Optimization of WD-XRF analytical technique to measure elemental abundance in PM2.5 dust collected on quartz-fibre filter

Kanpur is one of the most polluted industrial cities in the world, as tagged by the World Health Organization in 2018. Most studies on airborne particulate matter in the area have shown that the PM2.5 concentration in the city is much higher than that of other major cities around the country. In the present study, for analyzing the air quality (PM2.5) and elemental concentration (Zn, Ca, Fe, K, Mn, Ni, Pb, Al, Cr, and Na) over the winter season at Kanpur, sampling was done by collecting the air sample on quartz fiber filter paper. The air samples were analyzed using the Flame Atomic Absorption Spectrometer (FAAS). The elemental concentration was also estimated by using the optimized power for X-rays via WD-XRF. The PM2.5 concentration at the site was about 333.2 ± 52 μg/m3, which was 90% higher than the concentration measured in the year 2007 for the Kanpur city and 5-fold the safe limits as per Indian and global air quality standards for PM2.5. The inhomogeneous deposition was also observed, especially for the K and Na. The optimized power for the WD-XRF was about 2 kW for K and Ca, while 0.9 kW for Na. A high correlation coefficient was obtained between WD-XRF and FAAS concentration for Al, K, Na.