scholarly journals Characterization of Atmospheric PM2.5 Inorganic Aerosols Using the Semi-Continuous PPWD-PILS-IC System and the ISORROPIA-II

Atmosphere ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 820
Author(s):  
Thi-Cuc Le ◽  
Yun-Chin Wang ◽  
David Y. H. Pui ◽  
Chuen-Jinn Tsai
Keyword(s):  
Thermodynamic Equilibrium ◽  
Equilibrium Model ◽  
Inorganic Ions ◽  
Porous Metal ◽  
Water Soluble ◽  
Inorganic Aerosols ◽  
Daily Data ◽  
Water Soluble Inorganic Ions ◽  
Thermodynamic Equilibrium Model ◽  
Good Agreement

A semi-continuous monitoring system, a parallel plate wet denuder and particle into liquid sampler coupled with ion chromatography (PPWD-PILS-IC), was used to measure the hourly precursor gases and water-soluble inorganic ions in ambient particles smaller than 2.5 µm in diameter (PM2.5) for investigating the thermodynamic equilibrium of aerosols using the ISORROPIA-II thermodynamic equilibrium model. The 24-h average PPWD-PILS-IC data showed very good agreement with the daily data of the manual 5 L/min porous-metal denuder sampler with R2 ranging from 0.88 to 0.98 for inorganic ions (NH4+, Na+, K+, NO3−, SO42−, and Cl−) and 0.89 to 0.98 for precursor gases (NH3, HNO3, HONO, and SO2) and slopes ranging from 0.94 to 1.17 for ions and 0.87 to 0.95 for gases, respectively. In addition, the predicted ISORROPIA-II results were in good agreement with the hourly observed data of the PPWD-PILS-IC system for SO42− (R2 = 0.99 and slope = 1.0) and NH3 (R2 = 0.97 and slope = 1.02). The correlation of the predicted results and observed data was further improved for NH4+ and NO3− with the slope increasing from 0.90 to 0.96 and 0.95 to 1.09, respectively when the HNO2 and NO2− were included in the total nitrate concentration (TN = [NO3−] + [HNO3] + [HONO] + [NO2−]). The predicted HNO3 data were comparable to the sum of the observed [HNO3] and [HONO] indicating that HONO played an important role in the thermodynamic equilibrium of ambient PM2.5 aerosols but has not been considered in the ISORROPIA-II thermodynamic equilibrium model.

scholarly journals An inter-laboratory comparison of aerosol in organic ion measurements by Ion Chromatography: implications for aerosol pH estimate

2020 ◽  
Author(s):  
Jingsha Xu ◽  
Shaojie Song ◽  
Roy M. Harrison ◽  
Congbo Song ◽  
Lianfang Wei ◽  
...  
Keyword(s):  
Major Ions ◽  
Certified Reference Materials ◽  
Inorganic Ions ◽  
Water Soluble ◽  
Ion Concentration ◽  
Ion Concentrations ◽  
Inorganic Ion ◽  
Aerosol Acidity ◽  
Water Soluble Inorganic Ions ◽  
Good Agreement

Abstract. Water soluble inorganic ions such as ammonium, nitrate, and sulfate are major components of fine aerosols in the atmosphere and are widely used in the estimation of aerosol acidity. However, different experimental practices and instrumentation may lead to uncertainties in ion concentrations. Here, an inter-comparison experiment was conducted in 10 different laboratories (labs) to investigate the consistency of inorganic ion concentrations and resultant aerosol acidity estimates using the same set of aerosol filter samples. The results mostly exhibited good agreement for major ions Cl−, SO42−, NO3−, NH4+ and K+. However, F−, Mg2+ and Ca2+ were observed with more variations across the different labs. The Aerosol Chemical Speciation Monitor (ACSM) data of non-refractory SO42−, NO3−, NH4+ generally correlated very well with the filter analysis based data in our study, but the absolute concentrations differ by up to 42 %. Cl− from the two methods are correlated but the concentration differ by more than 3 times. The analyses of certified reference materials (CRMs) generally showed good recovery of all ions in all the labs, the majority of which ranged between 90 % and 110 %. Better agreements were found for Cl−, SO42−, NO3−, NH4+ and K+ across the labs after their concentrations were corrected with CRM recoveries; the coefficient of variation (CV) of Cl−, SO42−, NO3−, NH4+ and K+ decreased 1.7 %, 3.4 %, 3.4 %, 1.2 % and 2.6 %, respectively, after CRM correction. We found that the ratio of anion to cation equivalent concentrations (AE/CE) is not a good indicator for aerosol acidity estimates, as the results in different labs did not agree well with each other. Ion balance (anions – cations) calculated from SO42−, NO3− and NH4+ gave more consistent results, because of their relatively large concentrations and good agreement among different labs. In situ aerosol pH calculated from the ISORROPIA-II thermodynamic equilibrium model with measured ion and ammonia concentrations showed a similar trend and good agreement across the 10 labs. Our results indicate that although there are important uncertainties in aerosol ion concentration measurements, the estimated aerosol pH from the ISORROPIA-II model is more consistent.

