Rare-Earth Elements and Heavy Metals in Atmospheric Particulate Matter in an Urban Area

Abstract

Atmospheric particulate matter (PM10), one of the criteria air pollutants, significantly impacts human health and the climate. To enhance our fundamental understanding of atmospheric PM10 characteristics, rare-earth elements (REEs) and heavy metals were evaluated along with their source apportionment using the positive matrix factorization (PMF) model. The PM10 mass concentration and elemental (REEs and heavy metals) compositions were analyzed using the gravimetric and HR-ICPMS methods. Although the PM10 concentrations are close to the CPCB limit, with an average of 72.09 ± 24.74 μg m–3, the concentrations of heavy metals are below the critical levels prescribed by World Health Organization (WHO). The rare earth elements (REEs) are found in trace quantities in PM10 with a total concentration (ΣREE) of 0.97 ± 0.59 ng m–3. PMF modeling for source apportionment reveals the contributions of five significant sources of PM10 mass in the urban area, mainly from coal combustion and vehicular emission followed by biomass burning, soil dust, and industrial emission. The paper reports the presence of valuable REEs in Indian atmospheric particulate samples for the first time.