulocytic, whereas as expected FeNO and ECP were higher in eosinophilic and mixed asthma, while IL-8 was higher in patients with neutrophilic and mixed asthma (P<.001 for all comparisons). Interestingly, 14.8% of patients with paucigranulocytic asthma had poor asthma control.

CONCLUSION

Paucigranulocytic asthma most likely represents a "benign" asthma phenotype, related to a good response to treatment, rather than a "true" phenotype of asthma. However, paucigranulocytic patients that remain not well controlled despite optimal treatment represent an asthmatic population that requires further study for potential novel targeted interventions.

Nanomaterials Versus Ambient Ultrafine Particles: An Opportunity to Exchange Toxicology Knowledge

BACKGROUND

A rich body of literature exists that has demonstrated adverse human health effects following exposure to ambient air particulate matter (PM), and there is strong support for an important role of ultrafine (nanosized) particles. At present, relatively few human health or epidemiology data exist for engineered nanomaterials (NMs) despite clear parallels in their physicochemical properties and biological actions in in vitro models.

OBJECTIVES

NMs are available with a range of physicochemical characteristics, which allows a more systematic toxicological analysis. Therefore, the study of ultrafine particles (UFP, <100 nm in diameter) provides an opportunity to identify plausible health effects for NMs, and the study of NMs provides an opportunity to facilitate the understanding of the mechanism of toxicity of UFP.

METHODS

A workshop of experts systematically analyzed the available information and identified 19 key lessons that can facilitate knowledge exchange between these discipline areas.

DISCUSSION

Key lessons range from the availability of specific techniques and standard protocols for physicochemical characterization and toxicology assessment to understanding and defining dose and the molecular mechanisms of toxicity. This review identifies a number of key areas in which additional research prioritization would facilitate both research fields simultaneously.

CONCLUSION

There is now an opportunity to apply knowledge from NM toxicology and use it to better inform PM health risk research and vice versa. https://doi.org/10.1289/EHP424.

Ultrafine particles and black carbon personal exposures in asthmatic and non-asthmatic children at school age

Traffic-related air pollution (TRAP) exposure during childhood is associated with asthma; however, the contribution of the different TRAP pollutants in each microenvironment (home, school, transportation, others) in asthmatic and non-asthmatic children is unknown. Daily (24-h) personal black carbon (BC), ultrafine particle (UFP), and alveolar lung-deposited surface area (LDSA) individual exposure measurements were obtained from 100 children (29 past and 21 current asthmatics, 50 non-asthmatics) aged 9±0.7 years from the INMA-Sabadell cohort (Catalonia, Spain). Time spent in each microenvironment was derived by the geolocation provided by the smartphone and a new spatiotemporal map-matching algorithm. Asthmatics and non-asthmatics spent the same amount of time at home (60% and 61%, respectively), at school (20% and 23%), on transportation (8% and 7%), and in other microenvironments (7% and 5%). The highest concentrations of all TRAPs were attributed to transportation. No differences in TRAP concentrations were found overall or by type of microenvironment between asthmatics and non-asthmatics, nor when considering past and current asthmatics, separately. In conclusion, asthmatic and non-asthmatic children had a similar time-activity pattern and similar average exposures to BC, UFP, and LDSA concentrations. This suggests that interventions should be tailored to general population, rather than to subgroups defined by disease.

A qualitative study of the knowledge, attitudes, and behaviors of people exposed to diesel exhaust at the workplace in British Columbia, Canada

PURPOSE

To identify exposure-related knowledge, attitudes and behaviors of individuals occupationally exposed to diesel exhaust (DE); to reveal strengths, knowledge gaps and misperceptions therein.

METHODS

A Mental Models approach was used to gather information about current scientific understanding of DE exposure hazards and the ways in which exposure can be reduced. Thirty individuals in British Columbia who were regularly exposed to occupational DE were interviewed. The audio was recorded and transcribed. Data was grouped together and examined to draw out themes around DE awareness, hazard assessment and risk reduction behaviors. These themes were then compared and contrasted with existing grey and research literature in order to reveal strengths, gaps and misperceptions regarding DE exposure.

