Early life exposure to traffic-related air pollution and allergic rhinitis in preschool children

Multi-omic integration reveals alterations in nasal mucosal biology that mediate air pollutant effects on allergic rhinitis

BACKGROUND

Allergic rhinitis is a common inflammatory condition of the nasal mucosa that imposes a considerable health burden. Air pollution has been observed to increase the risk of developing allergic rhinitis. We addressed the hypotheses that early life exposure to air toxics is associated with developing allergic rhinitis, and that these effects are mediated by DNA methylation and gene expression in the nasal mucosa.

METHODS

In a case-control cohort of 505 participants, we geocoded participants' early life exposure to air toxics using data from the US Environmental Protection Agency, assessed physician diagnosis of allergic rhinitis by questionnaire, and collected nasal brushings for whole-genome DNA methylation and transcriptome profiling. We then performed a series of analyses including differential expression, Mendelian randomization, and causal mediation analyses to characterize relationships between early life air toxics, nasal DNA methylation, nasal gene expression, and allergic rhinitis.

RESULTS

Among the 505 participants, 275 had allergic rhinitis. The mean age of the participants was 16.4 years (standard deviation = 9.5 years). Early life exposure to air toxics such as acrylic acid, phosphine, antimony compounds, and benzyl chloride was associated with developing allergic rhinitis. These air toxics exerted their effects by altering the nasal DNA methylation and nasal gene expression levels of genes involved in respiratory ciliary function, mast cell activation, pro-inflammatory TGF-β1 signaling, and the regulation of myeloid immune cell function.

CONCLUSIONS

Our results expand the range of air pollutants implicated in allergic rhinitis and shed light on their underlying biological mechanisms in nasal mucosa.

Sources-attributed contributions to health risks associated with PM2.5-bound polycyclic aromatic hydrocarbons during the warm and cold seasons in an urban area of Eastern Asia

Despite the well-established recognition of the health hazards posed by PM2.5-bound PAHs, a comprehensive understanding of their source-specific impact has been lacking. In this study, the health risks associated with PM2.5-bound polycyclic aromatic hydrocarbons (PAHs) and source-specific contributions were investigated in the urban region of Taipei during both cold and warm seasons. The levels of PM2.5-bound PAHs and their potential health risks across different age groups of humans were also characterized. Diagnostic ratios and positive matrix factorization analysis were utilized to identify the sources of PM2.5-bound PAHs. Moreover, potential source contribution function (PSCF), concentration-weighted trajectory (CWT) and source regional apportionment (SRA) analyses were employed to determine the potential source regions. Results showed that the total PAHs (TPAHs) concentrations ranged from 0.08 to 2.37 ng m-3, with an average of 0.69 ± 0.53 ng m-3. Vehicular emissions emerged as the primary contributor to PM2.5-bound PAHs, constituting 39.8 % of the TPAHs concentration, followed by industrial emissions (37.6 %), biomass burning (13.8 %), and petroleum/oil volatilization (8.8 %). PSCF and CWT analyses revealed that industrial activities and shipping processes in northeast China, South China Sea, Yellow Sea, and East China Sea, contributed to the occurrence of PM2.5-bound PAHs in Taipei. SRA identified central China as the primary regional contributor of ambient TPAHs in the cold season and Taiwan in the warm season, respectively. Evaluations of incremental lifetime cancer risk demonstrated the highest risk for adults, followed by children, seniors, and adolescents. The assessments of lifetime lung cancer risk showed that vehicular and industrial emissions were the main contributors to cancer risk induced by PM2.5-bound PAHs. This research emphasizes the essential role of precisely identifying the origins of PM2.5-bound PAHs to enhance our comprehension of the related human health hazards, thus providing valuable insights into the mitigation strategies.

Prenatal Exposure to Air Pollutants Associated with Allergic Diseases in Children: Which Pollutant, When Exposure, and What Disease? A Systematic Review and Meta-analysis

This systematic review aims to identify the association between prenatal exposure to air pollutants and allergic diseases in children, focusing on specific pollutants, timing of exposure, and associated diseases. We searched PubMed, Scopus, and Web of Science for English articles until May 1, 2023, examining maternal exposure to outdoor air pollutants (PM1, PM2.5, PM10, NO, NO2, SO2, CO, and O3) during pregnancy and child allergic diseases (atopic dermatitis (AD), food allergy (FA), asthma (AT) and allergic rhinitis (AR)/hay fever (HF)). The final 38 eligible studies were included in the meta-analysis. Exposure to PM2.5 and NO2 during pregnancy was associated with the risk of childhood AD, with pooled ORs of 1.34 (95% confidence interval (CI), 1.10-1.63) and 1.10 (95%CI, 1.05-1.15) per 10 µg/m3 increase, respectively. Maternal exposure to PM1, PM2.5, and NO2 with a 10 µg/m3 increase posed a risk for AT, with pooled ORs of 1.34 (95%CI, 1.17-1.54), 1.11 (95%CI, 1.05-1.18), and 1.07 (95%CI, 1.02-1.12), respectively. An increased risk of HF was observed for PM2.5 and NO2 with a 10 µg/m3 increase, with ORs of 1.36 (95%CI, 1.17-1.58) and 1.26 (95%CI, 1.08-1.48), respectively. Traffic-related air pollutants (TRAP), particularly PM2.5 and NO2, throughout pregnancy, pose a pervasive risk for childhood allergies. Different pollutants may induce diverse allergic diseases in children across varying perinatal periods. AT is more likely to be induced by outdoor air pollutants as a health outcome. More research is needed to explore links between air pollution and airway-derived food allergies.

Intrauterine and early postnatal exposures to submicron particulate matter and childhood allergic rhinitis: A multicity cross-sectional study in China

BACKGROUND

Airborne particulate matter pollution has been linked to occurrence of childhood allergic rhinitis (AR). However, the relationships between exposure to particulate matter with an aerodynamic diameter ≤1 μm (PM1) during early life (in utero and first year of life) and the onset of childhood AR remain largely unknown. This study aims to investigate potential associations of in utero and first-year exposures to size-segregated PMs, including PM1, PM1-2.5, PM2.5, PM2.5-10, and PM10, with childhood AR.

METHODS

We investigated 29286 preschool children aged 3-6 years in 7 Chinese major cities during 2019-2020 as the Phase II of the China Children, Families, Health Study. Machine learning-based space-time models were utilized to estimate early-life residential exposure to PM1, PM2.5, and PM10 at 1 × 1-km resolutions. The concentrations of PM1-2.5 and PM2.5-10 were calculated by subtracting PM1 from PM2.5 and PM2.5 from PM10, respectively. Multiple mixed-effects logistic models were used to assess the odds ratios (ORs) and 95% confidence intervals (CIs) of childhood AR associated with per 10-μg/m3 increase in exposure to particulate air pollution during in utero period and the first year of life.

RESULTS

Among the 29286 children surveyed (mean ± standard deviation, 4.9 ± 0.9 years), 3652 (12.5%) were reported to be diagnosed with AR. Average PM1 concentrations during in utero period and the first year since birth were 36.3 ± 8.6 μg/m3 and 33.1 ± 6.9 μg/m3, respectively. Exposure to PM1 and PM2.5 during pregnancy and the first year of life was associated with an increased risk of AR in children, and the OR estimates were higher for each 10-μg/m3 increase in PM1 than for PM2.5 (e.g., 1.132 [95% CI: 1.022-1.254] vs. 1.079 [95% CI: 1.014-1.149] in pregnancy; 1.151 [95% CI: 1.014-1.306] vs. 1.095 [95% CI: 1.008-1.189] in the first year of life). No associations were observed between AR and both pre- and post-natal exposure to PM1-2.5, indicating that PM1 rather than PM1-2.5 contributed to the association between PM2.5 and childhood AR. In trimester-stratified analysis, childhood AR was only found to be associated with exposure to PM1 (OR = 1.077, 95% CI: 1.027-1.128), PM2.5 (OR = 1.048, 95% CI: 1.018-1.078), and PM10 (OR = 1.032, 95% CI: 1.007-1.058) during the third trimester of pregnancy. Subgroup analysis suggested stronger PM-AR associations among younger (<5 years old) and winter-born children.

CONCLUSIONS

Prenatal and postnatal exposures to ambient PM1 and PM2.5 were associated with an increased risk of childhood AR, and PM2.5-related hazards could be predominantly attributed to PM1. These findings highlighted public health significance of formulating air quality guideline for ambient PM1 in mitigating children's AR burden caused by particulate air pollution.

Air pollutants contribute to epithelial barrier dysfunction and allergic diseases

Air pollution is a global problem associated with various health conditions, causing elevated rates of morbidity and mortality. Major sources of air pollutants include industrial emissions, traffic-related pollutants, and household biomass combustion, in addition to indoor pollutants from chemicals and tobacco. Various types of air pollutants originate from both human activities and natural sources. These include particulate matter, pollen, greenhouse gases, and other harmful gases. Air pollution is linked to allergic diseases, including atopic dermatitis, allergic rhinitis, allergic conjunctivitis, food allergy, and bronchial asthma. These pollutants lead to epithelial barrier dysfunction, dysbiosis, and immune dysregulation. In addition, climate change and global warming may contribute to the exacerbation and the development of allergic diseases related to air pollutants. Epigenetic changes associated with air pollutants have also been connected to the onset of allergic diseases. Furthermore, these changes can be passed down through subsequent generations, causing a higher prevalence of allergic diseases in offspring. Modulation of the aryl hydrocarbon receptor could be a valuable strategy for alleviating air pollutant-induced epidermal barrier dysfunction and atopic dermatitis. A more effective approach to preventing allergic diseases triggered by air pollutants is to reduce exposure to them. Implementing public policies aimed at safeguarding individuals from air pollutant exposure may prove to be the most efficient solution. A pressing need exists for global policy initiatives that prioritize efforts to reduce the production of air pollutants.

