scholarly journals Primary and secondary contributions to aerosol light scattering and absorption in Mexico City during the MILAGRO 2006 campaign

2009 ◽  
Vol 9 (11) ◽  
pp. 3721-3730 ◽  
Author(s):  
G. Paredes-Miranda ◽  
W. P. Arnott ◽  
J. L. Jimenez ◽  
A. C. Aiken ◽  
J. S. Gaffney ◽  
...  
Keyword(s):  
Light Scattering ◽  
Mexico City ◽  
Light Absorption ◽  
Mass Concentration ◽  
Single Scattering ◽  
Single Scattering Albedo ◽  
Aerosol Mass ◽  
Aerosol Mass Concentration ◽  
532 Nm ◽  
Peak Value

Abstract. A photoacoustic spectrometer, a nephelometer, an aethalometer, and an aerosol mass spectrometer were used to measure at ground level real-time aerosol light absorption, scattering, and chemistry at an urban site located in North East Mexico City (Instituto Mexicano del Petroleo, Mexican Petroleum Institute, denoted by IMP), as part of the Megacity Impact on Regional and Global Environments field experiment, MILAGRO, in March 2006. Photoacoustic and reciprocal nephelometer measurements at 532 nm accomplished with a single instrument compare favorably with conventional measurements made with an aethalometer and a TSI nephelometer. The diurnally averaged single scattering albedo at 532 nm was found to vary from 0.60 to 0.85 with the peak value at midday and the minimum value at 07:00 a.m. local time, indicating that the Mexico City plume is likely to have a net warming effect on local climate. The peak value is associated with strong photochemical generation of secondary aerosol. It is estimated that the photochemical production of secondary aerosol (inorganic and organic) is approximately 75% of the aerosol mass concentration and light scattering in association with the peak single scattering albedo. A strong correlation of aerosol scattering at 532 nm and total aerosol mass concentration was found, and an average mass scattering efficiency factor of 3.8 m2/g was determined. Comparisons of photoacoustic and aethalometer light absorption with oxygenated organic aerosol concentration (OOA) indicate a very small systematic bias of the filter based measurement associated with OOA and the peak aerosol single scattering albedo.

scholarly journals Primary and secondary contributions to aerosol light scattering and absorption in Mexico City during the MILAGRO 2006 campaign

2008 ◽  
Vol 8 (5) ◽  
pp. 16951-16979 ◽  
Author(s):  
G. Paredes-Miranda ◽  
W. P. Arnott ◽  
J. L. Jimenez ◽  
A. C. Aiken ◽  
J. S. Gaffney ◽  
...  
Keyword(s):  
Light Scattering ◽  
Mexico City ◽  
Light Absorption ◽  
Mass Concentration ◽  
Single Scattering ◽  
Single Scattering Albedo ◽  
Aerosol Mass ◽  
Aerosol Mass Concentration ◽  
532 Nm ◽  
Peak Value

Abstract. A photoacoustic spectrometer, a nephelometer, an aetholemeter, and an aerosol mass spectrometer were used to measure at ground level real-time aerosol light absorption, scattering, and chemistry at an urban site located in north east Mexico City (Instituto Mexicano del Petroleo, Mexican Petroleum Institute, denoted by IMP), as part of the Megacity Impact on Regional and Global Environments field experiment, MILAGRO, in March 2006. Photoacoustic and reciprocal nephelometer measurements at 532 nm accomplished with a single instrument compare favorably with conventional measurements made with an aethelometer and a TSI nephelometer. The diurnally averaged single scattering albedo at 532 nm was found to vary from 0.60 to 0.85 with the peak value at midday and the minimum value at 7 a.m. local time, indicating that the Mexico City plume is likely to have a net warming effect on local climate. The peak value is associated with strong photochemical generation of secondary aerosol. It is estimated that the same-day photochemical production of secondary aerosol (inorganic and organic) is approximately 40 percent of the aerosol mass concentration and light scattering in association with the peak single scattering albedo. A strong correlation of aerosol scattering at 532 nm and total aerosol mass concentration was found, and an average mass scattering efficiency factor of 3.8 m2/g was determined. Comparisons of photoacoustic and aethalometer light absorption with oxygenated organic aerosol concentration (OOA) indicate a very small systematic bias of the filter based measurement associated with OOA and the peak aerosol single scattering albedo.

scholarly journals Vertical distribution of aerosols in the vicinity of Mexico City during MILAGRO-2006 Campaign

