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Atmospheric chemistry research has been growing rapidly in China in the last 25 years since the concept of the “air pollution complex” was first proposed by Professor Xiaoyan TANG in 1997. For papers published in 2021 on air pollution (only papers included in the Web of Science Core Collection database were considered), more than 24 000 papers were authored or co-authored by scientists working in China. In this paper, we review a limited number of representative and significant studies on atmospheric chemistry in China in the last few years, including studies on (1) sources and emission inventories, (2) atmospheric chemical processes, (3) interactions of air pollution with meteorology, weather and climate, (4) interactions between the biosphere and atmosphere, and (5) data assimilation. The intention was not to provide a complete review of all progress made in the last few years, but rather to serve as a starting point for learning more about atmospheric chemistry research in China. The advances reviewed in this paper have enabled a theoretical framework for the air pollution complex to be established, provided robust scientific support to highly successful air pollution control policies in China, and created great opportunities in education, training, and career development for many graduate students and young scientists. This paper further highlights that developing and low-income countries that are heavily affected by air pollution can benefit from these research advances, whilst at the same time acknowledging that many challenges and opportunities still remain in atmospheric chemistry research in China, to hopefully be addressed over the next few decades.

Atmospheric brown carbon (BrC) makes a substantial contribution to aerosol light absorption and thus global radiative forcing. Although BrC may change the lifetime of the clouds and ultimately affect precipitation, little is known regarding the optical properties and formation of BrC in the clouds. In the present study, the light-absorption properties of cloud droplet residual (cloud RES) were measured by coupled a ground-based counterflow virtual impactor (GCVI) and an aethalometer (AE-33), in addition to the cloud interstitial (cloud INT) and ambient (cloud-free) particles by PM2.5 inlet-AE-33 at Mt. Tianjing (1690 m a.s.l.), a remote mountain site in southern China, from November to December 2020. Meanwhile, the light-absorption and fluorescence properties of water-soluble organic carbon (WSOC) in the collected cloud water and PM2.5 samples were also obtained, associated with the concentration of water-soluble ions. The mean light-absorption coefficient (Abs370) of the cloud RES, cloud INT, and cloud-free particles were 0.25 ± 0.15, 1.16 ± 1.14, and 1.47 ± 1.23 Mm−1, respectively. The Abs365 of WSOC was 0.11 ± 0.08 Mm−1 in cloud water and 0.40 ± 0.31 Mm−1 in PM2.5, and the corresponding mass absorption efficiency (MAE365) was 0.17 ± 0.07 and 0.31 ± 0.21 m2 g−1, respectively. A comparison of the light-absorption coefficient between BrC in cloud RES and cloud INT particles, and WSOC in cloud water and PM2.5 indicates a considerable contribution (48 %–75 %) of water-insoluble BrC to total BrC light absorption. Secondary BrC estimated by minimum R squared (MRS) method dominated the total BrC in cloud RES (67 %–85 %), rather than in the cloud-free (11 %–16 %) and cloud INT (9 %–23 %) particles. It may indicate the formation of secondary BrC during cloud processing. Supporting evidence includes the enhanced WSOC and dominant contribution of the secondary formation and biomass burning factor (>80 %) to Abs365 in cloud water provided by positive matrix factorization (PMF) analysis. In addition, we showed that the light absorption of BrC in cloud water was closely related to humic-like substances and tyrosine-like and/or protein-like substances (r>0.63, p

Calcium is known to be enriched in sea spray aerosols (SSA), but its controlling factors and individual mixing states remain ambiguous. Here, we investigate the impact of various environmental factors on the water-soluble calcium (Ca2+) distribution in SSA through R/V Xuelong cruise observations over the Ross Sea, Antarctica, from December 2017 to February 2018. We observed enhanced Ca2+ enrichment in aerosol samples at lower temperatures (< -3.5 °C), lower wind speeds (< 7 m s-1) and in the presence of sea ice. Further individual particle mass spectral analysis indicated that considerable fractions of calcium in SSA likely bind with organic matter (a single-particle type, OC-Ca), which may be neglected in current water-soluble estimation of Ca2+ enrichment. Also, this is the first time that a calcium-dominated single-particle type has been observed in the Antarctic atmosphere. We suggest that a broader focus on individual OC-Ca and its subsequent environmental behavior should be included in future Antarctic atmospheric modeling. Given the context of global warming and sea ice retreat, an understanding of the mechanisms of calcium enrichment and mixing state of individual particles involved is valuable for further recognizing the aerosol-cloud-climate interactions in the Antarctica summer.