The incidence of upper respiratory infections in children is related to the concentration of vanadium in indoor dust aggregates

Background

It has been reported that the disease-initiated and disease-mediated effects of aerosol pollutants can be related to concentration, site of deposition, duration of exposure, as well as the specific chemical composition of pollutants.

Objectives

To investigate the microelemental composition of dust aggregates in primary schools of Vilnius and determine trace elements related to acute upper respiratory infections among 6-to 11-year-old children.

Methods

Microelemental analysis of aerosol pollution was performed using dust samples collected in the classrooms of 11 primary schools in Vilnius from 2016 to 2020. Sites included areas of its natural accumulation behind the radiator heaters and from the surface of high cupboards. The concentrations of heavy metals (Pb, W, Sb, Sn, Zr, Zn, Cu, Ni, Mn, Cr, V, and As) in dust samples were analyzed using a SPECTRO XEPOS spectrometer. The annual incidence rates of respiratory diseases in children of each school were calculated based on data from medical records.

Results

The mean annual incidence of physician-diagnosed acute upper respiratory infections (J00-J06 according to ICD-10A) among younger school-age children was between 25.1 and 71.3% per school. A significant correlation was found between vanadium concentration and the number of episodes of acute upper respiratory infections during each study year from 2016 to 2020. The lowest was r = 0.67 (p = 0.024), and the highest was r = 0.82 (p = 0.002). The concentration of vanadium in the samples of dust aggregates varied from 12.7 to 52.1 parts per million (ppm). No significant correlations between the other trace elements and the incidence of upper respiratory infections were found, which could be caused by a small number of study schools and relatively low concentrations of other heavy metals found in the samples of indoor dust aggregates.

Conclusion

A significant and replicable correlation was found between the concentration of vanadium in the samples of natural dust aggregates collected in primary schools and the incidence of acute upper respiratory infections in children. Monitoring the concentration of heavy metals in the indoor environment can be an important instrument for the prevention and control of respiratory morbidity in children.

Modification of Food Allergy on the Associations between Early Life Exposure to Size-Specific Particulate Matter and Childhood Allergic Rhinitis

Previous studies have reported the association between particulate matter (PM) and childhood allergic rhinitis (AR). However, it is unclear whether food allergy (FA) modifies the PM-AR association. We aimed at evaluating the effect of the modification of FA on PM-AR association in preschool children. We adopted a cross-sectional study and conducted a questionnaire survey among preschool children aged 3-6 years in 7 cities in China from June 2019 to June 2020 to collect information on AR and FA. We used a combination of multilevel logistic regression and restricted cubic spline functions to quantitatively assess whether FA modifies the associations between size-specific PM exposure (1 × 1 km) and the risk of AR. The adjusted odds ratios (ORs) for AR among the children with FA as per a 10 μg/m3 increase in early life PM1, PM2.5, and PM10 were significantly higher than the corresponding ORs among the children without FA [e.g., OR: 1.58, 95% CI: (1.32, 1.90) vs 1.29, 95% CI: (1.18, 1.41), per 10 μg/m3 increase in PM1]. The interactions between FA and size-specific PM exposure and their effects on AR were statistically significant (all p-int < 0.001). FA, as an important part of the allergic disease progression, may modify the PM-AR association in preschool children.

Comorbid asthma is associated with rhinitis severity in children exposed to air pollutants

BACKGROUND

The impact of asthma on the severity of rhinitis when children with allergic rhinitis (AR) are exposed to air pollutants has not been studied.

METHODS

Children with AR (65 with asthma, 208 without asthma), aged 6-13 years, were recruited from a hospital in Taichung, Taiwan, between 2007 and 2011. Correlations between Pediatric-Rhinoconjunctivitis-Quality-of-Life score, nasal peak expiratory flow, and air pollutants were compared. With the same age, research time, and form the same city, children with AR (660 with asthma, 3174 without asthma) were selected from a database. Correlations between clinical visit times for AR and air pollutants were compared.

RESULTS

In male children with AR and asthma, both clinical and database studies revealed a correlation between higher rhinitis discomfort (quality-of-life score), higher visit times for AR, and higher PM10, PM2.5, NO2, NMHC concentrations. Correlations between higher nasal inflammation/obstruction (lower expiratory flow) and higher air pollutant concentrations were observed in male children with AR and asthma.

CONCLUSION

In children with AR, comorbid asthma was associated with increased rhinitis severity when they were exposed to air pollutants, and the association was only noted in males. Increased nasal obstruction/inflammation from exposure to air pollutants may be the mechanisms underlying this association.

IMPACT STATEMENT

The influence of asthma on the severity of rhinitis when children with allergic rhinitis (AR) are exposed to air pollutants has not been studied. In children with AR, the correlation between higher rhinitis discomfort, higher number of clinical visits for AR, and higher PM10, PM2.5, NO2, NMHC concentrations were only noted in those who also had asthma. The correlation was only noted in male. Comorbid asthma was associated with higher rhinitis severity when children with AR are exposed to air pollutants The association was only noted in male.

Exploring Associations Between Short-Term Air Pollution and Daily Outpatient Visits for Allergic Rhinitis

Purpose

Many studies have reported that exposure to air pollution increases the likelihood of acquiring allergic rhinitis (AR). This study investigated associations between short-term air pollution exposure and AR outpatient visits.

Patients and Methods

The Department of Otorhinolaryngology, Affiliated Hospital of Hangzhou Normal University provided AR outpatient data from January 1, 2019 to December 31, 2021. Daily air quality information for that period was gathered from the Hangzhou Air Quality Inspection Station. We used the Poisson's generalized additive model (GAM) to investigate relationships between daily outpatient AR visits and air pollution, and investigated lag-exposure relationships across days. Subgroup analyses were performed by age (adult (>18 years) and non-adult (<18 years)) and sex (male and female).

Results

We recorded 20,653 instances of AR during the study period. Each 10 g/m3 increase in fine particulate matter (PM10 and PM2.5) and carbon monoxide (CO) concentrations was associated with significant increases in AR outpatient Visits. The relative risks (RR) were: 1.007 (95% confidence interval (CI): 1.001-1.013), 1.026 (95% CI: 1.008-1.413), and 1.019 (95% CI: 1.008-1.047). AR visits were more likely due to elevated PM2.5, PM10, and CO levels. Additionally, children were more affected than adults.

Conclusion

To better understand the possible effects of air pollution on AR, short-term exposure to ambient air pollution (PM2.5, PM10, and CO) may be linked to increased daily outpatient AR visits.

International consensus statement on allergy and rhinology: Allergic rhinitis - 2023

BACKGROUND

In the 5 years that have passed since the publication of the 2018 International Consensus Statement on Allergy and Rhinology: Allergic Rhinitis (ICAR-Allergic Rhinitis 2018), the literature has expanded substantially. The ICAR-Allergic Rhinitis 2023 update presents 144 individual topics on allergic rhinitis (AR), expanded by over 40 topics from the 2018 document. Originally presented topics from 2018 have also been reviewed and updated. The executive summary highlights key evidence-based findings and recommendation from the full document.

METHODS

ICAR-Allergic Rhinitis 2023 employed established evidence-based review with recommendation (EBRR) methodology to individually evaluate each topic. Stepwise iterative peer review and consensus was performed for each topic. The final document was then collated and includes the results of this work.

RESULTS

ICAR-Allergic Rhinitis 2023 includes 10 major content areas and 144 individual topics related to AR. For a substantial proportion of topics included, an aggregate grade of evidence is presented, which is determined by collating the levels of evidence for each available study identified in the literature. For topics in which a diagnostic or therapeutic intervention is considered, a recommendation summary is presented, which considers the aggregate grade of evidence, benefit, harm, and cost.

CONCLUSION

The ICAR-Allergic Rhinitis 2023 update provides a comprehensive evaluation of AR and the currently available evidence. It is this evidence that contributes to our current knowledge base and recommendations for patient evaluation and treatment.

Long-term exposure to particulate matter on cardiovascular and respiratory diseases in low- and middle-income countries: A systematic review and meta-analysis

Background

Long-term exposure to particulate matter (PM) has essential and profound effects on human health, but most current studies focus on high-income countries. Evidence of the correlations between PM and health effects in low- and middle-income countries (LMICs), especially the risk factor PM1 (particles &lt; 1 μm in size), remains unclear.

Objective

To explore the effects of long-term exposure to particulate matter on the morbidity and mortality of cardiovascular and respiratory diseases in LMICs.

Methods

A systematic search was conducted in the PubMed, Web of Science, and Embase databases from inception to May 1, 2022. Cohort studies and case-control studies that examine the effects of PM1, PM2.5, and PM10 on the morbidity and mortality of cardiovascular and respiratory diseases in LMICs were included. Two reviewers independently selected the studies, extracted the data, and assessed the risk of bias. Outcomes were analyzed via a random effects model and are reported as the relative risk (RR) with 95% CI.

