Atmospheric Signature and Potential Sources of Rare Earth Elements in Size-Resolved Particulate Matter in a Megacity of China

Abstract

The atmospheric signature and potential sources of rare earth elements (REEs) in ambient particulate matter (PM) collected at urban (ZH) and background sites (ZWY) between February 2011 and January 2012 in the Yangtze River Delta region were investigated in this study. The average total concentrations of REEs for TSP, PM 10 and PM 2.5 were measured to be 11.98, 9.37, 2.24 ng m -3 in ZH, which were 1.9, 1.8, 1.3 times higher than those measured in ZWY. The size distribution pattern of the REEs shows that they are significantly fractionated into coarse particles (e.g., approximately 50% in PM 2.5-10 ). However, La, Ce and Sm are even more enriched in PM with respect to each other and other REEs. It is also shown that Ce contamination is prevalent throughout the study area, which is particularly exemplified in the finer particulate matter fraction; this significant Ce contamination could be primarily attributed to vehicle emissions. Additionally, the REEs' pollution events during the sampling campaign were identified by the time series of the REE ratios. And the contaminations of La, Sm and Ce show clearly wind-induced variations. The enrichment factors for REEs indicate that La, Ce, Nd and Sm originated from a mix of anthropogenic and natural emission sources with small EF values.

Physical and Optical Properties of Atmospheric Aerosols in Summer at a Suburban Site in North China

“…In particular, serious atmospheric pollution events occurred more frequently in North China, which resulted in more complicated aerosol properties (Yan et al, 2008;Li et al, 2012a. Therefore, many observational studies have investigated the physical, chemical, and optical properties of aerosols in different areas such as Beijing (Li et al, 2007;He et al, 2009), Tianjin Ma et al, 2011), Shanghai (Xu et al, 2012;Han et al, 2015), Guangzhou Garland et al, 2008;Chen et al, 2016), Chengdu (Tao et al, 2014), Anhui (Fan et al, 2010;Wang et al, 2014Wang et al, , 2015b, Lanzhou (Pu et al, 2015;Wang et al, 2015a), and other areas (Yin et al, 2010;Li et al, 2011;Shen et al, 2011;Cao et al, 2012;Li et al, 2012b;Dai et al, 2016;Yuan et al, 2016).…”

Baseline Air Monitoring of Fine Particulate Matter and Trace Elements in Ontario’s Far North, Canada

“…The catalyst material is released to air during the refinery process. Consequently, La and Ce were found in airborne particulate matter [46,[48][49][50]. The La/Ce ratio from fluid catalytic cracking (FCC) units is enriched and generally higher than 1 [46,51].…”

Occurrence of uranium, thorium and rare earth elements in the environment: A review

“…In addition, thorium and REE concentrations of up to 1 × 10 −4 Bq•m −3 and 173-298 ng m −3 , respectively, have been detected in atmospheric particles from Chinese cities (Wang et al, 2014;Wang et al, 2016;Fesenko and Emlutina 2021). The average total concentration of REEs in total PM, PM 10 (coarse dust), and PM 2.5 (fine dust) measured in the Yangtze River Delta region of China was 12.0, 9.4, and 2.2 ng m −3 , respectively (Dai et al, 2016), with particle size distribution indicating significant fractionation in the coarse fraction (Dai et al, 2016;Hussein et al, 2018). REE concentrations in collected dust samples from Greater Cairo (Egypt) ranged from 1 to 60 μg g −1 , with the highest concentrations found in dust samples outside the city, indicating a possible natural source of REE (Shaltout et al, 2013).…”

“…Concentrations exceeding the recommended limits set by AAQCs (2012) are often found near mining and industrial areas (Tracy and Meyerhof, 1967;Shaltout et al, 2013;Wang et al, 2014;Dai et al, 2016;Wang et al, 2016;Hussein et al, 2018;Fesenko and Emlutina 2021;Kolawole et al, 2021), Table 3. For example, U concentrations of 2-200 ng m −3 have been measured within 2 km of a refinery (Tracy and Meyerhof, 1967), which exceeds the recommended limits by a factor of 6.…”