The diurnal variation of aerosol chemical composition during the 1995 summer campaign at the Jungfraujoch high-alpine station (3454 m), Switzerland

1996 ◽  
Vol 27 ◽  
pp. S105-S106 ◽  
Author(s):  
S. Nyeki ◽  
U. Baltensperger ◽  
M. Schwikowski
Keyword(s):  
Chemical Composition ◽  
Diurnal Variation ◽  
Aerosol Chemical Composition

scholarly journals Significant contribution of organics to aerosol liquid water content in winter in Beijing, China

2019 ◽  
Author(s):  
Xiaoai Jin ◽  
Yuying Wang ◽  
Zhanqing Li ◽  
Fang Zhang ◽  
Weiqi Xu ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Diurnal Variation ◽  
Water Content ◽  
Liquid Water ◽  
Significant Contribution ◽  
Liquid Water Content ◽  
Coefficient Of Determination ◽  
Urban Site ◽  
Hygroscopic Growth ◽  
Aerosol Chemical Composition

Abstract. The aerosol liquid water content (ALWC), an important component of atmospheric particles, has a significant effect on atmospheric optical properties, visibility and multiphase chemical reactions. In this study, ALWC is determined from aerosol hygroscopic growth factor and particle number size distribution (PNSD) measurements and also simulated by the ISORROPIA II thermodynamic model with measured aerosol chemical composition data at an urban site in Beijing from 8 November to 15 December 2017. Rich measurements made during the experiment concerning virtually all aerosol properties allow us not only to derive the ALWC but also to study the contributions by various species for which little has been done in this region. The simulated ALWC including the contribution of organics and the calculated ALWC are highly correlated (coefficient of determination R2 = 0.92). The ALWC contributed by organics (ALWCOrg) accounts for 30 % ± 22 % of the total ALWC during the sampling period. These results suggest a significant contribution of organics to ALWC, which is rather different from previous studies that showed negligible contributions by organics. Our results also show that ALWC correlates well with the mass concentrations of sulfate, nitrate, and secondary organic aerosols (SOA) (R2 = 0.66, 0.56, and 0.60, respectively). We further noted that accumulation mode particles play a key role in determining ALWC, dominating among all the aerosol modes. ALWC is an exponential function of ambient relative humidity (RH) whose strong diurnal variation influence the diurnal variation of ALWC. However, there is a three-hour lag between the extremes of ALWC and RH values, due to the diurnal variations in PNSD and aerosol chemical composition. Finally, a case study reveals that ALWCOrg plays an important role in the formation of secondary aerosols through multiphase reactions at the initial stage of a heavy haze episode.

scholarly journals Significant contribution of organics to aerosol liquid water content in winter in Beijing, China

2020 ◽  
Vol 20 (2) ◽  
pp. 901-914 ◽  
Author(s):  
Xiaoai Jin ◽  
Yuying Wang ◽  
Zhanqing Li ◽  
Fang Zhang ◽  
Weiqi Xu ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Diurnal Variation ◽  
Liquid Water ◽  
Significant Contribution ◽  
Sampling Period ◽  
Liquid Water Content ◽  
Coefficient Of Determination ◽  
Urban Site ◽  
Hygroscopic Growth ◽  
Aerosol Chemical Composition

