Effects of ambient air pollution on lung function growth in Chinese schoolchildren

Uncovering the cytotoxic effects of air pollution with multi-modal imaging of in vitro respiratory models

Annually, an estimated seven million deaths are linked to exposure to airborne pollutants. Despite extensive epidemiological evidence supporting clear associations between poor air quality and a range of short- and long-term health effects, there are considerable gaps in our understanding of the specific mechanisms by which pollutant exposure induces adverse biological responses at the cellular and tissue levels. The development of more complex, predictive, in vitro respiratory models, including two- and three-dimensional cell cultures, spheroids, organoids and tissue cultures, along with more realistic aerosol exposure systems, offers new opportunities to investigate the cytotoxic effects of airborne particulates under controlled laboratory conditions. Parallel advances in high-resolution microscopy have resulted in a range of in vitro imaging tools capable of visualizing and analysing biological systems across unprecedented scales of length, time and complexity. This article considers state-of-the-art in vitro respiratory models and aerosol exposure systems and how they can be interrogated using high-resolution microscopy techniques to investigate cell-pollutant interactions, from the uptake and trafficking of particles to structural and functional modification of subcellular organelles and cells. These data can provide a mechanistic basis from which to advance our understanding of the health effects of airborne particulate pollution and develop improved mitigation measures.

Chronic exposure to ambient PM2.5/NO2 and respiratory health in school children: A prospective cohort study in Hong Kong

Despite increasing concerns about the detrimental effects of air pollution on respiratory health, limited evidence is available on these effects in the Hong Kong population, especially in children. In this prospective cohort study between 2012 and 2017, we aimed to investigate the associations between exposure to air pollution (concentrations of fine particulate matter [PM_2.5] and nitrogen dioxide [NO₂]) and respiratory health (lung function parameters and respiratory diseases and symptoms) in schoolchildren. We recruited 5612 schoolchildren aged 6-16 years in Hong Kong. We estimated the annual average concentrations of ambient PM_2.5 and NO₂ at each participant's address using spatiotemporal models. We conducted spirometry tests on all participants to measure their lung function parameters and used a self-administered questionnaire to collect information on their respiratory diseases and symptoms and a wide range of covariates. Linear mixed models were used to investigate the associations between exposure to air pollution and lung function. Mixed-effects logistic regression models with random effects were used to investigate the associations of exposure to air pollution with respiratory diseases and symptoms. In all of the participants, every 5-μg/m³ increase in the ambient PM_2.5 concentration was associated with changes of - 13.90 ml (95 % confidence interval [CI]: -23.65 ml, -4.10 ml), - 4.20 ml (-15.60 ml, 7.15 ml), 27.20 ml/s (-3.95 ml/s, 58.35 ml/s), and - 19.80 ml/s (-38.35 ml/s, -1.25 ml/s) in forced expiratory volume in 1 s, forced vital capacity, peak expiratory flow, and maximal mid-expiratory flow, respectively. The corresponding lung function estimates for every 5-μg/m³ increase in the ambient NO₂ concentration were - 2.70 ml (-6.05 ml, 0.60 ml), - 1.40 ml (-5.40 ml, 2.60 ml), - 6.60 ml/s (-19.75 ml/s, 6.55 ml/s), and - 3.05 ml/s (-11.10 ml/s, 5.00 ml/s), respectively. We did not observe significant associations between PM_2.5/NO₂ exposure and most respiratory diseases and symptoms. Stratified analyses by sex and age showed that the associations between exposure to air pollution and lung function parameters were stronger in male participants and older participants (11-14 year old group) than in female participants and younger participants (6-10 year old group), respectively. Our results suggest that chronic exposure to air pollution is detrimental to the respiratory health of schoolchildren, especially that of older boys. Our findings reinforce the importance of air pollution mitigation to protect schoolchildren's respiratory health.

Long-term improvement of air quality associated with lung function benefits in Chinese young adults: A quasi-experiment cohort study

INTRODUCTION

Long-term exposure to air pollution is associated with lung function impairment. However, whether long-term improvements in air quality could improve lung function is unclear.

OBJECTIVES

To examine whether the reduction of long-term air pollution was associated with lung function improvement among Chinese young adults.

METHODS

We conducted a prospective quasi-experiment cohort study with 1731 college students in Shandong, China from September 2019 to September 2020, covering COVID-19 lockdown period. Data on air pollution concentrations were obtained from China Environmental Monitoring Station. Lung function indicators included forced vital capacity (FVC), forced expiratory volume in 1st second (FEV₁) and forced expiratory flow at 50 % of FVC (FEF50%). We used linear mixed-effects model to examine the associations between the change of air pollutants concentrations and the change of lung function, and additional adjustments for indoor air pollution (IAP) source. We also conducted stratified analysis by sex.

RESULTS

Compared with 2019, the mean FVC, FEV₁ and FEF50% were elevated by 414.4 ml, 321.5 ml, and 28.4 ml/s respectively in 2020. Every 5 μg/m³ decrease in annual average PM_2.5 concentrations was associated with 36.0 ml [95 % confidence interval (CI):6.0, 66.0 ml], 46.1 ml (95 % CI:16.7, 75.5 ml), and 124.2 ml/s (95 % CI:69.5, 178.9 ml/s) increment in the FVC, FEV₁, and FEF50%, respectively. Similar associations were found for PM₁₀. The estimated impact was almost unchanged after adjusting for IAP source. There was no significant effect difference between males and females.

CONCLUSION

Long-term improvement of air quality can improve lung function among young adults. Stricter policies on improving air quality are needed to protect human health.

Air pollution as an early determinant of COPD

COPD is a progressive and debilitating disease often diagnosed after 50 years of age, but more recent evidence suggests that its onset could originate very early on in life. In this context, exposure to air pollution appears to be a potential contributor. Although the potential role of air pollution as an early determinant of COPD is emerging, knowledge gaps still remain, including an accurate qualification of air pollutants (number of pollutants quantified and exact composition) or the "one exposure-one disease" concept, which might limit the current understanding. To fill these gaps, improvements in the field are needed, such as the use of atmosphere simulation chambers able to realistically reproduce the complexity of air pollution, consideration of the exposome, as well as improving exchanges between paediatricians and adult lung specialists to take advantage of reciprocal expertise. This review should lead to a better understanding of the current knowledge on air pollution as an early determinant of COPD, as well as identify the existing knowledge gaps and opportunities to fill them. Hopefully, this will lead to better prevention strategies to scale down the development of COPD in future generations.