Results

Of the 1,978 studies that were identified, 38 met all the eligibility criteria. The studies indicated that long-term exposure to PM2.5, PM10, and PM1 was associated with cardiovascular and respiratory diseases: (1) Long-term exposure to PM2.5 was associated with an increased risk of cardiovascular morbidity (RR per 1.11 μg/m3, 95% CI: 1.05, 1.17) and mortality (RR per 1.10 μg/m3, 95% CI: 1.06, 1.14) and was significantly associated with respiratory mortality (RR 1.31, 95% CI: 1.25, 1.38) and morbidity (RR 1.08, 95% CI: 1.02, 1.04); (2) An increased risk of respiratory mortality was observed in the elderly (65+ years) (RR 1.21, 95% CI: 1.00, 1.47) with long-term exposure to PM2.5; (3) Long-term exposure to PM10 was associated with cardiovascular morbidity (RR 1.07, 95% CI 1.01, 1.13), respiratory morbidity (RR 1.43, 95% CI: 1.21, 1.69) and respiratory mortality (RR 1.28, 95% CI 1.10, 1.49); (4) A significant association between long-term exposure to PM1 and cardiovascular disease was also observed.

Conclusions

Long-term exposure to PM2.5, PM10 and PM1 was all related to cardiovascular and respiratory disease events. PM2.5 had a greater effect than PM10, especially on respiratory diseases, and the risk of respiratory mortality was significantly higher for LMICs than high-income countries. More studies are needed to confirm the effect of PM1 on cardiovascular and respiratory diseases.

Allergic rhinitis in India

India is the home of nearly 20% of the global population with 1.35 billion people. Of all non-communicable diseases, allergic diseases such as allergic rhinitis (AR) and asthma appear to have increased in India over the past decades. Approximately 22% of adolescents currently suffer from AR in India. However, owing to the lack of adequate epidemiological studies in India, particularly in rural and suburban areas, this number may misrepresent the true burden of this disease. While the risk factors for AR are mainly environmental exposures or genetic factors, several new environmental, social, and behavioural risk factors such as the presence of dumpsters near residences, movement of vehicles near homes, and exposure to artificial light at night have been found to be associated with AR. However, despite international guidelines, the diagnosis and management of AR in India are often suboptimal, for multiple reasons such as the lack of specialized training in allergy and immunology among Indian clinicians, the lack of diagnostic facilities, and the high cost of medications. This review aims at highlighting the current scenario of AR in India and how it differs from the rest of the world. It also highlights the need for developing a strategic approach to enhance the quality of care for allergic diseases by upgrading education and training for healthcare professionals, creating awareness among clinicians and patients, and involving stakeholders and policymakers in making treatments accessible and affordable to patients.

Outdoor Air Pollution and Childhood Respiratory Disease: The Role of Oxidative Stress

The leading mechanisms through which air pollutants exert their damaging effects are the promotion of oxidative stress, the induction of an inflammatory response, and the deregulation of the immune system by reducing its ability to limit infectious agents' spreading. This influence starts in the prenatal age and continues during childhood, the most susceptible period of life, due to a lower efficiency of oxidative damage detoxification, a higher metabolic and breathing rate, and enhanced oxygen consumption per unit of body mass. Air pollution is involved in acute disorders like asthma exacerbations and upper and lower respiratory infections, including bronchiolitis, tuberculosis, and pneumoniae. Pollutants can also contribute to the onset of chronic asthma, and they can lead to a deficit in lung function and growth, long-term respiratory damage, and eventually chronic respiratory illness. Air pollution abatement policies, applied in the last decades, are contributing to mitigating air quality issues, but more efforts should be encouraged to improve acute childhood respiratory disease with possible positive long-term effects on lung function. This narrative review aims to summarize the most recent studies on the links between air pollution and childhood respiratory illness.

Air Pollution: Possible Interaction between the Immune and Nervous System?

Exposure to environmental pollutants is a serious and common public health concern associated with growing morbidity and mortality worldwide, as well as economic burden. In recent years, the toxic effects associated with air pollution have been intensively studied, with a particular focus on the lung and cardiovascular system, mainly associated with particulate matter exposure. However, epidemiological and mechanistic studies suggest that air pollution can also influence skin integrity and may have a significant adverse impact on the immune and nervous system. Air pollution exposure already starts in utero before birth, potentially causing delayed chronic diseases arising later in life. There are, indeed, time windows during the life of individuals who are more susceptible to air pollution exposure, which may result in more severe outcomes. In this review paper, we provide an overview of findings that have established the effects of air pollutants on the immune and nervous system, and speculate on the possible interaction between them, based on mechanistic data.

Association between short-term exposure to air pollution and respiratory diseases among children in China: a systematic review and meta-analysis

OBJECTIVE

To assess the quantitative association between short-term exposure to air pollution and respiratory disease outpatient visits among children in China.

METHODS

We searched articles from 1 January 2000 to 31 December 2020 in six peer-reviewed literature databases following PRISMA guidelines.

RESULTS

Of 2668 records, 33 were included in meta-analysis. The pooled excess risks of respiratory disease outpatient visits among children in China per 10 μg/m³ increase were 0.75% (95% CI: 0.54%, 0.96%) for PM_2.5, 0.70% (95% CI: 0.50%, 0.89%) for PM₁₀, 0.82% (95% CI: 0.58%, 1.05%) for SO₂, 1.61% (95% CI: 1.25%, 1.98%) for NO₂ and 0.74% (95% CI: 0.01%, 1.46%) for O₃. In subgroup analysis, air pollution had a greater impact in southern or central cities, cold seasons, and areas with high relative humidity.

CONCLUSIONS

Short-term exposure to air pollution was significantly associated with an increased excess risk of respiratory disease outpatient visits among children in China.

Correlation of Pollen Concentration and Meteorological Factors with Medical Condition of Allergic Rhinitis in Shenyang Area

Background

The pathogenesis of allergic rhinitis (AR) was affected by meteorological and environmental factors. This study investigated the association between clinical symptoms of AR patients with pollen dispersal and meteorological conditions.

Methods

The clinical features of 10,838 AR patients who were treated in the Department of Otorhinolaryngology, The First Hospital of China Medical University, Shenyang, from March 2021 to October 2021 were retrospectively analyzed. We collected pollen by a pollen collector, read and counted it under a microscope, identified the species of the pollen particles, and recorded meteorological data (average daily temperature, maximum and minimum temperature, average daily wind, average daily precipitation, average daily humidity, average pressure, air quality index, PM2.5, PM10, SO₂, NO₂, CO, and O₃), to analyze the correlation among meteorological conditions, pollen dispersal, and number of AR visits. Finally, pollen allergen-positive and symptoms were scored.

Results

Among the AR visits, patients >41 years old accounted for the highest proportion (64.15%). 43.67% of the patients were complicated with bronchial asthma, and the disease incidence peaked in September. During the period of the study, a total of 27,512 pollen grains were collected, and 17 species were identified. The pollens of Compositae and Moraceae were the main allergenic sources leading to the increase in AR visits from August to September. The peak of pollen dispersal was in spring, summer, and autumn. The total amount of pollen was not only related to the average daily minimum temperature, average daily precipitation, and average daily humidity but also had a significant correlation with air quality index and air pollutants (PM2.5 and PM10, SO₂, NO₂, and CO). In addition, there was a significant correlation between the number of daily pollen allergen-positive patients and the pollen concentration of Compositae and Moraceae as well as air pollution components. The clinical symptoms of pollen allergen-positive patients were mainly nasal congestion, red/itchy eyes, and epiphora.

Conclusion

The peak seasons of pollen dispersal in Shenyang were in spring, summer, and autumn, and the allergenic pollens were mainly Compositae and Moraceae. In addition, AR was substantially correlated with pollen concentration and meteorological factors. This study may help provide early warning information and prevention for AR patients.

Association between air pollution and the prevalence of allergic rhinitis in Chinese children: A systematic review and meta-analysis

Background: Allergic rhinitis (AR) is a common chronic inflammatory disease with bothersome symptoms. However, the effect of air pollution on the prevalence of AR in children is controversial. Objective: This study aimed to investigate the association between air pollution and the prevalence of AR in Chinese children. Methods: This study, in China, included 160,356 students ages 0-18 years who completed a questionnaire about the accuracy of the International Study of Asthma and Allergies in Childhood (ISAAC). The effect of different air pollutants on the prevalence rate were evaluated by meta-analysis. Also, it evaluated the effect of different air pollutants on the prevalence rate. Results: The differences in the effects of sulfur dioxide (SO₂) exposure (combined odds ratio [OR_combined] 1.03 [95% confidence interval {CI}, 1.01-1.05]; p = 0.010) and nitrogen dioxide (NO₂) exposure (OR_combined 1.11 [95% CI, 1.05-1.18]; p = 0.0006) on the risk of childhood AR was statistically significant. The effect of particulate matter with aerodynamic diameter of <10 μm (PM₁₀) exposure on the risk of childhood AR was statistically significant (OR_combined 1.02 [95% CI, 1.01-1.03]; p < 0.001), the effect of particulate matter with aerodynamic diameter of <2.5 μm (PM_2.5) exposure on the risk of childhood AR was statistically significant (OR_combined 1.15 [95% CI, 1.03-1.29]; p = 0.02), and the effect of ozone exposure on the risk of childhood AR was not statistically significant (OR_combined 0.98 [95% CI, 0.67-1.41]; p = 0.13). Conclusion: NO₂, SO₂, PM_2.5, and PM₁₀ were associated with the prevalence of AR in Chinese children. PM_2.5 had the highest correlation with AR prevalence.

The Association Between Air Pollutants and Daily Outpatient Visits for Allergic Rhinitis: A Time-Series Analysis Based on Distribution Lag Nonlinear Model in Chongqing, China

Background

Allergic rhinitis (AR) is a severe and the most common chronic allergic disease, affecting 10-40% of the world population. The effect of air pollutants on AR has been confirmed in clinical experiments.

