Odor Distribution Research Articles

Odor emission pattern of the waste storage workshop of kitchen waste treatment plant and control strategy study with CFD simulation.

Odor emission has become a great issue for kitchen waste management plants. Among all, unorganized emission source such as waste storage tank is the key cause. It is necessary to understand the odor emission characteristics and provide a proper control solution. In this study, a typical kitchen waste treatment plant located in Guangdong Province of China was selected to investigate the odor emission characteristics. According to the survey, the main complaint due to odor emission is on waste storage workshop. Hence, its odor emission has been investigated in this study. The gas samples were collected from the workshop in different season. According to the results, the odor emission during summer is the worst. In total, 105 odorous gases were detected from the waste storage workshop. The main odorous gases can be categorized into sulfur compounds, oxygen-containing organic compounds and terpenes. In specific, ethanol, acetic acid, methylmercaptan, α-pinene, methioether and limonene were the major odorous pollutants. Based on grey correlation, principal component analysis (PCA) and step-up regression analysis, methylmercaptan contributes the most to the odor concentration. It suggests that the odor emission control should pay more attention on methylmercaptan. The Computational Fluid Dynamics (CFD) stimulation was employed to investigate the odor distribution with applying air blowing as a curtain to separate the inside and outside atmosphere or suction to vacuum the inside air to prevent the odor emission. It was found that it could efficiently prevent odor emission by setting a 45° inclined air suction port at the top of the entrance gate. The study provides a theoretical basis on odor control for the waste storage workshop of kitchen waste management plants.

Assessing the spatial distribution of odor at an urban waterfront using AERMOD coupled with sensor measurements

ABSTRACT Impressions of a place are partly formed by smell. The urban waterfronts often leave a rather poor impression due to odor pollution, resulting in recurring complaints. The nature of such complaints can be subjective and vague, so there is a growing interest in quantitative measurements of emissions to explore the causes of malodorous influence. In the present work, an air quality monitor with an H2S sensor was employed to continuously measure emissions of malodors at 1-min resolution. H2S is often considered to be the predominant odorous substance from sludge and water bodies as it is readily perceptible. The integrated means of concentration from in situ measurements were combined with the AERMOD dispersion model to reveal the spatial distribution of odor concentrations and estimate the extent of odor-prone areas at a daily time step. Year-long observations showed that the diurnal profile exhibits a positively skewed distribution. Meteorology plays a vital role in odor dispersion; the degree of dispersion was explored on a case-by-case basis. There is a greater likelihood of capturing the concentration peaks at night (21:00 to 6:00) as the air is more stable then with less tendency for vertical mixing but favors a horizontal spread. This study indicates that malodors are changeable in time and space and establishes a new approach to using H2S sensor data and resolves a long-standing question about odor in Hong Kong. Implications: this study establishes a new approach combining dispersion model with novel H2S sensor data to understand the characteristics and pattern of odor emanated from the urban waterfront in Hong Kong. The sensor has dynamic concentration range to detect the episodic level of H2S and low level at background conditions. It provides more complete information in relation to odor annoyance, as well as quantitative information useful for odor regulation

An Odor Trace Visualization System Using a Two-Dimensional Backside Scattering Localized Surface Plasmon Resonance Gas Sensor

Odor information fills every corner of our lives yet obtaining its spatiotemporal distribution is a difficult challenge. Localized surface plasmon resonance has shown good sensitivity and a high response/recovery speed in odor sensing and converts chemical information such as odor information into optical information, which can be captured by charge-coupled device cameras. This suggests that the utilization of localized surface plasmon resonance has great potential in two-dimensional odor trace visualization. In this study, we developed a two-dimensional imaging system based on backside scattering from a localized surface plasmon resonance substrate to visualize odor traces, providing an intuitive representation of the spatiotemporal distribution of odor, and evaluated the performance of the system. In comparative experiments, we observed distinct differences between odor traces and disturbances caused by environmental factors in differential images. In addition, we noted changes in intensity at positions corresponding to the odor traces. Furthermore, for indoor experiments, we developed a method of finding the optimal capture time by comparing changes in differential images relative to the shape of the original odor trace. This method is expected to assist in the collection of spatial information of unknown odor traces in future research.

A comparison of odor plume-tracking behavior of walking and flying insects in different turbulent environments.

