Effects of personal nitrogen dioxide exposure on airway inflammation and lung function

Exposure to O3 and NO2 on the interfacial chemistry of the pulmonary surfactant and the mechanism of lung oxidative damage

Exposure to ozone (O3) and nitrogen dioxide (NO2) are related to pulmonary dysfunctions and various lung diseases, but the underlying biochemical mechanisms remain uncertain. Herein, the effect of inhalable oxidizing gas pollutants on the pulmonary surfactant (PS, extracted from porcine lungs), a mixture of active lipids and proteins that plays an important role in maintaining normal respiratory mechanics, is investigated in terms of the interfacial chemistry using in-vitro experiments; and the oxidative stress induced by oxidizing gases in the simulated lung fluid (SLF) supplemented with the PS is explored. The results showed that O3 and NO2 individually increased the surface tension of the PS and reduced its foaming ability; this was accompanied by the surface pressure-area isotherms of the PS monolayers shifting toward lower molecular areas, with O3 exhibiting more severe effects than NO2. Moreover, both O3 and NO2 produced reactive oxygen species (ROS) resulting in lipid peroxidation and protein damage to the PS. The formation of superoxide radicals (O2•-) was correlated with the decomposition of O3 and the reactions of O3 and NO2 with antioxidants in the SLF. These radicals, in the presence of antioxidants, led to the formation of hydrogen peroxide and hydroxyl radicals (•OH). Additionally, the direct oxidation of unsaturated lipids by O3 and NO2 further caused an increase in the ROS content. This change in the ROS chemistry and increased •OH production tentatively explain how inhalable oxidizing gases lead to oxidative stress and adverse health effects. In summary, our results indicated that inhaled O3 and NO2 exposure can significantly alter the interfacial properties of the PS, oxidize its active ingredients, and induce ROS formation in the SLF. The results of this study provide a basis for the elucidation of the potential hazards of inhaled oxidizing gas pollutants in the human respiratory system.

Constructing Adsorption Site-Enhanced Vo-BiOCl/rGO Heterostructures for Efficient Response to NO2/NH3 Gases at Room Temperature

Real-time detection of harmful gases at room temperature has become a serious problem in public health and environmental monitoring. Two-dimensional materials with semiconductor properties BiOCl is a promising gas-sensitive material due to its large specific surface area and adjustable band gap as well as outstanding safety characteristics. However, limited by the weak gas adsorption sites and sluggish charge-transfer ability, the performance of BiOCl could not be fully exploited. Oxygen vacancy (Vo) engineering can introduce lattice defects, thereby significantly increasing the local charge density and enhancing the adsorption of gases, which is an effective strategy to enhance the gas-sensing performance. In this work, we composite BiOCl with a vacancy (Vo-BiOCl) and reduced graphene oxide (rGO) to construct a Vo-BiOCl/rGO heterostructure with enhanced gas adsorption sites. Experimental and theoretical calculations show that Vo can enhance the adsorption of gases and the introduction of rGO forms a high-quality heterostructure with BiOCl, which can effectively reduce the band gap of BiOCl and promote electron transfer, thereby improving the sensitivity of the sensor. Benefiting from above, Vo-BiOCl/rGO achieves the ability to detect low concentrations of NO2/NH3 at room temperature, with high sensitivity (55% at 1 ppm of NO2 and -28% at 1 ppm of NH3), fast response time (40 s at 1 ppm of NO2 and 2 s at 1 ppm of NH3), good stability (over 150 days), and fully recoverable gas sensitivity.

The Association Between Personal Air Pollution Exposures and Fractional Exhaled Nitric Oxide (FeNO): A Systematic Review

PURPOSE OF REVIEW

Airway inflammation is a common biological response to many types of environmental exposures and can lead to increased nitric oxide (NO) concentrations in exhaled breath. In recent years, several studies have evaluated airway inflammation using fractional exhaled nitric oxide (FeNO) as a biomarker of exposures to a range of air pollutants. This systematic review aims to summarize the studies that collected personal-level air pollution data to assess the air pollution-induced FeNO responses and to determine if utilizing personal-level data resulted in an improved characterization of the relationship between air pollution exposures and FeNO compared to using only ambient air pollution exposure data.

RECENT FINDINGS

Thirty-six eligible studies were identified. Overall, the studies included in this review establish that an increase in personal exposure to particulate and gaseous air pollutants can significantly increase FeNO. Nine out of the 12 studies reported statistically significant FeNO increases with increasing personal PM2.5 exposures, and up to 11.5% increase in FeNO per IQR increase in exposure has also been reported between FeNO and exposure to gas-phase pollutants, such as ozone, NO2, and benzene. Furthermore, factors such as chronic respiratory diseases, allergies, and medication use were found to be effect modifiers for air pollution-induced FeNO responses. About half of the studies that compared the effect estimates using both personal and ambient air pollution exposure methods reported that only personal exposure yielded significant associations with FeNO response. The evidence from the reviewed studies confirms that FeNO is a sensitive biomarker for air pollutant-induced airway inflammation. Personal air pollution exposure assessment is recommended to accurately assess the air pollution-induced FeNO responses. Furthermore, comprehensive adjustments for the potential confounding factors including the personal exposures of the co-pollutants, respiratory disease status, allergy status, and usage of medications for asthma and allergies are recommended while assessing the air pollution-induced FeNO responses.

Methylomic, Proteomic, and Metabolomic Correlates of Traffic-Related Air Pollution in the Context of Cardiorespiratory Health: A Systematic Review, Pathway Analysis, and Network Analysis

A growing body of literature has attempted to characterize how traffic-related air pollution (TRAP) affects molecular and subclinical biological processes in ways that could lead to cardiorespiratory disease. To provide a streamlined synthesis of what is known about the multiple mechanisms through which TRAP could lead to cardiorespiratory pathology, we conducted a systematic review of the epidemiological literature relating TRAP exposure to methylomic, proteomic, and metabolomic biomarkers in adult populations. Using the 139 papers that met our inclusion criteria, we identified the omic biomarkers significantly associated with short- or long-term TRAP and used these biomarkers to conduct pathway and network analyses. We considered the evidence for TRAP-related associations with biological pathways involving lipid metabolism, cellular energy production, amino acid metabolism, inflammation and immunity, coagulation, endothelial function, and oxidative stress. Our analysis suggests that an integrated multi-omics approach may provide critical new insights into the ways TRAP could lead to adverse clinical outcomes. We advocate for efforts to build a more unified approach for characterizing the dynamic and complex biological processes linking TRAP exposure and subclinical and clinical disease and highlight contemporary challenges and opportunities associated with such efforts.

