Morphology and chemical composition of mineral particles in a special dust storm with high relative humidity in North China

• Published in: Environmental technology & innovation 2024-11, Vol.36, p.103823, Article 103823
• Main Authors: Wang, Wenhua, Zhou, Hui, Gao, Yutao, Lyu, Ruihe, Xing, Jiaoping, Zhou, Xiuyan, Li, Xian, Shao, Longyi
• Format: Article
• Language: English
• Subjects: Dust storm; Individual particle; Nitrate; Scanning electron microscope; Sulfate
• ISSN: 2352-1864; 2352-1864
• DOI: 10.1016/j.eti.2024.103823

A special dust storm characterized by high PM10 mass concentrations (921.9 ± 632.3 μg m−3) and high relative humidity (RH; 60.1 % ± 11.1 %) was observed on March 22–24, 2023 at a coastal city of North China. Aerosol particles of PM10 were analyzed by a scanning electron microscope coupled with energy dispersive X-ray and an ion chromatograph. The results showed that individual mineral particles were dominated by clay minerals, followed by quartz, feldspar, and carbonate. Bulk water-soluble inorganic ions analysis showed that SO42- mass concentrations varied from 3.7 μg m−3 to 23.3 μg m−3 with an average value of 12.4 μg m−3. However, their mass ratios to PM10 were relatively stable, being 1.15–2.01 % with an average value of 1.49 % ± 0.25 %, similar to the value near the dust sources (Tengger Desert). Although S-containing individual mineral dust varied from 5.2 % to 70.7 %, the average weight ratio of S on individual mineral dust was 2.1 %, much lower than that of non-dust periods (11.0 %). The results suggested limited sulfate formation on mineral dust surfaces even under high RH. In contrast, NO3-, which was very limited in dust sources, varied from 0.21 % to 4.11 % of the total PM10 with an average value of 1.61 % ± 1.07 %. The research highlighted that nitrate formation has exceeded sulfate formation during severe dust storm episodes, which might because the atmospheric compositions in China have changed significantly with a high mass ratio of NO2/SO2 after the implementation of the strict emission control measures. [Display omitted] •Particles were mainly composed of clay minerals, followed by quartz and feldspar.•Sulfate rarely formed on mineral particle surfaces and might be mainly from desert sources.•Nitrate formation has exceeded sulfate formation on the mineral particle surfaces under current atmospheric environment.