Many animals locate food, mates and territories by following plumes of attractive odors. There are clear differences in the structure of this plume-tracking behavior depending on whether an animal is flying, swimming, walking or crawling. These differences could arise from different control rules used by the central nervous system during these different modes of locomotion or one set of rules interacting with the different environments while walking on the surface versus flying or swimming. Flow speeds and turbulence that characterize the environments where walking and flying insects track plumes may alter the structure of odor plumes in an environment-specific way that results in the same control rules generating behaviors that appear quite different. We tested these ideas by challenging walking male cockroaches, Periplaneta americana, and flying male moths, Manduca sexta, to track plumes of their species' sex pheromones in low wind speeds characteristic of cockroach experimental environments, higher wind speeds characteristic of moth experimental environments, and conditions ranging from low to high turbulence. Introducing a turbulence-generating structure into the flow significantly improved the flying plume tracker's ability to locate the odor source, and changed the structure of the behavior of both flying and walking plume trackers. Our results support the idea that plume trackers moving slowly along the substrate may use the spatial distribution of odor, while faster moving flying plume trackers may use the timing of odor encounters to steer to locate the source.

Sniff the urban park: Unveiling odor features and landscape effect on smellscape in Guangzhou, China

Smellscape, as the sense of smell cross space, has a huge impact on human behavior, attitudes and health. However, so far it has rarely been addressed and measured in both landscape practice and theories. The present case study refined the quantitative smellwalk method to examine the spatial and temporal features of urban park smellscape. The effects of landscape patterns on smellscape were further unraveled combining with remote sensing techniques and field surveys. The results indicated that: (i) human activities and nature odors dominated the urban park odor environments, (ii) the temporal variation of the urban park smellscape was mainly driven by human activities, (iii) the different site types of urban park exerted a significant impact on the composition of the smellscape, and (iv) the landscape pattern characteristics of forest, shrubs, grass, water, buildings and roads had significant effects on different types of odors. This study poses a first systematic exploration of various odors in urban green environments and offers novel insights into the design of smellscape via unveiling spatial-temporal odor distribution patterns.

Joint majorization of waterworks and secondary chlorination points considering the chloric odor and economic investment in the DWDS using machine learning and optimization algorithms

The traditional methods of increasing the chlorine disinfectant dosage in the drinking water distribution system (DWDS) to control microorganisms and improve the safety of drinking water quality are subjected to several challenges. One noticeable problem is the unpleasant odor generated by chlorine and chloramines. However, the generally proposed chlorine dosage optimization model ignores the chloric odor distribution in the DWDS. This study proposes a comprehensive multi-parameter water quality model and aims to balance the trade-offs between: (i) minimize the flavor profile analysis (FPA) degree of the chloric odor produced by chlorine and chloramines in the DWDS, and (ii) minimize the economic investment (chlorine dosage and operation cost). EPANET and back propagation (BP) network integrated with the Borg algorithm were employed as innovative approaches to simulate the chlorine, chloramines, and chloric odor intensity in the DWDS. Moreover, the application of the multi-parameter model was demonstrated in a real-world DWDS case study. 0.5 mg-Cl2/L (mg/L) chlorine at 8 secondary chlorination points was added to the DWDS as an optimized chlorine dosing scheme considering the olfactory and financial objective functions simultaneously. When switching to a superior water source, the FPA of the chloric odor in DWDS increased by a maximum of 1.4 at most if the initial chlorine dosage remained as before. To avoid the occurrence of chloric odor and also control the residual free chlorine (residual chlorine) at a suitable value, the initial and secondary chlorine dosages were optimized to 0.4 mg/L and 0.3 mg/L, respectively. Under this condition, the initial chlorine dosage was reduced by 50% compared to the original operation scheme in City J, China, the qualification rate of the residual chlorine reached 97.2%, basically consistent with that before water source switching, and the chloric odor intensity of the DWDS was controlled below FPA 3.4.

Spatial odor discrimination in the hawkmoth, Manduca sexta (L.)