Methylomic, proteomic, and metabolomic correlates of traffic-related air pollution: A systematic review, pathway analysis, and network analysis relating traffic-related air pollution to subclinical and clinical cardiorespiratory outcomes

A growing body of literature has attempted to characterize how traffic-related air pollution (TRAP) affects molecular and subclinical biological processes in ways that could lead to cardiorespiratory disease. To provide a streamlined synthesis of what is known about the multiple mechanisms through which TRAP could lead cardiorespiratory pathology, we conducted a systematic review of the epidemiological literature relating TRAP exposure to methylomic, proteomic, and metabolomic biomarkers in adult populations. Using the 139 papers that met our inclusion criteria, we identified the omic biomarkers significantly associated with short- or long-term TRAP and used these biomarkers to conduct pathway and network analyses. We considered the evidence for TRAP-related associations with biological pathways involving lipid metabolism, cellular energy production, amino acid metabolism, inflammation and immunity, coagulation, endothelial function, and oxidative stress. Our analysis suggests that an integrated multi-omics approach may provide critical new insights into the ways TRAP could lead to adverse clinical outcomes. We advocate for efforts to build a more unified approach for characterizing the dynamic and complex biological processes linking TRAP exposure and subclinical and clinical disease, and highlight contemporary challenges and opportunities associated with such efforts.

Rutin hydrate relieves neuroinflammation in zebrafish models: Involvement of NF-κB pathway as a central network

Neuroinflammation is prevalent in multiple brain diseases and may also lead to dementia, cognitive impairment, and impaired spatial memory function associated with neurodegenerative diseases. A neuroprotective and antioxidant flavonoid, rutin hydrate (RH), was evaluated for the anti-neuroinflammatory activity mediated by copper sulfate (CuSO4) solution and lipopolysaccharide (LPS) in zebrafish. The results showed that 100 mg/L RH significantly reduced the ratio of neutrophil mobility in caudal hematopoietic tissue (CHT) region caused by CuSO4 and the number of neutrophils co-localized with facial peripheral nerves. In the LPS model, RH co-injection significantly diminished neutrophil and macrophage migration. Therefore, RH exhibited a significant rescue effect on both models. In addition, RH treatment remarkably reduced the effects of neuroinflammation on the locomotor ability, expression levels of genes associated with behavioral disorders, and acetylcholinesterase (AChE) activity. Furthermore, network pharmacology techniques were employed to investigate the potential mechanisms, and the associated genes and enzyme activities were validated in order to elucidate the underlying mechanisms. Network pharmacological analysis and zebrafish model indicated that RH regulated the expressions of NF-κB pathway-related targets (Toll-like receptor 9 (tlr9), nuclear factor kappa B subunit 1 (nfkb1), RELA proto-oncogene (RelA), nitric oxide synthase 2a, inducible (nos2a), tumour necrosis factor alpha-like (tnfα), interleukin 6 (il6), interleukin 1β (il1β), chemokine 8 (cxcl8), and macrophage migration inhibitory factor (mif)) as well as six key factors (arachidonic acid 4 alpha-lipoxygenase (alox4a), arachidonate 5-lipoxygenase a (alox5), prion protein a (prnpa), integrin, beta 2 (itgb2), catalase (CAT), and alkaline phosphatase (ALP) enzymes). Through this study, a thorough understanding of the mechanism underlying the therapeutic effects of RH in neuroinflammation has been achieved, thereby establishing a solid foundation for further research on the potential therapeutic applications of RH in neuroinflammatory disorders.

Long-term exposure to ambient fine particulate components and leukocyte epigenome-wide DNA Methylation in older men: the Normative Aging Study

BACKGROUND

Epigenome-wide association studies of ambient fine particulate matter (PM2.5) have been reported. However, few have examined PM2.5 components (PMCs) and sources or included repeated measures. The lack of high-resolution exposure measurements is the key limitation. We hypothesized that significant changes in DNA methylation might vary by PMCs and the sources.

METHODS

We predicted the annual average of 14 PMCs using novel high-resolution exposure models across the contiguous U.S., between 2000-2018. The resolution was 50 m × 50 m in the Greater Boston Area. We also identified PM2.5 sources using positive matrix factorization. We repeatedly collected blood samples and measured leukocyte DNAm with the Illumina HumanMethylation450K BeadChip in the Normative Aging Study. We then used median regression with subject-specific intercepts to estimate the associations between long-term (one-year) exposure to PMCs / PM2.5 sources and DNA methylation at individual cytosine-phosphate-guanine CpG sites. Significant probes were identified by the number of independent degrees of freedom approach, using the number of principal components explaining > 95% of the variation of the DNA methylation data. We also performed regional and pathway analyses to identify significant regions and pathways.

RESULTS

We included 669 men with 1,178 visits between 2000-2013. The subjects had a mean age of 75 years. The identified probes, regions, and pathways varied by PMCs and their sources. For example, iron was associated with 6 probes and 6 regions, whereas nitrate was associated with 15 probes and 3 regions. The identified pathways from biomass burning, coal burning, and heavy fuel oil combustion sources were associated with cancer, inflammation, and cardiovascular diseases, whereas there were no pathways associated with all traffic.

CONCLUSIONS

Our findings showed that the effects of PM2.5 on DNAm varied by its PMCs and sources.

Associations between ambient air pollutants and childhood hand, foot, and mouth disease in Sichuan, China: a spatiotemporal study

Hand, foot, and mouth disease (HFMD) is a major public health concern in the Asia-Pacific region. Previous studies have implied that ambient air pollution may affect the incidence of HFMD, but the results among different regions are inconsistent. We aimed to deepen the understanding of the associations between air pollutants and HFMD by conducting a multicity study. Daily data on childhood HFMD counts and meteorological and ambient air pollution (PM_2.5, PM₁₀, NO₂, CO, O₃, and SO₂) concentrations in 21 cities in Sichuan Province from 2015 to 2017 were collected. A spatiotemporal Bayesian hierarchical model framework was established, and then a distributed lag nonlinear models (DLNMs) was constructed to reveal exposure-lag-response relationships between air pollutants and HFMD while controlling for spatiotemporal effects. Furthermore, given the differences in the levels and seasonal trends of air pollutants between the basin region and plateau region, we explored whether these associations varied between different areas (basin and plateau). The associations between air pollutants and HFMD were nonlinear, with different lag responses. Low NO₂ concentrations and both low and high PM_2.5 and PM₁₀ concentrations were associated with a decreased risk of HFMD. No significant associations between CO, O₃, and SO₂ and HFMD were found. The associations between air pollutant concentrations and HFMD were different between the basin and plateau regions. Our study revealed associations between PM_2.5, PM₁₀, and NO₂ concentrations and HFMD, deepening the understanding of the relationships between air pollutants and HFMD. These findings provide evidence to support the formulation of relevant prevention measures and the establishment of an early warning system.

Characteristics and determinants of personal exposure to typical air pollutants: A pilot study in Beijing and Baoding, China

Personal exposure to fine particulate matter (PM_2.5), nitrogen oxides (NO_x, NO₂ and NO), ozone (O₃) and sulfur dioxide (SO₂) was repeatedly measured among fourteen office workers in Beijing and Baoding, China in summer, autumn and winter of 2019. Time-activity patterns were simultaneously recorded. Determinants of personal air pollution exposure were investigated for each pollutant via a linear mixed effect model. The personal concentrations of PM_2.5, NO₂, NO and O₃ were higher in autumn and winter than those in summer. A decreasing trend was found in the personal PM_2.5 level for a typical indoor population in Beijing, indicating that particulate pollution was effectively controlled in Beijing and its surrounding area. The personal levels of PM_2.5, NO₂, and O₃ were weakly correlated with those monitored at ambient stations and were lower than the respective ambient levels except for PM_2.5 in summer and NO₂ in winter. This pilot study showed that the indoor air environment, ambient pollution, traffic-related variables and temperature were significant exposure sources for office workers. Our study highlighted the significance of controlling traffic emissions and improving the workplace air quality to protect the health of office workers. More importantly, we demonstrated the feasibility of model development for personal air pollution exposure prediction.

