Inter-comparison of thermal and optical methods for determination of atmospheric black carbon and attenuation coefficient from an urban location in northern India

Abstract. We have used two methods for measuring emission factors (EFs) in real driving conditions on five cars in a controlled environment: the stationary method, where the investigated vehicle drives by the stationary measurement platform and the composition of the plume is measured, and the chasing method, where a mobile measurement platform drives behind the investigated vehicle. We measured EFs of black carbon and particle number concentration. The stationary method was tested for repeatability at different speeds and on a slope. The chasing method was tested on a test track and compared to the portable emission measurement system. We further developed the data processing algorithm for both methods, trying to improve consistency, determine the plume duration, limit the background influence and facilitate automatic processing of measurements. The comparison of emission factors determined by the two methods showed good agreement. EFs of a single car measured with either method have a specific distribution with a characteristic value and a long tail of super emissions. Measuring EFs at different speeds or slopes did not significantly influence the EFs of different cars; hence, we propose a new description of vehicle emissions that is not related to kinematic or engine parameters, and we rather describe the vehicle EF with a characteristic value and a super emission tail.

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Determination of black carbon, PM2.5, particle number and NOx emission factors from roadside measurements and their implications for emission inventory development

Atmospheric Environment ◽

10.1016/j.atmosenv.2018.05.042 ◽

2018 ◽

Vol 186 ◽

pp. 229-240 ◽

Cited By ~ 22

Author(s):

Patricia Krecl ◽

Admir Créso Targino ◽

Thiago Pereira Landi ◽

Matthias Ketzel

Keyword(s):

Black Carbon ◽

Emission Inventory ◽

Particle Number ◽

Emission Factors ◽

Nox Emission ◽

Inventory Development

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Development and Validation of Optical Methods for Zeta Potential Determination of Silica and Polystyrene Particles in Aqueous Suspensions

Materials ◽

10.3390/ma14020290 ◽

2021 ◽

Vol 14 (2) ◽

pp. 290

Author(s):

Yannic Ramaye ◽

Marta Dabrio ◽

Gert Roebben ◽

Vikram Kestens

Keyword(s):

Zeta Potential ◽

Particle Tracking ◽

Colloidal Stability ◽

Optical Methods ◽

Intermediate Precision ◽

Electrophoretic Light Scattering ◽

Measurement Uncertainties ◽

Development And Validation ◽

Direct Implementation

Zeta potential is frequently used to examine the colloidal stability of particles and macromolecules in liquids. Recently, it has been suggested that zeta potential can also play an important role for grouping and read-across of nanoforms in a regulatory context. Although the measurement of zeta potential is well established, only little information is reported on key metrological principles such as validation and measurement uncertainties. This contribution presents the results of an in-house validation of the commonly used electrophoretic light scattering (ELS) and the relatively new particle tracking analysis (PTA) methods. The performance characteristics were assessed by analyzing silica and polystyrene reference materials. The ELS and PTA methods are robust and have particle mass working ranges of 0.003 mg/kg to 30 g/kg and 0.03 mg/kg to 1.5 mg/kg, respectively. Despite different measurement principles, both methods exhibit similar uncertainties for repeatability (2%), intermediate precision (3%) and trueness (4%). These results confirm that the developed methods can accurately measure the zeta potential of silica and polystyrene particles and can be transferred to other laboratories that analyze similar types of samples. If direct implementation is impossible, the elaborated methodologies may serve as a guide to help laboratories validating their own methods.

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XXV.—The Determination of Temperature Gradients over the Greenland Ice Sheet by Optical Methods

Proceedings of the Royal Society of Edinburgh Section A Mathematical and Physical Sciences ◽

10.1017/s0080454100007597 ◽

1957 ◽

Vol 64 (4) ◽

pp. 381-397

Author(s):

R. A. Hamilton

Keyword(s):

