Short-Term Exposure to Fine Particulate Matter (PM₂.₅) and Hospital Admissions for Respiratory Illness in Children Under Six in Ahmedabad, India

Abstract

Background: Children in rapidly urbanizing cities of low- and middle-income countries are highly exposed to
outdoor air pollution. Fine particulate matter (PM₂.₅) is of particular concern because it penetrates deep into the
lungs and may trigger or worsen respiratory disease.
Objective: To examine the association between short-term exposure to ambient PM₂.₅ and hospital admissions
for respiratory illness among children younger than six years in Ahmedabad, western India, and to estimate the
seasonal burden of disease attributable to PM₂.₅.
Methods: We conducted a hospital-based, cross-sectional study of all pediatric admissions (age < 6 years) for
respiratory illness in a large tertiary-care teaching hospital in Ahmedabad from 1 November 2017 to 31 December
2018. Demographic data, clinical diagnoses and environmental risk factors were recorded using a structured
proforma. Daily city-level PM₂.₅ concentrations were obtained from the SAFAR monitoring network, and
meteorological data (temperature, relative humidity) from the India Meteorological Department. Respiratory
diagnoses were grouped into wheezing disorders (bronchiolitis, asthma, wheeze-associated lower respiratory
infection) and non-wheezing disorders (pneumonia, empyema, upper respiratory tract infections). Using WHO
AirQ+ software and a log-linear exposure–response function, we estimated relative risk (RR) and season-specific
numbers of respiratory admissions attributable to short-term PM₂.₅ exposure above a counterfactual level of 15
µg/m³.