Purpose

This study aimed to quantify the association between air pollutants and daily outpatient visits for AR in Chongqing, China.

Methods

Based on the data of AR outpatients in the primary urban area of Chongqing from 2016 to 2017, along with the atmospheric pollutants and meteorological data in the same period, the distributed lag nonlinear model (DLNM) and generalized additive model (GAM) were used to analyze the time-series. We examined the effects of the single and double pollutant models with a maximum lag day of 30 days. Effect estimates were described as relative risk (RR) and 95% confidence intervals (CIs) in daily outpatient visits for AR per 10 μg/m³ increases in PM_2.5, PM₁₀, SO₂, NO₂, O₃, and per 1 mg/m³ increase in CO.

Results

A single pollutant's O₃ level had an immediate positive effect on AR within two days, the relative risks (RR, 95% CI) were 1.066 (1.008-1.127), 1.057 (1.005-1.112) and 1.048 (1.002-1.097). PM_2.5 had a lag effect within 11-18 days, the max relative risks (RR, 95% CI) were 1.083 (1.010-1.160). Moreover, O₃, PM_2.5, PM₁₀, SO₂ and NO₂ had significant effects on AR in the two-pollutant model. The RR cumulative effect of PM_2.5 became more pronounced as the concentration increased. The cumulative effect of NO₂ was lesser than PM_2.5.

Conclusion

Air pollutants were associated with the daily outpatient visits for AR, which may have considerable implications for developing tailored health policies and services to prevent AR in Chongqing and even all over the world.

Health Outcomes in Children Associated with Prenatal and Early-Life Exposures to Air Pollution: A Narrative Review

(1) Background: The developmental origins of health and disease (DOHaD) hypothesis links adverse fetal exposures with developmental mal-adaptations and morbidity later in life. Short- and long-term exposures to air pollutants are known contributors to health outcomes; however, the potential for developmental health effects of air pollution exposures during gestation or early-childhood have yet to be reviewed and synthesized from a DOHaD lens. The objective of this study is to summarize the literature on cardiovascular and metabolic, respiratory, allergic, and neuropsychological health outcomes, from prenatal development through early childhood, associated with early-life exposures to outdoor air pollutants, including traffic-related and wildfire-generated air pollutants. (2) Methods: We conducted a search using PubMed and the references of articles previously known to the authors. We selected papers that investigated health outcomes during fetal or childhood development in association with early-life ambient or source-specific air pollution exposure. (3) Results: The current literature reports that prenatal and early-childhood exposures to ambient and traffic-related air pollutants are associated with a range of adverse outcomes in early life, including cardiovascular and metabolic, respiratory and allergic, and neurodevelopmental outcomes. Very few studies have investigated associations between wildfire-related air pollution exposure and health outcomes during prenatal, postnatal, or childhood development. (4) Conclusion: Evidence from January 2000 to January 2022 supports a role for prenatal and early-childhood air pollution exposures adversely affecting health outcomes during development. Future studies are needed to identify both detrimental air pollutants from the exposure mixture and critical exposure time periods, investigate emerging exposure sources such as wildfire, and develop feasible interventional tools.

Maternal exposure to PM2.5/BC during pregnancy predisposes children to allergic rhinitis which varies by regions and exclusive breastfeeding

BACKGROUND

Increasing prevalence of childhood allergic rhinitis(AR) needs a deeper understanding on the potential adverse effects of early life exposure to air pollution.

OBJECTIVES

The main aim was to evaluate the effects of maternal exposure to PM_2.5 and chemical constituents during pregnancy on preschool children's AR, and further to explore the modification effects of regions and exclusive breastfeeding.

METHODS

A multi-center population-based study was performed in 6 cities from 3 regions of China in 2011-2012. Maternal exposure to ambient PM_2.5 and main chemical constituents(BC, OM, SO₄^2-, NO₃^-, NH₄⁺) during pregnancy was assessed and a longitudinal prospective analysis was applied on preschool children's AR. The modification effects of regions and exclusive breastfeeding were investigated.

RESULTS

A total of 8.8% and 9.8% of children reported doctor-diagnosed allergic rhinitis(DDAR) and current hay fever, respectively, and 48.6% had less than 6 months of exclusive breastfeeding. The means of PM_2.5 during pregnancy were 52.7 μg/m³, 70.3 μg/m³ and 76.4 μg/m³ in the east, north and central south of China, respectively. Multilevel log-binomial model regression showed that each interquartile range(IQR) increase of PM_2.5 during pregnancy was associated with an average increase in prevalence ratio (PR) of DDAR by 1.43(95% confidence interval(CI): 1.11, 1.84) and current hay fever by 1.79(95% CI: 1.26, 2.55), respectively. Among chemical constituents, black carbon (BC) had the strongest associations. Across 3 regions, the eastern cities had the highest associations, followed by those in the central south and the north. For those equal to or longer than 6 months of exclusive breastfeeding, the associations were significantly reduced.

CONCLUSIONS

Children in east of China had the highest risks of developing AR per unit increase of maternal exposure to PM_2.5 during pregnancy, especially BC constituent. Remarkable decline was found in association with an increase in breastfeeding for ≥6 months, in particular in east of China.

Ambient NO2 exposure induced cardiotoxicity associated with gut microbiome dysregulation and glycerophospholipid metabolism disruption

An average daily increase of 10 μg/m³ in NO₂ concentrations could lead to an increased mortality in cardiovascular, cerebrovascular of 1.89%, 2.07%, but the mechanism by which NO₂ contributes to cardiotoxicity is rarely reported. In order to assess the cardiotoxicity of NO₂ inhalation (5 ppm), we firstly investigate the change of gut microbiota, serum metabonomics and cardiac proteome. Non-targeted LC-MS/MS metabonomics showed that NO₂ stress could perturb the glycerophospholipid metabolism in the serum, which might destabilize the bilayer configuration of cardiac lipid membranes. Furthermore, we observed that NO₂ inhalation caused augmented intercellular gap and inflammatory infiltration in the heart. Although 16 S rRNA gene amplification sequencing demonstrated that NO₂ exposure did not influence the intestinal microbial abundance and diversity, but glycerophospholipid metabolism disruption might be finally reflected in gut microbiom dysregulation, such as Sphingomonas, Koribacter, Actinomarina and Bradyrhizobium Turicibacter, Rothia, Globicatella and Aerococcus. Proteome mining revealed that differentially expressed genes (DEGs) in the heart after NO₂ stress were involved in necroptosis, mitophagy and ferroptosis. We further revealed that NO₂ increased the number of cardiac mitochondria with depletion of cristae by regulating the expression of Mfn2 and Hsp70. This study indicating Mfn2-meidcated imbalanced mitochondrial dynamics as a potential mechanism after NO₂-induced heart injury and suggesting microbiome dysregulation/glycerophospholipid metabolism exerts critical roles in cardiotoxicity caused by NO₂.

Toxicological effects of traffic-related air pollution on the lungs: Evidence, biomarkers and intervention

BACKGROUND

Numerous epidemiological studies have recently observed that exposure to traffic-related air pollution (TRAP) is associated with increased risk of various respiratory diseases. Major gaps in knowledge remain regarding the toxicological effects.

OBJECTIVES

We examined the toxicological effects of the gasoline exhaust particles (GEP), a paradigm of TRAP, in rats, with an objective to provide the evidence, obtain the biomarkers, and suggest effective intervention measure.

METHODS

We measured the airway hyperresponsiveness (AHR), inflammatory cells in the bronchoalveolar lavage (BAL) fluid, histological changes in the lung tissues, and the biomarkers so as to systematically examine the toxicological effects of GEPs at different dose levels (0.5, 2.5, 5 mg/kg BW). The intervention of vitamin E (VE), a natural antioxidant, on the toxicological effects was investigated.

RESULTS

The lung injury caused by GEP exposure was first indicated by the airway hyperresponsiveness (AHR). Compared with the control group, GEP exposure significantly increased the airway resistances and decreased the lung compliance; the higher the dose of GEP, the more serious the lung injury. Lung injury was also revealed by the increase of inflammatory cells, including the lymphocytes and neutrophils, in the BAL fluid. With the increase of GEP dose, histological changes in the lung tissues were further observed: inflammatory cell infiltration increased and alveolar wall thickened. The toxicology of GEP was demonstrated by the increase of the biomarkers of the oxidative stress, the pro-inflammatory cytokines and the apoptosis cytokine. However, administration of VE was found to be effective in restoring airway injury.

CONCLUSION

The toxicological effects of traffic-related air pollution (TRAP) on rat lungs are supported by evidence and biomarkers, and vitamin E intervention is feasible.

Probiotics, prebiotics, and synbiotics to prevent or combat air pollution consequences: The gut-lung axis

Air pollution exposure is a public health emergency, which attributes globally to an estimated seven million deaths on a yearly basis We are all exposed to air pollutants, varying from ambient air pollution hanging over cities to dust inside the home. It is a mixture of airborne particulate matter and gases that can be subdivided into three categories based on particle diameter. The smallest category called PM_0.1 is the most abundant. A fraction of the particles included in this category might enter the blood stream spreading to other parts of the body. As air pollutants can enter the body via the lungs and gut, growing evidence links its exposure to gastrointestinal and respiratory impairments and diseases, like asthma, rhinitis, respiratory tract infections, Crohn's disease, ulcerative colitis, and abdominal pain. It has become evident that there exists a crosstalk between the respiratory and gastrointestinal tracts, commonly referred to as the gut-lung axis. Via microbial secretions, metabolites, immune mediators and lipid profiles, these two separate organ systems can influence each other. Well-known immunomodulators and gut health stimulators are probiotics, prebiotics, together called synbiotics. They might combat air pollution-induced systemic inflammation and oxidative stress by optimizing the microbiota composition and microbial metabolites, thereby stimulating anti-inflammatory pathways and strengthening mucosal and epithelial barriers. Although clinical studies investigating the role of probiotics, prebiotics, and synbiotics in an air pollution setting are lacking, these interventions show promising health promoting effects by affecting the gastrointestinal- and respiratory tract. This review summarizes the current data on how air pollution can affect the gut-lung axis and might impact gut and lung health. It will further elaborate on the potential role of probiotics, prebiotics and synbiotics on the gut-lung axis, and gut and lung health.