Cold-chain environment could extend the survival duration of SARS-CoV-2 and increases the risk of transmission. However, the effect of clod-chain environmental factors and packaging materials on SARS-CoV-2 stability and the efficacy of intervention measures to inactivate SARS-CoV-2 under cold-chain environment remains uncertain. This study aimed to unravel cold-chain environmental factors that preserved the stability of SARS-CoV-2 and disinfection measures against SARS-CoV-2 under the cold-chain environment. The spike gene of SARS-CoV-2 isolated from Wuhan hu-1 was used to construct the SARS-CoV-2 pseudovirus and used as model of the SARS-CoV-2 virus. The decay rate of SARS-CoV-2 pseudovirus in the cold-chain environment, various types of packaging material surfaces i.e., PE plastic, stainless steel, Teflon and cardboard, and in frozen seawater was investigated. The influence of LED visible light(wavelength 450 nm-780 nm) and airflow movement on the stability of SARS-CoV-2 pseudovirus at -18° C were subsequently assessed. The results show that SARS-CoV-2 pseudovirus decayed more rapidly on porous cardboard surface compared with the non-porous surfaces including PE plastic, stainless steel and Teflon. Compared with 25° C, the decay rate of SARS-CoV-2 pseudovirus was significantly lower at low temperature. Seawater preserved viral stability both at -18° C and repeated freeze-thawing cycles compared with deionized water. LED visible light illumination and airflow movement environment at -18° C reduced the SARS-CoV-2 pseudovirus stability. In conclusion, our results indicate cold-chain temperature and seawater as risk factors for SARS-CoV-2 transmission and LED visible light illumination and airflow movement as possible disinfection measures of SARS-CoV-2 under the cold-chain environment.ImportanceIt is widely recognized that low temperature is a condition for maintaining virus vitality, and cold-chain transportation spreads the events of the SARS-CoV-2 were reported. This study provides that the decay rate of the SARS-CoV-2 pseudovirus at low temperatures varies on different packaging materials, and salt ions present in frozen foods such as seafood may protect virus survival. These results provide evidence for the possibility of SARS-CoV-2 transmission through cold-chain transport and also suggest the importance for disinfection of items. However, the commonly used disinfection methods of ultraviolet radiation and chemical reagents are generally not suitable for the disinfection of frozen food. Our study shows LED visible light illumination and airflow movement as possible disinfection measures of SARS-CoV-2 under the cold-chain environment. This has implications for reducing the long-distance transmission of the virus through cold-chain transportation.

Vehicle emissions are an important source of nitrated aromatic compounds (NACs) in particulate size smaller 2.5 μm (PM

While laboratory studies have demonstrated that aqueous reactions between carbonyls and reduced nitrogen species may contribute to the production of N-heterocycle brown carbon (BrC) such as imidazo...

The scientific and practical Conference on China and countries along the Silk Road development issues in the past and modern days. The Conference is held annually in the ‘NSU Confucius Institute / Class’ and the Institute of Archaeology and Ethnography SB RAS joint project framework. In 2019, among participants were experts and professors from Novosibirsk, Barnaul, Krasnoyarsk, Moscow, Omsk, Almaty, Nanjing, Urumqi.

The Confucius Institute at Novosibirsk State University focused on connotation construction, strengthened teaching management, and improved teaching level in its 2019 work. This year, the Confucius Institute successfully completed the established teaching tasks, successfully held various cultural activities, strengthened exchanges between Novosibirsk State University and Xinjiang Univeristy, and expanded foreign exchanges. In the future, the Confucius Institute will continue to work hard to coordinate all aspects of its work, improve quality and efficiency, and further enhance the influence of the Institute in the region.