Environmental factors linked to hospital admissions in young children due to acute viral lower respiratory infections: A bidirectional case-crossover study

OBJECTIVE

This study evaluated the association of the short-term exposure to environmental factors (relative humidity, temperature, NO₂, SO₂, O₃, PM₁₀, and CO) with hospital admissions due to acute viral lower respiratory infections (ALRI) in children under two years before the COVID-19 era.

METHODS

We performed a bidirectional case-crossover study in 30,445 children with ALRI under two years of age in the Spanish Minimum Basic Data Set (MBDS) from 2013 to 2015. Environmental data were obtained from Spain's State Meteorological Agency (AEMET). The association was assessed by conditional logistic regression.

RESULTS

Lower temperature one week before the day of the event (hospital admission) (q-value = 0.012) and higher relative humidity one week (q-value = 0.003) and two weeks (q-value<0.001) before the day of the event were related to a higher odds of hospital admissions. Higher NO₂ levels two weeks before the event were associated with hospital admissions (q-value<0.001). Moreover, higher concentrations on the day of the event for SO₂ (compared to lag time of 1-week (q-value = 0.026) and 2-weeks (q-value<0.001)), O₃ (compared to lag time of 3-days (q-value<0.001), 1-week (q-value<0.001), and 2-weeks (q-value<0.001)), and PM₁₀ (compared to lag time of 2-weeks (q-value<0.001)) were related to an increased odds of hospital admissions for viral ALRI.

CONCLUSION

Short-term exposure to environmental factors (climatic conditions and ambient air contaminants) was linked to a higher likelihood of hospital admissions due to ALRI. Our findings emphasize the importance of monitoring environmental factors to assess the odds of ALRI hospital admissions and plan public health resources.

Pulmonary Benefits of Intervention with Air Cleaner among Schoolchildren in Beijing: A Randomized Double-Blind Crossover Study

We conducted a crossover study employing air cleaner intervention among 125 schoolchildren aged 9-12 years in a boarding school in Beijing, China. The PM concentrations were monitored, and 27 biomarkers were analyzed. We used the linear mixed-effects model to evaluate the association of intervention/time-weighted PM concentrations with biomarkers. The outcomes showed that air cleaner intervention was associated with FeNO, exhaled breath condensate (EBC) IL-1β, and IL-6, which decreased by 12.57%, 10.83%, and 4.33%, respectively. Similar results were observed in the associations with PMs. Lag 1 day PMs had the strongest relationship with biomarkers, and significant changes were observed in biomarkers such as FEV₁, FeNO, EBC 8-iso, and MCP-1. Boys showed higher percentage changes than girls, and the related biomarkers were FeNO, EBC 4-HNE, IL-1β, IL-6, and MCP-1. The results showed that biomarkers such as FeNO, EBC IL-6, MCP-1, and 4-HNE could sensitively reflect the early abnormal response of the respiratory system under short-term PM exposure among healthy schoolchildren and indicated that (1) air cleaners exert a protective effect on children's respiratory system. (2) PM had lag and cumulative effect, lag 1 day had the greatest effect. (3) The boys were more sensitive than the girls.

Easy Breathing: A Review of the Impact of Air Quality on Pediatric Health Outcomes

Preventable environmental factors such as exposure to poor air quality are predicted to affect 23% of all global deaths. Although there have been efforts to reduce air pollution through federal guidelines for vehicle and industrial emissions, the air in the United States remains far from clean. Children and pregnant women have been identified as high-risk populations who are particularly susceptible to the negative effects of poor air quality. This paper provides an overview of health concerns related to poor air quality, pediatric considerations from pregnancy through childhood, the importance of increased awareness of air quality assessment and prevention in patient encounters, and current advocacy efforts and legislation.

Children's lung function in relation to changes in socioeconomic, nutritional, and household factors over 20 years in Lanzhou

Background

Lanzhou has experienced rapid urbanization, leading to changes in socioeconomic, nutritional, and household factors. These changes may affect children’s lung function.

Methods

Two cross-sectional studies of school-age children (6–13 years of age) from the urban (Chengguan) (Period 1 in 1996 with n=390; Period 2 in 2017 with n=192) and the suburban (Xigu) (Period 1 n=344; Period 2 n=492) district were conducted. Demographic information, household factors, and nutrition status were obtained via a questionnaire survey. Forced vital capacity (FVC) and forced expiratory volume in the first second (FEV₁) were measured in each period. Student’s t-test analysis of variance was used to assess the differences in FVC and FEV₁ between Periods 1 and 2. Generalized linear models were used to analyze the associations between questionnaire derived factors and lung function. Analyses were done separately for girls and boys.

Results

Children had significantly lower mean FEV₁ and FVC measures in Period 2 than in Period 1. This reduction was greater in children living in the urban area than those living in the suburban area. Obese children had significantly lower lung function but this was only statistically significant in Period 1.

Conclusions

Children’s lung function (FVC and FEV₁) were lower in 2017 than in 1996. Rapid urbanization may have contributed to the decline of lung function. Obesity may be a risk factor for impaired lung function in children living in Lanzhou and possibly elsewhere.

Environmental air pollution: respiratory effects

Environmental air pollution is a major risk factor for morbidity and mortality worldwide. Environmental air pollution has a direct impact on human health, being responsible for an increase in the incidence of and number of deaths due to cardiopulmonary, neoplastic, and metabolic diseases; it also contributes to global warming and the consequent climate change associated with extreme events and environmental imbalances. In this review, we present articles that show the impact that exposure to different sources and types of air pollutants has on the respiratory system; we present the acute effects-such as increases in symptoms and in the number of emergency room visits, hospitalizations, and deaths-and the chronic effects-such as increases in the incidence of asthma, COPD, and lung cancer, as well as a rapid decline in lung function. The effects of air pollution in more susceptible populations and the effects associated with physical exercise in polluted environments are also presented and discussed. Finally, we present the major studies on the subject conducted in Brazil. Health care and disease prevention services should be aware of this important risk factor in order to counsel more susceptible individuals about protective measures that can facilitate their treatment, as well as promoting the adoption of environmental measures that contribute to the reduction of such emissions.