ABSTRACTFlying insects track turbulent odor plumes to find mates, food and egg-laying sites. To maintain contact with the plume, insects are thought to adapt their flight control according to the distribution of odor in the plume using the timing of odor onsets and intervals between odor encounters. Although timing cues are important, few studies have addressed whether insects are capable of deriving spatial information about odor distribution from bilateral comparisons between their antennae in flight. The proboscis extension reflex (PER) associative learning protocol, originally developed to study odor learning in honeybees, was used as a tool to ask if hawkmoths, Manduca sexta, can discriminate between odor stimuli arriving on either antenna. We show moths discriminated the odor arrival side with an accuracy of >70%. Information about spatial distribution of odor stimuli may be available to moths searching for odor sources, opening the possibility that they use both spatial and temporal odor information.This article has an associated First Person interview with the first author of the paper.

Profile-Decomposing Output of Multi-Channel Odor Sensor Array

Profile-Decomposing Output of Multi-Channel Odor Sensor Array

Modeling of Odor from a Particleboard Production Plant

Production of particleboards is associated with volatile organic compounds emissions, many of which have odorous properties. The objective is to determine whether the odor emissions from the production, using spruce and aspen as raw material, comply with the local odor limit defined in a specific way—an hourly average odor concentration leading to 16% odor annoyance and not being exceeded more than 2% of the time in residential area. Complex data of odor are presented from two largest sources—dryer and press, providing odor emission concentration, flow, composition, and dispersion model. The odor emission flow from the dryer is by factor of 19 higher with the value of 7655 × 106 ouE h−1 than that from the press. The dependence between odor concentration and annoyance is defined and determined. Identifying the top 10 odorous compounds (the most relevant are hexanal, butanoic and acetic acids, and α- and β-pinenes) in the emissions, the concentration, which leads to 16% annoyance, is quantified to 0.62 µg m−3. The dispersion model provides odor distribution, proving that the given limit is not exceeded in the nearby residential area.

Distribution of odor and taste compounds in the lakes and reservoirs of Pearl River Delta and the removal efficiency in source discharges

采用固相微萃取-气质联用技术对珠江三角洲9个城市共48个湖库水体中的土臭素（GSM）、2-甲基异茨醇（MIB）和2，3，6-三氯苯甲醚（TCA）等5种嗅味物质进行检测，并探讨污水处理厂和自来水厂处理工艺中嗅味物质的浓度变化规律，同时研究强化混凝沉淀工艺对嗅味物质的去除效果.结果表明：珠江三角洲湖库水体中嗅味问题最严重的是广州、佛山、肇庆、东莞、惠州和深圳6个城市，各市湖库的嗅味物质平均浓度为70.93~116.61 ng/L；中山、珠海与江门3个城市的嗅味问题不明显，各市湖库的嗅味物质平均浓度为22.78~58.82 ng/L；珠江三角洲的湖库中浓度最高的嗅味物质是MIB、TCA和GSM，这3种嗅味物质占了嗅味物质总浓度的80.18%~100.00%；污水处理厂和自来水厂中的处理工艺对嗅味物质均有一定的去除效果，嗅味物质的去除主要发生在混凝沉淀阶段；污水处理厂对MIB、TCA和GSM的平均去除率分别为53.55%、57.40%和72.90%；自来水厂对MIB、TCA和GSM的平均去除率分别为64.14%、69.63%和36.86%；强化混凝沉淀实验中，当嗅味物质初始浓度为200 ng/L时，Al₂O₃投加量为13.75 mg/L可使得混凝沉淀工艺对嗅味物质的去除效果最佳且保证铝盐不超标，嗅味物质浓度增大时Al₂O₃投加量也需增大；反应体系的pH值处于5~8时，混凝沉淀工艺对嗅味物质的去除效果最佳；混凝搅拌速率越快，嗅味物质的去除率越高且越快达到稳定.;With the continuous improvement of people's living standards, residents put forward higher requirements for water quality, and pay more attention to odor and taste problem. Concentrations of odor and taste compounds in 48 lakes and reservoirs of 9 cities in Pearl River Delta were detected with the method of Solid Phase MicroExtraction-Gas Chromatography/Mass Spectrometry (SPME-GC/MS) technique. The changes of odor and taste compounds concentrations along the water treatment processes of wastewater treatment plants and water supply plants, as well as the removal effect of odor and taste compounds by enhanced coagulation-sedimentation process were studied. The results showed that:the most serious stench problem was the lakes and reservoirs of Guangzhou, Foshan, Zhaoqing, Dongguan, Huizhou and Shenzhen. The average concentrations of odor and taste compounds in the lakes and reservoirs of these 6 cities were from 70.93 to 116.61 ng/L. And the stench problem was not obvious in the lakes and reservoirs of Zhongshan, Zhuhai and Jiangmen. The average concentrations of odor and taste compounds in the lakes and reservoirs of these 3 cities were from 22.78 to 58.82 ng/L. 2-methylisoborneol (MIB), 2,3,6-trichloroanisole (TCA) and Geosmin (GSM) were the main odor and taste compounds in all lakes and reservoirs, which accounted for 80.18%-100.00% of total odor and taste compounds. The water treatment progresses of wastewater treatment plants and water supply plants could considerably remove odor and taste compounds. Coagulation-sedimentation process had the greatest contribution to the removal of odor and taste compounds. In the wastewater treatment plants, the average removal rates of MIB, TCA and GSM were 53.55%, 57.40% and 72.90%, respectively. In the water supply plants, the average removal rates of MIB, TCA and GSM were 64.14%, 69.63% and 36.86%, respectively. In the enhanced coagulation-sedimentation experiment, for the initial concentrations of odor and taste compounds of 200 ng/L, coagulation-sedimentation process could reach the greatest removal effect of them, and aluminum was not excessive as well when the coagulant (Al₂O₃) dosage was 13.75 mg/L. When the concentrations of odor and taste compounds increase, the dosage of Al₂O₃ should increase, too. When the pH value of the reaction system was between 5 and 8, coagulation-sedimentation process could reach the greatest removal effect of odor and taste compounds. The faster the stirring rate of coagulation was, the higher the removal rate of odor and taste compounds reached, and the faster the stability reached.

