Odour Measurement Research Articles

Detection and measurement of aroma compounds with the electronic nose and a novel method for MOS sensor signal analysis during the wheat bread making process

Characteristic aroma compounds are emitted in each of the three main stages of bread production. The present study consisted in detection and measurement of odors emitted during the dough fermentation and bread baking processes with use of metal oxide (MOS) sensors and identification of aroma compounds using gas chromatography coupled with mass spectrometry (GC-MS). The generated sensorgrams were analyzed using a new determination method based on three parameters read from the sensorgram. Groups of volatile compounds characteristic for the dough fermentation stage, i.e. alcohols, aldehydes, esters, ketones, acids, for the baking process, i.e. pyridines, hydrocarbons, amides, were determined. The investigations and statistical analysis of the results revealed the responses of the electronic nose and its potential to be used for detection of volatile organic compounds generated during bread production. The study indicates that the use of three sensorgram parameters yields precise identification of the type and stage of the process.

Development of a Mobile Device for Odor Identification and Optimization of Its Measurement Protocol Based on the Free-Hand Measurement.

Practical applications of machine olfaction have been eagerly awaited. A free-hand measurement, in which a measurement device is manually exposed to sample odors, is expected to be a key technology to realize practical machine olfaction. To implement odor identification systems based on the free-hand measurement, the comprehensive development of a measurement system including hardware, measurement protocols, and data analysis is necessary. In this study, we developed palm-size wireless odor measurement devices equipped with Membrane-type Surface stress Sensors (MSS) and investigated the effect of measurement protocols and feature selection on odor identification. By using the device, we measured vapors of liquids as odor samples through the free-hand measurement in different protocols. From the measurement data obtained with these protocols, datasets of transfer function ratios (TFRs) were created and analyzed by clustering and machine learning classification. It has been revealed that TFRs in the low-frequency range below 1 Hz notably contributed to vapor identification because the frequency components in that range reflect the dynamics of the detection mechanism of MSS. We also showed the optimal measurement protocol for accurate classification. This study has shown a guideline of the free-hand measurement and will contribute to the practical implementation of machine olfaction in society.

The influence of the methods of measuring odours nuisance on the quality of life

Quality of life in urban space has become an increasingly common problem arising from cooperation between various stakeholders, especially in the context of increasing odour nuisance. That is why it is extremely important to know and shape the expectations and perceptions of residents regarding quality of life by accepting the place of residence, especially in the context of the development of cities and urban areas.The analysis of the previous research has revealed a research gap that results from the imperfections of existing odour measurement methods and the lack of an objective measurement methodology that would allow for objectification of the subjective feelings of people to the extent of perception of unpleasant odours.The purpose of this article is to verify the hypothesis about the possibility of objectifying the assessment of odour nuisance based on the comparison of quantitative research results based on the opinions of residents and sensory tests. The specific objective is to verify residents' assessments of odour nuisance by an expert team and identify a gap in those assessments.The analysis of discrepancies gives the opportunity to identify the imperfections of various research methods and look for ways to improve them. The analysis of compliance of results, on the other hand, gives the opportunity to objectify measurements and build a methodology that may be used for the purpose of assessing odour nuisance by various stakeholders.Systematic measurement of odours in a public space may serve the basis for resolving local conflicts, creating maps of odour nuisance, assessing the attractiveness of places to live, work, spending free time and tourist value, as well as conscious actions of public authorities in shaping local policies in a specific area.

Determination of rainbow trout quality parameters with Arduino microcontroller

AbstractIn this study, the rainbow trout was stored under refrigeration conditions (3 ± 1°C) for 18 days. Changes in the resistance levels in head, meat and eyes, changes of color in the head and meat, changes of liquid levels in the skin and meat, and odor values in the head and the meat were measured with Arduino microcontroller card and recorded during the storing period. In order to perform a significant comparison with the data obtained via Ardunio, the total viable count, psychrotrophic count and Enterobacteriaceae count in the fish meat were identified on a daily basis during storage. The results of the study indicated that the resistance value on the meat decreased significantly as the storage period increased; and that the Arduino‐based color, odor and liquid level measurement sensors could be used effectively in identifying the food quality.