Air pollution during infancy and lung function development into adolescence: The GINIplus/LISA birth cohorts study

BACKGROUND

Limited evidence exists on how air pollution exposure during infancy, i.e. the first year of life, may affect lung function development into adolescence.

OBJECTIVES

To investigate the association between exposure to air pollution during the first-year of life and lung function development up to the age of 15 in Germany.

METHODS

We investigated 915 children from the GINIplus and LISA birth cohorts from Munich (n = 181) and Wesel (n = 734), who had at least two spirometric measurements at ages 6, 10 and 15. Z-scores of forced expiratory volume in one second (FEV₁) and forced vital capacity (FVC) were calculated. Annual average concentrations of nitrogen dioxide, particulate matter with diameters <2.5, <10 and 2.5-10 µm (PM_{2.5/10/coarse}), and PM_2.5 absorbance at home addresses during the first-year of life, were estimated by land-use regression models. Associations between infancy exposure and lung function changes were fitted using multivariable linear mixed models with adjustment for potential confounders.

RESULTS

For per interquartile range increase in air pollutants during the first-year life, FEV₁ z-scores declined annually by -0.012 (95% confidence interval (CI): -0.014, -0.009) for PM_2.5 to -0.023 (95%CI: -0.028, -0.018) for PM_coarse. The declines in FVC were lower than FEV₁ [-0.006 (95%CI: -0.008, -0.003) to -0.011 (95%CI: -0.019, -0.003)]. In Munich, the attenuations were only significant for FEV₁. Effect estimates of infancy exposure for certain air pollutants were higher for groups with asthma, older maternal age, and breastfeeding <12 weeks than their counterparts.

DISCUSSION

Infancy exposure to higher air pollution may reduce lung function development up to adolescence, with airway size more affected than lung volume restriction. The potential modifying effects of maternal age, asthmatic status of children and breastfeeding warrant further exploration.

The joint effect of ambient air pollution and agricultural pesticide exposures on lung function among children with asthma

BACKGROUND

Ambient environmental pollutants have been shown to adversely affect respiratory health in susceptible populations. However, the role of simultaneous exposure to multiple diverse environmental pollutants is poorly understood.

OBJECTIVE

We applied a multidomain, multipollutant approach to assess the association between pediatric lung function measures and selected ambient air pollutants and pesticides.

METHODS

Using data from the US EPA and California Pesticide Use Registry, we reconstructed three months prior exposure to ambient air pollutants ((ozone (O₃), nitrogen dioxide (NO₂), particulate matter with a median aerodynamic diameter < 2.5 μm (PM_2.5) and <10 μm (PM₁₀)) and pesticides (organophosphates (OP), carbamates (C) and methyl bromide (MeBr)) for 153 children with mild intermittent or mild persistent asthma from the San Joaquin Valley of California, USA. We implemented Bayesian kernel machine regression (BKMR) to estimate the association between simultaneous exposures to air pollutants and pesticides and lung function measures (forced expiratory volume in 1 s (FEV₁), forced vital capacity (FVC), and forced expiratory flow between 25% and 75% of vital capacity (FEF_25-75)).

RESULTS

In BKMR analysis, the overall effect of mixtures (pollutants and pesticides) was associated with reduced FEV₁ and FVC, particularly when all the environmental exposures were above their 60th percentile. For example, the effect of the overall mixture at the 70th percentile (compared to the median) was a -0.12SD (-50 mL, 95% CI: -180 mL, 90 mL) change in the FEV₁ and a -0.18SD (-90 mL, 95% CI: -240 mL, 60 mL) change in the FVC. However, 95% credible intervals around all of the joint effect estimates contained the null value.

CONCLUSION

At this agricultural-urban interface, we observed results from multipollutant analyses, suggestive of adverse effects on some pediatric lung function measures following a cumulative increase in ambient air pollutants and agricultural pesticides. Given the uncertainty in effect estimates, this approach should be explored in larger studies.

Associations of ambient air pollutants with airway and allergic symptoms in 13,335 preschoolers in Shanghai, China

Findings are inconsistent in studies for impacts of outdoor air pollutants on airway health in childhood. In this paper, we collected data regarding airway and allergic symptoms in the past year before a survey in 13,335 preschoolers from a cross-sectional study. Daily averaged concentrations of ambient sulphur dioxide (SO₂), nitrogen dioxide (NO₂), and particulate matter with an aerodynamic diameter ≤10 μm (PM₁₀) in the past year before the survey were collected in the kindergarten-located district. We investigated associations of 12-month average concentrations of these pollutants with childhood airway and allergic symptoms. In the two-level (district-child) logistic regression analyses, exposure to higher level of NO₂ and of PM₁₀ increased odds of wheeze symptoms (adjusted OR, 95%CI: 1.03, 1.01-1.05 for per 3.0 μg/m³ increase in NO₂; 1.22, 1.09-1.39 for per 7.6 μg/m³ increase in PM₁₀), wheeze with a cold (1.03, 1.01-1.06; 1.22, 1.08-1.39), dry cough during night (1.05, 1.03-1.08; 1.23, 1.09-1.40), rhinitis symptoms (1.11, 1.08-1.13; 1.32, 1.07-1.63), rhinitis on pet (1.11, 1.05-1.18; 1.37, 0.95-1.98) and pollen (1.12, 1.03-1.21; 1.23, 0.84-1.82) exposure, eczema symptoms (1.09, 1.05-1.12; 1.22, 0.98-1.52), and lack of sleep due to eczema (1.12, 1.07-1.18; 1.58, 1.25-1.98). Exposures to NO₂ and PM₁₀ were also significantly and positively associated with the accumulative score of airway symptoms. Similar positive associations were found of NO₂ and of PM₁₀ with the individual symptoms and symptom scores among preschoolers from different kindergarten-located district. These results indicate that ambient NO₂ and PM₁₀ likely are risk factors for airway and allergic symptoms in childhood in Shanghai, China.