Air pollution associated acute respiratory inflammation and modification by GSTM1 and GSTT1 gene polymorphisms: a panel study of healthy undergraduates

Epidemiological evidence has linked air pollution with adverse respiratory outcomes, but the mechanisms underlying susceptibility to air pollution remain unclear. This study aimed to investigate the role of glutathione S-transferase (GST) polymorphism in the association between air pollution and lung function levels. A total of 75 healthy young volunteers aged 18-20 years old were recruited for six follow-up visits and examinations. Spirometry was conducted to obtain lung function parameters such as forced vital capacity (FVC), and forced expiratory volume in 1 s (FEV₁). Nasal fluid concentrations of interleukin-6 (IL-6), interleukin-8 (IL-8), tumor necrosis factor-α (TNF-α), and 8-epi-prostaglandin F2α (8-epi-PGF2a) were measured using ELISA kits. Linear mixed-effect models were used to evaluate the association of air pollutants with respiratory outcomes. Additionally, polymorphisms of glutathione S-transferase mu 1 (GSTM1) and glutathione S-transferase theta 1 (GSTT1) were estimated to explore its role in the association between air pollutants and lung function. We found that short-term exposure to atmospheric particulates such as PM_2.5 and PM₁₀ can cause an increase in nasal biomarkers of inflammation, oxidative stress, and lung function, while air gaseous pollutant exposure is linked with decreased lung function, except for CO. Stratification analyses showed that an increase in nasal inflammatory cytokines caused by exposure to atmospheric particulates is more obvious in subjects with GSTM1-sufficient (GSTM1⁺) than GSTM1-null (GSTM1^-), while elevated lung function levels due to air particles are more significant in subjects with the genotype of GSTM1^- when compared to GSTM1⁺. As for air gaseous pollutants, decreased lung function levels caused by O₃, SO₂, and NO₂ exposure is more manifest in subjects with the genotype of GSTM1^- compared to GSTM1⁺. Taken together, short-term exposure to air pollutants is associated with alterations in nasal biomarkers and lung function levels in young healthy adults, and susceptible genotypes play an important mediation role in the association between exposure to air pollutants and inflammation, oxidative stress, and lung function levels.

Characteristics, health risks, and premature mortality attributable to ambient air pollutants in four functional areas in Jining, China

Air pollution is one of the leading causes for global deaths and understanding pollutant emission sources is key to successful mitigation policies. Air quality data in the urban, suburban, industrial, and rural areas (UA, SA, IA, and RA) of Jining, Shandong Province in China, were collected to compare the characteristics and associated health risks. The average concentrations of PM_2.5, PM₁₀, SO₂, NO₂, and CO show differences of -3.87, -16.67, -19.24, -15.74, and -8.37% between 2017 and 2018. On the contrary, O₃ concentrations increased by 4.50%. The four functional areas exhibited the same seasonal variations and diurnal patterns in air pollutants, with the highest exposure excess risks (ERs) resulting from O₃. More frequent ER days occurred within the 25-30°C, but much larger ERs are found within the 0-5°C temperature range, attributed to higher O₃ pollution in summer and more severe PM pollution in winter. The premature deaths attributable to six air pollutants can be calculated in 2017 and 2018, respectively. Investigations on the potential source show that the ER of O₃ (r of 0.86) had the tightest association with the total ER. The bivariate polar plots indicated that the highest health-based air quality index (HAQI) in IA influences the HAQI in UA and SA by pollution transport, and thus can be regarded as the major pollutant emission source in Jining. The above results indicate that urgent measures should be taken to reduce O₃ pollution taking into account the characteristics of the prevalent ozone formation regime, especially in IA in Jining.

Comprehensive study of health effects of plasma technology occupational environment: Exposure to high frequency and intensity noise and toxic gases

OBJECTIVES

To evaluate on animal models the health effects of the combined or separate exposure to main chemical and physical hazards of plasma-based material processing technology environment.

MATERIALS AND METHODS

Male Wistar rats were exposed to actual levels of hazardous factors in plasma technology occupational environment: i.e., ozone and nitrogen oxides (O₃ and NO_x) in respective concentrations of 0.5 mg/m³ and 1.0 mg/m³ and high-frequency (1000-1600 Hz) of 112 dB intensity noise for 3 h/day, 5 days/week for 12 weeks, with a recovery period of 1 month.

RESULTS

Exposure to noise or its combination with chemical factors (ozone, nitrogen oxides) causes non-specific CNS changes testifying for significant excitation dominance, especially in the case of joint exposure. Histological examination of rats' brain in experimental revealed a pronounced increase in blood filling of small vessels on the tenth day of the experiment, with subsequent intensification of vascular alterations and eventually to cerebral edema. The exposure to noise significantly reduced total thymus, bone marrow and spleen cell numbers and these was also more pronounced under the joint impact of noise and toxic gases. Thymus, but not bone marrow or spleen, mitotic activity was as well reduced under the same modes of exposure. Cytological investigation of film preparations of subcutaneous connective tissue revealed that joint exposure led to microcirculatory disorders, increased number of dark mast cells and reduced degranulation processes indicative of increased autoregulatory processes effective at microvasculature level.

CONCLUSIONS

High-frequency and intensity noise is main stressor factor that has negative impact on CNS and immune system, morphology and functioning of hematopoietic organs (spleen, bone marrow, thymus) and connective tissue. Its negative impact is significantly potentiated by concurrent exposure to ozone and nitrogen oxide, while exposure only to these toxic gases has no significant effect on the above targets.

Acute effects of ambient nitrogen dioxide exposure on serum biomarkers of nervous system damage in healthy older adults

Ambient nitrogen dioxide (NO₂)-induced adverse health effects have been studied, but documented evidence on neural systems is limited. This study aimed to determine the acute effect of NO₂ exposure on nervous system damage biomarker levels in healthy older adults. Five rounds of follow-up among 34 healthy retired people were scheduled from December 2018 to April 2019 in Xinxiang, China. The real-time NO₂ concentrations were measured using a fixed site monitor. Serum samples were acquired during each round to measure nervous system damage biomarker levels: brain-derived neurotrophic factor (BDNF), neurofilament light chain (NfL), neuron-specific enolase (NSE), protein gene product 9.5 (PGP9.5), and S100 calcium-binding protein B (S100B). A linear mixed-effect model was incorporated to analyze the association between short-term NO₂ exposure and serum concentrations of the above-mentioned biomarkers. Stratification analysis based on sex, educational attainment, glutathione S-transferase theta 1 gene (GSTT1) polymorphism, and physical activity intensity was conducted to explore their potential modification effect. The NO₂ concentration ranged from 34.7 to 59.0 µg/m³ during the study period. Acute exposure to ambient NO₂ was significantly associated with elevated serum levels of NfL, PGP9.5, and BDNF. In response to a 10 µg/m³ increase in NO₂ concentration, NfL and PGP9.5 levels increased by 76 % (95 % confidence interval [CI]: 12-140 %) and 54 % (95 % CI: 1-107 %) on the lag0 day, respectively, while BDNF levels increased by 49 % (95 % CI: 2-96 %) at lag4 day. The estimated effect of NO₂ on NSE levels in GSTT1-sufficient participants was significantly higher than that in GSTT1-null participants. Intriguingly, the estimation of NO₂ on PGP9.5 levels in females was significantly higher than that in males. Most two-pollutant models showed robust results, except for O₃, which might have had confounding effects on NO₂-induced BDNF stimulation. In summary, acute exposure to NO₂ was associated with increased levels of serum nervous system damage biomarker levels including NFL, PGP9.5, and BDNF. The present study provided insights into NO₂ exposure-induced adverse neural effects.