OVERVIEW OF ODOUR MEASUREMENT METHODS: THE ODOUR OBSERVATORY AS AN INFORMATIVE TOOL FOR CITIZEN SCIENCE BASED APPROACHES TO ODOUR MANAGEMENT

Odour pollution is a well-known problem related to a number of different industrial activities. It is also one of the main causes of citizens’ complaints to local authorities. Specific programs are needed to manage persistent odour pollution problems within communities in order to avoid possible socio-environmental conflicts. The H2020 project D-NOSES (Distributed Network for Odour Sensing, Empowerment and Sustainability) aims to help citizens co-create local solutions in collaboration with industries, regional & local authorities, and odour experts. The project will develop an innovative bottom-up approach to odour pollution governance by combining citizen science and stakeholder management methods using a quadruple helix model. The first aim of this article is to introduce the D-NOSES project and its methodology. Aside from that, the article presents an overview of the existing odour impact assessment methods currently available to quantify odour pollution. Finally, the different odour measurement methods are compared in terms of their applicability and limitations. This overview will be made available online as a first step towards the development of the International Odour Observatory, a platform to be created within the D-NOSES project to help promote odour pollution management and resolve regulation issues. The platform will become a global resource on odour issues and also include information about odour abatement systems, chemical substances in odour emissions, and odour regulations around the world.

악취배출시설주변 지역주민의 인식조사와 해결방안 연구

This study researched the odor influence of the areas where most of cement factories and lime manufacturing facilities were located. This study investigated the solutions for odor complaints by analyzing statistically the perception of odor based on a survey for residents around the areas. Specifically, the less they perceived odor, the more they trust either an odor measurement institute or a current law/policy regarding odor. On the other hands, the more sensitive to odor they became with the more experience and damage perception they have. This is because, being exposed to various environmental contamination such as water, soil and atmosphere, the residents were motivated to get concerned about environmental damage due to odor contamination. Such phenomenon confirmed that they perceived odor much less than expected through the processes in which environmental and administrative authorities made their endeavor to decrease odor generated by odor-emission facilities for local residents’public welfare.

Dispersion modeling and air quality measurements to evaluate the odor impact of a wastewater treatment plant in İzmir

Municipal wastewater treatment plants (WTP) are potential sources of offensive odors that can create annoyance in the communities. Therefore, odors have been rated as the primary concern of the public relative to the implementation of wastewater treatment facilities. In this study, dispersion modeling and air quality measurements were used to quantify the potential odor impact around a Wastewater Treatment Plant in İzmir. AERMOD atmospheric dispersion model was used to predict odor levels in OU/m3 around the treatment plant. Odor measurement results of the wastewater treatment plant units that are considered as area odor sources were used for odor modeling. Air quality measurements of H2S and NH3, which are two main odorous compounds emitted from wastewater treatment plants, were also conducted by using passive sampling methodology in the surroundings of the plant to evaluate the odor impact of the plant. Both odor emission and air quality measurements were conducted in the period of July–august 2018 for evaluation of odor impact, and consequent application of dispersion model. The air quality measurements of the pollutants which exceed the odor threshold values do not create annoying odor impact on residential areas. The dispersion modeling demonstrates that the odor concentrations exceeding 10 OU/m3 concentration levels that can be measured olfactometrically also do not create an odor impact on local residents.

Bad Breath (Halitosis): Narrative Overview

Halitosis is a health condition associated with an unpleasant odor from the oral cavity. The origin of bad breath may be related to systemic and oral conditions, but the large percentage of cases (about 85%) are related to oral factors. Because of its personal nature it can cause social embarrassment and psychological distress. Different society culture diverges acutely starts from those who believe that bad breath is genetically determined to those who turn to use crude scented items or over-the-counter products to camouflage the bad breath to others who consider the bad breath condition taboo subject finds it difficult to discuss or considered a private matter. The measurement of odors will not be as long as Corona is before Corona. Advanced dental clinics and also younger adults are newly equipped with many types of digital halite-testing devices and mobile phone applications making the diagnosis easy, safe and time-consuming. A Halitus patient initially visits the general dental practitioner for the betterment of the condition and here the responsibility lies on the dentists to diagnose and manage the condition. Treatment program must therefore address educative, preventive, curative and symptomatic line. In this review article we tried to highlight the bad breath condition and illustrate definitions, terminology, prevalence, etiology, classification, new measurement methods and management protocols.

