Session B – Enhancing health, safety and the environment

Session chair: Annarita Baldan, VSL (NL)

The session “Enhancing health, safety and the environment” will take place on Tuesday 18 June 2019 with the following lectures:

B.1 – KEYNOTE: A perspective on current standardisation activities in air quality and emissions measurement and implications for gas analysis by Rod Robinson, NPL and Chair CEN/TC 264 (GB)

Achieving reliable and comparable measurements of air quality and air emissions is underpinned by the use of international standardised methods. This talk will provide an overview of current activities in CEN technical committee ‘Air quality’ (CEN/TC 264). This TC is responsible for all European standards related to the measurement of air quality and emissions into the atmosphere. It is a very active TC with 25 active working groups currently developing nearly 30 different standards. The talk will outline the current work programme and the framework in which current standards work together to ensure traceable and comparable measurements are achievable to meet regulatory needs. The international context in which CEN/TC 264 fits will also be described and the interactions with other standardisation bodies, such as ISO committees will be described. In addition, some outputs of current research programmes in the EMPIR European metrology research programme will be given, in particular those which are developing improved gas measurement methods and assessing the performance of current standard methods. A review of future drivers for standardisation and research needs will be covered and upcoming standardisation activities will be described. The implications of these regulatory drivers on future gas analysis needs will be discussed including new measurement targets and emerging regulated compounds.

B.2SI traceability and scales for greenhouse gas measurements and standards by Robert Wielgosz, BIPM (FR)

The presentation will describe and contrast approaches, scale based and SI traceable, used in developing gas standards that can be used for the monitoring of atmospheric greenhouse gases and notably CO2, CH4 and N2O, and the progress that is being made to have fully SI traceable reference systems to allow global monitoring networks to achieve long term consistency of their measurements at the 0,1 μmol/mol, 2 μmol/mol, and 0,1 nmol/mol respectively for the gases mentioned previously. Improvements in comparison methods that have allowed CO2 in air standards to be value assigned with relative standard uncertainties of 0,01% will be described, including the requirement to measure and correct for differences in isotope ratios. In addition, progress in developing a manometric system, as the basis of an on-going comparison of CO2 in air standards worldwide (BIPM.QM-K2) will be presented. The presentation will conclude with the progress required to fully harmonize approaches on standards and the target uncertainties for greenhouse gas standard comparisons planned for 2019 (N2O), 2022 (CO2) and 2023 (CH4).

B.3Comparable measurements for mercury concentrations in gas emission sources and the atmosphere by Iris de Krom, VSL (NL)

A primary mercury vapour generator was developed at VSL to establish a traceable measurement standard for mercury concentrations in gas emission sources and in atmosphere. The majority of mercury concentration measurements are currently traceable to the vapour pressure of mercury. The primary mercury vapour generator contributes to comparable measurement results of mercury concentration in air and is especially important for certification of services related to ambient air monitoring (1 ng Hg/m3 – 2 ng Hg/m3), indoor and work place related mercury concentration levels according to health standards (from 50 ng Hg/m3 upwards) as well as to stationary source emissions (from 1 µg Hg/m3 upwards). During GAS Analysis 2017 the development and working principle of the primary mercury vapour generator, based on diffusion according to ISO 6154-8, was presented. In this paper, we present the full characterisation of the mercury diffusion using diffusion cells generating 1,4 ng Hg/min and 70 ng Hg/min. Furthermore, the results are presented of comparisons with current calibration facilities maintained by National Metrology Institutes (NMIs), Designated Institutes (DIs) and companies. For the comparisons different types of sorbents were loaded with mercury to obtain transfer standards with levels between 2 ng and 1 000 ng. Apart from its elemental form, mercury also occurs in oxidized forms in the environment. These forms are reactive and can be transformed into species such as methylmercury, the most toxic mercury species because of its bioaccumulation in aquatic systems. Within the European “Metrology for oxidised mercury” project the primary standard is used to establish a traceable calibration methodology for the most important oxidised mercury-containing species, especially for HgCl2. A concise overview and the first results are presented.

B.4Advances in underpinning measurements of nitrogen dioxide to understand population level by Sivan van Aswegen, NPL (GB)

Nitrogen dioxide (NO2) is one of the most important trace gases in the atmosphere influencing both climate and air quality. More accurate measurements of NO2 are needed to understand population level exposure, improve air quality models and emission inventories and to enforce air quality and vehicle emission legislation. This is essential for the timely evaluation of air pollution mitigation policies, and to improve our understanding of the influence of anthropogenic emissions on the climate system. Measurement accuracy is strongly dependent on the analytical methods employed and on the quality of the calibration gases used. Currently, NO2 is the only regulated air pollutant that is not directly measured or calibrated, being converted and detected as nitrogen monoxide (NO) using the chemiluminescence method. However, direct NO2 measurements are now possible due to recent advances in laser spectroscopy creating an urgent requirement for NO2 primary reference materials (PRMs). Stable and high accuracy static PRMs of NO2 are challenging to produce due to the high reactivity of NO2, especially with respect to water vapour. To achieve a low level of uncertainty for low amount fraction mixtures (1 – 10 µmol/mol), impurities must be fully characterised and the presence of water vapour minimised during preparation. Here we present recent advancements in the preparation of NO2 PRMs including the characterisation and evolution of key impurities using Fourier transform infrared spectroscopy (FTIR) and methods to minimise the presence of water vapour in the cylinder, cylinder valve, filling lines and matrix gases.

