Characteristics and Sources of Hourly Trace Elements in Airborne Fine Particles in Urban Beijing, China

Abstract

To better investigate the characteristics and sources of trace elements (TEs) in PM2.5 in urban Beijing, a 1‐year hourly observation was continuously made using an online multi‐element analyzer from 1 June 2016 to 31 May 2017. The average concentrations of 14 individual TEs ranged from 1.1 (V) to 900 ng/m3 (K). The occurrence levels of most TEs of interest in Beijing were lower than those in most domestic cities, but higher than those in most foreign countries. The formation of sulfate increased with the concentrations of all studied TEs during autumn and winter. Dust, industry, biomass burning and waste incineration, vehicle emissions, coal combustion, and oil combustion were identified by the positive matrix factorization (PMF) model, which accounted for 36.3%, 10.7%, 27.1%, 13.7%, 7.6%, and 4.6%, respectively, of the total elements. All factors exhibited higher concentrations on weekends than on weekdays. Local vehicular emissions and industry contributed to the loading of TEs, but dust, biomass burning and waste incineration, coal combustion, and oil combustion from neighboring areas appeared to be dominant sources of TEs. Except for dust and industry, the four other sources of TEs were mainly located in the south and southeast areas of the sampling site. The analysis by conditional probability function and potential source contribution function showed that the distribution of the PMF sources of TEs roughly agreed with the location of the main point sources. Overall, this work provides more detailed information on the characteristics of the TEs for the scientific community and modelling work.

Source apportionment of highly time-resolved elements during a firework episode from a rural freeway site in Switzerland

“…3b). Similar factor profiles were found in previous studies (Visser et al, 2015;Dall'Osto et al, 2013). This factor correlates well with ACSM SO 2− 4 measurements (r 2 = 0.91), suggesting a dominant contribution from the submicron fraction and thus a slow rate of dry deposition.…”

“…Secondary sulfate. This source is characterised by sulfur (S) and is most likely due to the regional background contribution of secondary sulfate due to conversion of SO 2 to SO 2− 4 , consistent with the results of many previous source apportionment studies (Dall'Osto et al, 2013;Richard et al, 2011). It explains the highest fraction of S (91 % of the factor mass) with relative contributions to S (73 %) and Pb (30 %; Fig.…”

“…Coarse particles from brake or disc wear could appear as flakes and mainly consist of iron oxides (Wahlström et al, 2010). The higher fraction of Fe in the non-exhaust traffic-related source has been found in several previous studies (Visser et al, 2015;Amato et al, 2014a;Bukowiecki et al, 2010;Dall'Osto et al, 2013;Crilley et al, 2016). However, the ratio of Fe to other elements is variable between studies.…”

“…Positive matrix factorisation (PMF) is one of the most widely used receptor models for SA of trace elements (Rahman et al, 2011;Ancelet et al, 2012;Cesari et al, 2014;Ducret-Stich et al, 2013;Kim et al, 2003;Rai et al, 2016;Zhang et al, 2013;Harrison et al, 2011;Hedberg et al, 2005). However, a limited number of studies are available for traceelement emission sources with high time resolution (hourly or sub-hourly; Visser et al, 2015;Crilley et al, 2016;Bukowiecki et al, 2010;Richard et al, 2011;Dall'Osto et al, 2013;Manousakas et al, 2015;Jeong et al, 2019;Wang et al, 2018, among others). Hourly elements data can be used to explore the diurnal patterns of emissions from traffic, biomass burning and industrial sources, thereby yielding more accurate and exposure-relevant SA results.…”

Levels and sources of hourly PM2.5-related elements during the control period of the COVID-19 pandemic at a rural site between Beijing and Tianjin

“…However, the variations and contributions of emission sources during this period are still rarely reported (Li et al, 2020;Zheng et al, 2020), in particular for rural areas. Trace elements can act as markers for specific source categories of PM 2.5 (Cui et al, 2019;Y. Liu et al, 2019).…”