Definition and Application of a Protocol for Electronic Nose Field Performance Testing: Example of Odor Monitoring from a Tire Storage Area

Odor pollution is nowadays recognized as a serious environmental concern. Italy still lacks a national regulation about odors, but several regions issued specific guidelines and regulations regarding odor emissions management, which combine olfactometric measurements with dispersion modeling for assessing odor impacts and verifying compliance with acceptability criteria. However, in cases of variable or diffuse sources, this approach is sometimes hardly applicable, because odor emission rates can hardly be estimated. In such cases, electronic noses, or more generally, Instrumental Odor Monitoring Systems (IOMS), represent a suitable solution for direct odor measurement. Accordingly, IOMS are explicitly mentioned in the most recent regional regulations as advanced tools for odor impact assessment. In Italy, data from instrumental odor monitoring have started to have regulatory value; thus the need arises to have specific quality programs to ensure and verify the reliability of IOMS outcomes. This paper describes the monitoring by a commercial electronic nose (EOS507F) of odors from an area dedicated to tire storage, a diffuse source with variable emissions over time, for which dispersion modeling is not applicable. The paper proposes also a protocol for IOMS performance testing in the field, to provide experimental data to support technical groups working on standardization both on the national and European level.

A Study of Odor Measurement Method Using Olfactory in the Field

A Study of Odor Measurement Method Using Olfactory in the Field

A Collaborative Approach between Japan and China for Implementing Interlaboratory Evaluation of Olfactometry

Odor measurement is a crucial element of odor management and regulation. This paper introduced a collaborative implementation of interlaboratory evaluation of olfactometry between Japan and China. An international comparison of olfactometry using the triangular odor bag method was carried out for the first time between Japan and China in 2018. A total of 134 olfactometry laboratories (130 Japanese and 4 Chinese) participated in the test, and the odor index of the test odorant (dimethyl disulfide with a concentration of 10.7 ppm) was measured three times at each laboratory. In the interlaboratory evaluation, a reference value and repeatability and reproducibility standard deviations were determined on the basis of measurement results of 13 ‘excellent qualified laboratories’ designated by the Japan Association on Odor Environment. Evaluation results of trueness and precision of the 133 laboratories that conducted duplicate or triplicate measurements showed that 110 (108 Japanese and 2 Chinese) and 104 (102 Japanese and 2 Chinese) laboratories (82.7% and 78.2%) conformed to the criterion of trueness and precision, respectively, and 87 (86 Japanese and 1 Chinese) laboratories (65.4%) conformed to both. Based on the meaningful experiences in 2018, a continuous international collaboration between Japan and China in the field of olfactometry should be implemented for the improvement of the quality of olfactometry laboratories and the reliability of odor measurement in both countries.

How Can Odors Be Measured? An Overview of Methods and Their Applications

In recent years, citizens’ attention towards air quality and pollution has increased significantly, and nowadays, odor pollution related to different industrial activities is recognized as a well-known environmental issue. For this reason, odors are subjected to control and regulation in many countries, and specific methods for odor measurement have been developed and standardized over the years. This paper, conceived within the H2020 D-NOSES project, summarizes odor measurement techniques, highlighting their applicability, advantages, and limits, with the aim of providing experienced as well as non-experienced users a useful tool that can be consulted in the management of specific odor problems for evaluating and identifying the most suitable approach. The paper also presents relevant examples of the application of the different methods discussed, thereby mainly referring to scientific articles published over the last 10 years.

Ligand-binding assays with OBPs and CSPs.

Assessing the ligand-binding properties of OBPs and CSPs is essential for understanding their physiological function. It also provides basic information when these proteins are used as biosensing elements for instrumental measurement of odors. Although different approaches have been applied in the past to evaluate the affinity of receptors and soluble binding proteins to their ligands, using a fluorescent reporter represents the method of choice for OBPs and CSPs. It offers the advantages of working at the equilibrium, being simple, fast and inexpensive, without requiring the use of radioactive tracers. However, as an indirect method, the fluorescence competitive binding approach presents drawbacks and sometimes requires an elaborate analysis to explain unexpected results. Here, after a brief survey of the different approaches to evaluate affinity constants, we focus on the fluorescence binding assay as applied to OBPs and CSPs, discussing situations that may require closer inspection of the results.