The association between ambient NO2 and PM2.5 with the respiratory health of school children residing in informal settlements: A prospective cohort study

BACKGROUND

No previous epidemiological study has investigated the combined association of long-term ambient nitrogen dioxide (NO₂) and particulate matter of diameter size-2.5 (PM_2.5) exposure with asthma outcomes among schoolchildren in Africa.

OBJECTIVES

This study investigated the independent and co-pollutant association of long-term exposures to ambient air pollutants on asthma-associated outcomes in a cohort of schoolchildren in the Western Cape Province of South Africa.

METHODS

A total of 590 grade-4 schoolchildren residing in four informal settlements were studied. Spirometry and fractional exhaled nitric-oxide (FeNO) measurements were conducted, including a standardized questionnaire administered to caregivers at baseline and 12-months follow-up. Annual NO₂ and PM_2.5 levels were estimated for each child's home using land-use regression modelling. Single- and two-pollutant models were constructed to assess the independent and co-pollutant association of both air pollutants (NO₂ and PM_2.5) on new cases of asthma-associated outcomes adjusting-for host characteristics, indoor exposures and study area.

RESULTS

The annual average concentration of PM_2.5 and NO₂ were 10.01μg/m³ and 16.62μg/m³ respectively, across the four study areas, and were below the local Standards of 20μg/m³ and 40μg/m³, for both pollutants, respectively. In the two-pollutant-adjusted models, an interquartile range (IQR) increase of 14.2μg/m³ in NO₂ was associated with an increased risk of new onset of ocular-nasal symptoms (adjusted odds ratio-aOR: 1.63, 95% CI: 1.01-2.60), wheezing (aOR: 3.57, 95% CI: 1.18-10.92), more than two or more asthma symptom score (aOR: 1.71, 95% CI: 1.02-2.86), and airway inflammation defined as FeNO > 35 ppb (aOR: 3.10, 95% CI: 1.10-8.71), independent of PM_2.5 exposures.

CONCLUSION

This study provided evidence that ambient NO₂ levels below local standards and international guidelines, independent of PM_2.5 exposure, increases new cases of asthma-associated outcomes after 12-months.

A Bibliometric Analysis of the Impacts of Air Pollution on Children

In recent years, many researchers have investigated the association between air pollution and children. However, there has been little research to provide a macroscopic overview in this field. The aim of this study is to characterize the scientific production around the world in this area and map the trends. The relevant literature was searched from 1999 to 2018. To guarantee the quality of the literature, we combined the PubMed and WoS databases. The built-in statistics tools of the Web of Science website were used to display the trend of articles published by year and the distribution of journals. By CiteSpace (5.5.R2), the reference co-citation and burst keywords were extracted. In total, 15,999 target English documents were obtained. We summarized the characteristics of published documents, of research institutes' cooperation, and of the contents. As part of a research hotspot, ten clusters are presented, four popular topics are elaborated. Twenty-four burst words were obtained and analyzed. China has received more attention in recent years. Researchers in this field could carry out more cohorts' studies and fine particulate matter is one good air pollution index. Household air pollution exposure and children's lung function should be paid more attention.

Reduction in mouse allergen exposure is associated with greater lung function growth

BACKGROUND

Current childhood asthma therapies have little effect on lung function trajectory.

OBJECTIVE

We sought to determine whether mouse allergen exposure reduction is associated with lung function growth in mouse-sensitized/exposed asthmatic children.

METHODS

Three hundred fifty mouse-sensitized/exposed asthmatic children (5-17 years old) were enrolled in a 1-year randomized trial of integrated pest management plus education versus education alone. Prebronchodilator/postbronchodilator spirometry was performed at baseline and 6 and 12 months, and bedroom floor mouse allergen levels were measured every 3 months. Mouse allergen reduction was defined as a 75% or greater decrease in mouse allergen levels from baseline. Treatment groups were combined for analyses because there were no differences in outcomes between groups. Changes in lung function over time were modeled, adjusting for age, sex, race, atopy, group, and bronchodilator reversibility and including an interaction term (allergen reduction*time).

RESULTS

The study population was predominantly black (79.4%) and low income (66.3% [<$30,000]). At baseline, the median mouse allergen level was 5.7 μg/g (interquartile range, 1.5-22.8 μg/g), and the mean (SD) prebronchodilator FEV₁/forced vital capacity ratio was 80.2% (9.0%). Ninety-two (26.3%) participants had 75% or greater reduction in mouse allergen levels. For a 10-year-old black boy, 75% or greater allergen reduction was associated with an increase in prebronchodilator FEV₁ of 238 mL/y (95% CI, 177-299 mL/y), whereas less than 75% allergen reduction was associated with an increase in prebronchodilator FEV₁ of 131 mL/y (95% CI, 97-166 mL/y). Estimated differences in prebronchodilator and postbronchodilator FEV₁ growth were as follows: 107 mL/y (95% CI, 37-177 mL/y; P_int = .003) and 48 mL/y (95% CI, -17 to 113 mL/y; P_int = .15), respectively. Estimated differences in prebronchodilator and postbronchodilator forced expiratory flow at 25% to 75% of vital capacity growth were as follows: 182 mL/y (95% CI, 61-304 mL/y; P_int = .003) and 181 mL/y (95% CI, 48-314 mL/y; P_int = .008), respectively.

CONCLUSION

Mouse allergen reduction is associated with greater increases in prebronchodilator FEV₁ and prebronchodilator/postbronchodilator forced expiratory flow at 25% to 75% of vital capacity over 1 year among sensitized/exposed asthmatic children.