RESULTS

Study participants were aware and concerned about their exposure to DE but had incomplete and sometimes incorrect understanding of exposure pathways, health effects, and effective strategies to reduce their exposures. The perceived likelihood of exposure to DE was significantly greater compared to that of other work hazards (p<0.01), whereas the difference for their perceived severity of consequences was not significant. There was no universally perceived main source of information regarding DE, and participants generally distrusted sources of information based on their past experience with the source. Most of the actions that were taken to address DE exposure fell into the area of administrative controls such as being aware of sources of DE and avoiding these sources.

CONCLUSIONS

This study of the knowledge, attitude, and behavior of those occupationally exposed to DE found, most notably, that more education and training and the creation of a health effects inventory regarding DE exposure were desired.

Ambient Size Distributions and Lung Deposition of Aerosol Dithiothreitol-Measured Oxidative Potential: Contrast between Soluble and Insoluble Particles

Ambient particulate matter may upset redox homeostasis, leading to oxidative stress and adverse health effects. Size distributions of water-insoluble and water-soluble OPDTT (dithiothreitol assay, measure of oxidative potential per air volume) are reported for a roadside site and an urban site. The average water-insoluble fractions were 23% and 51%, and 37% and 39%, for fine and coarse modes at the roadside and urban sites, respectively, measured during different periods. Water-soluble OPDTT was unimodal, peaked near 1-2.5 μm due to contributions from fine-mode organic components plus coarse-mode transition metal ions. In contrast, water-insoluble OPDTT was bimodal, with both fine and coarse modes. The main chemical components that drive both fractions appear to be the same, except that for water-insoluble OPDTT the compounds were absorbed on surfaces of soot and non-tailpipe traffic dust. They were largely externally mixed and deposited in different regions in the respiratory system, transition metal ions predominately in the upper regions and organic species, such as quinones, deeper in the lung. Although OPDTT per mass (toxicity) was highest for ultrafine particles, estimated lung deposition was mainly from accumulation and coarse particles. Contrasts in the phases of these forms of OPDTT deposited in the respiratory system may have differing health impacts.

Short-term air pollution exposure decreases lung function: a repeated measures study in healthy adults

BACKGROUND

Daily changes in ambient concentrations of particulate matter, nitrogen oxides and ozone are associated with increased cardiopulmonary morbidity and mortality, with the lungs and their function being a vulnerable target.

METHODS

To evaluate the association between daily changes in air pollution and lung function in healthy adults we obtained annual lung function measurements from a routine worker health surveillance program not designed for research purposes. Forced Vital Capacity (FVC), Forced Expiratory Volume in the first second (FEV1), FEV1/FVC and Peak Expiratory flow (PEF) from a cohort of 2449 employees were associated with daily measurements of PM₁₀, NO₂ and ozone at a nearby monitoring station in the North of Belgium. Repeated measures were available for the period 2011-2015.

RESULTS

The mean (SD) PM₁₀ concentration on the day of the lung function test was 24.9 (15.5) μg/m³. A 10 μg PM₁₀/m³ increase on the day of the clinical examination was associated with a 18.9 ml lower FVC (95% CI: -27.5 to -10.3, p < 0.0001), 12.8 ml lower FEV1 (-19.1 to -6.5; p < 0.0001), and a 51.4 ml/s lower PEF (-75.0 to -27.0; p < 0.0001). The FEV1/FVC-ratio showed no associations. An increase of 10 μgNO₂/m³ was associated with a reduction in PEF (-66.1 ml/s (-106.6 to -25.6; p < 0.001)) on the day of the examination.

CONCLUSIONS

We found negative associations between daily variations in ambient air pollution and FVC, FEV1 and PEF in healthy adults.