2010 ◽  
Vol 10 (3) ◽  
pp. 1017-1030 ◽  
Author(s):  
P. A. Lewandowski ◽  
W. E. Eichinger ◽  
H. Holder ◽  
J. Prueger ◽  
J. Wang ◽  
...  
Keyword(s):  
Size Distribution ◽  
Mexico City ◽  
Mass Concentration ◽  
Heavy Traffic ◽  
Aerosol Size Distribution ◽  
Lidar System ◽  
Aerosol Mass ◽  
Aerosol Mass Concentration ◽  
Lidar Measurements ◽  
Ground Based Lidar

Abstract. On 7 March 2006, a mobile, ground-based, vertical pointing, elastic lidar system made a North-South transect through the Mexico City basin. Column averaged, aerosol size distribution (ASD) measurements were made on the ground concurrently with the lidar measurements. The ASD ground measurements allowed calculation of the column averaged mass extinction efficiency (MEE) for the lidar system (1064 nm). The value of column averaged MEE was combined with spatially resolved lidar extinction coefficients to produce total aerosol mass concentration estimates with the resolution of the lidar (1.5 m vertical spatial and 1 s temporal). Airborne ASD measurements from DOE G-1 aircraft made later in the day on 7 March 2006, allowed the evaluation of the assumptions of constant ASD with height and time used for estimating the column averaged MEE. The results showed that the aerosol loading within the basin is about twice what is observed outside of the basin. The total aerosol base concentrations observed in the basin are of the order of 200 μg/m3 and the base levels outside are of the order of 100 μg/m3. The local heavy traffic events can introduce aerosol levels near the ground as high as 900 μg/m3. The article presents the methodology for estimating aerosol mass concentration from mobile, ground-based lidar measurements in combination with aerosol size distribution measurements. An uncertainty analysis of the methodology is also presented.

Research on the fractal model and calibration of the aerosol mass concentration measurement based on the particle group light scattering

2016 ◽  
Vol 14 (11) ◽  
pp. 112901-112906
Author(s):  
Fang Gu Fang Gu ◽  
Yi Liu Yi Liu ◽  
Jiahong Zhang Jiahong Zhang ◽  
Yunyun Chen Yunyun Chen ◽  
and Fengping Cui and Fengping Cui
Keyword(s):  
Light Scattering ◽  
Mass Concentration ◽  
Fractal Model ◽  
Concentration Measurement ◽  
Aerosol Mass ◽  
Aerosol Mass Concentration ◽  
Particle Group

Aerosol mass concentration measurements: Recent advancements of real-time nano/micro systems

2017 ◽  
Vol 114 ◽  
pp. 42-54 ◽  
Author(s):  
U. Soysal ◽  
E. Géhin ◽  
E. Algré ◽  
B. Berthelot ◽  
G. Da ◽  
...  
Keyword(s):  
Real Time ◽  
Mass Concentration ◽  
Aerosol Mass ◽  
Aerosol Mass Concentration ◽  
Concentration Measurements ◽  
Micro Systems

scholarly journals Key factors affecting single scattering albedo calculation: Implications for aerosol climate forcing

2017 ◽  
Author(s):  
Duseong S. Jo ◽  
Rokjin J. Park ◽  
Jaein I. Jeong ◽  
Gabriele Curci ◽  
Hyung-Min Lee ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Radiative Forcing ◽  
Transport Model ◽  
Geometric Mean ◽  
Single Scattering ◽  
Single Scattering Albedo ◽  
Geometric Standard Deviation ◽  
Physical Parameters ◽  
Chemical Transport Model ◽  
Aerosol Mass

Abstract. Single Scattering Albedo (SSA), the ratio of scattering efficiency to total extinction efficiency, is an essential parameter used to estimate the Direct Radiative Forcing (DRF) of aerosols. However, SSA is one of the large contributors to the uncertainty of DRF estimations. In this study, we examined the sensitivity of SSA calculations to the physical properties of absorbing aerosols, in particular, Black Carbon (BC), Brown Carbon (BrC), and dust. We used GEOS-Chem 3-D global chemical transport model (CTM) simulations and a post-processing tool for the aerosol optical properties (FlexAOD). The model and input parameters were evaluated by comparison against the observed aerosol mass concentrations and the Aerosol Optical Depth (AOD) values obtained from global surface observation networks such as the global Aerosol Mass Spectrometer (AMS) dataset, the Surface Particulate Matter Network (SPARTAN), and the Aerosol Robotic Network (AERONET). The model was generally successful in reproducing the observed variability of both the Particulate Matter 2.5 μm (PM2.5) and AOD (R ~ 0.76) values, although it underestimated the magnitudes by approximately 20 %. Our sensitivity tests of the SSA calculation revealed that the aerosol physical parameters, which have generally received less attention than the aerosol mass loadings, can cause large uncertainties in the resulting DRF estimation. For example, large variations in the calculated BC absorption may result from slight changes of the geometric mean radius, geometric standard deviation, real and imaginary refractive indices, and density. The inclusion of BrC and observationally-constrained dust size distributions also significantly affected the SSA, and resulted in a remarkable improvement for the simulated SSA at 440 nm (bias was reduced by 44–49 %) compared with the AERONET observations. Based on the simulations performed during this study, we found that the global aerosol direct radiative effect was increased by 10 % after the SSA bias was reduced.