Temperature Gradient ◽

Ice Sheet ◽

Greenland Ice Sheet ◽

Temperature Gradients ◽

Lower Atmosphere ◽

Optical Methods ◽

Snow Surface ◽

Vertical Angle ◽

Gradient Measurements

SynopsisThe temperature gradient in the lower atmosphere can be directly determined by measuring the optical refractive index of the air. This method is suitable for use on the Greenland ice sheet where errors introduced by water vapour are small, and where the strong solar radiation reflected by the snow surface makes it difficult to measure temperature differences over height differences of about I metre.The refraction was measured by observing the apparent vertical angle of each of a set of targets at distances up to 4 km. from a theodolite. The refraction was found to vary linearly with the distance of the target. The true vertical angle to the targets was determined when a second theodolite was available and reciprocal sights could be taken with it from the site of target to the fixed theodolite. The true vertical angle varied with time due to slow descent of the theodolite as the firn slumped; a correction for this was made. The standard error of the temperature gradient measurements was about 1.5 × 10−2 C.° per metre. It is considered that the method could be developed and improved so that over a range of only 100 metres temperature gradients could be measured to an accuracy of about 0·1° C. per metre.

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Supplementary material to "The determination of highly time resolved and source separated black carbon emission rates using radon as a tracer of atmospheric dynamics"

10.5194/acp-2019-911-supplement ◽

2019 ◽

Author(s):

Asta Gregorič ◽

Luka Drinovec ◽

Irena Ježek ◽

Janja Vaupotič ◽

Matevž Lenarčič ◽

...

Keyword(s):

Black Carbon ◽

Carbon Emission ◽

Atmospheric Dynamics ◽

Emission Rates ◽

Time Resolved ◽

Supplementary Material

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Determination of Mass Attenuation Coefficient for some Technetium‐99m Compounds

Macromolecular Symposia ◽

10.1002/masy.202000095 ◽

2020 ◽

Vol 393 (1) ◽

pp. 2000095

Author(s):

A. Manjunath ◽

A. Ashwini ◽

B. R. Kerur ◽

G. M. Pushpanjali

Keyword(s):

Attenuation Coefficient ◽

Mass Attenuation Coefficient ◽

Technetium 99M ◽

Mass Attenuation

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Field test of available methods to measure remotely SO<sub>x</sub> and NO<sub>x</sub> emissions from ships

Atmospheric Measurement Techniques ◽

10.5194/amt-7-2597-2014 ◽

2014 ◽

Vol 7 (8) ◽

pp. 2597-2613 ◽

Cited By ~ 24

Author(s):

J. M. Balzani Lööv ◽

B. Alfoldy ◽

L. F. L. Gast ◽

J. Hjorth ◽

F. Lagler ◽

...

Keyword(s):

Field Studies ◽

Emission Factors ◽

Sulphur Content ◽

Nox Emission ◽

Optical Methods ◽

Optical Absorption Spectroscopy ◽

Open Sea ◽

Remote Measurements ◽

Convenient Technique

Abstract. Methods for the determination of ship fuel sulphur content and NOx emission factors based on remote measurements have been compared in the harbour of Rotterdam and compared to direct stack emission measurements on the ferry Stena Hollandica. The methods were selected based on a review of the available literature on ship emission measurements. They were either optical (LIDAR, Differential Optical Absorption Spectroscopy (DOAS), UV camera), combined with model-based estimates of fuel consumption, or based on the so called "sniffer" principle, where SO2 or NOx emission factors are determined from simultaneous measurement of the increase of CO2 and SO2 or NOx concentrations in the plume of the ship compared to the background. The measurements were performed from stations at land, from a boat and from a helicopter. Mobile measurement platforms were found to have important advantages compared to the land-based ones because they allow optimizing the sampling conditions and sampling from ships on the open sea. Although optical methods can provide reliable results it was found that at the state of the art level, the "sniffer" approach is the most convenient technique for determining both SO2 and NOx emission factors remotely. The average random error on the determination of SO2 emission factors comparing two identical instrumental set-ups was 6%. However, it was found that apparently minor differences in the instrumental characteristics, such as response time, could cause significant differences between the emission factors determined. Direct stack measurements showed that about 14% of the fuel sulphur content was not emitted as SO2. This was supported by the remote measurements and is in agreement with the results of other field studies.

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