B.5Impurities in gases and gas mixtures: metals and bacteria by Giorgio Bissolotti, SIAD (IT)

Gases have been sold for long time considering only the gaseous impurities specification. This type of specification is useful for usual application, but for special or new applications more information about other impurities are needed. The main impurities that are of interest in electronic applications since long time are the level of metals content, while for food industry and pharmaceutical and medical field, in addition to metals, the presence of bacteria are now more and more requested. In the last years, there was an increase of requests by the final users to have knowledge of the concentration of metals and to have specification for the number of bacteria presence. This increase of requests was due to both new special uses in which the gases are used and compliance with new standard. In the study, the results of hundreds of analysis on the more usual gases (oxygen, air; nitrogen, carbon dioxide) are presented. The experimental results cover many years of gases controls. The results obtained up to now allow identifying the range of this impurities that can be expected. Knowing this concentration, the user can introduce some purifier, or different solutions, if lower concentrations are needed in its process. As the analyses of metals and bacteria are quite difficult, because of their low concentration, some specific sample methods have been prepared to have the repeatability of the results. In particular, some test to establish the ability of the recovery of added concentration of bacteria was performed and, thus, obtain a validation of the method used. These methods are shortly described. Finally, some problems in this field remain still open, like how to have quick results. The paper will summarise what should be improved in the next future.

B.6TDLAS NH3 and HF measurement to improve life quality by David Janssens, Siemens (DE)

Coming from the world of process control gas analyzers, Siemens devices perform not only gas measurements to monitor and improve processes but also provide very robust and reliable devices for continuous emissions monitoring. The tunable diode laser absorption spectroscopy (TDLAS) technology, of which Siemens is a pioneer back in the 90’s, provides the most stable, reliable, accurate and sensitive, in situ gas concentrations measurement in this field. Many applications, among which within fertilizer DAP and phosphoric acid plant, are served by this technology. The measurement of NH3 and HF for instance, in di-ammonium phosphate production facility, leads to improvement of the process efficiency, bringing a great impact on savings and on the neighbourhood environment. This way of measuring initiates a virtuous circle concept, which by improving the process efficiency, improves the emission values, keeping them lower than the emissions limit values allowed by the local authorities.

B.7Development of a long-range, open-path ammonia analyzer based on novel, mid-infrared laser spectroscopy by Mohammed Belal, MIRICO (GB)

We present the development and field demonstration of a monitoring system fulfilling the needs for analyzing ammonia. The instrument technology provides long-range multi-beam open path concentration analysis, using mid-infrared laser light. The sensor is based on laser dispersion spectroscopy (LDS): a new approach to tuneable laser spectroscopy delivering unique benefits for long open-path molecular sensing. Contrary to optical absorption techniques, LDS derives concentrations from the variation in refractive index induced by molecular resonance. The instrument effectively measures phase variations of light, which yields unique open-path sensing benefits: a) strong immunity to light intensity fluctuations, b) large and linear measurement dynamic range, and c) improved molecular selectivity. These instrument-level benefits deliver key advantages for long-open path sensing in turbid and particulate-loaded atmospheres (e.g. rain, fog, snow) and detecting dispersing gas, including complex molecular mixtures. The LDS sensor was evaluated in field tests using an extensive series of calibrated test releases of methane. The instrument is coupled to an array of 7 retroreflectors providing a fan of beams of different lengths. Each open-path beam is sequentially measured over ~0,1 second using an angular stepping motor mounted mirror. The precision of CH4 concentration measurements was found to be ~20 ppbv in 100 ms over a ~100 m single open path. Applying an inverse solver method to the multiple open path-integrated temporal records of CH4 concentration and associated wind velocity data, we were able to recover the source emission rates and locations for 4 separate source patterns over the ~120 m x 120 m test area. Accurate mapping and quantification of methane sources down to 1,2 kg/h was successfully demonstrated, even for sources outside the open path fan.