Mathematical modeling in the health risk assessment of air pollution-related disease burden in China: A review

This review paper covers an overview of air pollution-related disease burden in China and a literature review on the previous studies which have recently adopted a mathematical modeling approach to demonstrate the relative risk (RR) of air pollution-related disease burden. The associations between air pollution and disease burden have been explored in the previous studies. Therefore, it is necessary to quantify the impact of long-term exposure to ambient air pollution by using a suitable mathematical model. The most common way of estimating the health risk attributable to air pollution exposure in a population is by employing a concentration-response function, which is often based on the estimation of a RR model. As most of the regions in China are experiencing rapid urbanization and industrialization, the resulting high ambient air pollution is influencing more residents, which also increases the disease burden in the population. The existing RR models, including the integrated exposure-response (IER) model and the global exposure mortality model (GEMM), are critically reviewed to provide an understanding of the current status of mathematical modeling in the air pollution-related health risk assessment. The performances of different RR models in the mortality estimation of disease are also studied and compared in this paper. Furthermore, the limitations of the existing RR models are pointed out and discussed. Consequently, there is a need to develop a more suitable RR model to accurately estimate the disease burden attributable to air pollution in China, which contributes to one of the key steps in the health risk assessment. By using an updated RR model in the health risk assessment, the estimated mortality risk due to the impacts of environment such as air pollution and seasonal temperature variation could provide a more realistic and reliable information regarding the mortality data of the region, which would help the regional and national policymakers for intensifying their efforts on the improvement of air quality and the management of air pollution-related disease burden.

Acute cardiorespiratory response to air quality index in healthy young adults

BACKGROUND

Little is known about the acute health impacts of air quality index (AQI) on cardiorespiratory risk factors.

OBJECTIVES

To assess the short-term links of AQI with cardiorespiratory risk factors in young healthy adults.

METHODS

We performed a longitudinal panel study with 4 repeated visits in 40 healthy young adults in Hefei, Anhui Province, China from August to October 2021. Cardiorespiratory factors included systolic blood pressure (BP), diastolic BP (DBP), mean arterial pressure (MAP) and fractional exhaled nitric oxide (FeNO). We collected hourly AQI data from a nearby air quality monitoring site. Linear mixed-effects model was applied to assess the effects of AQI on BP and FeNO.

RESULTS

The study participants (75.0% females) provided 160 pairs of valid health measurements with average age of 24 years. The mean AQI level was 44.43 during the study period. There were significant positive associations of AQI with three BP parameters and FeNO at different lag periods. For example, an interquartile range increase in AQI (26.54 unit) over lag 0-24 h was associated with increments of 6.69 mmHg (95%CI: 2.95-10.44), 5.71 mmHg (95%CI: 3.30-8.13), 6.04 mmHg (95%CI: 3.46-8.62) and 5.67% (95%CI: 1.05%-16.05%) in SBP, DBP, MAP and FeNO, respectively. The results were robust after controlling for PM₁. We did not find effect modifications by gender, BMI, physical activity, or AQI category level on the associations.

CONCLUSIONS

The current findings on associations of AQI with cardiorespiratory factors might add evidence of the acute adverse cardiorespiratory consequences following air pollution.

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.

Fine particulate matter, airway inflammation, stress response, non-specific immune function and buccal microbial diversity in young adults

Fine particulate matter (PM_2.5) has been associated with risk of oral and respiratory diseases. However, the biological mechanisms of adverse oral and respiratory health response to PM_2.5 fluctuation have not been well characterized. This study aims to explore the relationships of PM_2.5 with airway inflammation, salivary biomarkers and buccal mucosa microbiota. We performed a panel study among 40 college students involving 4 follow-ups from August to October 2021 in Hefei, Anhui Province, China. Health outcomes included fractional exhaled nitric oxide (FeNO), salivary biomarkers [C-reactive protein (CRP), cortisol, lysozyme and alpha-amylase] and buccal mucosa microbial diversity. Linear mixed-effect models were applied to explore the cumulative impacts of PM_2.5 on health indicators. PM_2.5 was positively correlated with FeNO, CRP, cortisol and alpha-amylase, while negatively with lysozyme. Per 10-μg/m³ increase in PM_2.5 was linked to maximum increments in FeNO of 10.71% (95%CI: 2.01%, 19.41%) at lag 0-24 h, in CRP of 7.10% (95%CI: 5.39%, 8.81%) at lag 0-24 h, in cortisol of 1.25% (95%CI: 0.44%, 2.07%) at lag 0-48 h, and in alpha-amylase of 2.12% (95%CI: 0.53%, 3.71%) at lag 0-24 h, while associated with maximum decrement in lysozyme of 0.53% (95%CI: 0.12%, 0.95%) at lag 0-72 h. Increased PM_2.5 was linked to reduction in the richness and evenness of buccal microbe and o_Bacillales and o_Bacteroidales were identified as differential microbes after PM_2.5 inhalation. Bio-information analysis indicated that immunity system pathway was the most important enriched abundant process altered by PM_2.5 exposure. In summary, short-term PM_2.5 exposure may impair oral and respiratory health by inducing inflammatory and stress responses, weakening immune function and altering buccal mucosa microbial diversity.

Gestational exposure to NO2 aggravates placental senescence

Placental senescence is a normal physiological process of placenta, while premature placental senescence has been confirmed to be associated with some adverse pregnancy complications. Epidemiological studies indicate that NO₂ exposure can aggravate placental senescence which is represented by fibrosis and abnormal telomere homeostasis, etc. In this study, pregnant C57BL/6 mice were exposed to NO₂ (2.5 ppm, 5 h/day) daily in a dynamic exposure chamber throughout the gestation period, and were sacrificed at embryonic day 13.5 (E13.5), E15.5 and E18.5. Placenta were harvested and conducted for histopathological examination and telomere evaluation. Our results showed that gestational NO₂ exposure significantly aggravated placental fibrosis and calcification, and up-regulated the related bio-markers (connective tissue growth factor (Ctgf) and transforming growth factor-β1 (Tgf-β1)) at E18.5. In addition, gestational exposure to NO₂ also activated senescence related pathway (p53/p21) at E18.5. Furthermore, gestational NO₂ exposure significantly shortened telomere length at E18.5, and the expression of telomere homeostasis regulation genes telomeric repeat binding factor 1 (Trf1), protection of telomeres 1a (Pot1a) and Pot1b were significantly increased while telomerase reverse transcriptase (Tert) was suppressed after NO₂ exposure at E13.5 or E18.5, respectively. Importantly, DNA methylation status of the 22^nd at E13.5 and 32^nd at E18.5 site in sub-telomeric region of chromosome 1 was significantly altered. Based on the above results, our present study indicated that gestational NO₂ exposure could lead to premature placental senescence during the late trimester of pregnancy via aggravation of fibrosis and telomere length shortening regulated by telomere regulatory enzyme and DNA methylation.

