Odorous Air Research Articles

Influence of host origin on host choice of the parasitoid Dinarmus basalis: does upbringing influence choices later in life?

The aim of this study was to investigate the influence of volatile compounds from four secondary host plants on the ability of Dinarmus basalis Rond. (Hymenoptera: Pteromalidae) to locate, recognize, and parasitize its host, 4 th instar larvae or pupae of Callosobruchus maculatus F. (Coleoptera: Chrysomelidae). To examine this, strains of D. basalis were transferred from cow-pea seeds ( Vigna unguiculata (L.) Walp. (Fabales: Fabaceae)) to pigeon pea ( Cajanus cajan (L.) Millsp.) and two varieties of Bambara groundnut ( Vigna subterranea (L.) Verdc.) seeds. The ability of D. basalis females to recognize the volatile compounds emanating from their complex host plant was tested by using a Y-tube olfactometer and a three-dimensional device. The results suggest that when females have a choice between pure air and the air emanating from their com-plex host of origin, they are attracted to the air tainted by the volatile compounds they have become accustomed to. They spent significantly more time ( p < 0.0001) in the branch of the tube leading to the odorous air than in the tube leading to the pure air. When females from pigeon pea seed hosts were offered a choice between cowpea and pigeon pea seeds, all containing 4 th instar larvae, the familiar odor of pigeon pea seeds were most attractive. When females from Bambara groundnut (white and striped) seed hosts were offered a choice between cowpea and pigeon pea seeds, all containing 4 th instar larvae, they were significantly attracted to the odour of cowpea seeds. In the three-dimensional system, the females from the four strains did not appear to have any preference for a given type of seed containing 4 th instar larvae or pupae. The parasitism rate remained high on all four types of seeds used. These results show that the use of D. basalis as a biological control agent is possible in host changing situations where C. maculatus starts to attack other legumes. The results of this study also provide information supporting the behavioral plas-ticity of D. basalis . Understanding the mechanisms involved in the adaptive phenomena of biological control agents is discussed in the context of the development of adequate methods of pest control.

Subjective Olfactory Desensitization and Recovery in Humans

Adaptation to smells is a well-known phenomenon and appears to be one of the major characteristics of olfaction. However, no standardized protocols for the psychophysical measurement of olfactory adaptation and recovery are available to date. Twenty normosmic participants were included. Hydrogen sulfide (H2S) and phenylethyl alcohol were used in different concentrations based on air dilution olfactometry. Volunteers were exposed to a constant flow of odorous air until perception disappeared completely. For testing recovery, the volunteers were exposed to a reference stimulus following complete self-desensitization with the same odor. The subjects were then again exposed to the same odorant after recovery periods of different lengths and instructed to rate stimulus intensity. The time to complete desensitization increased with increasing stimulus concentration for both odorants. Subjects desensitized more rapidly using H2S. Olfactory adaptation led to a reduction in stimulus intensity for the subsequent identical stimulation. Longer recovery periods resulted in increased intensity of the subsequent stimulus independent of the stimulus used. The results confirm current knowledge regarding the dynamics of olfactory adaptation and demonstrate differences in olfactory desensitization between the 2 odorants used. Olfactory recovery was independent of the odorant used, indicating that olfactory recovery after complete desensitization may be a uniform process.

Correlation of symptoms of sick-building syndrome to chemical and odor concentration levels

[Background] Sick-building syndrome (SBS) is a range of symptoms such as eye irritation, sore throat and headaches that occur when entering a newly constructed or remodelled building.Volatile organic compounds (VOCs) are suspected to be one of the major causes of SBS. In addition, there are reports that when people complain of symptoms of SBS, most of them also claim to smell an odour. [Aims] The aims of this study were (1) to quantify the odour in indoor air, (2) to examine the correlation between the concentration levels of total VOCs (TVOC) and SBS symptoms, and (3) to examine the correlation between odour and SBS symptoms. [Methods] The concentration levels of chemicals in indoor air of the 13 study sites in Chiba University were measured and analyzed.The odour threshold ratio (OTR) was developed to quantify odour by using odour threshold and concentration values for each VOC in indoor air.Next, for the evaluation of indoor air quality by human sensory perception, 218 healthy volunteers stayed for 15 minutes at the 13 study sites and answered questionnaires which inquired about the odour and symptoms. Then correlations of SBS symptoms to TVOC andtotal odour threshold ratio (TOTR) values were examinedstatistically among sensitive and insensitive groups. [Results] There were 218 subjects,of which 134 were female and 84 were male. 35.8% of females and 34.5% of males were classified as being sensitive to chemicals. The percentage of participants who complained of symptoms was 36.7%. It was found that TVOC and TOTR values were significantly correlated with SBS symptoms, especially among the sensitive group when the concentration level of TVOCs was greater than about 400 ?g/m3 (95%CI 1.06-14.33) and the level of TOTR was greater than about 40 (95%CI 1.03-20.35). [Conclusion] This study revealed the baseline level of TVOC that may cause SBS symptoms to be about 400 ?g/m3and a TOTR value of about 40.It also suggests that TOTR could be used asa new indicator forevaluating the effects ofindoor air quality on human health.