Water-soluble inorganic ions of size-differentiated atmospheric particles from a suburban site of Mexico City

2017 ◽  
Vol 75 (2) ◽  
pp. 155-169 ◽  
Author(s):  
Telma Castro ◽  
Oscar Peralta ◽  
Dara Salcedo ◽  
José Santos ◽  
María I. Saavedra ◽  
...  
Keyword(s):  
Mexico City ◽  
Inorganic Ions ◽  
Atmospheric Particles ◽  
Water Soluble ◽  
Water Soluble Inorganic Ions ◽  
Suburban Site

scholarly journals The sensitivity of PM<sub>2.5</sub> acidity to meteorological parameters and chemical composition changes: 10-year records from six Canadian monitoring sites

2019 ◽  
Author(s):  
Ye Tao ◽  
Jennifer G. Murphy
Keyword(s):  
Chemical Composition ◽  
Meteorological Parameters ◽  
Inorganic Ions ◽  
Water Soluble ◽  
Seasonal Cycles ◽  
Accuracy And Precision ◽  
Different Seasons ◽  
Water Soluble Inorganic Ions ◽  
Composition Changes

Abstract. Aerosol pH is difficult to measure directly but can be calculated if the chemical composition is known with sufficient accuracy and precision to calculate the aerosol water content and the H+ concentration through ion balance. In practical terms, simultaneous measurements of at least one semi-volatile constitute, e.g. NH3 or HNO3, are required to provide a constraint on the calculation of pH. Long-term records of aerosol pH are scarce due to the limited monitoring of NH3 in conjunction with PM2.5. In this study, 10-year (2007–2016) records of pH of PM2.5 at six eastern Canadian sites were calculated using the E-AIM II model with the input of gaseous NH3, gaseous HNO3 and major water-soluble inorganic ions in PM2.5 provided by Canada's National Air Pollution Surveillance (NAPS) Program. Clear seasonal cycles of aerosol pH were found with lower pH (~2) in summer and higher pH (~3) in winter consistently across all six sites, while the day-to-day variations of aerosol pH were higher in winter compared to summer. Tests of the sensitivity of aerosol pH to meteorological parameters demonstrate that the changes in ambient temperature largely drive the seasonal cycle of aerosol pH. The sensitivity of pH to chemical composition shows that pH has different responses to the changes in chemical composition in different seasons. During summertime, aerosol pH was mainly determined by temperature with limited impact from changes in NHx or sulfate concentrations. However, in wintertime, both meteorological parameters and chemical composition contribute to the variations in aerosol pH, resulting in the larger variation during wintertime. This study reveals that the sensitivity of aerosol pH to chemical composition is distinctly different under different meteorological conditions and needs to be carefully examined for any particular region.

A modified thermodynamic equilibrium model for woody biomass gasification

2013 ◽  
Vol 92 (4) ◽  
pp. 593-602 ◽  
Author(s):  
Pardis Rofouie ◽  
Maryam Moshkelani ◽  
Michel Perrier ◽  
Jean Paris
Keyword(s):  
Thermodynamic Equilibrium ◽  
Equilibrium Model ◽  
Woody Biomass ◽  
Biomass Gasification ◽  
Thermodynamic Equilibrium Model
Sign in / Sign up

Export Citation Format

Share Document