Effects of ambient air pollution on emergency room visits of children for acute respiratory symptoms in Delhi, India

Recent Insights into the Environmental Determinants of Childhood Asthma

PURPOSE OF REVIEW

Ubiquitous environmental exposures, including ambient air pollutants, are linked to the development and severity of childhood asthma. Advances in our understanding of these links have increasingly led to clinical interventions to reduce asthma morbidity.

RECENT FINDINGS

We review recent work untangling the complex relationship between air pollutants, including particulate matter, nitrogen dioxide, and ozone and asthma, such as vulnerable windows of pediatric exposure and their interaction with other factors influencing asthma development and severity. These have led to interventions to reduce air pollutant levels in children's homes and schools. We also highlight emerging environmental exposures increasingly associated with childhood asthma. Growing evidence supports the present threat of climate change to children with asthma. Environmental factors play a large role in the pathogenesis and persistence of pediatric asthma; in turn, this poses an opportunity to intervene to change the course of disease early in life.

Social determinants of respiratory health from birth: still of concern in the 21st century?

Respiratory symptoms are ubiquitous in children and, even though they may be the harbinger of poor long-term outcomes, are often trivialised. Adverse exposures pre-conception, antenatally and in early childhood have lifetime impacts on respiratory health. For the most part, lung function tracks from the pre-school years at least into late middle age, and airflow obstruction is associated not merely with poor respiratory outcomes but also early all-cause morbidity and mortality. Much would be preventable if social determinants of adverse outcomes were to be addressed. This review presents the perspectives of paediatricians from many different contexts, both high and low income, including Europe, the Americas, Australasia, India, Africa and China. It should be noted that there are islands of poverty within even the highest income settings and, conversely, opulent areas in even the most deprived countries. The heaviest burden of any adverse effects falls on those of the lowest socioeconomic status. Themes include passive exposure to tobacco smoke and indoor and outdoor pollution, across the entire developmental course, and lack of access even to simple affordable medications, let alone the new biologicals. Commonly, disease outcomes are worse in resource-poor areas. Both within and between countries there are avoidable gross disparities in outcomes. Climate change is also bearing down hardest on the poorest children. This review highlights the need for vigorous advocacy for children to improve lifelong health. It also highlights that there are ongoing culturally sensitive interventions to address social determinants of disease which are already benefiting children.

Efficacy of Bhramari pranayama and Om chanting on asthma control, quality of life, and airway inflammation in asthmatic children: an open-label randomized controlled trial

OBJECTIVES

To explore the efficacy of combination of Bhramari pranayama and om chanting as an adjunct to standard pharmacological treatment on asthma control, quality of life, pulmonary function, and airway inflammation in asthmatic children.

METHODS

Children (n = 110; 8-15 years) with uncontrolled or partly controlled asthma were recruited from the Pediatric Chest Clinic of All India Institute of Medical Sciences, New Delhi. Eligible participants were randomized to either home-based online Bhramari pranayama and om chanting plus standard treatment (YI + ST) group, or standard treatment (ST) alone group. Primary outcome measures were 12-week change in level of asthma symptom control; asthma control questionnaire (ACQ) score, spirometry indices, impulse oscillometry parameters, and pediatric asthma quality of life questionnaire (PAQLQ) score. Secondary outcome was a change in fractional exhaled nitric oxide (FeNO) levels at 12 weeks. Beginning from the enrollment, every participant was evaluated at 0, 2, 6, and 12 weeks.

RESULTS

After 12 weeks of intervention, higher proportion (68.2%) of children were found to have controlled asthma symptoms in the YI + ST group as compared to ST group (38.5%) according to per protocol analysis (p = 0.03). When compared to ST group, children in YI + ST group showed significantly lower ACQ score, higher PAQLQ score and reduced FeNO levels. No significant changes were observed for the lung function parameters.

CONCLUSION

Children practicing Bhramari pranayama and om chanting for 12 weeks have better asthma symptom control, quality of life, and reduced airway inflammation than those taking standard pharmacotherapy alone.