Hydrodynamic features, appearance of scum, and spatial distribution of odor in urban estuaries

Hydrodynamic features, appearance of scum, and spatial distribution of odor in urban estuaries

Information-theoretic analysis of realistic odor plumes: What cues are useful for determining location?

Many species rely on olfaction to navigate towards food sources or mates. Olfactory navigation is a challenging task since odor environments are typically turbulent. While time-averaged odor concentration varies smoothly with the distance to the source, instaneous concentrations are intermittent and obtaining stable averages takes longer than the typical intervals between animals’ navigation decisions. How to effectively sample from the odor distribution to determine sampling location is the focus in this article. To investigate which sampling strategies are most informative about the location of an odor source, we recorded three naturalistic stimuli with planar lased-induced fluorescence and used an information-theoretic approach to quantify the information that different sampling strategies provide about sampling location. Specifically, we compared multiple sampling strategies based on a fixed number of coding bits for encoding the olfactory stimulus. When the coding bits were all allocated to representing odor concentration at a single sensor, information rapidly saturated. Using the same number of coding bits in two sensors provides more information, as does coding multiple samples at different times. When accumulating multiple samples at a fixed location, the temporal sequence does not yield a large amount of information and can be averaged with minimal loss. Furthermore, we show that histogram-equalization is not the most efficient way to use coding bits when using the olfactory sample to determine location.

Midair Ultrasound Fragrance Rendering.

We propose a system that controls the spatial distribution of odors in an environment by generating electronically steerable ultrasound-driven narrow air flows. The proposed system is designed not only to remotely present a preset fragrance to a user, but also to provide applications that would be conventionally inconceivable, such as: 1) fetching the odor of a generic object placed at a location remote from the user and guiding it to his or her nostrils, or 2) nullifying the odor of an object near a user by carrying it away before it reaches his or her nostrils (Fig. 1). These are all accomplished with an ultrasound-driven air stream serving as an airborne carrier of fragrant substances. The flow originates from a point in midair located away from the ultrasound source and travels while accelerating and maintaining its narrow cross-sectional area. These properties differentiate the flow from conventional jet- or fan-driven flows and contribute to achieving a midair flow. In our system, we employed a phased array of ultrasound transducers so that the traveling direction of the flow could be electronically and instantaneously controlled. In this paper, we describe the physical principle of odor control, the system construction, and experiments conducted to evaluate remote fragrance presentation and fragrance tracking.