Gas-Phase Ozone Oxidation of Hydrogen Sulfide for Odor Treatment in Water Reclamation Plants

Gas-phase O3 oxidation is effective to treat H2S emitted from wastewater treatment processes. The reaction is fast for full-scale applications. In most cases, 67–96% of total H2S removed in 40-s reaction time was achieved within the first 8 s of reaction time. The initial [O3]/[H2S] ratio of 8 was sufficient to reduce H2S from up to 8 ppmv to less than 0.5 ppmv in 40-s reaction time. The reaction stoichiometry ratio of [O3]/[H2S] ranged from 2.0 to 3.7, depending on the initial [O3]/[H2S] ratio. The moisture content, dimethyl sulfide, and dimethyl disulfide in the odorous air influence H2S removal.

Olfactory Cues Used in Host Selection by Frankliniella occidentalis (Thysanoptera: Thripidae) in Relation to Host Suitability

Olfactory responses of Frankliniella occidentalis (Pergande) to odors from six vegetable host plants-cabbage (Brassica oleracea), lettuce (Lactuca sativa), cucumber (Cucumis sativus), eggplant (Solanum melongena), celery (Apium graveolens) and garlic (Allium sativum) - were measured in choice tests in a Y-tube olfactometer, while host suitability of these same plants was assessed based on life table parameters-development time, survival rates, fertility, offspring sex ratio, female longevity, and an index of population change (I) - measured on leaf disks. Olfactory response was measured on both undamaged and mechanically-damaged plants. Regardless of plant damaged, female F. occidentalis responded positively to the odors of cabbage, lettuce, cucumber, and eggplant, but showed negative responses to celery and garlic, when offered a choice of plant odor or clean air. When female thrips were offered choices between each possible pairing of undamaged plants, or pairings of mechanically-damaged plants, the order of preference was cabbage = lettuce = cucumber > eggplant > celery = garlic. Male thrips responded differently, males responded positively only to undamaged lettuce and eggplant compared to clean air, while among mechanically-damaged plants only cucumber elicited a positive response. Given a choice between all possible pairings of undamaged plants, male thrips preferred lettuce to celery, and eggplant to garlic, whereas among pairings of mechanically-damaged plants male thrips preferred lettuce to celery, and cucumber to eggplant. The order of suitability of the six host plants based on life table parameters for F. occidentalis was essentially the same as the order of preference by female thrips. These results indicate that host plant odor is an important cue for female F. occidentalis in recognizing hosts suitable for oviposition. Information on plant attraction and repellency may be useful in thrips pest management. In addition, the correspondence of preference and performance that we found suggests that evolution of local host adaptation and, perhaps, host specialization, is possible.

Host feeding experience affects host plant odour preference of the polyphagous leafminer Liriomyza bryoniae

AbstractHerbivorous insects use highly specific volatiles or blends of volatiles characteristic to particular plant species to locate their host plants. Thus, data on olfactory preferences can be valuable in developing integrated pest management tools that deal with manipulation of pest insect behaviour. We examined host plant odour preferences of the tomato leafminer, Liriomyza bryoniae (Kaltenbach) (Diptera: Agromyzidae), which is an economically important agricultural pest widespread throughout Europe. The odour preferences of leafminers were tested in dependence of feeding experiences. We ranked host plant odours by their appeal to L. bryoniae based on two‐choice tests using a Y‐tube olfactometer with five host plants: tomato, Solanum lycopersicum Mill.; bittersweet, Solanum dulcamara L.; downy ground‐cherry, Physalis pubescens L. (all Solanaceae); white goosefoot, Chenopodium album L. (Chenopodiaceae); and dead nettle, Lamium album L. (Lamiaceae). The results imply that ranking of host plant odours by their attractiveness to L. bryoniae is complicated due to the influence of larval and adult feeding experiences. Without any feeding experience as an adult, L. bryoniae males showed a preference for the airflow with host plant odour vs. pure air, whereas females did not display a preference. Further tests revealed that adult feeding experience can alter the odour choice of L. bryoniae females. After feeding experience, females showed a preference for host plant odour vs. pure air. Feeding experience in the larval stage influenced the choice by adults of both sexes: for males as well as females reared on bittersweet the odour of that plant was the most attractive. Thus, host feeding experience both in larval and/or adult stage of polyphagous tomato leafminer L. bryoniae influences host plant odour preference by adults.

