Respirable Mercury Particulates and Other Chemical Constituents in Festival Aerosols in Delhi

Abstract

The display of fireworks emits a large amount of gaseous and particulate pollutants which accumulate in the atmosphere for a short period and have adverse effects on human health, and climate. Significant accumulation takes place due to episodic emissions of fireworks during special events such as New Year, Cricket match and Deepawali festivals etc. This study reports PM10 loads and chemical compounds during episodic emission of Deepawali by collecting aerosols samples during Pre-Deepawali period (Pre), on the day of Deepawali (D), and Post-Deepawali period (Post), in order to assess the change in chemical composition of air due to fireworks. PM10 aerosol samples were collected by using Respirable Dust Sampler (RDS) at JNU in South Delhi. The samples were analyzed for chemical constituents such as Particulate Mercury (HgP) by using Differential Pulse Anodic Stripping Voltammetry (DPASV) technique, Elemental Carbon (EC) and Organic Carbon (OC) by using a thermal/optical analyzer and metal oxides by using Energy Dispersive X-Ray (EDX). For the morphological characterization of particles Scanning Electron Microscope (SEM) was used. The results showed that particulate mercury (HgP) and PM10 loadings were relatively higher in the samples collected on Deepawali day as compared to Pre- Deepawali and Post-Deepawali samples. The order of metal oxides was recorded as K>Al>S>Cl>Ca>Fe and Ba, Mg and Ti were present only on the day of Deepawali, indicating its contribution from fireworks. OC and EC showed a strong correlation with PM10 concentrations. A strong linkage of K with Al (r=0.92) and S (r=0.83), as well as of Fe with Ca (r=0.94) was observed during Deepawali festival week. Also, S showed its association with PM10 concentration suggesting its emission from combustion of sulphur containing raw material of fireworks. The study suggests that the firework emissions significantly affect air quality, increasing the possibility of respiratory illness.