Straw burning comprises more than 30% of all types of burned biomass in Asia, while the estimation of the emitted aerosols' direct radiative forcing effect suffers from large uncertainties, especially when atmospheric aging processes are considered. In this study, the light absorption properties of primary and aged straw burning aerosols in open fire were characterized at 7 wavelengths ranging from 370 nm to 950 nm in a chamber. The primary rice, corn and wheat straw burning bulk aerosols together had a mass absorption efficiency (MAE) of 2.43 ± 1.36 m

While the formation and evolution of nitrate in airborne particles are extensively investigated, little is known about the processing of nitrate in clouds. Here we present a detailed investigation on the in-cloud formation of nitrate, based on the size-resolved mixing state of nitrate in the individual cloud residual and cloud-free particles obtained by single particle mass spectrometry, and also the mass concentrations of nitrate in the cloud water and PM2.5 at a mountain site (1690 m a.s.l. – above sea level) in southern China. The results show a significant enhancement of nitrate mass fraction and relative intensity of nitrate in the cloud water and the cloud residual particles, respectively, reflecting a critical role of in-cloud processing in the formation of nitrate. We first exclude the gas-phase scavenging of HNO3 and the facilitated activation of nitrate-containing particles as the major contribution for the enhanced nitrate, according to the size distribution of nitrate in individual particles. Based on regression analysis and theoretical calculations, we then highlight the role of N2O5 hydrolysis in the in-cloud formation of nitrate, even during the daytime, attributed to the diminished light in clouds. Nitrate is highly related (R2= ∼ 0.6) to the variations in [NOx][O3], temperature, and droplet surface area in clouds. Accounting for droplet surface area greatly enhances the predictability of the observed nitrate, compared with using [NOx][O3] and temperature. The substantial contribution of N2O5 hydrolysis to nitrate in clouds with diminished light during the daytime can be reproduced by a multiphase chemical box model. Assuming a photolysis rate at 30 % of the default setting, the overall contribution of N2O5 hydrolysis pathway to nitrate formation increases by ∼ 20 % in clouds. Given that N2O5 hydrolysis acts as a major sink of NOx in the atmosphere, further model updates would improve our understanding about the processes contributing to nitrate production in cloud and the cycling of odd nitrogen.

Imidazoles (IMs) are potential contributors to brown carbon; they may notably contribute to climate radiative forcing. However, only a few studies have assessed the mixing state, seasonal and spatial distributions of IMs, and influencing factors for IM formation in urban aerosols. In this study, two single-particle aerosol mass spectrometers were employed to investigate the IM-containing particles in the urban areas of Beijing and Guangzhou, China. IM-containing particles were identified in the size range (d

Nine amine species in atmospheric particles during haze and low-pollution days with low and high relative humidity (RH) were analyzed in urban Guangzhou, China. The mean concentrations of total measured amines (Ʃamines) in fine particles were 208 ± 127, 63.7 ± 21.3, and 120 ± 20.1 ng m

Atmospheric brown carbon (BrC) makes a substantial contribution to aerosol light-absorbing and thus the global radiative forcing. Although BrC may change the lifetime of the cloud and ultimately affect precipitation, little is known regarding the optical properties and formation of BrC in the cloud. In the present study, the light-absorption properties of cloud droplet residual (cloud RES) were measured by coupled a ground-based counterflow virtual impactor (GCVI) and an Aethalometer (AE-33), in addition to the cloud interstitial (cloud INT) and ambient (cloud-free) particles by PM2.5 inlet-AE-33, at Mt. Tianjing (1690 m a.s.l.), a remote mountain site in southern China, from November to December 2020. Meanwhile, the light-absorption and fluorescence properties of water-soluble organic carbon (WSOC) in the collected cloud water and PM2.5 samples were also obtained, associated with the concentration of water-soluble ions. The mean light-absorption coefficient (Abs370) of the cloud RES, cloud INT, and cloud-free particles were 0.25 ± 0.15, 1.16 ± 1.14, and 1.47 ± 1.23 Mm−1, respectively. The Abs365 of WSOC was 0.11 ± 0.08 Mm−1 in cloud water and 0.40 ± 0.31 Mm−1 in PM2.5, and the corresponding mass absorption efficiency (MAE365) was 0.17 ± 0.07 and 0.31 ± 0.21 m2·g−1, respectively. A comparison of the light-absorption coefficient between BrC in the cloud RES/cloud INT and WSOC in cloud water/PM2.5 indicates a considerable contribution (48–75 %) of water-insoluble BrC to total BrC light-absorption. Secondary BrC estimated by minimum R squared (MRS) method dominated the total BrC in cloud RES (67–85 %), rather than in the cloud-free (11–16 %) and cloud INT (9–23 %) particles. It may indicate the formation of secondary BrC during cloud processing. Supporting evidence includes the enhanced WSOC and dominant contribution of secondary formation/biomass burning factor (> 80 %) to Abs365 in cloud water provided by Positive Matrix Factorization (PMF) analysis. In addition, we showed that the light-absorption of BrC in cloud water was closely related to humic-like substances and tyrosine/proteins-like substances (r > 0.63, p < 0.01), whereas only humic-like substances for PM2.5, as identified by excitation-emission matrix fluorescence spectroscopy.