Characteristics of air pollutants inside and outside a primary school classroom in Beijing and respiratory health impact on children

This study investigated the spatial and temporal distributions of particulate and gaseous air pollutants in a primary school in Beijing and assessed their health impact on the children. The results show that air quality inside the classroom was greatly affected by the input of outdoor pollutants; high levels of pollution were observed during both the heating and nonheating periods and indicate that indoor and outdoor air pollution posed a threat to the children's health. Traffic sources near the primary school were the main contributors to indoor and outdoor pollutants during both periods. Moreover, air quality in this primary school was affected by coal combustion and atmospheric reactions during the heating and nonheating periods, respectively. Based on the estimation by exposure-response functions and the weighting of indoor and outdoor pollutants during different periods, the levels of PM_2.5, PM ₁₀ and O₃ at school had adverse respiratory health effects on children. Longer exposures during the nonheating period contributed to higher health risks. These results emphasized that emission sources nearby had a direct impact on air quality in school and children's respiratory health. Therefore, measures should be taken for double control on air pollution inside and outside the classroom to protect children from it.

Children environmental exposure to particulate matter and polycyclic aromatic hydrocarbons and biomonitoring in school environments: A review on indoor and outdoor exposure levels, major sources and health impacts

Children, an important vulnerable group, spend most of their time at schools (up to 10 h per day, mostly indoors) and the respective air quality may significantly impact on children health. Thus, this work reviews the published studies on children biomonitoring and environmental exposure to particulate matter (PM) and polycyclic aromatic hydrocarbons (PAHs) at school microenvironments (indoors and outdoors), major sources and potential health risks. A total of 28, 35, and 31% of the studies reported levels that exceeded the international outdoor ambient air guidelines for PM₁₀, PM_2.5, and benzo(a)pyrene, respectively. Indoor and outdoor concentrations of PM₁₀ at European schools, the most characterized continent, ranged between 7.5 and 229 μg/m³ and 21-166 μg/m³, respectively; levels of PM_2.5 varied between 4 and 100 μg/m³ indoors and 6.1-115 μg/m³ outdoors. Despite scarce information in some geographical regions (America, Oceania and Africa), the collected data clearly show that Asian children are exposed to the highest concentrations of PM and PAHs at school environments, which were associated with increased carcinogenic risks and with the highest values of urinary total monohydroxyl PAH metabolites (PAH biomarkers of exposure). Additionally, children attending schools in polluted urban and industrial areas are exposed to higher levels of PM and PAHs with increased concentrations of urinary PAH metabolites in comparison with children from rural areas. Strong evidences demonstrated associations between environmental exposure to PM and PAHs with several health outcomes, including increased risk of asthma, pulmonary infections, skin diseases, and allergies. Nevertheless, there is a scientific gap on studies that include the characterization of PM fine fraction and the levels of PAHs in the total air (particulate and gas phases) of indoor and outdoor air of school environments and the associated risks for the health of children. There is a clear need to improve indoor air quality in schools and to establish international guidelines for exposure limits in these environments.

The association of early-life exposure to air pollution with lung function at ~17.5 years in the "Children of 1997" Hong Kong Chinese Birth Cohort

BACKGROUND

Early-life air pollution exposure is associated with lung function in children and adolescents. However, whether the association of prenatal and early postnatal exposure to air pollution with lung function continues into adulthood remains unclear.

OBJECTIVE

To investigate the associations of early exposure to air pollution with lung function at ~17.5 years in a non-western developed setting with more concentrated air pollutants.

METHODS

We examined the associations of exposure to particular matter with an aerodynamic diameter of <10 μm (PM₁₀), nitrogen dioxides (NO₂), nitric oxide (NO), sulfur dioxide (SO₂) in standard deviations (SD)) at different early life stages with lung function (indicated by forced vital capacity (FVC), forced expiratory volume in 1 s (FEV₁) and forced expiratory flow at 25%-75% of the pulmonary volume (FEF_25%-75%)) in SD at ~17.5 years, personal history of wheezing and asthma in the population-representative Hong Kong Chinese birth cohort "Children of 1997"(n = 2942).

RESULTS

Higher in utero and infancy and toddlerhood NO₂ were associated with lower FEV₁ (-0.022, 95% confidence interval (CI) -0.029 to -0.015 and - 0.026, 95% CI -0.033 to -0.019), FEV₁/FVC (-0.035, 95% CI -0.050 to -0.021 and -0.052, 95% CI -0.066 to -0.038) and FEF_25%-75% (-0.031, 95% CI -0.040 to -0.022 and -0.043, 95% CI -0.051 to -0.035). A similar association was observed for NO. Weak associations of NO₂ and NO with FVC were observed (-0.011, 95% CI -0.018 to -0.003 and -0.010, 95% CI -0.020 to -0.001). NO_x was associated with higher risk of wheezing (1.08, 95% CI 1.03 to 1.14) but not asthma (1.02, 95% CI 0.94 to 1.11). SO₂ and PM₁₀ were not clearly associated with lung function, wheezing or asthma.

CONCLUSION

Our findings suggest that early exposure to air pollution from NO₂ may have long-term effects on lung function, which could affect respiratory health throughout life.

Short-term effects of ambient air pollution exposure on lung function: A longitudinal study among healthy primary school children in China

BACKGROUND

Short-term exposure to ambient air pollution has been associated with reduced lung function among asthmatic children. However, there is little information about the effects among healthy children, especially in areas with relatively high exposure background.

OBJECTIVE

To examine the association between short-term effects of ambient air pollutants and lung function among healthy primary school-aged children in China.

METHODS

A total of 334 healthy children (7-11 years) from four cities (Chengdu (Southwest China), Guangzhou (Southern China), Wuhan (Central China), and Xi'an (Northwest China)) in China with repeated lung function measurement in 2014-2016 were included. Daily ambient concentrations of PM_2.5, PM₁₀, NO₂, SO₂, mean temperature, and relative humidity data were obtained. Linear mixed model was used to estimate the percent change in lung function associated with per inter-quartile range (IQR) exposure (up to 3 days) increase after adjusting for confounders.