Air pollution and lung cancer survival in Pennsylvania

OBJECTIVE

Lung cancer is a leading cause of cancer death in the United States. Exposure to outdoor air pollution (OAP) is associated with increased lung cancer incidence, however little is known about the association of OAP and survival after diagnosis.

METHODS

We investigated the effects of OAP and lung cancer survival in Pennsylvania using data from Pennsylvania Cancer Registry. The study population consisted of 252,123 patients diagnosed between 1990 and 2017. The Environmental Protection Agency's ambient air monitoring network provided information on OAP exposure of NO₂, O₃, PM_2.5, and PM₁₀. Mean OAP exposures were calculated by interpolating exposure concentrations from the five nearest monitors within a 50-kilometer radius of each patient's residential address from date of diagnosis to date of death or last contact. Cox proportional-hazards models were used to estimate the hazard ratios (HR) for OAP exposures for overall and lung cancer-specific survival. Statistical analyses were stratified by SEER cancer stage groupings (localized, regional, and distant) and adjusted for individual-level and area-level covariates.

RESULTS

Median survival time was 0.76 [CIs: 0.75, 0.77] years for the study population and for localized, regional, and distant site diagnosis were 2.2 [CIs: 2.17, 2.23], 1.13 [CIs: 1.12, 1.15], and 0.42 [CIs: 0.41, 0.43] years, respectively. NO₂ indicated the greatest HR which increased with increasing magnitude of exposure across all cancer staging groups for deaths before 2-years post-diagnosis. HRs varied by stage and magnitude of OAP exposure with greatest overall effects shown in NO₂ followed by PM_2.5, O_3, and PM₁₀. A subgroup analysis of patients with treatment status information (2010-2017) showed similar associations of increasing HRs with increasing exposure.

CONCLUSION

These findings supported the hypotheses that OAP can influence the carcinogenic process, impairing chemotherapy treatment, and provide important public health implications since environmental factors are not often considered in prognosis of survival after diagnosis.

DNA methylation: a potential mediator between air pollution and metabolic syndrome

Given the global increase in air pollution and its crucial role in human health, as well as the steep rise in prevalence of metabolic syndrome (MetS), a better understanding of the underlying mechanisms by which environmental pollution may influence MetS is imperative. Exposure to air pollution is known to impact DNA methylation, which in turn may affect human health. This paper comprehensively reviews the evidence for the hypothesis that the effect of air pollution on the MetS is mediated by DNA methylation in blood. First, we present a summary of the impact of air pollution on metabolic dysregulation, including the components of MetS, i.e., disorders in blood glucose, lipid profile, blood pressure, and obesity. Then, we provide evidence on the relation between air pollution and endothelial dysfunction as one possible mechanism underlying the relation between air pollution and MetS. Subsequently, we review the evidence that air pollution (PM, ozone, NO₂ and PAHs) influences DNA methylation. Finally, we summarize association studies between DNA methylation and MetS. Integration of current evidence supports our hypothesis that methylation may partly mediate the effect of air pollution on MetS.

Nitrogen dioxide pollution increases vulnerability to COVID-19 through altered immune function

Previous ecological studies suggest the existence of possible interplays between the exposure to air pollutants and SARS-CoV-2 infection. Confirmations at individual level, however, are lacking. To explore the relationships between previous exposure to particulate matter < 10 μm (PM₁₀) and nitrogen dioxide (NO₂), the clinical outcome following hospital admittance, and lymphocyte subsets in COVID-19 patients with pneumonia. In 147 geocoded patients, we assessed the individual exposure to PM₁₀ and NO₂ in the 2 weeks before hospital admittance. We divided subjects according to the clinical outcome (i.e., discharge at home vs in-hospital death), and explored the lymphocyte-related immune function as an index possibly affecting individual vulnerability to the infection. As compared with discharged subjects, patients who underwent in-hospital death presented neutrophilia, lymphopenia, lower number of T CD45, CD3, CD4, CD16/56 + CD3 + , and B CD19 + cells, and higher previous exposure to NO₂, but not PM₁₀. Age and previous NO₂ exposure were independent predictors for mortality. NO₂ concentrations were also negatively related with the number of CD45, CD3, and CD4 cells. Previous NO₂ exposure is a co-factor independently affecting the mortality risk in infected individuals, through negative immune effects. Lymphopenia and altered lymphocyte subsets might precede viral infection due to nonmodifiable (i.e., age) and external (i.e., air pollution) factors. Thus, decreasing the burden of air pollutants should be a valuable primary prevention measure to reduce individual susceptibility to SARS-CoV-2 infection and mortality.

The effects of air pollution on the lung cancer mortality in rural areas of eastern China: a multi-region study

Recently, the burden of lung cancer (LC) has attracted global attention. Meanwhile, LC has become the leading cause of death in China. Many studies found a strong link between air pollutants and the risk of LC mortality in some large cities, but the results have been inconsistent, and most studies have only focused on the daily effects of six pollutants in large cities, ignoring their potential cumulative effects. This study was to investigate the weekly effects of six air pollutants (CO, NO₂, O₃, PM_2.5, PM₁₀, and SO₂) on LC mortality in rural areas of eastern China and to further clarify which population groups were susceptible to air pollution and seasonal trends. First, a generalized additive model was combined with a distributed lag nonlinear model to evaluate the individual impact of air pollution on LC deaths in each area. The random-effect model was then used to pool the associations between air pollutants and LC mortality risk in ten counties or districts. The results showed that six air pollutants had a statistically significant effect on the risk of LC mortality at different lag weeks. The effects of NO₂, PM₁₀, and CO on weekly LC mortality were strongest at a cumulative lag of 1, 0, and 1 week, respectively, the maximum cumulative risk ratio (RR) of 1.37 (95%CI: 1.23 to 1.52), 1.30 (95%CI: 1.15 to 1.46), and 1.30 (95%CI: 1.17 to 1.43), with interquartile concentrations increasing. In summary, air pollution was an important factor in LC mortality, and the effect was stronger on males, the elderly, and during cold season. It was suggested that relevant departments should formulate air pollution management measures for the elderly, males, and in different seasons in rural areas and reduce the burden of lung cancer caused by air pollution.