Associations of sleep problems with asthma and allergic rhinitis among Chinese preschoolers

The aim of this study was to examine the associations of sleep problems with asthma and allergic rhinitis among Chinese preschoolers. This cross-sectional survey was conducted in Guangzhou, China. Children aged 3–6 years were recruited from 32 kindergartens in 7 administrative districts. Asthma, allergic rhinitis and sleep problems were evaluated using a valid questionnaire. Binary logistic regression models were employed to estimate the odds ratios (OR) and 95% confidence intervals (CI) for the associations of asthma and allergic rhinitis with short sleep duration, late bedtime and frequent nocturnal awakening. We included 4876 preschool children in the current analysis. Of these, 182 (3.7%) diagnosed as asthma, and 511 (10.5%) diagnosed as allergic rhinitis. Frequent nocturnal awakening was associated with asthma and allergic rhinitis, with adjusted OR were 1.49 (95% CI 1.05–2.13) and 1.59 (95% CI 1.27–1.99), respectively. Subgroup analysis showed the OR for frequent nocturnal awakening with asthma was higher in girls (1.68; 95% CI 1.02–2.78) than in boys (1.35; 95% CI 0.81–2.24), but the OR for frequent nocturnal awakening with allergic rhinitis were similar in girls (1.73; 95% CI 1.15–2.30) and boys (1.57; 95% CI 1.17–2.12). No significant associations of short sleep duration and late bedtime with asthma or allergic rhinitis were identified. Our data suggested that frequent nocturnal awakening was associated with asthma and allergic rhinitis among preschoolers, and the association of frequent nocturnal awakening with asthma differed by gender. Further studies are warranted to address the causal relationship between nocturnal awakening and asthma and allergic rhinitis.

Association between air pollution and outpatient visits for allergic rhinitis: Effect modification by ambient temperature and relative humidity

Mounting evidence indicated the associations between air pollution and outpatient visits for allergic rhinitis (AR), while few studies assessed the effect modification of these associations by ambient temperature and relative humidity (RH). In this study, dataset of AR outpatients was obtained from Chinese People's Liberation Army Strategic Support Force Characteristic Medical Center in Beijing during 2014 to 2019, and the average concentrations of air pollutants including particulate matter ≤2.5 μm in diameter (PM_2.5) and ≤10 μm (PM₁₀), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), and meteorological factors (temperature and RH) at the same period were collected from one nearby air monitoring station. We performed a time-series study with Poisson regression model to examine the effects of air pollutants on AR outpatients after adjustment for potential confounders. And the effects modification analysis was further conducted by stratifying temperature and RH by tertiles into three groups of low, middle and high. In total of 33,599 outpatient visits for AR were recorded during the study period. Results found that a 10 μg/m³ increase in PM_2.5, PM₁₀, NO₂ and SO₂ was associated with significant increases in AR outpatients of 1.24% (95% confidence interval (CI): 0.69%, 1.78%), 0.79% (95% CI: 0.43%, 1.15%), 3.05% (95% CI: 1.72%, 4.40%) and 5.01% (95% CI: 1.18%, 8.96%), respectively. Stronger associations were observed in males than those in females, as well as in young adults (18-44 years) than those in other age groups. Air pollution effects on AR outpatients increased markedly at low temperature (<33.3th percentile) and high RH (>66.7th percentile). Findings in this study indicate that air pollution is associated with increased risk of AR outpatients, and the effects of air pollution on AR could be enhanced at low temperature and high RH.

Association between Serum Total and Specific Immunoglobulin E Levels and Body Height: A Cross-Sectional Study of Children and Adolescents

Background: The atopy rate in children has increased significantly. Atopy and growth are connected in a multifactorial manner and are important health issues for children around the world. The principal research question in this cross-sectional investigation concerned the association between serum total, specific immunoglobulin E (IgE) levels, and body height (BH)/weight (BW)/body mass index (BMI). Methods: A total of 993 subjects were enrolled for analysis retrospectively with allergic diseases and aged from 6 months to 18 years during the years 2015−2016. A complete panel of 36 allergen-specific IgE was taken from each participant using the MAST allergen test as well as their BH, BW, BMI, and total IgE levels. Results: There was a statistically significant positive association between the total IgE levels with BH (N = 348) and BW (N = 623) in the preschool age group (<6 years old, p-values of 0.009 and 0.034, respectively). In the preschool group, the total IgE levels showed a positive association with house dust (p < 0.001), cockroach mix (p < 0.001), Dermatophagoides farina (p < 0.001), and Dermatophagoides pteronyssinus (p < 0.001). After performing a general linear model followed by a backward selection of variables with age, sex, specific IgE, and total IgE, egg white sensitization demonstrated a significant negative association with BH (p = 0.009), and Dermatophagoides farina sensitization showed a significant positive association with BH (p = 0.006). The analysis showed that, in this model, the level of total IgE was not associated with BH. Conclusions: The results of this study indicate that the level of total IgE was not associated with BH in the preschool age group. Future studies are needed to replicate the results in outcome with follow-up allergic cohorts.

Frequent occurrence of respiratory symptoms in children is associated with exposure to air pollution, land use types, and parental mental health in the Greater Taipei area

Although studies have investigated the individual effects of air pollution, land use types, and parental mental health on children's respiratory health, few studies have examined the effects of these risk factors simultaneously in children aged <2 years. We investigated the effects of exposure to air pollution, land use types surrounding residences, and parental mental health on the frequent occurrence of respiratory symptoms in children aged <2 years in the Greater Taipei area. Participants were recruited from an ongoing Taiwanese birth cohort study. We analyzed the data of the participants who had been recruited from January 2011 to April 2014 and had responded to the follow-up questionnaires at 6, 12, and 24 months. Self-administered questionnaires were used to collect participants' sociodemographic background and health, such as respiratory symptoms, and parental mental health. Pre- and postnatal pollution levels were estimated using the spatial interpolation technique (ordinary kriging) at children's residential addresses. Land use types surrounding participants' homes were evaluated by performing buffer analysis. Multiple logistic regression analyses were conducted to examine the effects of risk factors on the frequent occurrence of child respiratory symptoms in children aged 6, 12, and 24 months. We included 228, 360, and 441 children aged 6, 12, and 24 months, respectively. Our results indicated that postnatal exposure to PM_2.5 and O₃ was positively associated with children's respiratory symptoms. Traffic-related land-use types, sports facilities, and commercial land surrounding homes exerted adverse effects on children's respiratory symptoms, whereas the presence of schools in the neighborhood was beneficial. Parental mental health was also associated with children's respiratory symptoms. Postnatal exposure to air pollution and land use types surrounding residences were associated with respiratory health in children aged <2 years. The residential environment is a critical factor affecting children's respiratory health of children aged <2 years.

Association between exposure to air pollution and risk of allergic rhinitis: A systematic review and meta-analysis

BACKGROUND

Allergic rhinitis (AR) is one of the most common allergic diseases in the world, and usually persists throughout the activity. Epidemiological studies have shown a positive association between air pollution and allergic rhinitis. However, we could not find any meta-analysis of the risk of air pollutants (PM_2.5, PM₁₀, NO₂, SO₂, O₃ and CO) on the prevalence of AR in people of all ages.

OBJECTIVES

Carry out a meta-analysis on the results of recent studies (up to 2020) to present valid information about exposure to air pollution and risk of prevalence of AR.

METHODS

We systematically searched three databases for studies up to December 17, 2020, including air pollution and AR. Random effect models were conducted to estimate the pooled odds ratios (ORs) and 95% confidence intervals (95% CIs). Subgroup analysis, funnel plot, Egger's test, and the trim-and-fill method were also conducted.

RESULTS

Thirty-five studies across 12 countries, including a total of 453,470 participants, were included. The OR per 10 μg/m³ increase of pollutants was 1.13 (1.04-1.22) for PM₁₀ and 1.12 (1.05-1.20) for PM_2.5. The OR per 10 μg/m³ increment of gaseous pollutants were 1.13 (1.07-1.20) for NO₂, 1.13 (1.04-1.22) for SO₂ and 1.07 (1.01-1.12) for O₃. No significant association was observed between CO and AR. Children or adolescents are more sensitive to air pollution than adults. The effects of PM₁₀ and SO₂ were significantly stronger in Europe than Asia. The effects of air pollutants were more significant and higher in developing countries than in developed countries, except for PM₁₀. A significant difference of subgroup test was found between developed and developing countries of NO₂.

CONCLUSION

This meta-analysis showed a positive association between air pollution and the prevalence of allergic rhinitis, and identified geographic area and economic level as the potential modifiers for the association.