RESULTS

Ambient PM_2.5 and PM₁₀ exposure were associated with decrements in lung function measurements. The moving average exposures generally showed stronger effect estimates than the single lag day exposures. An IQR increase in two-day average (lag01 day) PM₁₀ exposure (IQR, 144 μg/m³) was significantly associated with 2.56% decrease in FVC, 5.46% in FEV₁, 4.23% in PEF, and 7.35% in FEF_25%, respectively. The effect estimates were stronger after adjusting for gaseous pollutants in particulate matter (PM) models. The strengths of these associations were stronger in girls than those in boys.

CONCLUSION

Short-term exposure to PM was associated with reduced lung function in healthy children. The estimated adverse effects were greater in girls than in boys.

Housing characteristics, home environmental factors, and pulmonary function deficit in Chinese children: Results from the Seven Northeast Cities (SNEC) Study

To assess the effects of housing characteristics and home environmental factors on lung function of Chinese children, 6740 children (aged 6–16 years) were recruited from seven cities in Northeast China in 2012. Performance of lung function was determined by comparison of forced vital capacity (FVC), forced expiratory volume (FEV1), peak expiratory flow (PEF), and maximal mid-expiratory flow (MMEF). Multivariate regression models were used to evaluate the associations with lung function deficit. The results showed that housing conditions were associated with lung function deficit in children. The adjusted odds ratios were 0.47 (95% CI: 0.26–0.83) for FVC for “ping-fang” housing compared with “dan-yuan-lou-fang” housing and 2.90 (95% CI: 2.43–3.47) for FEV1 with home renovations completed within two years compared with counterparts. The linear regression models consistently showed a significant association of housing conditions and home environmental factors with lung function measurements across subjects. A residence taller than seven stories was negatively associated with FEV1 ( β = −55; 95% CI: −97 to −13). In conclusion, housing conditions and home environmental factors are particularly important to the development of lung function and respiratory health in children. These factors are concerning and action should be taken to improve them.

Effects of Long-Term Exposure to Traffic-Related Air Pollution on Lung Function in Children

Lung function in early life has been shown to be an important predictor for peak lung function in adults and later decline. Reduced lung function per se is associated with increased morbidity and mortality. With this review, we aim to summarize the current epidemiological evidence on the effect of traffic-related air pollution on lung function in children and adolescents. We focus in particular on time windows of exposure, small airway involvement, and vulnerable sub-groups in the population. Findings from studies published to date support the notion that exposure over the entire childhood age range seems to be of importance for lung function development. We could not find any conclusive data to support evidence of sup-group effects considering gender, sensitization status, and asthma status, although a possibly stronger effect may be present for children with asthma. The long-term effects into adulthood of exposure to air pollution during childhood remains unknown, but current studies suggest that these deficits may be propagated into later life. In addition, further research on the effect of exposure on small airway function is warranted.

Factors Affecting Parent's Perception on Air Quality-From the Individual to the Community Level

The perception of air quality significantly affects the acceptance of the public of the government’s environmental policies. The aim of this research is to explore the relationship between the perception of the air quality of parents and scientific monitoring data and to analyze the factors that affect parents’ perceptions. Scientific data of air quality were obtained from Wuhan’s environmental condition reports. One thousand parents were investigated for their knowledge and perception of air quality. Scientific data show that the air quality of Wuhan follows an improving trend in general, while most participants believed that the air quality of Wuhan has deteriorated, which indicates a significant difference between public perception and reality. On the individual level, respondents with an age of 40 or above (40 or above: OR = 3.252; 95% CI: 1.170–9.040), a higher educational level (college and above: OR = 7.598; 95% CI: 2.244–25.732) or children with poor healthy conditions (poor: OR = 6.864; 95% CI: 2.212–21.302) have much more negative perception of air quality. On the community level, industrial facilities, vehicles and city construction have major effects on parents’ perception of air quality. Our investigation provides baseline information for environmental policy researchers and makers regarding the public’s perception and expectation of air quality and the benefits to the environmental policy completing and enforcing.

The effect of pollutional haze on pulmonary function

Detrimental health effects of atmospheric exposure to ambient particulate matter (PM) have been investigated in numerous studies. Exposure to pollutional haze, the carrier of air pollutants such as PM and nitrogen dioxide (NO2) has been linked to lung and cardiovascular disease, resulting increases in both hospital admissions and mortality. This review focuses on the constituents of pollutional haze and its effects on pulmonary function. The article presents the available information and seeks to correlate pollutional haze and pulmonary function.

Relationship between exposure to fine particulates and ozone and reduced lung function in children

BACKGROUND

A limited number of studies have reported an association between long-term exposure to ambient air pollutants and lung function growth among children, with inconclusive results.

OBJECTIVES

To assess the relationship between air pollutant exposure and lung function growth, and to examine potential sex differences in the susceptibility of lung function growth to air pollution.

METHODS

We conducted a two-year prospective cohort study of Taiwanese children aged 12 at baseline who were followed from October 1, 2007 to November 31, 2009. The study population comprised 2941 non-smoking children who completed pulmonary function tests at both baseline and follow-up surveys. We applied spatial modeling for individual-level exposure assessment to capture relevant exposures and also attempted to eliminate potential community-level confounding. The exposure parameters were annual averages and values calculated from 24-hourly PM2.5 and 8-hourly ozone (O3) concentrations, corresponding to the residential addresses over the study period. The effect estimates were presented as lung function growth deficits per interquartile range (IQR) for PM2.5 and O3.

RESULTS

In a multiple linear mixed effect model, adjusted for confounding, growth deficits in the forced vital capacity (FVC), forced expiration volume in 1s (FEV1), and forced expiratory flow between the 25th and 75th percentiles of the FVC were associated with increased exposure to PM2.5 and O3. For example, greater exposure to PM2.5 (IQR, 17.92μg/m(3)) was associated with an annual deficit in FVC growth of 75mL in boys and 61mL in girls (p for interaction <0.05). Similar associations were found for O3.

CONCLUSIONS

The study provides evidence that long-term exposure to PM2.5 and O3 may have a detrimental effect on the development of lung function in children. The estimated deficits were generally larger in boys, compared to girls.