Evaluation of the Relationship between Fractional Exhaled Nitric Oxide (FeNO) with Indoor PM10, PM2.5 and NO2 in Suburban and Urban Schools

Numerous epidemiological studies have evaluated the association of fractional exhaled nitric oxide (FeNO) and indoor air pollutants, but limited information available of the risks between schools located in suburban and urban areas. We therefore investigated the association of FeNO levels with indoor particulate matter (PM10 and PM2.5), and nitrogen dioxide (NO2) exposure in suburban and urban school areas. A comparative cross-sectional study was undertaken among secondary school students in eight schools located in the suburban and urban areas in the district of Hulu Langat, Selangor, Malaysia. A total of 470 school children (aged 14 years old) were randomly selected, their FeNO levels were measured, and allergic skin prick tests were conducted. The PM2.5, PM10, NO2, and carbon dioxide (CO2), temperature, and relative humidity were measured inside the classrooms. We found that the median of FeNO in the school children from urban areas (22.0 ppb, IQR = 32.0) were slightly higher as compared to the suburban group (19.5 ppb, IQR = 24.0). After adjustment of potential confounders, the two-level hierarchical multiple logistic regression models showed that the concentrations of PM2.5 were significantly associated with elevated of FeNO (>20 ppb) in school children from suburban (OR = 1.42, 95% CI = 1.17−1.72) and urban (OR = 1.30, 95% CI = 1.10−1.91) areas. Despite the concentrations of NO2 being below the local and international recommendation guidelines, NO2 was found to be significantly associated with the elevated FeNO levels among school children from suburban areas (OR = 1.11, 95% CI = 1.06−1.17). The findings of this study support the evidence of indoor pollutants in the school micro-environment associated with FeNO levels among school children from suburban and urban areas.

Epigenetic Regulation in Exposome-Induced Tumorigenesis: Emerging Roles of ncRNAs

Environmental factors, including pollutants and lifestyle, constitute a significant role in severe, chronic pathologies with an essential societal, economic burden. The measurement of all environmental exposures and assessing their correlation with effects on individual health is defined as the exposome, which interacts with our unique characteristics such as genetics, physiology, and epigenetics. Epigenetics investigates modifications in the expression of genes that do not depend on the underlying DNA sequence. Some studies have confirmed that environmental factors may promote disease in individuals or subsequent progeny through epigenetic alterations. Variations in the epigenetic machinery cause a spectrum of different disorders since these mechanisms are more sensitive to the environment than the genome, due to the inherent reversible nature of the epigenetic landscape. Several epigenetic mechanisms, including modifications in DNA (e.g., methylation), histones, and noncoding RNAs can change genome expression under the exogenous influence. Notably, the role of long noncoding RNAs in epigenetic processes has not been well explored in the context of exposome-induced tumorigenesis. In the present review, our scope is to provide relevant evidence indicating that epigenetic alterations mediate those detrimental effects caused by exposure to environmental toxicants, focusing mainly on a multi-step regulation by diverse noncoding RNAs subtypes.

The influence of dietary intake of omega-3 polyunsaturated fatty acids on the association between short-term exposure to ambient nitrogen dioxide and respiratory and cardiovascular outcomes among healthy adults

BACKGROUND

Short-term exposure to ambient nitrogen dioxide (NO₂) is associated with adverse respiratory and cardiovascular outcomes. Supplementation of omega-3 polyunsaturated fatty acids (PUFA) has shown protection against exposure to fine particulate matter. This study aims to investigate whether habitual omega-3 PUFA intake differentially modify the associations between respiratory and cardiovascular responses and short-term exposure to ambient NO₂.

METHODS

Sixty-two healthy participants were enrolled into low or high omega-3 groups based on their habitual omega-3 PUFA intake. Each participant was repeatedly assessed for lung function, blood lipids, markers of coagulation and fibrinolysis, vascular function, and heart rate variability (HRV) in up to five sessions, each separated by at least 7 days. This study was carried out in the Research Triangle area of North Carolina, USA between October 2016 and September 2019. Daily ambient NO₂ concentrations were obtained from an area air quality monitoring station on the day of outcome assessment (Lag0), 4 days prior (Lag1-4), as well as 5-day moving average (5dMA). The associations between short-term exposure to NO₂ and the measured indices were evaluated using linear mixed-effects models stratified by omega-3 levels and adjusted by covariates including relative humidity and temperature.

RESULTS

The average concentration of ambient NO₂ during the study periods was 5.3±3.8 ppb which was below the National Ambient Air Quality Standards (NAAQS). In the high omega-3 group, an interquartile range (IQR) increase in short-term NO₂ concentrations was significantly associated with increased lung function [e.g. 1.2% (95%CI: 0.2%, 2.2%) in FVC at lag1, 2.6% (95%CI: 0.4%, 4.8%) in FEV1 at 5dMA], decreased blood lipids [e.g. -2.6% (95%CI: -4.4%, -0.9%) in total cholesterol at lag2, -3.1% (95%CI: -6.1%, 0.0%) in HDL at 5dMA, and -3.1% (95%CI: -5.5%, -0.7%) in LDL at lag2], improved vascular function [e.g. 8.9% (95%CI: 0.6%, 17.2%) increase in FMD and 43.1% (95%CI: -79.8%, -6.3%) decrease in endothelin-1 at 5dMA], and changed HRV parameters [e.g. -7.2% (95%CI: -13.6%, -0.8%) in HFn and 13.4% (95%CI: 0.2%, 28.3%) in LF/HF ratio at lag3]. In the low omega-3 group, an IQR increase in ambient NO₂ was associated with elevations in coagulation markers (von Willebrand Factor, D-dimer) and a decrease in HRV (very-low frequency); however, null associations were observed between short-term NO₂ exposure and changes in lung function, blood lipids, and vascular function.

CONCLUSIONS

The results in this study imply that dietary omega-3 PUFA consumption may offer respiratory and vascular benefits in response to short-term exposure of healthy adults to NO₂ levels below the NAAQS.

TRIAL REGISTRATION

ClinicalTrials.gov ( NCT02921048 ).

The Impact of the Synergistic Effect of Temperature and Air Pollutants on Chronic Lung Diseases in Subtropical Taiwan

Previous studies have suggested an association between air pollution and lung disease. However, few studies have explored the relationship between chronic lung diseases classified by lung function and environmental parameters. This study aimed to comprehensively investigate the relationship between chronic lung diseases, air pollution, meteorological factors, and anthropometric indices. We conducted a cross-sectional study using the Taiwan Biobank and the Taiwan Air Quality Monitoring Database. A total of 2889 participants were included. We found a V/U-shaped relationship between temperature and air pollutants, with significant effects at both high and low temperatures. In addition, at lower temperatures (<24.6 °C), air pollutants including carbon monoxide (CO) (adjusted OR (aOR):1.78/Log 1 ppb, 95% CI 0.98–3.25; aOR:5.35/Log 1 ppb, 95% CI 2.88–9.94), nitrogen monoxide (NO) (aOR:1.05/ppm, 95% CI 1.01–1.09; aOR:1.11/ppm, 95% CI 1.07–1.15), nitrogen oxides (NO_x) (aOR:1.02/ppm, 95% CI 1.00–1.05; aOR:1.06/ppm, 95% CI 1.04–1.08), and sulfur dioxide (SO₂) (aOR:1.29/ppm, 95% CI 1.01–1.65; aOR:1.77/ppm, 95% CI 1.36–2.30) were associated with restrictive and mixed lung diseases, respectively. Exposure to CO, NO, NO₂, NO_x and SO₂ significantly affected obstructive and mixed lung disease in southern Taiwan. In conclusion, temperature and air pollution should be considered together when evaluating the impact on chronic lung diseases.