Although recent laboratory simulations have demonstrated that organic matter prevents the degradation of polycyclic aromatic hydrocarbons (PAHs), their role in the long-range transport of PAHs in the real atmosphere remains poorly understood. In this study, we measured the chemical composition and mixing state of PAHs-containing individual particles in aerosols from three sources, one urban area and one remote area. PAHs-containing particles were classified into five types: organic carbon (OC), potassium mixed with organic carbon (KOC), potassium mixed with sodium (KNa), Krich and PAH-rich. The PAH-rich and KOC particles were the main types of particles produced by vehicle exhaust/coal burning and biomass burning, respectively, accounting for50% of the PAHs-containing particles. It was found that organic matter enhancement of PAHs-containing particles occurs in the ambient atmosphere, with organic-rich (OC and KOC) particles accounting for90%. Further analysis revealed that the increase in the fractions of PAHs was related to the mixing state with organic compounds due to the protection of organics against PAHs and/or the aging of PAHs-containing particles. The results of this study improve our understanding of the chemical composition and mixing state of PAHs particles in atmospheric aerosols from emission sources and urban and remote areas, and provide field observation evidence to support the promotion of the study of long-range transport of PAHs by organics.

Characterizing the molecular composition of cloud water could provide unique insights into aqueous chemistry. Field measurements were conducted at Mt. Tianjing in southern China in May, 2018. There are thousands of formulas (C$_{5-30}$H$_{4-55}$O$_{1-15}$N$_{0-2}$S$_{0-2}$) identified in cloud water by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). CHON formulas (formulas containing C, H, O, and N elements; the same is true for CHO and CHOS) represent the dominant component (43.6 %���65.3 % of relative abundance), followed by CHO (13.8 %���52.1%). S-containing formulas constitute ���5 %���20 % of all assigned formulas. Cloud water has a relative-abundance-weighted average O/C of 0.45���0.56, and the double bond equivalent of 5.10���5.70. Most of the formulas (>85 %) are assigned as aliphatic and olefinic species. No statistical difference in the oxidation state is observed between cloud water and interstitial PM$_{2.5}$. CHON with aromatic structures are abundant in cloud water, suggesting their enhanced in-cloud formation. Other organics in cloud water are mainly from biomass burning and oxidation of biogenic volatile organic compounds. The cloud water contains more abundant CHON and CHOS at night, which are primarily contributed by ���N$_{2}$O$_{5}$ function and organosulfates, demonstrating the enhanced formation in dark aqueous or multi-phase reactions. While more abundant CHO is observed during the daytime, likely due to the photochemical oxidation and photolysis of N- or S-containing formulas. The results provide an improved understanding of the in-cloud aqueous-phase reactions.

Lightning can cause a variety of atmospheric chemical reactions because of its high temperature and high pressure. Known as a major natural source of atmospheric nitrogen oxides (NOx), lightning can also affect the abundance of ozone (O3) and result in the generation of new particles in the atmosphere. This study explores the effect of lightning activities on surface atmospheric nitric oxide (NO), O3 and submicron particles utilizing artificially triggered lightning experiments. Five lightning flashes were successfully triggered in Guangzhou on 19th August 2014. Concentrations of surface NO, O3 and submicron particles were observed together with lightning and meteorological parameters. Results show that NO concentration increased rapidly from 0.4 ppbv to 220.5 ppbv after a successful upwind artificially triggered lightning flash. Wind direction played an important role in the enhancement of NO concentration at different levels caused by each triggered lightning flash. O3 concentration increased from 15.8 ppbv to 28.7 ppbv before triggering lightning. After the first triggered lightning flash, O3 concentration decreased rapidly to the valley value of 16.9 ppbv because of titration effect. In addition, the number concentration of submicron particles also increased rapidly after successful triggered lightning experiments. The finds resulting from this study give a deeper insight into the impact of lightning on atmospheric chemistry.

