European Journal of Cardiovascular Medicine

The respiratory health of adolescents is increasingly becoming a matter of public health concern, particularly due to the rising levels of air pollution in urban environments. Adolescence is a critical period for lung growth and development, and any environmental insult during this stage may lead to long-term respiratory complications (1). Air quality, defined by the concentration of pollutants such as particulate matter (PM2.5, PM10), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), and ground-level ozone (O₃), has been shown to directly impact lung function parameters (2).

Urbanization has led to an increase in vehicular emissions, industrial discharge, and construction activities, contributing significantly to poor air quality in metropolitan areas (3). In contrast, rural areas typically experience lower pollutant levels due to less industrialization and lower traffic density. However, rural populations may still face air quality issues from sources like biomass fuel combustion and agricultural activities (4). Several studies have suggested that long-term exposure to ambient air pollution is associated with a decline in lung function, increased incidence of asthma, and other chronic respiratory diseases among children and adolescents (5,6).

Spirometry is a simple, non-invasive technique used to evaluate lung function and detect early signs of respiratory impairment. Parameters such as Forced Vital Capacity (FVC) and Forced Expiratory Volume in one second (FEV1) are reliable indicators of pulmonary health and are sensitive to environmental changes, including air quality variations (7). Comparing these parameters in adolescents from different geographical settings offers valuable insights into how environmental exposures influence respiratory outcomes.

Given the limited literature assessing the differential impact of air quality on adolescent lung function in urban versus rural populations in developing regions, this study aims to compare spirometric values among adolescents exposed to varying air quality levels. The findings can help inform region-specific policies and preventive strategies aimed at mitigating pollution-related respiratory effects.

Study Design and Population
This was a comparative cross-sectional study conducted over a period of three months to assess pulmonary function among adolescents residing in urban and rural environments. A total of 120 healthy adolescents aged 13 to 18 years were recruited, with 60 participants each from an urban region with high vehicular and industrial activity, and a rural area characterized by minimal pollution sources. Participants were selected using simple random sampling from local schools after obtaining informed consent from parents and assent from the adolescents.

Inclusion and Exclusion Criteria
Adolescents with no history of chronic respiratory illness, recent respiratory infections (within the past four weeks), or smoking habits were included in the study. Those with diagnosed asthma, congenital respiratory disorders, or current use of bronchodilators were excluded.

Air Quality Monitoring
Ambient air quality data, including levels of PM2.5, PM10, NO₂, and SO₂, were obtained from local environmental monitoring stations in both urban and rural regions. The Air Quality Index (AQI) was calculated using the Central Pollution Control Board (CPCB) standards to categorize pollution levels in each area.

Pulmonary Function Testing
Spirometry was performed using a calibrated portable spirometer (Model: RMS Helios 401) according to the American Thoracic Society (ATS) guidelines. Each participant underwent three acceptable and reproducible maneuvers, and the highest values of Forced Vital Capacity (FVC), Forced Expiratory Volume in one second (FEV1), and FEV1/FVC ratio were recorded. The tests were conducted during morning hours (9 AM to 11 AM) to minimize diurnal variation, and participants were advised to avoid vigorous physical activity or heavy meals at least 2 hours prior to testing.

Statistical Analysis
Data were analyzed using SPSS software version 25.0. Continuous variables were expressed as mean ± standard deviation (SD). Independent t-tests were used to compare spirometric parameters between urban and rural groups. A p-value less than 0.05 was considered statistically significant.

A total of 120 adolescents participated in the study, with 60 individuals each from urban and rural settings. The mean age of participants was 15.4 ± 1.6 years in the urban group and 15.2 ± 1.4 years in the rural group, with no statistically significant difference (p = 0.48). The distribution of males and females was comparable between the two groups (urban: 32 males, 28 females; rural: 30 males, 30 females).

