Size-Segregated Characteristics of Carbonaceous Aerosols during the Monsoon and Non-Monsoon Seasons in Lhasa in the Tibetan Plateau

Abstract

In this paper, we intensively collected atmospheric particulate matter (PM) with different diameters (size ranges: <0.49, 0.49–0.95, 0.95–1.5, 1.5–3.0, 3.0–7.2, and >7.2 μm) in Lhasa during the monsoon and non-monsoon seasons. The results clearly showed that the concentrations of PM, organic carbon (OC), elemental carbon (EC), and water-soluble organic carbon (WSOC) during the non-monsoon season were much higher than the concentrations during the monsoon season. During the monsoon season, a bimodal size distribution of the OC and WSOC, which were at <0.49 μm and >7.2 μm, respectively, and a unimodal size distribution at <0.49 μm for the EC were observed. However, during the non-monsoon season, there was a trimodal size distribution of the OC and WSOC (<0.49 μm, 1.5–3.0 μm, and >7.2 μm), and a unimodal size distribution of the EC (<0.49 μm). Possible sources of the carbonaceous components were revealed by combining the particle size distribution and the correlation analysis. OC, EC, and WSOC were likely from the photochemical transformation of biogenic and anthropogenic VOC, and the incomplete combustion of biomass burning and fossil fuels at <0.49 μm, whilst they were also likely to be from various types of dust and biogenic aerosols at >7.2 μm. OC and WSOC at 1.5–3.0 μm were likely to have been from the burning of yak dung and photochemical formation. The above results may draw attention in the public and scientific communities to the issues of air quality in the Tibetan Plateau.

Size-Segregated Atmospheric Humic-Like Substances (HULIS) in Shanghai: Abundance, Seasonal Variation, and Source Identification

“…This area is close to the high-altitude areas of China, with relatively more mountainous regions. In pioneering studies of Nam Co with less human activities, and Lhasa, a typical city in this area, lower concentrations of HULIS and WSOC were sampled [54,67]. In addition, there were fewer fire spots in the winter air mass pathway and the adjacent YRD area.…”

First systematic review on PM-bound water: exploring the existing knowledge domain using the CiteSpace software

“…Gas chromatography-mass spectrometry (GC-MS;Mayol-Bracero et al 2002;Wang et al 2006) and a combination of ion chromatography and high performance liquid chromatography (HPLC; Yang et al 2004) characterized less than 10% and 20% of WSOC, respectively. Therefore only small part of WSOC could be analyzed at the molecular level (Wei et al 2019). The most frontier research in this area is to know to which extent the water content of atmospheric particles is influenced by the presence of organics and how the aggregate hygroscopic properties of inorganic particles are altered when organics are also present (Saxena et al 1995).…”

Characteristics of Soil Temperature Change in Lhasa in the Face of Climate Change

“…Lhasa is located in the central and southern part of the Qinghai-Tibet Plateau, which is one of the most developed areas in Tibet [22]. The Qinghai-Tibet Plateau has a special topographic structure and a high altitude, so there are few temperature observations from meteorological stations [23]. Most of the observed temperature data are from the eastern and central regions of the Qinghai-Tibet Plateau.…”