scholarly journals Characterization of ambient aerosols in Mexico City during the MCMA-2003 campaign with Aerosol Mass Spectrometry – Part I: quantification, shape-related collection efficiency, and comparison with collocated instruments

2005 ◽  
Vol 5 (3) ◽  
pp. 4143-4182 ◽  
Author(s):  
D. Salcedo ◽  
K. Dzepina ◽  
T. B. Onasch ◽  
M. R. Canagaratna ◽  
Q. Zhang ◽  
...  
Keyword(s):  
Mexico City ◽  
Mass Concentration ◽  
Collection Efficiency ◽  
Beam Width ◽  
Soil Mass ◽  
Emission Spectrometry ◽  
Ambient Aerosols ◽  
Pixe Analysis ◽  
Aerosol Mass ◽  
Beam Broadening

Abstract. An Aerodyne Aerosol Mass Spectrometer (AMS) was deployed at the CENICA Supersite, while another was deployed in the Aerodyne Mobile Laboratory (AML) during the Mexico City Metropolitan Area field study (MCMA-2003) from 31 March–4 May 2003 to investigate particle concentrations, sources, and processes. This is the first of a series of papers reporting the AMS results from this campaign. The AMS provides real time information on mass concentration and composition of the non-refractory species in particulate matter less than 1 µm (NR-PM1) with high time and size-resolution. For the first time, we report field results from a beam width probe, which was used to study the shape and mixing state of the particles and to quantify potential losses of irregular particles due to beam broadening inside the AMS. Data from this probe show that no significant amount of irregular particles was lost due to excessive beam broadening. A comparison of the CENICA and AML AMSs measurements is presented, being the first published intercomparison between two quadrupole AMSs. The speciation, and mass concentrations reported by the two AMSs compared relatively well. The differences found are likely due to the different inlets used in both instruments. In order to account for the refractory material in the aerosol, we also present measurements of Black Carbon (BC) using an aethalometer and an estimate of the aerosol soil component obtained from Proton-Induced X-ray Emission Spectrometry (PIXE) analysis of impactor substrates. Comparisons of AMS + BC + soil mass concentration with other collocated particle instruments (a LASAIR Optical Particle Counter, a Tapered Element Oscillating Microbalance (TEOM) and a DustTrak Aerosol Monitor) are also presented. The comparisons show that the AMS + BC + soil mass concentration during MCMA-2003 is a good approximation to the total PM2.5 mass concentration.

scholarly journals Retrieval of Vertical Mass Concentration Distributions—Vipava Valley Case Study

2019 ◽  
Vol 11 (2) ◽  
pp. 106 ◽  
Author(s):  
Longlong Wang ◽  
Samo Stanič ◽  
Klemen Bergant ◽  
William Eichinger ◽  
Griša Močnik ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Mass Concentration ◽  
Mineral Dust ◽  
Small Scale ◽  
Vertical Profiles ◽  
Total Uncertainty ◽  
Aerosol Mass ◽  
Aerosol Mass Concentration ◽  
Aerosol Types

Aerosol vertical profiles are valuable inputs for the evaluation of aerosol transport models, in order to improve the understanding of aerosol pollution ventilation processes which drive the dispersion of pollutants in mountainous regions. With the aim of providing high-accuracy vertical distributions of particle mass concentration for the study of aerosol dispersion in small-scale valleys, vertical profiles of aerosol mass concentration for aerosols from different sources (including Saharan dust and local biomass burning events) were investigated over the Vipava valley, Slovenia, a representative hot-spot for complex mixtures of different aerosol types of both anthropogenic and natural origin. The analysis was based on datasets taken between 1–30 April 2016. In-situ measurements of aerosol size, absorption, and mass concentration were combined with lidar remote sensing, where vertical profiles of aerosol concentration were retrieved. Aerosol samples were characterized by SEM-EDX, to obtain aerosol morphology and chemical composition. Two cases with expected dominant presence of different specific aerosol types (mineral dust and biomass-burning aerosols) show significantly different aerosol properties and distributions within the valley. In the mineral dust case, we observed a decrease of the elevated aerosol layer height and subsequent spreading of mineral dust within the valley, while in the biomass-burning case we observed the lifting of aerosols above the planetary boundary layer (PBL). All uncertainties of size and assumed optical properties, combined, amount to the total uncertainty of aerosol mass concentrations below 30% within the valley. We have also identified the most indicative in-situ parameters for identification of aerosol type.

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