SSCI-VIDE+CARE+CGO:XWG; International audience; Laboratory studies have demonstrated that uptake of SO2 on oleic acid (OLA) could directly produce organosulfates (OS); yet, it is unknown whether this pathway is significant in secondary organosulfur production in ambient air. Here, we collected filter-based samples of ambient fine particles (PM2.5) in the Pearl River Delta region in southern China and determined organosulfur compounds with Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). The results are in agreement with the occurrence of organosulfurs formed from the reactive uptake of SO2 by OLA and a wider range of C14−C24 unsaturated fatty acids in ambient air as reported by laboratory studies, as well as additional species that are likely oxidation products of the primary products previously identified. OS formed from the heterogeneous reaction between SO2 and unsaturated fatty acids accounted for 7%−13% sulfur of the CHOS species and 5%−7% sulfur of all the CHOS and CHONS species. They contributed about 0.3‰−0.9‰ of the total organic mass of the fine particle samples collected.

Various water-soluble inorganic compounds, including Na+, NH4+, K+, Ca2+, Mg2+, Cl–, NO3–, PO43– and SO42–, were analyzed in 130 sets of size-segregated (< 0.49, 0.49–0.95, 0.95–1.5, 1.5–3.0, 3.0–7.2 and 7.2–10.0 µm) aerosol samples collected from March 2013 to April 2014 in Guangzhou, China. SO42– was unimodally distributed and peaked during a typical droplet mode (0.49–0.95 µm). However, the distribution of NO3– significantly varied across the four seasons. It was unimodally distributed in summer and autumn, peaking in the coarse mode (3.0–7.2 µm), and bimodally distributed in winter and spring, peaking in the size ranges of 0.49–0.95 µm and 3.0–7.2 µm, respectively. The coarse-mode NO3– was mainly related to the influence of soil/dust. The additional mode during winter and spring was attributable to the formation of ammonium nitrate. Compared to clean days, polluted days favored the formation of SO42– in summer and autumn and NO3– in winter and spring. The sulfur oxidation ratios (SORs) for < 0.49, 0.49–0.95 and 0.95–1.5 µm particles were negatively correlated with the relative humidity (RH) in spring, summer and autumn, respectively. However, the SORs for 0.49–3.0 µm particles were positively correlated with the RH in winter, implying an important contribution from the aqueous oxidation of SO2. Further analysis shows that the SO42– in < 0.49 µm particles was formed primarily through gas-phase photochemical oxidation of SO2 during all four seasons. The formation of NO3– was mainly attributable to heterogeneous reactions for 1.5–3.0 µm particles year-round and homogeneous gas-phase reactions for < 0.49 µm particles in winter. Correlation analysis also indicates a positive influence from biomass burning on the formation of nitrate and sulfate. The average pH of PM3 was calculated to be 2.6–5.6. Thus, the aqueous oxidation of SO2 by NO2 plays a limited role in the formation of sulfate in the atmosphere of Guangzhou.

The toxic effects of lead on human health and the environment have long been a focus of research. To explore sources of lead in Guangzhou, China, we investigated atmospheric lead-containing particles (LCPs) during wintertime using a single particle aerosol mass spectrometer (SPAMS). Based on mass spectral features, LCPs were classified into eight major particle types, including Pb-Cl and Pb-Cl-Li (coal combustion and waste incineration), Pb-Cl-EC and Pb-Cl-OC (diesel trucks and coal combustion), Pb-Cl-Fe (iron and steel industry), Pb-Cl-AlSi (dust), Pb-Sec (secondary formation), and Pb-Cl-Zn (industrial process); these sources (in parentheses) were identified by comparing atmospheric LCP mass spectra with authentic Pb emission source mass spectra. Sampling periods with LCP number fractions (NFs) more than three times the average LCP NF (APF = 4.35%) and below the APF were defined as high LCP NF periods (HLFPs: H1, H3, and H5) and low LCP NF APF periods (LLFPs: L2 and L4), respectively. Diurnal patterns and high Pb-Sec content during LLFPs indicate that photochemical activity and heterogeneous reactions may have controlled Pb-Sec particle formation. The inverse Pb-Cl and Pb-Sec particle diurnal trends during LLFPs suggest the replacement of Cl by sulfate and nitrate. On average over the five periods, ~ 76% of the LCPs likely arose from coal combustion and/or waste incineration, which were dominant sources during all five periods, followed by diesel trucks during LLFPs and iron- and steel-related sources during HLFPs; HLFP LCPs arose mainly from primary emissions. These results can be used to more efficiently control Pb emission sources and prevent harm to human and environmental health from Pb toxicity.