Evaluation of storage bags for odour sampling from intensive pig production measured by proton-transfer-reaction mass-spectrometry

The selection of sampling bags for odour measurement by olfactometry is critical and challenging since the loss of odorants during storage and transportation is usually high. However, there are no recommendations or limitations on the storage time for the standard Triangle odour bag method used in China. In order to optimise the selection of sampling bags, selected types of sampling bags (Fluode, BOPET, FEP and Tedlar) were tested and compared by using selected key odorants (dimethyl sulphide, 2-butanone, 2,3-butanedione, 4-methylphenol, indole, skatole, acetic acid, propanoic acid, butyric acid, valeric acid and hexanoic acid). The concentrations of key odorants were detected by PTR-MS. Firstly, background contamination was tested, with total amount of background pollutants produced by Tedlar being significantly higher than the other three types of sampling bags, while FEP and BOPET had less background contaminants. Secondly, recovery tests showed that the SOAV (sum of odour activity values) recoveries after 24 h of storage of Fluode, Tedlar, FEP and BOPET were 19.5%, 24.2%, 47.7% and 27.7%, respectively. FEP had better recovery than others, especially for the storage of 4-methylphenol (~55% recovery after 48 h), which is one of the key odorants emitted from intensive pig production. Finally, the recovery tests for 2,3-butanedione were performed under various conditions and results indicated that the storage of 2,3-butanedione in sampling bags depends on bag type (e.g. single bags or double bags), initial concentration level (10 ppbv, 100 ppbv or 1000 ppbv), the inner surface area-to-volume ratio and light condition (dark, natural light or LED light).

Report of The 7th National Offensive Odor Measurement and Management Technology Study meeting in China

Report of The 7th National Offensive Odor Measurement and Management Technology Study meeting in China

Measurement of Odour on Source of Drinking Water Using Threshold Odour Number and Modified Olfactometry

Concerns on odour of water have increased rapidly. However, odour measurement in water for drinking sources has yet to be established in Malaysia. More study is needed for an approach to quantify the odour incidences in water supply, one that is effective and applicable as a guideline towards the early identification of contamination occurrences. Thus, the objective of this study was to identify correlation (if any) between Threshold Odour Number (TON) test with a portable olfactometry plus odour wheel (POPOW) combination method for assessing odour in drinking water. Water samples collected from a drinking water supply system was tested for odour concentration as well as its character based on an odour wheel. Results from the Pearson correlation showed that the TON and POPOW gave the r-value of 0.833 which indicates that both method highly correlate with a level of confidence of 99 percent. Sample water that was taken near the main source of drinking water was given off as earthy smell, indicating geosmin as a likely contaminant. On the other hand, treated water samples taken directly at the treatment plant had a distinctive, chlorinous odour, which was expected from it use of chlorine as a disinfectant. This study has demonstrated the effectiveness of the portable olfactometer and odour wheel combination method for detecting odour in drinking water supply with at par results to the standard TON. More importantly, POPOW would enable the assessment of odour at site and at a shorter test preparation time, traits which are important especially for remotely located sites.

Evaluation of Health Hazard Due to Emission of Volatile Organic Compounds from Various Processing Units of Wastewater Treatment Plant.

The paper describes an attempt at health risk assessment and odour concentration determination in the most important units of a wastewater treatment plant. The cancer risk (CR) and hazard index (HI) parameters in selected measurement locations were calculated based on the results of chromatographic analyses (GCxGC-TOF-MS) and the United States Environmental Protection Agency (US EPA) guidelines. No exceedance of the CR and HI acceptable levels was observed for identified and quantitatively determined compounds from the VOCs group. The acceptable level was exceeded for the summary HI parameter. Following a classification of the International Agency for Research on Cancer (IARC), it was noticed that the highest hazard was connected to the presence of formaldehyde belonging to group 1—the compounds regarded as carcinogenic. Based on the olfactometric analyses, it was estimated that the highest odour concentration, 37.2 ou/m3, occurred at the solid waste composting piles. It was also revealed that an increase in odour concentration corresponded to a higher health risk for employees of the wastewater treatment plant, due to exposure to volatile odorous compounds. Accordingly, this method of odour measurement can be a fast indicator describing health risk level.

Heuristic Random Forests (HRF) for Drift Compensation in Electronic Nose Applications

Electronic nose is an instrument equipped with chemical gas sensors and is used to sense, identify, and measure different odors. The problem arises when these sensors incorporate drift by the passage of time. The effect of drift is so adverse that the pattern recognition algorithms used for identification and measurement of odors fail to respond accurately. To overcome the challenge of drift in sensors, one of the most widely used techniques is system re-calibration, which is a cumbersome process. Keeping in mind the challenges of drift and issues of system re-calibration for real-life applications, this paper proposes a novel method to compensate drift in gas sensors with the following contributions: 1) the fitness function of a recursive metaheuristic optimization method is modified by embedding random forests learning for the quantification of six different gases under drift; 2) the proposed approach is able to compensate the long-term sensors drift without requiring any system re-calibration; and 3) the feature vector exploitation using particle swarm optimization reduces the computational complexity and increases the prediction accuracy of the system. A comparison is provided with different state-of-the-art approaches, and the proposed approach is found better in terms of prediction accuracy when tested on a benchmark dataset publically available.