An investigation into the impact of variations of ambient air pollution and meteorological factors on lung cancer mortality in Yangtze River Delta

Lung cancer (LC) mortality, as one of the top cancer deaths in China, has been associated with increased levels of exposure to ambient air pollutants. In this study, different lag times on weekly basis were applied to study the association of air pollutants (PM2.5, PM10, and NO2) and LC mortality in Ningbo, and in subpopulations at different age groups and genders. Furthermore, seasonal variations of pollutant concentrations and meteorological variables (temperature, relative humidity, and wind speed) were analysed. A generalised additive model (GAM) using Poisson regression was employed to estimate the effect of single pollutant model on LC mortality in Yangtze River Delta using Ningbo as a case study. It was reported that there were statistically significant relationships between lung cancer mortality and air pollutants. Increases of 6.2% (95% confidence interval [CI]: 0.2% to 12.6%) and 4.3% (95% CI: 0.1% to 8.5%) weekly total LC mortality with a 3-week lag time were linked to each 10 μg/m³ increase of weekly average PM_2.5 and PM₁₀ respectively. The association of air pollutants (PM_2.5, PM₁₀ and NO₂) and LC mortality with a 3-week lag time was also found statistically significant during periods of low temperature (T < 18 °C), low relative humidity (H < 73.7%) and low wind speed (u < 2.8 m/s), respectively. The female population was found to be more susceptible to the exposure to air pollution than the male population. In addition, the population with an age of 50 years or above was shown to be more sensitive to ambient air pollutant. These outcomes indicated that increased risk of lung cancer mortality was evidently linked to exposure to ambient air pollutant on a weekly basis. The impact of weekly variation on the LC mortality and air pollutant levels should be considered in air pollution-related health burden analysis.

Associations of fine particulate matter and its constituents with airway inflammation, lung function, and buccal mucosa microbiota in children

BACKGROUND

Previous studies have suggested acute effects of ambient fine particulate matter (PM_2.5) air pollution on respiratory health among children, but evidence for PM_2.5 constituents and respiratory health were still limited.

OBJECTIVES

To investigate associations of short-term exposure to PM_2.5 and its constituents with airway inflammation, lung function, and airway microbiota in children.

METHODS

We conducted a longitudinal panel study with 3 repeated health measurements among 62 children in Shanghai, China from November 2018 to June 2019. Respiratory health was measured by fractional exhaled nitric oxide (FeNO), saliva tumor necrosis factor-α (TNF-α), lung function (forced vital capacity and forced exhaled volume in 1 s), and microbiota diversity in buccal mucosa samples. Based on the linear mixed-effect models, we applied the single-constituent models and the constituent-PM_2.5 adjustment models to examine the associations between PM_2.5 constituents and health outcomes.

RESULT

Short-term exposure to PM_2.5 was associated with higher TNF-α, FeNO levels and reduced lung function. Among all constituents, organic carbon, elemental carbon, NO₃^- and NH₄⁺ had the consistent and strongest associations with airway inflammation biomarkers and lung function parameters, followed by metallic elements. We also found short-term PM_2.5 exposure was associated with decreased diversity in buccal mucosa bacterial community and two bacterial phyla, Fusobacteria and Proteobacteria, were identified as differential microbes with PM_2.5 exposure.

CONCLUSION

Short-term exposure to PM_2.5 may impair children's respiratory health represented by higher airway inflammation, lower lung function and altered buccal mucosa microbial colonization. Organic carbon, elemental carbon, NO₃^- and NH₄⁺ may dominate these effects.

A review of current air quality indexes and improvements under the multi-contaminant air pollution exposure

The air quality is one of the major concerns in the urban environment due to the rapid changes in pollutant emissions driven by complex and intensive human activities. Therefore, quantification of the urban air quality has become an essential need for both urban residents and authorities to quickly assess air quality conditions. To reach this aim, the air quality index (AQI) is the primary way to better understand the urban air quality. However, the varied AQIs in different countries are difficult to directly compare due to the varied calculation methods. Thus, this research presents an updated review of the major AQIs worldwide by dividing them into two categories: single- and multi-contaminant-oriented AQIs. Single-contaminant-oriented AQIs are based on the maximum value of individual pollutants and are applied in most countries with location-dependent standards, such as the United States, China, the United Kingdom and New South Wales, Australia. However, these may greatly underestimate the impact of multiple contaminants, be difficult to dynamically update or to be compared internationally. Moreover, multi-contaminant-oriented AQIs are available in the literature, which consider the combined effects of exposure to multiple contaminants. Among these AQIs, arithmetic pollutant aggregation simply integrates pollutants in a linear or nonlinear way, and weighted pollutant aggregation further assigns varied weights from different perspectives. Combining the advantages and disadvantages of the existing AQIs, the general air quality health index (GAQHI) is proposed as a pollutant-aggregated, local health-based AQI paradigm suitable for the present complex multi-contaminant situation. It provides a direction for the construction of a more accurate, consistent and comparable AQI system and can help both researchers and governments improve human well-being and achieve sustainable development.

Impact of weather and emission changes on NO2 concentrations in China during 2014-2019

Nitrogen dioxide (NO₂) is one of the most important air pollutants that highly affect the formation of secondary fine particles and tropospheric ozone. In this study based on hourly NO₂ observations from June 2014 to May 2019 and a regional air quality model (WRF-CMAQ), we comprehensively analyzed the spatiotemporal variations of NO₂ concentrations throughout China and in 12 urban agglomerations (UAs) and quantitatively showed the anthropogenic and meteorological factors controlling the interannual variations (IAVs). The ground observations and tropospheric columns show that high NO₂ concentrations are predominantly concentrated in UAs such as Beijing-Tianjin-Hebei (BTH), the Shandong Peninsula (SP), the Central Plain (CP), Central Shaanxi (CS), and the Yangtze River Delta (YRD). For different UAs, the NO₂ IAVs are different. The NO₂ increased first and then decreased in 2016 or 2017 in BTH, YRD, CS, and Cheng-Yu, and decreased from 2014 to 2019 in Harbin-Changchun, CP, SP, Northern Slope of Tianshan Mountain, and Beibu-Gulf, while increased slightly in the Pearl River Delta (PRD) and Hohhot-Baotou-Erdos-Yulin (HBEY). The NO₂ IAVs were primarily dominated by emission changes. The net wintertime decreases of NO₂ in BTH, Yangtze River Middle-Reach, and PRD were mostly contributed by emission reductions from 2014 to 2018, and the significant increase in the wintertime in HBEY was also dominated by emission changes (93%). Weather conditions also have an important effect on the NO₂ IAVS. In BTH and HBEY, the increases of NO₂ in winter of 2016 are mainly attributed to the unfavorable weather conditions and for the significant decreases in the winter of 2017, the favorable weather conditions also play a very important role. This study provides a basic understanding on the current situation of NO₂ pollution and are helpful for policymakers as well as those interested in the study of tropospheric ozone changes in China and downwind areas.

