Assessment of air pollution around the panzhihua V-Ti magnetite mine region, Southwest China

Abstract

This study investigated variations in air quality by evaluating trace gases, inhalable particulate matter (PM10), and associated trace elements at three sites in Panzhihua (a mining city located in Panxi Rift Valley, Southwest China) between January and December 2014. The concentrations of 19 trace elements in PM10 were determined through inductively coupled plasma mass spectrometry. Single particle morphology and chemical composition were determined through scanning electron microscopy with energy-dispersive X-ray analysis to identify their possible sources. Mean sulfur dioxide, nitrogen dioxide, and carbon monoxide concentrations were highest near the steel smelting district, whereas ozone concentrations were highest in the residential region. Annual mean concentrations of PM10 at three sites were 129.4, 165.5, and 187.2 µg m–3; all these exceed the annual mean (70.0 µg m–3) of the National Ambient Air Quality Standard. In addition, the concentrations of trace elements in PM10 exhibited significant spatial and seasonal variations at the three sites. The mean concentrations of trace elements in PM10 were in the order of Fe > Ti > Zn > Pb > Cu > Mn > Ba > V > Cr > Ni > Sr > Bi > Cd > As > Co > Sb > Sc > TI > U. The enrichment factor values of the trace elements suggested that anthropogenic activities were the dominant sources of As, Cd, Sb, Ti, TI, Zn, Cu, Pb, and Bi. Particle morphology and chemical composition analysis revealed five major particle types, namely aluminosilicate, Fe-containing, mineral, soot, and Ca-containing particles.