Abstract. The aerosol liquid water (ALW) content (ALWC), an important component of atmospheric particles, has a significant effect on atmospheric optical properties, visibility and multiphase chemical reactions. In this study, ALWC is determined from aerosol hygroscopic growth factor (GF) and particle number size distribution (PNSD) measurements and is also simulated by ISORROPIA II, a thermodynamic equilibrium model, with measured aerosol chemical composition data taken at an urban site in Beijing from 8 November to 15 December 2017. Rich measurements made during the experiment concerning virtually all aerosol properties allow us not only to derive the ALWC but also to study the contributions by various species for which little has been done in this region. The simulated ALWC including the contribution of organics and the calculated ALWC are highly correlated (coefficient of determination R2=0.92). The ALWC contributed by organics (ALWCOrg) accounts for 30 %±22 % of the total ALWC during the sampling period. These results suggest a significant contribution of organics to ALWC, which is rather different from previous studies that showed negligible contributions by organics. Our results also show that ALWC correlates well with the mass concentrations of sulfate, nitrate, and secondary organic aerosols (SOAs) (R2=0.66, 0.56 and 0.60, respectively). We further noted that accumulation mode particles play a key role in determining ALWC, dominating among all the aerosol modes. ALWC is an exponential function of ambient relative humidity (RH), whose strong diurnal variation influence the diurnal variation of ALWC. However, there is a 3 h lag between the extremes of ALWC and RH values, due to the diurnal variations in PNSD and aerosol chemical composition. Finally, a case study reveals that ALWCOrg plays an important role in the formation of secondary aerosols through multiphase reactions at the initial stage of a heavy-haze episode.

Aerosol chemical composition and light scattering during a winter season in Beijing

2015 ◽  
Vol 110 ◽  
pp. 36-44 ◽  
Author(s):  
Jun Tao ◽  
Leiming Zhang ◽  
Jian Gao ◽  
Han Wang ◽  
Faihe Chai ◽  
...  
Keyword(s):  
Light Scattering ◽  
Chemical Composition ◽  
Winter Season ◽  
Aerosol Chemical Composition

Aerosol chemical composition over Istanbul

2010 ◽  
Vol 408 (12) ◽  
pp. 2482-2491 ◽  
Author(s):  
C. Theodosi ◽  
U. Im ◽  
A. Bougiatioti ◽  
P. Zarmpas ◽  
O. Yenigun ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Aerosol Chemical Composition

scholarly journals Chemical composition, diurnal variation and sources of PM2.5 at two industrial sites of South China

2013 ◽  
Vol 4 (3) ◽  
pp. 298-305 ◽  
Author(s):  
Bo Huang ◽  
Ming Liu ◽  
Zhaofang Ren ◽  
Xinhui Bi ◽  
Guohua Zhang ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Diurnal Variation ◽  
South China ◽  
Industrial Sites

scholarly journals CCN activity of organic aerosols observed downwind of urban emissions during CARES

2013 ◽  
Vol 13 (4) ◽  
pp. 9355-9399 ◽  
Author(s):  
F. Mei ◽  
A. Setyan ◽  
Q. Zhang ◽  
J. Wang
Keyword(s):  
Chemical Composition ◽  
Water Solubility ◽  
Volume Fraction ◽  
Field Studies ◽  
High Water ◽  
Carbonaceous Aerosols ◽  
Mass Spectral ◽  
Least Squares Fit ◽  
The Relationship ◽  
Aerosol Chemical Composition

Abstract. During the Carbonaceous Aerosols and Radiative Effects Study (CARES), activation fraction of size-resolved aerosol particles and aerosol chemical composition were characterized at the T1 site (~60 km downwind of Sacramento, California) from 10 June to 28 June 2010. The hygroscopicity of CCN-active particles (κCCN) with diameter from 100 to 171 nm, derived from the size-resolved activated fraction, varied from 0.10 to 0.21, with an average of 0.15, which was substantially lower than that proposed for continental sites in earlier studies. The low κCCN value was due to the high organic volume fraction, averaged over 80% at the T1 site. The derived κCCN exhibited little diurnal variation, consistent with the relatively constant organic volume fraction observed. At any time, over 90% of the size selected particles with diameter between 100 and 171 nm were CCN active, suggesting most particles within this size range were aged background particles. Due to the large organic volume fraction, organic hygroscopicity (κorg) strongly impacted particle hygroscopicity and therefore calculated CCN concentration. For vast majority of the cases, an increase of κorg from 0.03 to 0.18, which are within the typical range, doubled the calculated CCN concentration. Organic hygroscopicity was derived from κCCN and aerosol chemical composition, and its variations with the fraction of total organic mass spectral signal at m/z 44 (f44) and O : C were compared to results from previous studies. Overall, the relationships between κorg and f44 are quite consistent for organic aerosol (OA) observed during field studies and those formed in smog chamber. Compared to the relationship between κorg and f44, the relationship between κorg and O : C exhibits more significant differences among different studies, suggesting κorg may be better parameterized using f44. A least squares fit yielded κorg = 2.04 (± 0.07) × f44 − 0.11 (± 0.01) with the Pearson R2 value of 0.71. One possible explanation for the stronger correlation between κorg and f44 is that the m/z 44 signal (mostly contributed by the CO2+ ion) is more closely related to organic acids, which may dominate the overall κorg due to their relatively high water solubility and hygroscopicity.