Nitrogen dioxide exposures from LPG stoves in a cleaner-cooking intervention trial

BACKGROUND

Liquefied petroleum gas (LPG) stoves have been promoted in low- and middle-income countries (LMICs) as a clean energy alternative to biomass burning cookstoves.

OBJECTIVE

We sought to characterize kitchen area concentrations and personal exposures to nitrogen dioxide (NO₂) within a randomized controlled trial in the Peruvian Andes. The intervention included the provision of an LPG stove and continuous fuel distribution with behavioral messaging to maximize compliance.

METHODS

We measured 48-hour kitchen area NO₂ concentrations at high temporal resolution in homes of 50 intervention participants and 50 control participants longitudinally within a biomass-to-LPG intervention trial. We also collected 48-hour mean personal exposures to NO₂ among a subsample of 16 intervention and 9 control participants. We monitored LPG and biomass stove use continuously throughout the trial.

RESULTS

In 367 post-intervention 24-hour kitchen area samples of 96 participants' homes, geometric mean (GM) highest hourly NO₂ concentration was 138 ppb (geometric standard deviation [GSD] 2.1) in the LPG intervention group and 450 ppb (GSD 3.1) in the biomass control group. Post-intervention 24-hour mean NO₂ concentrations were a GM of 43 ppb (GSD 1.7) in the intervention group and 77 ppb (GSD 2.0) in the control group. Kitchen area NO₂ concentrations exceeded the WHO indoor hourly guideline an average of 1.3 h per day among LPG intervention participants. GM 48-hour personal exposure to NO₂ was 5 ppb (GSD 2.4) among 35 48-hour samples of 16 participants in the intervention group and 16 ppb (GSD 2.3) among 21 samples of 9 participants in the control group.

DISCUSSION

In a biomass-to-LPG intervention trial in Peru, kitchen area NO₂ concentrations were substantially lower within the LPG intervention group compared to the biomass-using control group. However, within the LPG intervention group, 69% of 24-hour kitchen area samples exceeded WHO indoor annual guidelines and 47% of samples exceeded WHO indoor hourly guidelines. Forty-eight-hour NO₂ personal exposure was below WHO indoor annual guidelines for most participants in the LPG intervention group, and we did not measure personal exposure at high temporal resolution to assess exposure to cooking-related indoor concentration peaks. Further research is warranted to understand the potential health risks of LPG-related NO₂ emissions and inform current campaigns which promote LPG as a clean-cooking option.

SARS-CoV-2 and mitochondrial health: implications of lifestyle and ageing

Infection with SARs-COV-2 displays increasing fatality with age and underlying co-morbidity, in particular, with markers of the metabolic syndrome and diabetes, which seems to be associated with a "cytokine storm" and an altered immune response. This suggests that a key contributory factor could be immunosenescence that is both age-related and lifestyle-induced. As the immune system itself is heavily reliant on mitochondrial function, then maintaining a healthy mitochondrial system may play a key role in resisting the virus, both directly, and indirectly by ensuring a good vaccine response. Furthermore, as viruses in general, and quite possibly this new virus, have also evolved to modulate immunometabolism and thus mitochondrial function to ensure their replication, this could further stress cellular bioenergetics. Unlike most sedentary modern humans, one of the natural hosts for the virus, the bat, has to "exercise" regularly to find food, which continually provides a powerful adaptive stimulus to maintain functional muscle and mitochondria. In effect the bat is exposed to regular hormetic stimuli, which could provide clues on how to resist this virus. In this paper we review the data that might support the idea that mitochondrial health, induced by a healthy lifestyle, could be a key factor in resisting the virus, and for those people who are perhaps not in optimal health, treatments that could support mitochondrial function might be pivotal to their long-term recovery.

The association between short-term exposure to ambient air pollution and fractional exhaled nitric oxide level: A systematic review and meta-analysis of panel studies

Several epidemiological studies have evaluated the fractional exhaled nitric oxide (FeNO) of ambient air pollution but the results were controversial. We therefore conducted a systematic review and meta-analysis to investigate the associations between short-term exposure to air pollutants and FeNO level. We searched PubMed and Web of Science and included a total of 27 articles which focused on associations between ambient air pollutants (PM₁₀, PM_2.5, black carbon (BC), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), ozone (O₃)) exposure and the change of FeNO. Random effect model was used to calculate the percent change of FeNO in association with a 10 or 1 μg/m³ increase in air pollutants exposure concentrations. A 10 μg/m³ increase in short-term PM₁₀, PM_2.5, NO₂, and SO₂ exposure was associated with a 3.20% (95% confidence interval (95%CI): 1.11%, 5.29%), 2.25% (95%CI: 1.51%, 2.99%),4.90% (95%CI: 1.98%, 7.81%), and 8.28% (95%CI: 3.61%, 12.59%) change in FeNO, respectively. A 1 μg/m³ increase in short-term exposure to BC was associated with 3.42% (95%CI: 1.34%, 5.50%) change in FeNO. The association between short-term exposure to O₃ and FeNO level was insignificant (P＞0.05). Future studies are warranted to investigate the effect of multiple pollutants, different sources and composition of air pollutants on airway inflammation.

Chronic alteration of circadian rhythm is related to impaired lung function and immune response

BACKGROUND

Alterations of the circadian rhythm negatively impact several aspects of the health, including the lung function. Chronic shiftwork scale classically induces alterations in the circadian rhythm. However, its effects on pulmonary immune response are unknown.

AIMS

To evaluate the impact of chronic alteration of circadian rhythm on pulmonary function and immune response.

METHODS

In this context, a 12 × 24 hours and 12 × 48 hours work scale in shiftwork scale policemen (n = 25; 38.73 ± 6.92 years old) were compared with fixed work scale (8 h/d) civil men (n = 25; 34.00 ± 9.60 years old) who were evaluated for perceived stress, sleepiness, physical activity levels, anthropometric characteristics, lung function, pulmonary and systemic cellular and humoral immune response.

RESULTS

Policemen presented increased levels of perceived stress (P < .0008), impaired sleepiness (P < .04) and lung function as demonstrated by reduced forced vital capacity (FVC) (P < .053) and FEV1 (P < .043) when compared with civil men. In addition, increased levels of exhaled nitric oxide (P < .037) and of IL-2 (P < .0046) in the breath condensate revealed that policemen presented chronic lung inflammation compared with civil men. Although the whole blood analysis did not showed any differences between the two groups concerning the number of leucocytes, the humoral response revealed that policemen presented increased levels of IL-2 (P < .002) and lower levels of IL-10 (P < .001), clearly displaying a clinical status of low-grade inflammation.

CONCLUSIONS

Chronic alteration of circadian rhythm in shiftwork scale policemen results in impaired lung function, beyond to impair pulmonary and systemic immune function.