Development of an Electronic Nose for Environmental Odour Monitoring

Exhaustive odour impact assessment should involve the evaluation of the impact of odours directly on citizens. For this purpose it might be useful to have an instrument capable of continuously monitoring ambient air quality, detecting the presence of odours and also recognizing their provenance. This paper discusses the laboratory and field tests conducted in order to evaluate the performance of a new electronic nose, specifically developed for monitoring environmental odours. The laboratory tests proved the instrument was able to discriminate between the different pure substances being tested, and to estimate the odour concentrations giving correlation indexes (R2) of 0.99 and errors below 15%. Finally, the experimental monitoring tests conducted in the field, allowed us to verify the effectiveness of this electronic nose for the continuous detection of odours in ambient air, proving its stability to variable atmospheric conditions and its capability to detect odour peaks.

Method development for determining the malodor source and pollution in industrial park

Malodor pollution emitted from industrial park has become an important environmental issue. However, the difficulty in investigating malodor pollution is in determining the malodor source. The objective of this study was to develop a model for determining the malodor source and pollution in industrial park, via multiple time and site measurements of odor intensity and air pollutants, together with wind direction in different seasons, and the critical environmental factors could be also identified by correlating the odor intensities with meteorological conditions and the concentrations of air pollutants. A high-malodor-polluted industrial park involving metal and petrochemistry processing industries was selected as the study subject, and sampling was performed close to residential districts. Nine sites were selected as sampling points by a chessboard design, with each site measured for 5days in fall and spring, respectively. Odor intensity (ratings 0–5) and environmental factors, including meteorological condition, PM10, PM2.5, total volatile organic compounds (TVOCs), ammonia and reduced sulfides, were evaluated six times daily. The results indicated that the incidences of odor ratings 1–5 were 71.9% and 81.0% in two seasons in the sampling area, and an open ditch for collecting industrial wastewater for feeding to the wastewater treatment plant was identified as the main odor source. Multiple regression analysis showed that the odor rating significantly correlated with TVOC concentration and wind speed (P<0.05); odor intensity increased by 0.001 units on the rating scale for each 1ppb increase in TVOCs, and decreased by 0.154 units for each 1m/s increase in wind speed. This study developed a method to explore malodor pollution in industrial park, providing a novel thinking to understand and resolve malodor problems.

Evaluation of the Nano-Confined Catalytic Oxidation Technology for Air Purification and Odor Reduction

Air pollution has a significant impact of human health. As modern individuals spend most of the day in tightly insulated buildings, there is a strong need for strategies to improve the quality of indoor air. A number of air cleaning methods ranging from simple filtration to photonic technologies have been used in commercial and residential air purifiers. Recently, a novel technology called Nano-Confined Catalytic Oxidation (NCCO) has been developed. In this study, the potential of NCCO versus two other commonly-used air purifiers to reduce odor nuisances caused by ammonia, toluene and hydrogen sulfide is evaluated. Twenty volunteers are asked to evaluate the odor levels before and after air purification, in a safe, controlled environment. The changes in odorant concentrations are also measured. The findings suggest that the NCCO-based air purifier outperforms the two other common residential air purifiers.

Integrating Air-related Health Surveillance into Air Quality Management: Perceptions and Practicalities

Health surveillance is presently not an integral part of air quality management in South Africa, although ambient air pollution standards are derived from health effects of personal exposure. In a survey to air quality officials and environmental health practitioners (n = 361 ), respondents were asked to comment on a discussion document regarding ways to put health onto the air quality management agenda. Less than 7% of the sample (n = 23) responded, the most likely reasons being: overloaded staff; lack of knowledge about air quality-related health; and apathy. All respondents acknowledged their support of the concepts, one suggested inclusion of PM25 and airspora over and above criteria pollutants, and one mentioned use of an indicator 'number of complaints of visual air pollution and odour'. In general, it would appear that the links between air quality and health risks are not well understood and, more importantly, assessing airrelated health outcomes with respect to air quality is not a part of Local Municipalities' Integrated Development Plans. To motivate for necessary changes in Health Information Systems and data management, evidence of valuable application is required. Without readily available health facility and local municipality-specific data on respiratory and cardiovascular illnesses, it will prove difficult to track whether implemented air pollution mitigation measures will have positive health impacts.

