Short-term air quality degradation during Diwali in a rural region: elemental composition and source insights

Firecracker emissions during Diwali are known to elevate air pollution in Indian cities; however, their short-term impacts in rural regions remain poorly characterized. This study evaluates the influence of Diwali celebrations on PM_2.5 mass and elemental composition at a rural monitoring site in Baghpat District, Uttar Pradesh. Continuous sampling was carried out over a 20-day period (October-November 2024) using a day-night split protocol, covering the pre-Diwali, Diwali, and post-Diwali phases. PM_2.5 concentrations showed a sharp nocturnal escalation during Diwali night, peaking at 632 µg/m³, approximately 2.5 times higher than Diwali daytime levels and 3.3 times higher than normal days, substantially exceeding National Ambient Air Quality Standards. Elemental analysis revealed clear firecracker signatures, with Pb, Ba, Ca, and Fe increasing by 3-20 times, and Al, Mg, Na, K, and Sb rising by 1.5-3 times relative to Diwali daytime. A Diwali-Induced Enrichment (DIE) factor was developed to quantify short-duration metal spikes, revealing a clear enhancement associated with firecracker activity. Multivariate analysis (PCA and Pearson correlations) confirmed pyrotechnics as the dominant pollution source, with PCA explaining 35% (night) and 25% (day) of the variance associated with firecracker-related elements. Although the pollution event was transient, acute exposure to metal-rich PM_2.5 poses serious health risks, particularly for children and the elderly. This rural-based analysis reveals distinct Diwali-related pollution patterns and underscores the need for stronger control measures during festival periods.