Characterization of aerosol chemical composition from urban pollution in Brazil and its possible impacts on the aerosol hygroscopicity and size distribution

2019 ◽  
Vol 202 ◽  
pp. 149-159 ◽  
Author(s):  
Gerson P. Almeida ◽  
Antônio T. Bittencourt ◽  
Marçal S. Evangelista ◽  
Marcelo S. Vieira-Filho ◽  
Adalgiza Fornaro
Keyword(s):  
Chemical Composition ◽  
Size Distribution ◽  
Urban Pollution ◽  
Aerosol Hygroscopicity ◽  
Aerosol Chemical Composition

scholarly journals Towards an online-coupled chemistry-climate model: evaluation of trace gases and aerosols in COSMO-ART

2011 ◽  
Vol 4 (4) ◽  
pp. 1077-1102 ◽  
Author(s):  
C. Knote ◽  
D. Brunner ◽  
H. Vogel ◽  
J. Allan ◽  
A. Asmi ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Size Distribution ◽  
Urban Areas ◽  
Climate Model ◽  
Transport Model ◽  
Climate Impacts ◽  
Chemistry Transport Model ◽  
Pm2.5 And Pm10 ◽  
Phase Chemistry ◽  
Aerosol Chemical Composition

Abstract. The online-coupled, regional chemistry transport model COSMO-ART is evaluated for periods in all seasons against several measurement datasets to assess its ability to represent gaseous pollutants and ambient aerosol characteristics over the European domain. Measurements used in the comparison include long-term station observations, satellite and ground-based remote sensing products, and complex datasets of aerosol chemical composition and number size distribution from recent field campaigns. This is the first time these comprehensive measurements of aerosol characteristics in Europe are used to evaluate a regional chemistry transport model. We show a detailed analysis of the simulated size-resolved chemical composition under different meteorological conditions. Mean, variability and spatial distribution of the concentrations of O3 and NOx are well reproduced. SO2 is found to be overestimated, simulated PM2.5 and PM10 levels are on average underestimated, as is AOD. We find indications of an overestimation of shipping emissions. Time evolution of aerosol chemical composition is captured, although some biases are found in relative composition. Nitrate aerosol components are on average overestimated, and sulfates underestimated. The accuracy of simulated organics depends strongly on season and location. While strongly underestimated during summer, organic mass is comparable in spring and autumn. We see indications for an overestimated fractional contribution of primary organic matter in urban areas and an underestimation of SOA at many locations. Aerosol number concentrations compare well with measurements for larger size ranges, but overestimations of particle number concentration with factors of 2–5 are found for particles smaller than 50 nm. Size distribution characteristics are often close to measurements, but show discrepancies at polluted sites. Suggestions for further improvement of the modeling system consist of the inclusion of a revised secondary organic aerosols scheme, aqueous-phase chemistry and improved aerosol boundary conditions. Our work sets the basis for subsequent studies of aerosol characteristics and climate impacts with COSMO-ART, and highlights areas where improvements are necessary for current regional modeling systems in general.

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