Street children exposure to ambient fine particulate matter (PM2.5) and environmental noise: an exposure assessment and health risk analysis study

Street children, particularly those aged 3-8 years, are highly vulnerable to environmental stressors. This study assessed their exposure to ambient fine particulate matter (PM2.5) and environmental noise at 30 high-traffic intersections in Tehran, Iran. Measurements were conducted using calibrated Plantower PMS5003 aerosol sensors for PM2.5 and TES 52A noise meters for sound levels. Parameters such as temperature, humidity, and traffic intensity were also recorded. Health risks were evaluated using hazard quotients (HQs) for different age groups, focusing on non-carcinogenic and cognitive effects. PM2.5 levels exceeded 15 mu g/m(3) at nearly all locations, with concentrations over 40 mu g/m(3) at key intersections. Noise levels consistently surpassed 70 dB, exceeding the World Health Organization (WHO) daytime limit of 53 dB. HQ values exceeded 2.0 in several intersections for younger children, indicating elevated risk. These findings highlight the urgent need for policy interventions to reduce pollution exposure in vulnerable populations like street children.