B.8Photonic system for real time remote monitoring of air quality by Rao Tatavarti, CATS Ecosytems (IN)

Conventional air pollution monitoring at a single location involves measurements by a suite of sensors having different technologies from different manufacturers – integrated and housed in a rather bulky shipping container. The monitoring of air pollution at a single location with the disparate sensors of varying sensitivities, accuracies and temporal responses not only poses significant challenges in data acquisition and assimilation, but also involves significantly high costs in order to arrive at digestible information for researchers, policy makers as well as the common public. Against this backdrop, we designed and developed a compact photonic system capable of remote real-time monitoring of various air pollutants in situ – either at a particular location or across a spatial domain of interest. The photonic system was designed and developed using COTS (commercially-off-the-shelf) technologies, making it significantly cheaper for wider deployment, in sync with the WHO’s roadmap. The uniqueness and novelty of the system lies in its ability to innovatively apply the concepts of laser back scattering, artificial intelligence and machine (deep) learning to identify, classify and quantify various air pollutants simultaneously. The photonic system was extensively evaluated in the laboratory as well as in the field, and was found to be good; yielding air quality estimates at very high sampling frequencies with high sensitivity and accuracy. The system is now ready for commercialization. The authors will present the pertinent technical aspects and capabilities of the novel photonic system along with the results of validation experiments conducted with calibrated gases at EffecTech India – to demonstrate the efficacy and sensitivity of the system for real-time remote monitoring of all pollutants.

B.9Improved PTR-TOF sensitivities open new scenarios in breath analysis by Luca Cappellin, University of Padua and Tofwerk (IT)

Proton transfer reaction – mass spectrometry (PTR-MS) is a well-known technique for the monitoring of volatile organic compounds (VOCs). Particularly if coupled to a time-of-flight detector (PTR-TOF) it provides enough speed for real-time breath analysis. However, breath analysis represents a real challenge in terms of detection limits (LODs), separation power, and humidity dependence of calibration factors. VOCs in the breath are a complex mixture and can be present at concentrations not detectable with standard PTR-TOF. Thanks to a new concept of the PTR reaction cell (denominated VOCUS PTR), ion losses caused by scattering and diffusion are avoided. This is achieved by superimposing an oscillating field to the typical static field in the reaction cell. Ions are not only moved along the cell as in conventional PTR, but are also focused. The VOCUS PTR technology has been coupled to a state-of-the-art TOF detector having mass resolving power R > 12 000. The new development leaded to a PTR-TOF sensitivity gain and a LOD improvement of more ten folds. Previous boundaries in LODs are therefore overcome. Ion fragmentation is not significantly changed and the humidity dependence of sensitivity is eliminated. Levels of N-Methyl-2-pyrrolidone as low as 10 pptv were detected in 0,2 second (5 Hz) time resolution measurements in previously exposed people. VOCUS PTR-TOF is a new concept for real-time breath analysis having lower LODs, improved sensitivity, better mass resolving power and no dependence on humidity compared to any other PTR-TOF currently available, while maintaining all other features of PTR-TOF unaffected.

B.10Developing metrology capabilities to underpin breath analysis in the medical sector by Sergi Moreno, NPL (GB)

The studies in the area of breath analysis have grown considerably in the recent years due to the development of new analytical instruments such as proton reaction mass spectrometry (PTR-MS), selective ion flow mass spectrometry (SIFT-MS) and secondary electrospray ionisation spectrometry (SESI-MS). Analysis of volatile organic compounds (VOC) in exhaled breath is a non-invasive technique that has the potential to revolutionise the early diagnosis of diseases as well as optimising many medical treatments and care programmes and is an area of great social and economic impact. However, the lack of standardisation is a barrier to the adoption of breath tests into clinical practice. Widespread diversity in sampling and measurement methods and the lack of reference materials contribute to the poor comparability of clinical trial results, which inhibits the verifiable identification of VOC biomarkers. Recent recognition that variation in amount fraction of biomarkers is more important than qualitative detection of unique markers also drives the requirement for more accurate quantitation. The National Physical Laboratory (NPL) maintains primary reference materials (PRMs) that sit at the top of the traceability chain with the smallest uncertainties. It is only by comparison of these primary realisations of the mole with other National Metrology Institutes (NMIs) and Designated Institutes (DIs) around the world, using the measurement redundancy that this provides, that the full uncertainty of the realisation can be achieved. We present developments at NPL in static and dynamic generation of reference materials for underpinning diagnostic devices and a breath simulator that mimics the transient composition of human breath. These developments will make a significant impact on the breath analysis community and will enable the introduction of a bank of breath analysis data, bringing reliability and confidence from measurement. 

B.11Fastest refinery gas analysis and new innovative sulfur chemiluminescence detector first in industry horizontal redox cell by Raj Makhamale,  Shimadzu (AE)

Analysis of sulfur has always been challenging in the hydrocarbon processing industry. There are various detection techniques used like FPD, PFPD, AED and SCD. Among all SCD is the most suitable detector due to its very high sensitivity, equimolar response and minimum or no quenching effect. But the challenges with SCD’s available is the maintenance, changes in response which requires frequent calibration, and not complete burning of components in plasma. The new innovative design of Shimadzu SCD-2030 detector overcomes these problems. This SCD consist industries first adaptation of horizontal redox cell, which accelerates the redox reactions and allows enough path lengths for burning the components. This gives rise to best detection limits among all SCD’s. Also, horizonal position allows use of short transfer line preventing unstable SO to convert to SO2. The overall design consideration maintains the stability of detector over much longer period than currently available SCD’s.

 

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