Impact of ambient air pollution and socio-environmental factors on the health of children younger than 5 years in India: a population-based analysis

Background

Ambient air pollution and household environmental factors affect child health, particularly in low-income and middle-income countries. This study aimed to investigate the association between ambient air pollution (PM2·5) levels, socio-environmental factors (including household wealth, housing quality measures, smoking status), and the occurrence of respiratory illness in Indian children.

Methods

In this retrospective and observational study, we analysed data from India's National Family Health Survey (NFHS-5, 2019-2021) combined with NASA's Global Annual PM2·5 Grids database. Bivariate and multivariable generalized additive models were employed to examine associations between key social-environmental factors and respiratory illness in children younger than 5 years.

Findings

We analysed data from 224,214 children younger than 5 years, representing 165,561 families from 29,757 geographic clusters. Our results showed extremely high annual PM2·5 levels throughout India (median 63·4·g/m3, IQR 41·9-81·6), with higher exposure for rural and impoverished families. In bivariate analyses, PM2·5 was significantly associated with reported respiratory illness (p < 0·001). Using generalized additive models and after accounting for key social and environmental factors, a monotonic increasing and non-linear relationship was observed between PM2·5 and respiratory illness (p < 0·001), with increased likelihood of illness observed even at values near and below India's National Ambient Air Quality Standards of 40 μg/m3.

Interpretation

The study highlights the significant association of social-environmental conditions with health outcomes among young children in India. Efforts specifically targeting ambient air pollution and child health during monsoon season could have significant health benefits among this population and help achieve the goal of ending preventable deaths of children younger than 5 years.

Funding

National Institutes of Health (NIH T-32-HL139443-3).

"I have to stay inside …": Experiences of air pollution for people with asthma

Asthma, characterized by airway inflammation, sensitization and constriction, and leading to symptoms including cough and dyspnoea, affects millions of people globally. Air pollution is a known asthma trigger, yet how it is experienced is understudied and how individuals with asthma interact with air quality information and manage exacerbation risks is unclear. This study aimed to explore how people living with asthma in Scotland, UK, experienced and managed their asthma in relation to air pollution. We explored these issues with 36 participants using semi-structured interviews. We found that self-protection measures were influenced by place and sense of control (with the home being a "safe space"), and that the perception of clean(er) air had a liberating effect on outdoor activities. We discuss how these insights could shape air quality-related health advice in future.

The association of asthma and air pollution: Evidence from India

In the last two decades, air pollution has increased throughout India resulting in the deterioration of air quality. This paper estimates the prevalence of self-reported asthma in women aged 15-49 years and examines the link between outdoor air pollution and disease prevalence in India by combining satellite data on particulate matter (PM2.5) and the National Family Health Survey (NFHS-4), 2015-16. The results indicate that both indoor pollution as well as outdoor air pollution are important risk factors for asthma in women as both independently increase the probability of asthma among this group. Strategies around the prevention of asthma need to recognize the role of both indoor as well as outdoor air pollution. The other significant risk factors for asthma are smoking, second-hand smoking, type of diet and obesity.

Personal exposure to fine particulate matter (PM2.5) and self-reported asthma-related health

PM2.5 (fine particulate matter ≤2.5 μm in diameter) is a key pollutant that can produce acute asthma exacerbations and longer-term deterioration of respiratory health. Individual exposure to PM2.5 is unique and varies across microenvironments. Low-cost sensors (LCS) can collect data at a spatiotemporal resolution previously unattainable, allowing the study of exposures across microenvironments. The aim of this study is to investigate the acute effects of personal exposure to PM2.5 on self-reported asthma-related health. Twenty-eight non-smoking adults with asthma living in Scotland collected PM2.5 personal exposure data using LCS. Measurements were made at a 2-min time resolution for a period of 7 days as participants conducted their typical daily routines. Concurrently, participants were asked to keep a detailed time-activity diary, logging their activities and microenvironments, along with hourly information on their respiratory health and medication use. Health outcomes were modelled as a function of hourly PM2.5 concentration (plus 1- and 2-h lag) using generalized mixed-effects models adjusted for temperature and relative humidity. Personal exposures to PM2.5 varied across microenvironments, with the largest average microenvironmental exposure observed in private residences (11.5 ± 48.6 μg/m3) and lowest in the work microenvironment (2.9 ± 11.3 μg/m3). The most frequently reported asthma symptoms, wheezing, chest tightness and cough, were reported on 3.4%, 1.6% and 1.6% of participant-hours, respectively. The odds of reporting asthma symptoms increased per interquartile range (IQR) in PM2.5 exposure (odds ratio (OR) 1.29, 95% CI 1.07-1.54) for same-hour exposure. Despite this, no association was observed between reliever inhaler use (non-routine, non-exercise related) and PM2.5 exposure (OR 1.02, 95% CI 0.71-1.48). Current air quality monitoring practices are inadequate to detect acute asthma symptom prevalence resulting from PM2.5 exposure; to detect these requires high-resolution air quality data and health information collected in situ. Personal exposure monitoring could have significant implications for asthma self-management and clinical practice.

