Chromatography related performance of the Monitor for AeRosols and GAses in ambient air (MARGA): laboratory and field-based evaluation

被引:31
作者
Chen, Xi [1 ]
Walker, John T. [1 ]
Geron, Chris [1 ]
机构
[1] US EPA, Natl Risk Management Res Lab, Off Res & Dev, Res Triangle Pk, NC 27711 USA
关键词
ATMOSPHERIC PARTICULATE MATTER; INORGANIC AEROSOL; UNITED-STATES; SEMICONTINUOUS METHOD; CHEMICAL-COMPOSITION; ION-CHROMATOGRAPHY; AMMONIA; SITE; NITROGEN; CONSTITUENTS;
D O I
10.5194/amt-10-3893-2017
中图分类号
P4 [大气科学(气象学)];
学科分类号
0706 ; 070601 ;
摘要
Evaluation of the semi-continuous Monitor for AeRosols and GAses in ambient air (MARGA, Metrohm Applikon B.V.) was conducted with an emphasis on examination of accuracy and precision associated with processing of chromatograms. Using laboratory standards and atmospheric measurements, analytical accuracy, precision and method detection limits derived using the commercial MARGA software were compared to an alternative chromatography procedure consisting of a custom Java script to reformat raw MARGA conductivity data and Chromeleon (Thermo Scientific Dionex) software for peak integration. Our analysis revealed issues with accuracy and precision resulting from misidentification and misintegration of chromatograph peaks by the MARGA automated software as well as a systematic bias at low concentrations for anions. Reprocessing and calibration of raw MARGA data using the alternative chromatography method lowered method detection limits and reduced variability (precision) between parallel sampler boxes. Instrument performance was further evaluated during a 1-month intensive field campaign in the fall of 2014, including analysis of diurnal patterns of gaseous and particulate water-soluble species (NH3, SO2, HNO3, NH4+, SO42- and NO3-), gas-to-particle partitioning and particle neutralization state. At ambient concentrations below similar to 1 mu g m(-3), concentrations determined using the MARGA software are biased +30 and +10% for NO3- and SO42-, respectively, compared to concentrations determined using the alternative chromatography procedure. Differences between the two methods increase at lower concentrations. We demonstrate that positively biased NO3- and SO42- measurements result in overestimation of aerosol acidity and introduce nontrivial errors to ion balances of inorganic aerosol. Though the source of the bias is uncertain, it is not corrected by the MARGA online single-point internal LiBr standard. Our results show that calibration and verification of instrument accuracy by multilevel external standards is required to adequately control analytical accuracy. During the field intensive, the MARGA was able to capture rapid compositional changes in PM2.5 due to changes in meteorology and air mass history relative to known source regions of PM precursors, including a fine NO3- aerosol event associated with intrusion of Arctic air into the southeastern US.
引用
收藏
页码:3893 / 3908
页数:16
相关论文
共 35 条
[1]   A continuous analyzer for soluble anionic constituents and ammonium in atmospheric particulate matter [J].
Al-Horr, R ;
Samanta, G ;
Dasgupta, PK .
ENVIRONMENTAL SCIENCE & TECHNOLOGY, 2003, 37 (24) :5711-5720
[2]   Influence of crustal dust and sea spray supermicron particle concentrations and acidity on inorganic NO3- aerosol during the 2013 Southern Oxidant and Aerosol Study [J].
Allen, H. M. ;
Draper, D. C. ;
Ayres, B. R. ;
Ault, A. P. ;
Bondy, A. L. ;
Takahama, S. ;
Modini, R. L. ;
Baumann, K. ;
Edgerton, E. ;
Knote, C. ;
Laskin, A. ;
Wang, B. ;
Fry, J. L. .
ATMOSPHERIC CHEMISTRY AND PHYSICS, 2015, 15 (18) :10669-10685
[3]  
[Anonymous], 2006, ATMOS CHEM PHYS
[4]   Atmospheric concentrations and deposition of reactive nitrogen in Grand Teton National Park [J].
Benedict, Katherine B. ;
Chen, Xi ;
Sullivan, Amy P. ;
Li, Yi ;
Day, Derek ;
Prenni, Anthony J. ;
Levin, E. J. T. ;
Kreidenweis, Sonia M. ;
Malm, William C. ;
Schichtel, Bret A. ;
Collett, Jeffrey L., Jr. .
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 2013, 118 (20) :11875-11887
[5]  
Chen X., 2017, LAB FIELD DATA SUMMA
[6]   Seasonal ambient ammonia and ammonium concentrations in a pilot IMPROVE NHx monitoring network in the western United States [J].
Chen, Xi ;
Day, Derek ;
Schichtel, Bret ;
Malm, William ;
Matzoll, Ashleigh K. ;
Mojica, Jose ;
McDade, Charles E. ;
Hardison, Eva D. ;
Hardison, David L. ;
Walters, Steven ;
De Water, Mark Van ;
Collett, Jeffrey L., Jr. .
ATMOSPHERIC ENVIRONMENT, 2014, 91 :118-126
[7]   Nomenclature in evaluation of analytical methods including detection and quantification capabilities (IUPAC Recommendations 1995) [J].
Currie, LA .
ANALYTICA CHIMICA ACTA, 1999, 391 (02) :105-126
[8]  
Draxler R.R., 2010, HYSPLIT HYBRID SINGL
[9]  
Finlayson-Pitts B.J., 2000, Chemistry of the Upper and Lower Atmosphere: Theory, Experiments, and Applications, Vfirst
[10]   A case study of the highly time-resolved evolution of aerosol chemical and optical properties in urban Shanghai, China [J].
Huang, Y. ;
Li, L. ;
Li, J. ;
Wang, X. ;
Chen, H. ;
Chen, J. ;
Yang, X. ;
Gross, D. S. ;
Wang, H. ;
Qiao, L. ;
Chen, C. .
ATMOSPHERIC CHEMISTRY AND PHYSICS, 2013, 13 (08) :3931-3944