Surface Characterization of Aerosol Particles in Guangzhou, China: A Study by XPS

Abstract

X-ray photoelectron spectroscopy (XPS) is a powerful techniquefor determining the surface chemical composition of atmospheric particles. In this article, we employed XPS to study atmospheric particles collected from Guangzhou city in typical sites and seasons. The results showed that the weight percentage of carbon, oxygen, nitrogen, and sulfur were about 70.5-87.1%, and these species dominated the surface structure of the particles independent of the collection site and season. Inorganic elements including Si, Na, Ca, Cl, Fe, K, Al, and Cu were also found on the particle surfaces. The high-resolution XPS spectra revealed: (1) High aromatic and aliphatic C-H, and other oxidized carbons were found on the surface of particles. (2) The nitrogen species were characterized by pyridinic, pyrrolic/amide, quaternary type nitrogen functionalities, and nitrate groups, indicating that inorganic and organic N species are both important components of N-containing particles. (3) Sulfate and sulfone groups were also present on the surface and were important components. The oxidized groups of C, N, and S were higher in winter samples, consistent with the monsoon weather of Guangzhou in winter, which is favorable for the formation of oxidized species. A comparison between total and surface analyses showed that the surface of particles was relatively high in organic carbon, NO

Surface Chemical Composition of Size-Fractionated Urban Walkway Aerosols Determined by X-Ray Photoelectron Spectroscopy

“…The presence of this type of carbon can be explained by the deposition of gas-phase species, like polycyclic aromatic hydrocarbons (PAHs), on EC particles followed by internal rearrangement of the solid phase carbon (Grieco et al 2000;Zhu et al 2004). C-H was the main carbon state on the surfaces of the aerosol particles regardless of particle size due possibly to the condensation of aliphatic/aromatic organic materials on the surfaces of existing particles (Faude and Goschnick 1997;Song and Peng 2009). The surface organic composition of the accumulation-mode particles is more complex because of their longer atmospheric lifetime.…”

“…High-resolution N1s spectra of the particles show three types of functional groups: the amide group (400.2 eV), the quaternary ammonium group (402.1 eV), and the nitrate group (407.2 eV) (Song and Peng 2009). A typical N1s spectrum is shown in Figure 5.…”

“…The alcohol and ketone groups were slightly more abundant in the larger particles. The O/C ratios for the fine particles (<2 μm) were calculated using the peaks areas of the oxygen-containing carbon chemical states to the total C1s peak (excluding the contribution from the inorganic carbon) and are shown in Table 2 (Song and Peng 2009;Song et al 2012). The results reveal that the O/C ratio increased as the particle size increased from 0.1 to 0.56 μm, suggesting that the accumulation-mode particles were more oxidized than the smaller fresher particles.…”

“…A number of studies have used XPS to analyze particulate matters collected with filters (Hutton and Williams 2000;Zhu et al 2001;Paoletti et al 2003;Song and Peng 2009;Vander Wal et al 2011). XPS analysis provides important information about elemental concentrations and chemical states (Faude and Goschnick 1997;Lei et al 2003;Lau et al 2009;Ng et al 2011).…”

Comparison of isolation and quantification methods to measure humic-like substances (HULIS) in atmospheric particles

“…Two sampling sites included Wushan (WS) and Maofengshan (MFS), representing urban and biomass dominated areas, respectively. Detailed information on sampling sites was provided by Song and Peng (2009). PM2.5 aerosol samples were collected on 20 cm  25 cm quartz fiber filters (Whatman) with a high-volume sampler at a flow rate of 1.05 m 3 min À1 (Tianhong Intelligent Instrument Plant of Wuhan, China).…”