Effects of Ambient Air Pollutants on Hospital Admissions among Children Due to Asthma and Wheezing-Associated Lower Respiratory Infections in Mysore, India: A Time Series Study

Air pollutants are known to trigger asthma and wheezing-associated lower respiratory infections in children, but evidence regarding their effect on hospital admissions in India is limited. We conducted a time-series study over a period of five years to assess the role of ambient air pollutants in daily asthma-related hospital admissions in children in Mysore, India. Daily asthma and wheeze (associated with lower respiratory infections) admissions were modelled using a generalised additive model (GAM) to examine the non-linear effects and generalised linear models (GLM) for linear effects, if any. Models were adjusted by day of the week and lag days, with smooth terms for time, maximum temperature, and relative humidity, and they were stratified by sex and age group. Of the 362 children admitted, more than 50% were boys, and the mean age was 5.34 years (±4.66). The GAMs showed non-linear associations between NO2, PM2.5, and NH3. For example, a 10 µgm-3 (or 10%) increase in NO2 increased admissions by 2.42. These non-linear effects were more pronounced in boys. A linear effect was detected for PM10 with a relative risk (95% CI) of 1.028, 1.013, and 1.043 with admission. Further research is needed to explore whether these findings can be replicated in different cities in India. Air pollution needs to be controlled, and policies that focus on lower cut-off levels for vulnerable populations are necessary.

Use of symptom diary in primary students: association of nitrogen dioxide with prevalence of symptoms

Air pollution is a global public health concern, and numerous studies have attempted to identify the health effects of air pollutants, including nitrogen dioxide (NO₂). In China, there are few studies investigating the relationship between NO₂ exposure and symptoms among children at an individual level. The aim of the study was to evaluate the acute effects of NO₂ on prevalence of symptoms of primary students. An environmental and health questionnaire survey was administered to 4240 primary students in seven districts of Shanghai. Daily symptoms, as well as the daily air pollution and meteorological data from each community, were recorded during the corresponding period. A multivariable logistic regression model was utilized to analyze the relationship between the prevalence of symptoms and NO₂ exposure in school-age children. A model with interaction items was adopted to estimate the interactive effects of NO₂ and confounding factors on symptoms. The average NO₂ level in central urban, industrial and rural areas were 62.07 ± 21.66, 54.86 ± 18.32 and 36.62 ± 21.23 μg m^-3, respectively. Our findings demonstrate that the occurrence of symptoms was significantly affected by NO₂ exposure in the short-term. The largest associations were observed for a 10 μg m^-3 increase in 5-day moving average (lag04) NO₂ concentration with prevalence of general symptoms (odds ratio [OR] = 1.15, 95% confidence interval [95% CI]: 1.07-1.22), throat symptoms (OR = 1.23, 95% CI: 1.13-1.35) and nasal symptoms (OR = 1.142, 95% CI: 1.02-1.27). Subgroup analysis showed that non-rural areas, boys, nearby environmental pollution source and history of present illness were all susceptible factors to the effects of NO₂ exposure. Furthermore, there were interactive effects between NO₂ exposure and area types on reported symptoms. NO₂ can increase the risk of symptoms in primary students in the short-term, which could be significantly enhanced in central urban and industrial areas.

Associations between air pollutant and pneumonia and asthma requiring hospitalization among children aged under 5 years in Ningbo, 2015-2017

Introduction

Exposure to ambient air pollutants is associated with an increased incidence of respiratory diseases such as pneumonia and asthma, especially in younger children. We investigated the relationship between rates of hospitalization of children aged under 5 years for pneumonia and asthma and the concentration of air pollutants in Ningbo between January 1, 2015 and August 29, 2017.