The impact of traffic-related air pollution on lung function status and respiratory symptoms among children in Klang Valley, Malaysia

Increasing the range of vehicles on traffic roads in the urban area has led to traffic-related air pollution (TRAP) and is currently becoming the main concern for health, especially among children. The study aimed to determine associations between TRAP and respiratory health, also to identify the main factors that influenced them. A cross-sectional comparative study was carried out among children in high and low traffic areas. Air quality monitoring was conducted in six primary schools. A set of standardized questionnaires was distributed to obtain respondents' exposure history and respiratory health symptoms, while spirometry test was carried out to determine the lung function status. There were associations between TRAP and abnormality of FEV₁% among children. NO₂ was the main predictor that influenced both chest tightness and abnormality of FEV₁%. Children exposed to a high level of traffic-related air pollution have an increased risk of respiratory symptoms and abnormality of lung function.

Associations between long term exposures to outdoor air pollution and indoor solid fuel use and depression in China

Depression is one of the most common mental disorders. Effects of air pollution from outdoor and indoor on depression were inconsistent. We assessed 30,139 participants from Northeast China to explore the associations between long term exposures of outdoor and indoor solid fuel use and depressive symptoms. Multiple logistic regressions models as well as multiplicative interaction and additive interaction analysis were used. Outdoor exposures to air pollutants of particulate matter (with an aerodynamic diameter <2.5 μm, [PM_2.5], odds ratio [OR] = 1.98 per standard deviation [SD], 95% confidence interval [CI]: 1.78, 2.19; with an aerodynamic diameter <10 μm, [PM₁₀], OR = 1.83, 95% CI:1.68, 2.00), sulfur dioxide (SO₂, OR = 1.42, 95% CI: 1.33, 1.52), and nitrogen dioxide (NO₂, OR = 1.62, 95% CI: 1.49, 1.76) were significantly associated with higher occurrence of depressive symptoms. A significant linear trend for increased occurrence of depressive symptoms was observed in participants using both solid fuels for cooking and heating (P = 0.04). Indoor air pollution exposures from solid fuel use for heating (OR = 1.16, 95%CI: 1.00, 1.35) and high cooking frequency (OR = 1.17, 95%CI: 1.00, 1.37) were significantly associated with increased occurrence of depressive symptoms. We observed significant interactions of indoor solid fuel use and outdoor air pollution exposures on depressive symptoms (indoor fuel use for cooking and SO₂, P value = 0.04; solid fuel use for heating and NO₂, P value = 0.02). Solid fuel use for cooking weakened the associations between SO₂(relative excess risk due to interaction [RERI] = -1.37, 95% CI: -1.88, -0.86) and depressive symptoms. Solid fuel use for heating weakened the associations between NO₂ (RERI = -1.91, 95% CI: -2.55, -1.27) and depressive symptoms. Compared with individual associations, antagonistic interactions of outdoor air pollution and indoor solid fuel use on depressive symptoms might exist. Our findings contribute to better understandings for the associations between air pollution and depressive symptoms, which might be useful for developing effective strategies for depression prevention and air pollution control.

Cogeneration plant and environmental allergic diseases: is it really an eco-friendly energy source?

Background

Combined heat and power generation (CHP generation, also called ‘cogeneration’) is attracting public attention for its high thermal efficiency, without considering possible adverse environmental health effects.This study investigated the potential role of cogeneration plants in inducing 3 environmental diseases: asthma, allergic rhinitis, and atopic dermatitis.

Methods

From 1 January 2013 to 31 December 2017, the towns (dongs) of South Korea in which a cogeneration plant started operation were selected as study sites. For comparison, a matched control dong with the most similar Gross Regional Domestic Product for each case dong was selected. The numbers of outpatient visits, inpatient admissions, and emergency visits provided by the National Health Insurance Sharing Service (NHISS) were analyzed using an interrupted time-series design. For air pollutants, the concentrations of 5 air pollutants from the AIRKOREA dataset were used.

Results

A total of 6 cogeneration plants in 6 case dongs started operation during the study period. For overall case dongs, the pre-CHP trend was 1.04 (95% confidence interval [CI]: 1.038–1.042), and the post-CHP trend was 1.248 (95% CI: 1.244–1.253). The intercept change due to the CHP plant was 1.15 (95% CI: 1.137–1.162). For overall control dongs, the pre-CHP trend was 1.133 (95% CI: 1.132–1.135), and the post-CHP trend was 1.065 (95% CI: 1.06–1.069). The intercept change due to the CHP plant was 0.888 (95% CI: 0.878–0.899). Only for CO and NO₂, the relative risk (RR) for overall case dongs was statistically significantly increased, and the RR for the overall control dongs was statistically insignificant.

Conclusions

Possible hazardous emissions, like CO and NO_2, from cogeneration plants could induce environmental diseases in nearby community populations. The emissions from cogeneration plants should be investigated regularly by a governmental agency, and the long-term health outcomes of nearby community residents should be investigated.

The impact of environmental injustice and social determinants of health on the role of air pollution in asthma and allergic disease in the United States

There is clear evidence that exposure to environmental air pollution is associated with immune dysregulation, asthma, and other allergic diseases. However, the burden of air pollution exposure is not equally distributed across the United States. Many social and environmental factors place communities of color and people who are in poverty at increased risk of exposure to pollution and morbidity from asthma and allergies. Here, we review the evidence that supports the relationship between air pollution and asthma, while considering the social determinants of health that contribute to disparities in exposures and outcomes.

Associations of Exposure to Nitrogen Oxides with Prevalent Asthma and Other Atopic Diseases in Israel

Childhood exposure to nitrogen oxides (NOx) is considered a risk factor for the onset of asthma. However, associations of this exposure with other atopic diseases and factors that modify this association are less clear. We aimed to study associations between exposure to NOx and the prevalence of atopic diseases in Israeli adolescents using a cross-sectional design. The study population comprised all Israeli-born adolescents whose medical status was evaluated for mandatory military recruitment during 1967–2017 (n = 2,523,745), of whom 5.9% had prevalent asthma. We based the exposure assessments on a land-use regression model and estimated associations using multivariable logistic regression models. Across all periods, mean exposure to NOx from birth to adolescence was associated with prevalent asthma at the examination in a dose-response manner, with an odds ratio for the upper quintile of 1.61 (95% CI: 1.56–1.67), in comparison to the lowest quintile. Associations were stronger in males and in lower socioeconomic strata. We found the strongest associations for asthma with comorbid rhinitis, with an almost twofold increase in the odds of upper versus lower quintile of exposure (odds ratio = 1.96, 95% CI: 1.82–2.11). Rhino-conjunctivitis and allergic atopic dermatitis suggested a possible threshold level with NOx. Capsule Summary: Research indicates that half of the global population will suffer from an allergic condition at some point in life. Childhood exposure to nitrogen oxides is a risk factor for the onset of asthma. The association between exposure and allergic diseases other than asthma is unclear. We demonstrate a strong, dose-response relationship between exposure and a group of allergic outcomes, using data comprising 2.5 million subjects over 50 years. The large health benefits from clean air should motivate governments to prioritize mitigation measures.

Loss of E-cadherin due to road dust PM2.5 activates the EGFR in human pharyngeal epithelial cells

Exposure to road dust particulate matter (PM) causes adverse health impacts on the human airway. However, the effects of road dust on the upper airway epithelium in humans remain unclear. We investigated the involvement of the epidermal growth factor receptor (EGFR) after PM with an aerodynamic diameter of < 2.5 μm (PM_2.5)-induced E-cadherin disruption of human pharyngeal epithelial cells. First, we collected road dust PM_2.5 from 10 Chinese cities, including Wuhan, Nanjing, Shanghai, Guangzhou, Chengdu, Beijing, Lanzhou, Tianjin, Harbin, and Xi'an. Human pharyngeal FaDu cells were exposed to road dust PM_2.5 at 50 μg/mL for 24 h, cytotoxicity (cell viability and lactate dehydrogenase (LDH)) was assessed, and expressions of the proinflammatory interleukin (IL)-6 and high-mobility group box 1 (HMGB1) protein, receptor for advanced glycation end products (RAGE), occludin, E-cadherin, EGFR, and phosphorylated (p)-EGFR were determined. The E-cadherin gene was then knocked down to investigate EGFR activation in FaDu cells. Exposure to road dust PM_2.5 resulted in a decrease in cell viability and increases in LDH and IL-6. Our data suggested that PM_2.5 could decrease expressions of occludin and E-cadherin and increase expressions of EGFR and p-EGFR, which was confirmed by E-cadherin-knockdown. Our results showed a negative association between the alterations in E-cadherin and total elemental components in correlation analysis, especially S, Cl, K, Ti, Mn, Fe, Cu, Zn, and Pb. Exposure to metals in PM_2.5 from road dust may lead to loss of the barrier function of the upper airway epithelium and activation of the EGFR. Our study showed the adverse effects of road dust PM_2.5 on pharyngeal epithelial cells of the human upper airway.

The Role of Environmental Risk Factors on the Development of Childhood Allergic Rhinitis

Environmental factors play an important role in the development and exacerbation of allergic rhinitis (AR) in childhood. Indoor air pollution, such as house dust mites and secondhand smoke, can significantly increase the onset of AR, while pet dander may affect the exacerbation of AR symptoms in children. Furthermore, traffic related air pollution and pollen are outdoor air pollutants that can affect immune competency and airway responsiveness, increasing the risk of AR in children. Climate change has increased AR in children, as growth patterns of allergenic species have changed, resulting in longer pollen seasons. More extreme and frequent weather events also contribute to the deterioration of indoor air quality due to climate change. Additionally, viruses provoke respiratory tract infections, worsening the symptoms of AR, while viral infections alter the immune system. Although viruses and pollution influence development and exacerbation of AR, a variety of treatment and prevention options are available for AR patients. The protective influence of vegetation (greenness) is heavily associated with air pollution mitigation, relieving AR exacerbations, while the use of air filters can reduce allergic triggers. Oral antihistamines and intranasal corticosteroids are common pharmacotherapy for AR symptoms. In this review, we discuss the environmental risk factors for AR and summarize treatment strategies for preventing and managing AR in children.

