Carbonaceous species and physicochemical characteristics of PM10 in coal mine fire area—a case study

Abstract

When exposed to air, coal catches fire due to self-oxidation. Coal mine fire is one of the major sources of particulate matter (PM) emissions in coal mining areas. Coal mine is widespread in India with Jharia Coalfield having a number of coal seams and coal dumps under fire. The understanding of magnitude and character of particulate matter emitted from coal mine fire areas is important in order to understand its health impacts, about which not many studies have been carried out. The paper presents findings of a study aimed to characterize physical and chemical properties of airborne respirable particle (PM10) in the fire-affected area at Jharia Coalfield, India. The study was carried out for a period of 8 months from October 2011 to June 2012. The mean concentrations of PM10 were 338.0, 369.0, and 357.0 μg m−3 during summer, winter, and post-monsoon, respectively. Scanning electron microscopy (SEM) showed the presence of rounded, spherical, and oval formed particulate in ambient air that is characteristics of combustion sources. Dominance of irregular-shaped particulate in all samples indicated road dust as the source. Abundance of fine PM (<4 mm) indicated burning process to be the source. For the “qualitative analysis,” techniques like Fourier transform infrared (FTIR) spectroscopy, gas chromatography–mass spectrometry (GC-MS), and inductively coupled plasma optical emission spectrometry (ICP-OES) were used. Chemical analysis shows the presence of elements like Fe, Al, Cu, Si, Na, Cr, Mn, Zn, Cd, Ni, K, and Pb. Anionic concentrations of SO4 2−, NO3 −,Cl−, F−, and PO4 2− were analyzed using ion chromatography. Carbonaceous aerosol analysis results indicated that concentrations of carbonaceous species were 19.51 μg m−3 for organic carbon (OC) and 238.0 μg m−3 for elemental carbon (EC) in PM10 samples.