Methods

Data were obtained from the Ningbo Air Quality Data Real-time Publishing System and the big data platform of the Ningbo Health Information Center. A generalized additive model was established via logarithmic link function and utilized to evaluate the effect of pollutant concentration on lag dimension and perform sensitivity analysis.

Results

A total of 10,301 cases of pneumonia and 115 cases of asthma were identified over the course of this study. Results revealed that PM2.5, PM10, SO2 and NO2 were significantly associated with hospitalization for pneumonia and asthma in children under 5 years of age. For every 10-unit increase in lag03 air pollutant concentration, hospitalization for pneumonia and asthma due to PM2.5, PM10, SO2 and NO2 increased by 2.22% (95%CI: 0.64%, 3.82%), 1.94% (95%CI: 0.85%, 3.04%), 11.21% (95%CI: 4.70%, 18.10%) and 5.42% (95%CI: 3.07%, 7.82%), respectively.

Discussion

Adverse effects of air pollutants were found to be more severe in children aged 1 to 5 years and adverse effects due to PM2.5, PM10 and SO2 were found to be more severe in girls. Our findings underscore the need for implementation of effective public health measures to urgently improve air quality and reduce pediatric hospitalizations due to respiratory illness.

A 28-day, 2-year study reveals that adolescents are more fatigued and distressed on days with greater NO2 and CO air pollution

This 2-year, 28-day study examined whether adolescents felt greater fatigue and emotional distress the same day and the day after air quality was worse. We linked objective daily air quality measurements to daily self-reports from 422 Mexican-American adolescents in Los Angeles County, California from 2009 to 2011 (50% girls, M_Age = 15 years). A robust, within-subject analysis of 9696 observations revealed that adolescents with ongoing physical complaints reported greater fatigue and emotional distress on days that the air contained higher levels of nitrogen dioxide (NO₂) and carbon monoxide (CO). Regardless of physical complaints, adolescents on average also reported greater fatigue the day after NO₂ levels were higher. The same-day and next-day associations between air pollution and distress were mediated via daily increases in fatigue. Results were robust when controlling for day of the week, and daily temperature and humidity. Sulfur dioxide (SO₂), ozone (O₃), PM_2.5 and PM₁₀ were not related to daily fatigue or distress.

Issue 1 - "Update on adverse respiratory effects of outdoor air pollution" Part 2): Outdoor air pollution and respiratory diseases: Perspectives from Angola, Brazil, Canada, Iran, Mozambique and Portugal

OBJECTIVE

To analyse the GARD perspective on the health effects of outdoor air pollution, and to synthesise the Portuguese epidemiological contribution to knowledge on its respiratory impact.

RESULTS

Ambient air pollution has deleterious respiratory effects which are more apparent in larger, densely populated and industrialised countries, such as Canada, Iran, Brazil and Portugal, but it also affects people living in low-level exposure areas. While low- and middle-income countries (LMICs), are particularly affected, evidence based on epidemiological studies from LMICs is both limited and heterogeneous. While nationally, Portugal has a relatively low level of air pollution, many major cities face with substantial air pollution problems. Time series and cross-sectional epidemiological studies have suggested increased respiratory hospital admissions, and increased risk of respiratory diseases in people who live in urban areas and are exposed to even a relatively low level of air pollution.

CONCLUSIONS

Adverse respiratory effects due to air pollution, even at low levels, have been confirmed by epidemiological studies. However, evidence from LMICs is heterogeneous and relatively limited. Furthermore, longitudinal cohort studies designed to study and quantify the link between exposure to air pollutants and respiratory diseases are needed. Worldwide, an integrated approach must involve multi-level stakeholders including governments (in Portugal, the Portuguese Ministry of Health, which hosts GARD-Portugal), academia, health professionals, scientific societies, patient associations and the community at large. Such an approach not only will garner a robust commitment, establish strong advocacy and clear objectives, and raise greater awareness, it will also support a strategy with adequate measures to be implemented to achieve better air quality and reduce the burden of chronic respiratory diseases (CRDs).