Characterization, mixing state, and evolution of single particles in a megacity of Sichuan Basin, southwest China

Zhang, Junke; Huang, Xiaojuan; Wang, Yuesi; Luo, Bin; Zhang, Jianqiang; Song, Hongyi; Zhang, Wei; Liu, Peichuan; Schäfer, Klaus; Wang, Shigong; Luo, Jinqi; Wu, Pan

doi:10.1016/j.atmosres.2018.03.014

Cited by 31 publications

(12 citation statements)

References 64 publications

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“…Due to the blocking effects of surrounding terrains, the wind in the SCB is quite weak, especially in the western part [93]. From the clean stage to polluted stage, the wind speed in Chengdu typically shows a substantial decrease [94]. The lower wind speed is unfavorable to the diffusion of pollutants.…”

Section: Sichuan Basinmentioning

confidence: 99%

“…The wind direction also differs under various polluted/clean stages. For example, the stronger northeasterly wind often prevails during the clean period in Chengdu, which carries cleaner air masses from the less polluted areas to the city [94]; while during the polluted period, the wind usually comes from the south of Chengdu, where many industrial cities are located (e.g., Luzhou, Panzhihua), leading to the transport of pollutants and the deterioration of air quality in Chengdu [94]. Moreover, the mountain ranges to the west of Chengdu act as a barrier to the air flow from the east and cause the accumulation of pollutants in front of the mountain [93,95].…”

Section: Sichuan Basinmentioning

confidence: 99%

“…In addition to the weak wind, the high RH is also critical to the pollution in the SCB. The aqueous-phase reaction is a key formation pathway for the PM 2.5 species [94].…”

Section: Sichuan Basinmentioning

confidence: 99%

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Interaction Between Planetary Boundary Layer and PM2.5 Pollution in Megacities in China: a Review

Miao

et al. 2019

Curr Pollution Rep

120

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Purpose of Review During the past decades, the number and size of megacities have been growing dramatically in China. Most of Chinese megacities are suffering from heavy PM 2.5 pollution. In the pollution formation, the planetary boundary layer (PBL) plays an important role. This review is aimed at presenting the current state of understanding of the PBL-PM 2.5 interaction in megacities, as well as to identify the main gaps in current knowledge and further research needs. Recent Findings The PBL is critical to the formation of urban PM 2.5 pollution at multiple temporal scales, ranging from diurnal change to seasonal variation. For the essential PBL structure/process in pollution, the coastal megacities have different concerns from the mountainous or landlocked megacities. In the coastal cities, the recirculation induced by sea-land breeze can accumulate pollutants, whereas in the valley/basin, the blocking effects of terrains can lead to stagnant conditions and thermal inversion. Within a megacity, although the urbanization-induced land use change can cause thermodynamic perturbations and facilitate the development of PBL, the increases in emissions outweigh this impact, resulting in a net increase of aerosol concentration. Moreover, the aerosol radiative effects can modify the PBL by heating the upper layers and reducing the surface heat flux, suppressing the PBL and exacerbating the pollution. Summary This review presented the PBL-PM 2.5 interaction in 13 Chinese megacities with various geographic conditions and elucidated the critical influencing processes. To further understand the complicated interactions, long-term observations of meteorology and aerosol properties with multi-layers in the PBL need to be implemented.

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Section: Sichuan Basinmentioning

confidence: 99%

Section: Sichuan Basinmentioning

confidence: 99%

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Interaction Between Planetary Boundary Layer and PM2.5 Pollution in Megacities in China: a Review

Miao

et al. 2019

Curr Pollution Rep

120

View full text Add to dashboard Cite

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“…It not only avoids the disadvantages of the traditional offline analysis method, but also excludes the tedious sample pretreatment processes. In addition, the information of particle size, chemical composition and source resolution of single particles can be obtained quickly by SPAMS (Bi et al, 2015;Ma et al, 2016;Zhang et al, 2018;Peng et al, 2019;Shen et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

Characteristics and Sources of Single Particles in the Urban Liaocheng of North China during the Heating Period

Song

Meng

Zhou

et al. 2021

Aerosol Air Qual. Res.