Distribution of glucosinolate and pungent odors in rapeseed oils from raw and microwaved seeds

ABSTRACTThe current study was aimed to investigate the effect of glucosinolate degradation on the flavor precursors and pungent odors in raw and microwaved rapeseeds. Five isothiocyanates and six sulfur compounds were identified using comprehensive two-dimensional gas chromatography and time-of-flight mass spectrometry (GC× GC-TOF/MS). Comprehensive analysis with headspace solid-phase microextraction (HS-SPME) and aroma extract dilution analysis (AEDA) with altering split ratio showed that 1-isothiocyanato butane, allyl isothiocyanate and 4-isothiocyanato-1-butene were responsible for the sulfur, pungent and green odors in rapeseed oils, due to their high flavor dilution factor. Dimethyl sulfide, dimethyl trisulfide and dimethyl sulfoxide, might be derived from methionine or isothiocyanate rearrangement reactions imparted onion-like, cabbage-like, garlic-like, and sulfurous-pungent odors. Rapeseed samples were heated in a microwave for seven minutes, and the total glucosinolate content decreased from 28.2 ± 0.8 μmol/g to 14.5 ± 0.6 μmol/g in Brassica napus, from 101.2±3.0 μmol/g to 42.2 ± 5.4 μmol/g in Brassica campestris, and from 132.02 ± 9.31 μmol/g to 52.50 ± 6.50 μmol/g in Brassica juncea, compared to untreated ones. Differences in the concentrations of six main odorants and the glucosinolate precursors from genetic types were responsible for the intensity of the pungent odors in raw and microwaved rapeseeds. The result can assist to determine the flavor of the commercial rapeseed oils.

Display System for Presenting Spatial Odor, /or Airflow Distribution

Display System for Presenting Spatial Odor, /or Airflow Distribution

Odor Space Navigation Using Multisensory E-Nose

A spatial odor distribution in an environment can be used for navigation, goal search, localization and mapping, like by video, ultrasonic, temperature and other sensors. Modern e-noses can perform the selective detection of different gases with an extremely low concentration but the source localization algorithms of a selected gas against the background of other odors are still underinvestigated. This paper studies an odor field representation in terms of an e-nose based on an array of low-selective sensors. Using a simulation model, we show how the vector measurements of a field of several odor sources can be processed to navigate for reaching a selected odor source. In addition, we demonstrate that the source having a high level of odor intensity can interfere with the search of another odor source of a low intensity. The well-known class of matching receivers does not solve this problem. However, a solution can be obtained by distributed measurements. As shown below, the spatial structure of an odor field allows to implement vector selection. Using deep learning machines, we may reach a high resolution of odor sources in the space. Our future research will be focused on augmented odor reality and autonomous mobile e-nose (e-dog) design.

匂い濃度と気流の空間分布提示装置( 香り・人・システム)

匂い濃度と気流の空間分布提示装置( 香り・人・システム)

Multi-Sensor Integration to Map Odor Distribution for the Detection of Chemical Sources.

This paper addresses the problem of mapping odor distribution derived from a chemical source using multi-sensor integration and reasoning system design. Odor localization is the problem of finding the source of an odor or other volatile chemical. Most localization methods require a mobile vehicle to follow an odor plume along its entire path, which is time consuming and may be especially difficult in a cluttered environment. To solve both of the above challenges, this paper proposes a novel algorithm that combines data from odor and anemometer sensors, and combine sensors’ data at different positions. Initially, a multi-sensor integration method, together with the path of airflow was used to map the pattern of odor particle movement. Then, more sensors are introduced at specific regions to determine the probable location of the odor source. Finally, the results of odor source location simulation and a real experiment are presented.

ポータブル版匂いと気流の空間分布提示装置

Here we report a portable wind/olfactory display system that can present a virtual airflow and/or odor source at an arbitrary position on a screen of a tablet computer. The system is named a smelling screen mini. As in our original-size smelling screen, airflows generated by four fans are made to impinge on each other, and thus, an airflow directed toward the user from a specified position on the screen is generated. By introducing odor vapor into the airflows, the odor distribution is as if odor vapor had been released from a certain position on the screen. However, it has been found that the airflows generated by the fans in the smelling screen mini are not properly impinging on each other and that the airflow directed toward the user is obliquely distorted. We have shown that the distortion is caused by the irregularities of the airflows from the fans. Experimental results are presented to show that the distortion of the airflow distribution can be effectively reduced by adding airflow straightening vanes and tapered flow paths to suppress the swirling motion of the airflows. The smelling screen mini can be used to add special effects to mobile games and electronic picture books.

ポータブル版匂いと気流の空間分布提示装置

ポータブル版匂いと気流の空間分布提示装置