Case study on odour measurements in India

Case study on odour measurements in India

PUBLICZNOPRAWNE FORMY PRZECIWDZIAŁANIA ZJAWISKU TZW. UCIĄŻLIWOŚCI ODOROWEJ WYNIKAJĄCEJ Z DZIAŁALNOŚCI ROLNICZEJ OPARTEJ NA PRODUKCJI TRZODY CHLEWNEJ W FERMACH WIELKOTOWAROWYCH

Ujemnym skutkiem zachodzących w rolnictwie procesów komercjalizacji i intensyfikacji produkcji rolnej jest stopniowa degradacja środowiska oraz konflikty społeczne. Szczególnie destrukcyjny wpływ w tym zakresie odnotowywany jest w związku z działalnością tzw. agrokoncernów przybierających postać ferm, w których dochodzi do koncentracji dużej liczby zwierząt.W opracowaniu opisano jeden z prawnych aspektów dotyczących funkcjonowania ferm postrzeganych jako czynnik odorogenny dla powietrza. Rozważania ograniczono do ferm trzody chlewnej, co wynika z faktu, że rynek wieprzowiny należy do istotnych w Polsce branżowych rynków rolnych.Celem artykułu stała się analiza obowiązujących de lege lata w polskim systemie normatywnyminstrumentów publicznoprawnych służących do przeciwdziałania zjawisku tzw. uciążliwości odorowejwynikającej z działalności rolniczej opartej na produkcji zwierząt w fermach wielkotowarowych.Przeprowadzone rozważania doprowadziły do wniosku, że polskie regulacje, podobnie jak przepisyUE, nie wprowadziły odpowiedniej normy dotyczącej ochrony powietrza przed zapachami, lecz tylkoprzed określonymi substancjami w powietrzu. Obecnie istnieją tylko przepisy, które wywierają wpływna zmniejszenie uciążliwości zapachowych, ale czynią to niejako przy okazji i w niepełnym zakresie.Brak przepisów odnoszących się do zapachów sprawia, że nie mogą być one badane w procesie uzyskiwania decyzji o środowiskowych uwarunkowaniach zgody na realizację fermy trzody chlewnej.Okoliczność wytwarzania przez takie fermy nieprzyjemnych zapachów nie może sama w sobie stanowić o formalnych rozstrzygnięciach administracyjno-prawnych. W szczególności nie jest możliwe wydanie skutecznej prawnie decyzji o odmowie ustalenia środowiskowych uwarunkowań zgodyna realizację fermy trzody chlewnej ze względu na brak uregulowań prawnych w zakresie odorówi metod ich oceny.Brak regulacji prawnych określających procedurę dokonywania miarodajnych analiz rozprzestrzeniania się emisji odorów uniemożliwia dokonanie prawidłowej i właściwej oceny oddziaływaniatakich przedsięwzięć na środowisko, w tym na zdrowie ludzi. Mimo to wykładnia stosowana przezsądy administracyjne pozwala przyjąć, że także odorowy aspekt powinien być brany pod rozwagęprzy wydawaniu takich decyzji. Jako że istniejące instrumenty prawne wprowadzają bardzo ograniczoną i niezadowalającą ochronę prawną mieszkańców rejonów, w których funkcjonują takie fermy,niezbędne okazuje się sięganie do konstytucyjnej zasady zrównoważonego rozwoju, ogólnych zasad prawa środowiska, a nawet do ustaleń WHO i orzecznictwa Europejskiego Trybunału Praw Człowieka. Świadczy to o ujawnieniu się w judykaturze wyraźnego nurtu, w którym dostrzegane są nie tylko prawa osób do życia w wolności od uciążliwości zapachowych, ale także, w ślad za nimi,konieczność ich ochrony metodami prawnymi.Z wymienionych względów zagadnienie uciążliwości zapachowych wymaga wprowadzenia kompleksowego i systemowego rozwiązania. Dlatego należy uznać, że podjęcie próby normatywnej regulacji tego obszaru życia społeczno-gospodarczego, polegającej na wypracowaniu klarownych i precyzyjnych zasad dotyczących standardów zapachowych i metod oceny zapachowej jakości powietrza jest możliwe, zasadne i pożądane.