Modification of the effects of nitrogen dioxide and sulfur dioxide on congenital limb defects by meteorological conditions

STUDY QUESTION

Can meteorological conditions modify the associations between NO2 and SO2 exposure and congenital limb defects (CLDs) during the first trimester of pregnancy?

SUMMARY ANSWER

Increases in NO2 and SO2 exposure were consistently associated with higher risks of CLDs during the first trimester of pregnancy; both low- and high-temperature exposure and high air humidity act synergistically with the two air pollutants on CLDs.

WHAT IS KNOWN ALREADY

Animal studies have indicated air pollutants are associated with CLDs, but corresponding epidemiological studies are limited with equivocal conclusions. Meteorological conditions are closely connected to the generation, diffusion, distribution and even chemical toxicity of air pollutants.

STUDY DESIGN, SIZE, DURATION

This case-control study included 972 cases of CLDs and 9720 controls in Changsha, China during 2015-2018.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Cases from the hospital based monitoring system for birth defects (including polydactyly, syndactyly, limb shortening, and clubfoot) and healthy controls from the electronic medical records system were studied. Complete data on daily average NO2 and SO2 concentrations and meteorological variables were obtained from local monitoring stations to estimate monthly individual exposures during the first trimester of pregnancy, using the nearest monitoring station approach for NO2 and SO2 concentrations, and the city-wide average approach for temperature and relative humidity, respectively. The 25th and 75th percentiles of daily mean temperature, as well as the 50th percentile of daily mean relative humidity during the study period were used to classify high- and low-temperature exposure, and high humidity exposure based on existing evidence and local climate characteristics. Multivariate logistic regression models were used to estimate the independent effects per 10 μg/m3 increase in NO2 and SO2 on CLDs, and the attribute proportions of interaction (API) were used to quantify the additive joint effects of air pollutants with meteorological conditions after including a cross product interaction term in the regression models.

MAIN RESULTS AND THE ROLE OF CHANCE

NO2 and SO2 exposures during the first trimester of pregnancy were consistently and positively associated with overall CLDs and subtypes, with adjusted odd ratios (aORs) ranging from 1.13 to 1.27 for NO2, and from 1.37 to 2.49 for SO2. The effect estimates were generally observed to be the strongest in the first month and then attenuated in the second and third months of pregnancy. Synergistic effects of both low and high temperature in combination with NO2 (with APIs ranging from 0.07 to 0.38) and SO2 (with APIs ranging from 0.18 to 0.51) appeared in the first trimester of pregnancy. Several significant modifying effects by high humidity were also observed, especially for SO2 (with APIs ranging from 0.13 to 0.38). Neither NO2 nor SO2 showed an interactive effect with season of conception.

LIMITATIONS, REASONS FOR CAUTION

The methods used to estimate individual exposure levels of air pollutants and meteorological factors may lead to the misclassification bias because of the lack of information on maternal activity patterns and residential mobility during pregnancy. Moreover, we were unable to consider several potentially confounding factors, including socioeconomic status, maternal nutrient levels, alcohol use and smoking during early pregnancy due to unavailable data, although previous studies have suggested limited change to the results after when including these factors in the analysis.

WIDER IMPLICATIONS OF THE FINDINGS

The findings are helpful for understanding the combined effects of air pollution and meteorological conditions on birth defects. Environmental policies and practices should be formulated and implemented to decrease air pollutant emissions and improve meteorological conditions to reduce their harmful effects on pregnancy. Additionally, pregnant women should be suggested to reduce outdoor time when the air quality is poor, especially when ambient temperature is higher or lower than what is comfortable, or when it is excessively humid.

STUDY FUNDING/COMPETING INTEREST(S)

The study is funded by Major Scientific and Technological Projects for Collaborative Prevention and Control of Birth Defects in Hunan Province (2019SK1012), Major Research and Development Projects in Hunan Province (2018SK2060) and Scientific and Technological Department Projects in Hunan Province (2017SK50802). There are no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Prevalence, comorbidities, diagnosis, and treatment of nonallergic rhinitis: real-world comparison with allergic rhinitis

Rhinitis is among the most common respiratory diseases in children. Nonallergic rhinitis, which involves nasal symptoms without evidence of systemic allergic inflammation or infection, is a heterogeneous entity with diverse manifestations and intensities. Nonallergic rhinitis accounts for 16%-89% of the chronic rhinitis cases, affecting 1%-50% (median 10%) of the total pediatric population. The clinical course of nonallergic rhinitis is generally rather mild and less likely to be associated with allergic comorbidities than allergic rhinitis. Here, we aimed to estimate the rate of coexisting comorbidities of nonallergic rhinitis. Nonallergic rhinitis is more prevalent during the first 2 years of life; however, its underestimation for children with atopic tendencies is likely due to low positive rates of specific allergic tests during early childhood. Local allergic rhinitis is a recently noted phenotype with rates similar to those in adults (median, 44%; range, 4%-67%), among patients previously diagnosed with nonallergic rhinitis. Idiopathic rhinitis, a subtype of nonallergic rhinitis, has been poorly studied in children, and its rates are known to be lower than those in adults. The prevalence of nonallergic rhinitis with eosinophilia syndrome is even lower. A correlation between nonallergic rhinitis and pollution has been suggested owing to the recent increase in nonallergic rhinitis rates in highly developing regions such as some Asian countries, but many aspects remain unknown. Conventional treatments include antihistamines, intranasal corticosteroids, and recent treatments include combination of intranasal corticosteroids with azelastin or decongestants. Here we review the prevalence, diagnosis, comorbidities, and treatment recommendations for nonallergic rhinitis versus allergic rhinitis in children.

Contributions of Coagulation, Deposition, and Ventilation to the Removal of Airborne Nanoparticles in Indoor Environments

Airborne nanoparticles are frequently released in occupied spaces due to episodic indoor source activities. Once generated, nanoparticles undergo aerosol transformation processes such as coagulation and deposition. These aerosol processes lead to changes in particle concentration and size distribution over time and accordingly affect human exposure to nanoparticles. The present study establishes a framework for an indoor particle dynamic model that can predict time- and size-dependent particle concentrations after episodic indoor emission events. The model was evaluated with six experimental data sets obtained from previous measurement studies in the literature. The indoor particle dynamic model quantified the relative contributions of three particle loss mechanisms (i.e., coagulation, deposition, and ventilation) to the total reduction in number concentration. The results show that particle coagulation and indoor surface deposition are two dominant processes responsible for temporal changes in particle size and concentration following indoor emission events. The first-order equivalent coagulation loss rate notably varies with indoor emission source and accounts for up to 59% of the total particle loss for burning a candle, 42% for broiling a fish, and 10% for burning incense. The results reveal that while the coagulation loss rate changes markedly with the particle concentration and source type, the deposition loss rate is more dependent on particle size. Compared to coagulation and deposition, the effect of ventilation is marginal for most of the nanoparticle emission events indoors; however, ventilation loss becomes pronounced with the decrease of particle concentration below 5 × 10⁴ cm^-3, especially for particles larger than 100 nm in aerodynamic diameter.

Oligomerization and Nitration of the Grass Pollen Allergen Phl p 5 by Ozone, Nitrogen Dioxide, and Peroxynitrite: Reaction Products, Kinetics, and Health Effects

The allergenic and inflammatory potential of proteins can be enhanced by chemical modification upon exposure to atmospheric or physiological oxidants. The molecular mechanisms and kinetics of such modifications, however, have not yet been fully resolved. We investigated the oligomerization and nitration of the grass pollen allergen Phl p 5 by ozone (O₃), nitrogen dioxide (NO₂), and peroxynitrite (ONOO^-). Within several hours of exposure to atmospherically relevant concentration levels of O₃ and NO₂, up to 50% of Phl p 5 were converted into protein oligomers, likely by formation of dityrosine cross-links. Assuming that tyrosine residues are the preferential site of nitration, up to 10% of the 12 tyrosine residues per protein monomer were nitrated. For the reaction with peroxynitrite, the largest oligomer mass fractions (up to 50%) were found for equimolar concentrations of peroxynitrite over tyrosine residues. With excess peroxynitrite, the nitration degrees increased up to 40% whereas the oligomer mass fractions decreased to 20%. Our results suggest that protein oligomerization and nitration are competing processes, which is consistent with a two-step mechanism involving a reactive oxygen intermediate (ROI), as observed for other proteins. The modified proteins can promote pro-inflammatory cellular signaling that may contribute to chronic inflammation and allergies in response to air pollution.

Early childhood traffic-related air pollution and risk of allergic rhinitis at 2-4 years of age modification by family stress and male gender: a case-control study in Shenyang, China

Background

Few studies have explored the modifications by family stress and male gender in the relationship between early exposure to traffic-related air pollution (TRAP) and allergic rhinitis (AR) risk in preschool children.

Methods

We conducted a case-control study of 388 children aged 2–4 years in Shenyang, China. These children AR were diagnosed by clinicians. By using measured concentrations from monitoring stations, we estimated the exposures of particulate matter less than 10 μm in diameter (PM₁₀), nitrogen dioxide (NO₂), ozone (O₃), carbon monoxide (CO), and sulfur dioxide (SO₂) in preschool children aged 2–4 years. After adjusted potential confounding factors, we used logistic regression model to evaluate the odds ratio (OR) and 95% confidence interval (CI) for childhood AR with exposure to different air pollutants according to the increasing of the interquartile range (IQR) in the exposure level.