Physical activity, black carbon exposure, and DNA methylation in the FOXP3 promoter

Background

Physical activity is associated with improvement in lung function; however, pollution exposure during physical activity can lead to a transient reduction in lung function. This paradoxical relationship may be linked to altered T regulatory (Treg) cell activity, which increases with exercise and suppresses airway inflammation, but decreases in association with exposure to air pollution. To clarify these relationships, we investigated buccal cell DNA methylation of the forkhead box p3 (FOXP3) gene promoter, a proposed biomarker of Treg activity. We hypothesized that active urban children would have lower FOXP3 promoter methylation, associated with better lung function compared to non-active children. We also hypothesized that this relationship would be attenuated by high exposure to the air pollutant black carbon (BC).

Methods

We performed a cross-sectional study of 135 children ages 9–14 who live in New York City. Activity was measured across 6 days. BC exposure was assessed by personal monitors worn for two 24-h periods, followed by lung function assessment. Buccal swabs were collected for DNA methylation analysis of three regions (six CpG sites) in the FOXP3 promoter.

Results

In multivariable regression models, overall, there was no significant relationship between physical activity and FOXP3 promoter methylation (p > 0.05). However, in stratified analyses, among children with higher BC exposure (≥1200 ng/m³), physical activity was associated with 2.37% lower methylation in promoter 2 (CpGs −77, −65, and −58) (β_estimate = −2.37%, p < 0.01) but not among those with lower BC exposure (β_estimate = 0.54%, p > 0.05). Differences across strata were statistically significant (p_interaction = 0.04). Among all children, after controlling for BC concentration, promoter 2 methylation was associated with reduced FEV₁/FVC (β_estimate = −0.40%, p < 0.01) and reduced FEF_25–75% (β_estimate = −1.46%, p < 0.01).

Conclusions

Physical activity in urban children appeared associated with lower FOXP3 promoter methylation, a possible indicator of greater Treg function, under conditions of high BC exposure. Reduced FOXP3 promoter methylation was associated with higher lung function. These findings suggest that physical activity may induce immunologic benefits, particularly for urban children with greater risk of impaired lung function due to exposure to higher air pollution. FOXP3 promoter buccal cell methylation may function as a useful biomarker of that benefit.

Electronic supplementary material

The online version of this article (doi:10.1186/s13148-017-0364-0) contains supplementary material, which is available to authorized users.

Pulmonary toxicity following acute coexposures to diesel particulate matter and α-quartz crystalline silica in the Sprague-Dawley rat

The effects of acute pulmonary coexposures to silica and diesel particulate matter (DPM), which may occur in various mining operations, were investigated in vivo. Rats were exposed by intratracheal instillation (IT) to silica (50 or 233 µg), DPM (7.89 or 50 µg) or silica and DPM combined in phosphate-buffered saline (PBS) or to PBS alone (control). At one day, one week, one month, two months and three months postexposure bronchoalveolar lavage and histopathology were performed to assess lung injury, inflammation and immune response. While higher doses of silica caused inflammation and injury at all time points, DPM exposure alone did not. DPM (50 µg) combined with silica (233 µg) increased inflammation at one week and one-month postexposure and caused an increase in the incidence of fibrosis at one month compared with exposure to silica alone. To assess susceptibility to lung infection following coexposure, rats were exposed by IT to 233 µg silica, 50 µg DPM, a combination of the two or PBS control one week before intratracheal inoculation with 5 × 105 Listeria monocytogenes. At 1, 3, 5, 7 and 14 days following infection, pulmonary immune response and bacterial clearance from the lung were evaluated. Coexposure to DPM and silica did not alter bacterial clearance from the lung compared to control. Although DPM and silica coexposure did not alter pulmonary susceptibility to infection in this model, the study showed that noninflammatory doses of DPM had the capacity to increase silica-induced lung injury, inflammation and onset/incidence of fibrosis.