Air Quality Levels

The average Air Quality Index (AQI) over the study period was significantly higher in the urban region (182.5 ± 15.3) compared to the rural area (68.4 ± 12.1) (p < 0.001), indicating moderate to poor air quality in the urban zone and good air quality in the rural setting (Table 1).

Table 1. Mean AQI and Pollutant Concentrations in Urban and Rural Areas

(Source: Environmental Monitoring Station Data)

Pulmonary Function Comparison

Urban adolescents demonstrated significantly reduced pulmonary function compared to their rural counterparts. The mean FEV1 in the urban group was 2.52 ± 0.38 L, while in the rural group, it was 2.89 ± 0.33 L (p < 0.001). Likewise, FVC values were lower in the urban group (3.14 ± 0.40 L) than in the rural group (3.48 ± 0.36 L; p < 0.001). The FEV1/FVC ratio was also reduced in the urban group, indicating a possible obstructive pattern (Table 2).

Table 2. Comparison of Pulmonary Function Parameters Between Urban and Rural Adolescents

(Source: Spirometry Data, Present Study)

These findings confirm that adolescents residing in areas with higher air pollution levels exhibit decreased lung function across all key spirometric parameters (Table 2). This reinforces the direct impact of ambient air quality on respiratory health during adolescence.

This study highlights a significant disparity in pulmonary function among adolescents residing in urban and rural environments, closely associated with differing levels of air pollution. The urban cohort demonstrated lower mean FEV1, FVC, and FEV1/FVC values when compared to their rural counterparts, supporting the hypothesis that exposure to higher levels of ambient air pollutants adversely affects respiratory health in adolescents.

Numerous studies have reported a strong correlation between exposure to air pollution and reduced lung function in children and adolescents (1,2). Urban areas, due to industrialization, high traffic density, and population concentration, tend to have elevated concentrations of particulate matter (PM2.5, PM10), nitrogen dioxide (NO₂), and sulfur dioxide (SO₂) — pollutants known to impair pulmonary development (3,4). Our findings align with those of Gauderman et al., who observed a reduction in lung function growth among children exposed to high ambient pollution in Southern California (5).

The lower FEV1 and FVC values observed in the urban group can be attributed to chronic inhalation of particulate matter, which leads to airway inflammation, oxidative stress, and mucosal damage, consequently resulting in airway remodeling and functional decline (6,7). In contrast, rural adolescents, though potentially exposed to biomass smoke or dust from agricultural practices, generally encounter lower concentrations of vehicular and industrial pollutants, which may explain their comparatively better spirometric indices (8,9).

FEV1/FVC ratios were significantly lower in the urban population, which may indicate the early development of obstructive airway changes — a pattern that has been observed in previous studies conducted in urban Asian populations (10). The impact of air pollution on airway resistance and bronchial hyperreactivity has been well documented, particularly in adolescents with prolonged exposure during peak lung development periods (11,12).

Importantly, adolescence represents a window of vulnerability as the lungs undergo rapid growth and maturation, and impaired development during this phase may have long-term health implications (13). Our study supports the need for stringent air quality control measures, especially in urban regions, to prevent the onset of chronic respiratory diseases.

The findings of this study are consistent with those of recent multi-center studies that revealed reduced spirometric values in children exposed to urban air pollution across India and Southeast Asia (14,15). Although lifestyle and indoor air quality factors also influence pulmonary health, the magnitude of difference observed in this study emphasizes the significant role of outdoor air quality.

However, this study is not without limitations. The cross-sectional design precludes establishing causality, and variations in indoor exposures, socioeconomic factors, and nutritional status were not comprehensively controlled. Future longitudinal studies incorporating these variables are needed to better elucidate the long-term impact of ambient air pollution on adolescent respiratory health.

In conclusion, our results underscore the critical influence of environmental air quality on adolescent lung function. Early identification and intervention through air quality monitoring, policy enforcement, and public health education are imperative to mitigate the adverse effects of pollution on respiratory health.

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