Investigation on the lung function of general population in Ilam, west of Iran, as a city exposed to dust storm

BACKGROUND

Dust storm is one of the most important natural sources of air pollution in the Middle East that has caused a major concern in recent years. The aim of this study was to evaluate the respiratory tract function of people living in Ilam city (Iran) during dust storm.

METHODS

A sample size of 250 people was selected and the cluster sampling was randomly used from 13 health centers in Ilam city. Pulmonary function test (PFT) was determined via a standard spirometry apparatus. Vital capacity (VC), Forced Vital capacity (FVC), FVC in first second (FEV1), FEV1/VC, FEV1/FVC, peek expiratory flow (PEF), forced expiratory flow (FEF25-75%), forced expiratory flow (FEF25-75%), forced expiratory flow (FEF75-85%), forced mid flow time (FMFT) and maximum voluntary ventilation (MVV) were measured.

RESULTS

Mean values of respiratory capacities measured in all participants excluding FEV1/VC and FMFT were less than predicted mean values by ECCS reference. 21.6% of the population suffered from obstructive lesions. This value among males (24.1%) was more than females (19.6%). This could be related to more exposure (outdoor jobs) of males with dust storms.

CONCLUSION

The results also showed a negative significant relationship between duration of inhabitance in Ilam city and all respiratory capacities. Further studies are needed for confident confirmation of whether reduction of respiratory capacities among Ilamian people is only related to dust storms.

Understanding the characteristics of the microenvironments in urban street canyons through analysis of pollution measured using a novel pervasive sensor array

This paper presents results of comprehensive analyses of data from the first 122 commercially available wireless environmental pervasive sensors (motes), developed by Newcastle University and deployed in England. Measurements of pollution, meteorology and traffic are used to investigate the complexity of the physical and chemical processes governing the levels of traffic-related pollution in urban areas. Following a brief introduction on health impacts associated with air quality, description of the mote technology is given. Cluster analysis statistics to investigate the relationship between different pollutant types and traffic data demonstrated that traffic flow regimes alone cannot be used to estimate diurnal kerbside pollutant concentrations. Also, the absolute levels, whilst dependent on meteorological conditions and static parameters are only partially governed by the pollutant dispersion. The research clearly illustrates the benefits and added value of pervasive concentration measurement in urban micro environments with potential to effectively evaluate human exposure to transport-related emissions.

Early-life exposure to combustion-derived particulate matter causes pulmonary immunosuppression

Elevated levels of combustion-derived particulate matter (CDPM) are a risk factor for the development of lung diseases such as asthma. Studies have shown that CDPM exacerbates asthma, inducing acute lung dysfunction and inflammation; however, the impact of CDPM exposure on early immunological responses to allergens remains unclear. To determine the effects of early-life CDPM exposure on allergic asthma development in infants, we exposed infant mice to CDPM and then induced a mouse model of asthma using house dust mite (HDM) allergen. Mice exposed to CDPM+HDM failed to develop a typical asthma phenotype including airway hyper-responsiveness, T-helper type 2 (Th2) inflammation, Muc5ac expression, eosinophilia, and HDM-specific immunoglobulin (Ig) compared with HDM-exposed mice. Although HDM-specific IgE was attenuated, total IgE was twofold higher in CDPM+HDM mice compared with HDM mice. We further demonstrate that CDPM exposure during early life induced an immunosuppressive environment in the lung, concurrent with increases in tolerogenic dendritic cells and regulatory T cells, resulting in the suppression of Th2 responses. Despite having early immunosuppression, these mice develop severe allergic inflammation when challenged with allergen as adults. These findings demonstrate a mechanism whereby CDPM exposure modulates adaptive immunity, inducing specific antigen tolerance while amplifying total IgE, and leading to a predisposition to develop asthma upon rechallenge later in life.

Impact of microenvironments and personal activities on personal PM2.5 exposures among asthmatic children

Personal activity patterns have often been suggested as a source of unexplained variability when comparing personal particulate matter (PM2.5) exposure to modeled data using central site or microenvironmental data. To characterize the effect of personal activity patterns on asthmatic children's personal PM2.5 exposure, data from the Windsor, Ontario Exposure Assessment Study were analyzed. The children spent on an average 67.1±12.7% (winter) and 72.3±22.6% (summer) of their time indoors at home where they received 51.7±14.8% and 66.3±19.0% of their PM2.5 exposure, respectively. In winter, 17.7±5.9% of their time was spent at school where they received 38.6±11.7% of their PM2.5 exposure. In summer, they spent 10.3±11.8% 'indoors away from home', which represented 23.4±18.3% of their PM2.5 exposure. Personal activity codes adapted from those of the National Human Activity Pattern Survey and the Canadian Human Activity Pattern Survey were assigned to the children's activities. Of the over 100 available activity codes, 19 activities collectively encompassed nearly 95% of their time. Generalized estimating equation (GEE) models found that, while indoors at home, relative to daytime periods when sedentary activities were conducted, several personal activities were associated with significantly elevated personal PM2.5 exposures. Indoor playing represented a mean increase in PM2.5 of 10.1 μg/m(3) (95% CI 6.3-13.8) and 11.6 μg/m(3) (95% CI 8.1-15.1) in winter and summer, respectively, as estimated by a personal nephelometer.

Air pollution and respiratory symptoms among children with asthma: vulnerability by corticosteroid use and residence area

RATIONALE

Information on how ambient air pollution affects susceptible populations is needed to ensure protective air quality standards.

OBJECTIVES

To estimate the effect of community-level ambient particulate matter (PM) and ozone (O) on respiratory symptoms among primarily African-American and Latino, lower-income asthmatic children living in Detroit, Michigan and to evaluate factors associated with heterogeneity in observed health effects.

METHODS

A cohort of 298 children with asthma was studied prospectively from 1999 to 2002. For 14days each season over 11 seasons, children completed a respiratory symptom diary. Simultaneously, ambient pollutant concentrations were measured at two community-level monitoring sites. Logistic regression models using generalized estimating equations were fit for each respiratory symptom in single pollutant models, looking for interactions by area or by corticosteroid use, a marker of more severe asthma. Exposures of interest were: daily concentrations of PM<10μm, <2.5μm, and between 10 and 2.5μm in aerodynamic diameter (PM, PM, and PM respectively), the daily 8-hour maximum concentration of O (8HrPeak), and the daily 1-hour maximum concentration of O (1HrPeak).

