Health Under Haze: Symptom Burden Among Adult Outpatients During the 2024-2025 Winter Smog Season in Lahore, Pakistan.

BACKGROUND

Severe urban air pollution is a major public health challenge in many low- and middle-income countries. Lahore experiences recurrent winter smog episodes with pollution levels far exceeding international guidelines, but hospital-based evidence on associated symptom burden remains limited.

METHODS

We conducted a cross-sectional study of 400 adult outpatients attending a tertiary hospital in Lahore between October 2024 and January 2025, during a period of sustained severe air pollution. A structured questionnaire collected data on demographic characteristics, behavioural factors, occupational exposure proxies, medical history and respiratory and non-respiratory symptoms. Symptom burden was analysed using descriptive statistics and multivariable regression models, including an exploratory composite vulnerability index. City-level air quality index (AQI), PM2.5, PM10, carbon monoxide (CO), and temperature data were summarised relative to World Health Organization guidelines to contextualise environmental conditions.

RESULTS

In this health-seeking outpatient sample, 98% of participants reported at least one symptom. The most common complaints were shortness of breath (74%), eye irritation (56%), cough (53%) and sore throat (50%). PM2.5 and PM10 exceeded WHO 24-h guideline values on all monitored days. Mean AQI was 180, mean PM2.5 was 96 µg/m3, and mean CO was 979, indicating sustained multi-pollutant exposure. Higher cumulative vulnerability was associated with greater symptom counts (p < 0.01), and current smoking was associated with increased symptom burden (incidence rate ratio [IRR] 1.15, 95% CI 1.00-1.32). Routine mask use was not significantly associated with lower symptom burden (IRR 0.96, 95% CI 0.84-1.09). Perceived worsening air quality showed limited concordance with vulnerability and symptom patterns.

CONCLUSION

During Lahore's 2024-2025 winter smog season, adult outpatients reported substantial multisystem symptom burden. These findings support strengthened environmental control measures and public health responses in heavily polluted urban settings.