Mental health impacts of particulate matter exposure and non-optimal temperature among rural and urban children in eastern China.

Over 100 million children worldwide suffer from mental distress, with incidence rates steadily increasing. However, the combined impacts of air pollution and non-optimal temperature on schoolchildren's mental health, as well as the disparities across urban and rural schools and between genders, remain insufficiently explored. Utilizing 95,658 mental distress records from school children in eastern China, we developed nine composite exposure scenarios to evaluate the mental health impacts of short-term (0-14 days) exposure to particulate matter (PM) air pollution (i.e., PM₁, PM_2.5, PM₁₀), average temperature, and temperature variability (including both intra-day and inter-day temperature fluctuations). We found that children's mental distress was significantly associated with PM pollution, particularly in urban schools, with rising risk trends and intensified hazards for finer particles (PM₁₀ < PM_2.5 < PM₁). For each 10 μg/m³ increase, the relative risks of mental distress absenteeism for PM₁, PM_2.5, and PM₁₀ were 1.017, 1.011, and 1.008, respectively. Polluted days coupled with warming temperature >10 °C and large intra-day (>10 °C) and inter-day fluctuations (<-2.5 or >0 °C) consistently exhibited higher and increasing risks, with relative risks ranging from 1.031 to 1.534 (p < 0.05). Girls, constituting 61.4% of the cases examined, exhibited greater vulnerability than boys, with higher threats and rising trends across all scenarios. Among the affected children, 77.9% didn't receive medical assistance. Given the global warming trend, it's crucial to address the combined impacts of extreme weather and PM pollution on schoolchildren's mental health, particularly for girls and in rapidly urbanizing areas.