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Liaocheng represents one of the most serious polluted cities in Northern China. To investigate the impact of residential heating activities on atmospheric particles, the chemical composition, size distribution, and evolution process of single particles collected during the wintertime of 2019 were investigated using a single-particle aerosol mass spectrometer (SPAMS). The results showed that the concentrations of four air pollutants including PM2.5, SO2, NO2, and CO during the heating period were 1.1-1.2 times higher than those before the heating period largely due to the increase of pollutant emissions from coal combustion, while O3 concentration during the heating period decreased by 40.2%. The mass spectra and unscaled size distributions of single particles suggested that the particles had undergone a significant aging process during the whole observation period. The acidity of single particles was calculated by the relative acidity ratio (Rra), which increased from 36.1 ± 13.9 before the heating period to 64.8 ± 43.9 during the heating period, implying that the single particles were more acidic and less aged during the heating period, mainly due to the enhanced formation of sulfate and nitrate and the decreased O3 concentration during the heating period. Moreover, Rra decreased from clean days to polluted days before and during the heating period, suggesting that the atmospheric particles in polluted days were less acidic and more aged. The percentage of elemental carbon (EC) particles increased by 13.6% and 11.5% from clean days to polluted days before and during the heating period, respectively, suggesting the significant contribution of EC particles to the polluted days. Source identification results showed that single particles before the heating period were mostly derived from secondary inorganic source (26.5%) and vehicle exhaust (21.4%), whereas those during the heating period were largely from coal combustion (24.0%) and secondary inorganic source (21.4%).

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“…Studies such as these that utilize the traditional offline measurement technique involving collection of particles on filters followed by chemical processing are susceptible to biases originating from the potential decay or degeneration of chemical species during preservation, transportation, and sample analysis. To overcome these challenges, high time resolution analytical techniques have been recently developed to characterize short-term variability in aerosol concentrations and to isolate individual sources (Prather et al, 2008;Zhang et al, 2018;Zhang et al, 2018;Wang et al, 2019). Despite potential issues of bias, as discussed before, filter-based analysis still remains the most widely used approach worldwide and is considered as the benchmark (e.g., United States and China).…”

Section: Introductionmentioning

confidence: 99%

Comparative study of chemical characterization and source apportionment of PM2.5 in South China by filter-based and single particle analysis

Mao

Yang

et al. 2021

Elementa: Science of the Anthropocene

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Single particle aerosol mass spectrometers (SPAMS) have created significant interest among atmospheric scientists by virtue of their ability to provide real-time size-resolved information on the chemical composition of aerosols. The objective of this study is to evaluate the newly developed single particle analysis technique in terms of chemical characterization and source apportionment of ambient aerosols by comparing it with traditional filter-based methods. In this study, an air quality monitoring campaign was conducted over a period of 25 days at an urban area in Yulin city, southern China, by employing both SPAMS and traditional filter-based measurements to establish the performance of SPAMS. It was observed that the chemical characterization of particles based on SPAMS did not agree well with the filter-based analysis. Based on the filter analysis, sulfate was the most abundant component in PM2.5 (23.5%), followed by OC (18.1%), while for single particle analysis (number concentration), EC-containing particles showed the largest contribution to PM2.5 (>40%), followed by OC (15.7%). In terms of source apportionment via positive matrix factorization, six sources were identified by each of the two approaches. Both the approaches showed relatively good agreements for secondary species, traffic, and dust sources; however, discrepancies were noted for industry, fossil fuel, and biomass burning sources. Finally, investigation of diurnal profiles and two specific emission episodes monitored during the Chinese New Year and traffic activities demonstrated the relative advantage of single particle analysis over filter-based methods. Overall, single particle analysis can provide source apportionment with a high time resolution, which is helpful for policy makers to analyze and implement emergency control strategies during air pollution episodes. However, SPAMS performs quantification of number concentration rather than mass concentration and is limited to particles larger than 200 nm, which leads to discrepancies between the two methods. SPAMS measurements can therefore not simply replace traditional filter-based analyses, which needs to be carefully considered in the selection of the monitoring implementation.

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Characterization, mixing state, and evolution of single particles in a megacity of Sichuan Basin, southwest China

Cited by 31 publications

References 64 publications

Interaction Between Planetary Boundary Layer and PM2.5 Pollution in Megacities in China: a Review

Interaction Between Planetary Boundary Layer and PM2.5 Pollution in Megacities in China: a Review

Characteristics and Sources of Single Particles in the Urban Liaocheng of North China during the Heating Period

Comparative study of chemical characterization and source apportionment of PM2.5 in South China by filter-based and single particle analysis

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