Results

The prevalence of AR in children aged 2–4 years (6.4%) was related to early TRAP exposure. With an IQR (20 μg/m³) increase in PM₁₀ levels, an adjusted OR was significantly elevated by 1.70 (95% CI, 1.19 to 2.66). Also, with an IQR (18 μg/m³) increase in NO₂, an elevated adjusted OR was 1.85 (95% CI, 1.52 to 3.18). Among children with family stress and boys, PM₁₀ and NO₂ were positively related to AR symptoms. No significant association was found among children without family stress and girls.

Conclusions

Family stress and male gender may increase the risk of AR in preschool children with early exposure to PM₁₀ and NO₂.

Effect of particulate matter exposure on the prevalence of allergic rhinitis in children: A systematic review and meta-analysis

Among various air pollutants, particulate matter (PM) is the most harmful and representative pollutant. At the same time, allergic rhinitis (AR) is getting more and more attention, so we explore the relationship between PM and the prevalence of AR among children. Then, PubMed, Web of Science, Google Scholar was used to search for relevant studies up to January 2020. Literature quality assessment was processed using the Newcastle-Ottawa Scale (NOS) evaluation scale. Adjusted odds ratio (OR) with corresponding 95% confidence interval (CI) was retrieved from individual studies and pooled to generate a summary effect via STATA software. Besides, we test the result stability by Egger's test and funnel plot, and using the trim-and-fill method to modify the possible asymmetric funnel graph. 21 studies were included in the meta-analysis. 9 articles reported about PM_2.5 on childhood AR (1.09, 95%CI: 1.01, 1.17, per 10 μg/m³ increase). 15 articles reported about PM₁₀ on childhood AR (1.06, 95%CI: 1.02,1.11, per 10 μg/m³ increase), PM_2.5 exposure has a bigger effect on children AR than PM₁₀. In addition, a series of subgroup analysis was performed, and we found that PM_2.5 and PM₁₀ have different performances in different subgroups. In addition to this, we analyzed the sources of heterogeneity of the study. Apart from the results we got all have good stability without publication bias. Therefore, it can be concluded that exposure to PM may increase the prevalence of AR among children.

Allergic rhinitis is associated with atmospheric SO2: Follow-up study of children from elementary schools in Ulsan, Korea

Objectives

The purpose of this study was to examine the association of allergic rhinitis with air pollutant concentrations using the follow-up data of elementary school children in Ulsan, Korea.

Methods

All students of four elementary schools in Ulsan, South Korea were surveyed at two-year intervals. The survey used data collected five times, over a nine-year period from June 2009 to April 2018. The questionnaire used in the survey was a modified version of the ISAAC (International society of asthma and allergy of children) questionnaire. A skin prick test (SPT) was performed with 24 standard antigens. To estimate the levels of exposure to outdoor air pollution, the concentrations of sulfur dioxide (SO₂), nitrogen dioxide (NO₂), ozone (O₃), carbon monoxide (CO), and particulate matter 10 μm or less in diameter (PM10) were used. As a dependent variable, a history of allergic rhinitis diagnosed by a doctor during the last 1-year was considered. Logistic regression analysis was used to select variables suitable for the statistical model. The selected variables were then used to assess their association with the dependent variable using the generalized estimation equation.

Results

Among environmental factors, SO₂ was associated with a high risk and PM10 was associated with a low risk of allergic rhinitis. The risk of allergic rhinitis from living in a house built within the last year was high, and the risk from living in a multi-family house or apartment was higher than that from living in a segregated house. History of allergic diseases in the family was a high-risk factor for allergic rhinitis. There was a relationship between a history of bronchiolitis at less than 2 years of age and a high risk of allergic rhinitis. Boys were at a higher risk than girls.

Conclusion

From the follow-up data of elementary school students in Ulsan, Korea, the concentration of SO₂, which is an indicator of the degree of industrialization, was related to the prevalence of allergic rhinitis. Among all the risk factors, history of allergic disease in the parents was the most important factor, and the study reconfirmed the results of the previous studies.

Effect of exposure to fine particulate matter during pregnancy and infancy on paediatric allergic rhinitis

BACKGROUND

The effect of prenatal and postnatal exposure to fine particulate matter (PM_2.5) on the development of allergic rhinitis (AR) is poorly understood. We further identified the vulnerable period for AR development to determine methods to decrease adverse effects.

METHODS

We used a large population-based birth cohort of 140 911 singleton live infants in Taichung, Taiwan with a highly temporal-resolution satellite-based hybrid model to evaluate the effects of prenatal and early postnatal exposure on the onset of AR.

RESULTS

Among 140 911 children, 47 276 (33.55%) were cases of incident AR. The mean age of the children with AR at initial diagnosis was 2.97±1.78 years. We identified a significant association of AR with an interquartile range (IQR 17.98 µg/m³) increase in PM_2.5 from 30 gestational weeks to 52 weeks after birth. The exposure-response relationship revealed that AR had a significant positive association between PM_2.5 of 26-76 µg/m³ (adjusted hazard ratios ranged from 1.00 to 1.05).

CONCLUSION

Our study provides evidence that both prenatal and postnatal exposures to PM_2.5 are associated with later development of AR. The vulnerable time window may be within late gestation and the first year of life. Further study is required to confirm the vulnerable time period of PM_2.5 on AR.

Fetal-Derived Immune Cells at the Roots of Lifelong Pathophysiology

Tissue-resident innate immune cells exert a wide range of functions in both adult homeostasis and pathology. Our understanding of when and how these cellular networks are established has dramatically changed with the recognition that many lineages originate at least in part from fetal sources and self-maintain independently from hematopoietic stem cells. Indeed, fetal-derived immune cells are found in most organs and serous cavities of our body, where they reside throughout the entire lifespan. At the same time, there is a growing appreciation that pathologies manifesting in adulthood may be caused by adverse early life events, a concept known as “developmental origins of health and disease” (DOHaD). Yet, whether fetal-derived immune cells are mechanistically involved in DOHaD remains elusive. In this review, we summarize our knowledge of fetal hematopoiesis and its contribution to adult immune compartments, which results in a “layered immune system.” Based on their ontogeny, we argue that fetal-derived immune cells are prime transmitters of long-term consequences of prenatal adversities. In addition to increasing disease susceptibility, these may also directly cause inflammatory, degenerative, and metabolic disorders. We explore this notion for cells generated from erythro-myeloid progenitors (EMP) produced in the extra-embryonic yolk sac. Focusing on macrophages and mast cells, we present emerging evidence implicating them in lifelong disease by either somatic mutations or developmental programming events resulting from maternal and early environmental perturbations.

Acute effects of ambient air pollution on outpatients with chronic rhinitis in Xinxiang, China

Air pollution exposure leads to increased mortality and morbidity rates of respiratory diseases. Most of the evidence was founded on acute diseases such as acute lower respiratory diseases. However, limited studies have been conducted to evaluate the effects of air pollution on chronic respiratory diseases. This time-series study was conducted to examine the acute effects of 6 criteria ambient air pollutants on hospital outpatients with chronic rhinitis (CR) in Xinxiang, China. We retrieved 223,826 outpatient records of patients with respiratory diseases, of which 62,901 were those of patients with CR. Results showed that the current 10-μg/m³ increase in fine particulate matter (PM_2.5), inhalable particulate matter (PM₁₀), sulfur dioxide (SO₂), nitrogen dioxide (NO₂), and carbon monoxide (CO) corresponds to 0.67% (95% confidence interval [CI]: 0.15-1.18%), 0.58% (95% CI: 0.24-0.92%), 1.89% (95% CI: 0.52-3.27%), 3.01% (95% CI: 1.66-4.35%), and 0.06% (95% CI: 0.03-0.10%) increments in outpatients with CR, respectively. In addition, the effects in the male were stronger than those in the female. Higher effect estimates were observed in the old (≥ 65 years of age) and younger (< 15 years of age) groups. Our study confirmed the association between air pollution and outpatients with CR in Xinxiang, China. More stringent air pollution control measures must be implemented.

Reduced occludin and claudin-7 expression is associated with urban locations and exposure to second-hand smoke in allergic rhinitis patients

The breakdown of nasal epithelial barrier occurs in allergic rhinitis (AR) patients. Impairment of cell junction molecules including tight junctions (TJs) and desmosomes plays causative roles in the pathogenesis of AR. In this study, we investigated the transcript expression levels of TJs including occludin (OCLN), claudin-3 and -7 (CLDN3 and CLDN7), desmoglein 3 (DSG3) and thymic stromal lymphopoietin (TSLP) in AR patients (n = 30) and non-allergic controls (n = 30). Nasal epithelial cells of non-allergic controls and AR patients were collected to examine their mRNA expression levels, and to correlate with clinico-demographical and environmental parameters. We demonstrated that the expression of OCLN (p = 0.009), CLDN3 (p = 0.032) or CLDN7 (p = 0.004) transcript was significantly lower in AR patients compared with non-allergic controls. No significant difference was observed in the expression of DSG3 (p = 0.750) or TSLP (p = 0.991) transcript in AR patients compared with non-allergic controls. A significant association between urban locations and lower OCLN expression (p = 0.010), or exposure to second-hand smoke with lower CLDN7 expression (p = 0.042) was found in AR patients. Interestingly, none of the TJs expression was significantly associated with having pets, frequency of changing bedsheet and housekeeping. These results suggest that defective nasal epithelial barrier in AR patients is attributable to reduced expression of OCLN and CLDN7 associated with urban locations and exposure to second-hand smoke, supporting recent findings that air pollution represents one of the causes of AR.