RESULTS

Outdoor PM, PM, 8HrPeak, and 1HrPeak O concentrations were associated with increased odds of respiratory symptoms, particularly among children using corticosteroid medication and among children living in the southwest community of Detroit. Similar patterns of associations were not seen with PM.

CONCLUSIONS

PM and O at levels near or below annual standard levels are associated with negative health impact in this population of asthmatic children. Variation in effects within the city of Detroit and among the subgroup using steroids emphasizes the importance of spatially refined exposure assessment and the need for further studies to elucidate mechanisms and effective risk reduction interventions.

Particulate matter containing environmentally persistent free radicals and adverse infant respiratory health effects: a review

The health impacts of airborne particulate matter (PM) are of global concern, and the direct implications to the development/exacerbation of lung disease are immediately obvious. Most studies to date have sought to understand mechanisms associated with PM exposure in adults/adult animal models; however, infants are also at significant risk for exposure. Infants are affected differently than adults due to drastic immaturities, both physiologically and immunologically, and it is becoming apparent that they represent a critically understudied population. Highlighting our work funded by the ONES award, in this review we argue the understated importance of utilizing infant models to truly understand the etiology of PM-induced predisposition to severe, persistent lung disease. We also touch upon various mechanisms of PM-mediated respiratory damage, with a focus on the emerging importance of environmentally persistent free radicals (EPFRs) ubiquitously present in combustion-derived PM. In conclusion, we briefly comment on strengths/challenges facing current PM research, while giving perspective on how we may address these challenges in the future.

Variations in peak expiratory flow measurements associated to air pollution and allergic sensitization in children in Sao Paulo, Brazil

BACKGROUND

In the last 20 years, there has been an increase in the incidence of allergic respiratory diseases worldwide and exposure to air pollution has been discussed as one of the factors associated with this increase. The objective of this study was to investigate the effects of air pollution on peak expiratory flow (PEF) and FEV1 in children with and without allergic sensitization.

METHODS

Ninety-six children were followed from April to July, 2004 with spirometry measurements. They were tested for allergic sensitization (IgE, skin prick test, eosinophilia) and asked about allergic symptoms. Air pollution, temperature, and relative humidity data were available.

RESULTS

Decrements in PEF were observed with previous 24-hr average exposure to air pollution, as well as with 3-10-day average exposure and were associated mainly with PM(10), NO(2), and O(3) in all three categories of allergic sensitization. Even though allergic sensitized children tended to present larger decrements in the PEF measurements they were not statistically different from the non-allergic sensitized. Decrements in FEV1 were observed mainly with previous 24-hr average exposure and 3-day moving average.

CONCLUSIONS

Decrements in PEF associated with air pollution were observed in children independent from their allergic sensitization status. Their daily exposure to air pollution can be responsible for a chronic inflammatory process that might impair their lung growth and later their lung function in adulthood.

Traffic-related air pollution and lung function in children at 8 years of age: a birth cohort study

RATIONALE

Long-term exposure to air pollution has been related to lung function decrements in children, but the role of timing of exposure remains unknown.

OBJECTIVES

To assess the role of long-term exposure to air pollution on lung function in school-age children.

METHODS

More than 1,900 children in the Swedish birth cohort BAMSE were followed with repeated questionnaires, dynamic spirometry, and IgE measurements until 8 years of age. Outdoor concentrations of particulate matter with an aerodynamic diameter less than 10 μm (PM(10)) from road traffic were estimated for residential, day care, and school addresses from birth and onward using dispersion modeling. The relationship between time-weighted average exposure during different time windows and FEV at 8 years was analyzed by linear regression, adjusting for potential confounding factors, including short-term exposure to air pollution.

MEASUREMENTS AND MAIN RESULTS

A 5th to 95th percentile difference in time-weighted average particulate matter less than 10 μm in aerodynamic diameter exposure during the first year of life was associated with a reduced FEV(1) of -59.3 ml (95% confidence interval, -113 to -5.6) at 8 years of age. The negative association was particularly pronounced in children concomitantly sensitized to common inhalant or food allergens (-136.9 ml; 95% confidence interval, -224.1 to -49.7). Exposure after the first year of life seemed to have less impact on lung function at 8 years.

CONCLUSIONS

Our results indicate that exposure to traffic-related air pollution during infancy affects lung function in children up to 8 years of age and particularly in those sensitized to common inhalant or food allergens.

Ambient particulate matter and lung function growth in Chinese children

BACKGROUND

Exposure to particulate matter (PM) has been associated with deficits in lung function growth among children in Western countries. However, few studies have explored this association in developing countries, where PM levels are often substantially higher.

METHODS

Children (n = 3273) 6-12 years of age were recruited from 8 schools in 4 Chinese cities. The lung function parameters of forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1) were measured using computerized spirometers twice a year for up to 3 years (1993-1996). Dichotomous samplers placed in each schoolyard were used to measure PM2.5 and PM10 (PM with diameter ≤ 2.5 μm and ≤ 10 μm, respectively). Multivariable generalized estimating equations were used to examine the association between the quarterly average PM levels and lung function growth during the period of follow-up.

RESULTS

Annual average PM2.5 and PM10 levels in the 4 cities ranged from 57 to 158 μg/m and 95 to 268 μg/m, respectively. In multivariable models, an increase of 10 μg/m of PM2.5 was associated with decreases of 2.7 mL FEV1 (95% confidence interval = -3.5 to -2.0), 3.5 mL FVC (-4.3 to -2.7), 1.4 mL/year FEV1 growth (-1.8 to -0.9), and 1.5 mL/year FVC growth (-2.0 to -1.0). Similar results were seen with PM10 exposure.

CONCLUSIONS

Exposure to ambient particulate matter was associated with decreased growth in lung function among Chinese children.