The role of perceived pollution and health risk perception in annoyance and health symptoms: a population-based study of odorous air pollution

Health effects associated with air pollution at exposure levels below toxicity may not be directly related to level of exposure, but rather mediated by perception of the air pollution and by top-down processing (e.g., beliefs that the exposure is hazardous). The aim of the study was to test a model that describes interrelations between odorous air pollution at non-toxic exposure levels, perceived pollution, health risk perception, annoyance and health symptoms. A population-based questionnaire study was conducted in a Swedish community of residents living near a biofuel facility that emitted odorous substances. Individuals aged 18-75 years were selected at random for participation (n = 1,118); 722 (65 %) agreed to participate. Path analyses were performed to test the validity of the model. The data support a model proposing that exposure level does not directly influence annoyance and symptoms, and that these relations instead are mediated by perceived pollution and health risk perception. Perceived pollution and health risk perception play important roles in understanding and predicting environmentally induced annoyance and health symptoms in odorous environments at non-toxic levels of exposure.

Case study of odor and indoor air quality assessment in the dewatering building at the Stickney Water Reclamation Plant

Indoor air quality (IAQ) and odors were determined using sampling/monitoring, measurement, and modeling methods in a large dewatering building at a very large water reclamation plant. The ultimate goal was to determine control strategies to reduce the sensory impacts on the workforce and achieve odor reduction within the building. Study approaches included: (1) investigation of air mixing by using CO(2) as an indicator, (2) measurement of airflow capacity of ventilation fans, (3) measurement of odors and odorants, (4) development of statistical and IAQ models, and (5) recommendation of control strategies. The results showed that air quality in the building complies with occupational safety and health guidelines; however, nuisance odors that can increase stress and productivity loss still persist. Excess roof fan capacity induced odor dispersion to the upper levels. Lack of a local air exhaust system of sufficient capacity and optimum design was found to be the contributor to occasional less than adequate indoor air quality and odors. Overall, air ventilation rate in the building has less effect on persistence of odors in the building. Odor/odorant emission rates from centrifuge drops were approximately 100 times higher than those from the open conveyors. Based on measurements and modeling, the key control strategies recommended include increasing local air exhaust system capacity and relocation of exhaust hoods closer to the centrifuge drops.

Indoor odor exposure effects on psycho-physiological states during intellectual tasks and rest

The responses of five human subjects to two indoor airborne odors (mint and cypress) were examined to determine the effect of perceived air quality and odor type and duration on several psycho-physiological variables during periods of rest and while performing intellectual tasks. An olfactometer system was installed in a climate chamber at the University of Tokyo, with the nozzle located on a desk just to the right of the task-performance screen. The odor concentration presented to the subject was adjusted to keep the perceived odor intensity constant at level 2 (weak) as established in a pretest. Subjects performed a simulated office task, 12 min of Sudoku (number placing puzzle), or rested for 7 min. The task and the rest periods were repeated six times each (except for first and last rests) during one day's exposure. Odor exposures during tasks and rest involved one of the two odors for either a short or long period. During the 3 min between a task and rest, subjects rated their perceptions of odor intensity, degree of odor preference (enjoyment, pleasing quality), comfort, indoor air satisfaction, effect on work efficiency, and several other affective responses. Heart rate variability was continuously monitored by electrocardiographs to assess the activity of the autonomic nervous system. Exposure to a preferred odor may improve comfort, satisfaction, and mood, as well as increase self-reported work efficiency; it may also enhance the activity of the parasympathetic system. Sensitivity to a preferred odor was higher at rest than during a task. The exposure time that produces a positive effect on a subject's physiological responses differs with activity level, being 1 min during work and 10 min when at rest.

Typical Odor Mitigation Technologies for Swine Production Facilities - A Review

Odorous air emissions from confined animal feeding operation are causing public nuisance. Accordingly, different odor mitigation technologies were designed, developed, and evaluated in the last decades to reduce odor emissions. The purpose of this paper is to review the previous research related to odor mitigation from swine rearing facilities and provide information on the effectiveness of currently available and emerging odor mitigation technologies. This review focused on odor mitigation approaches at different stages of swine production, manure storage and handling, and land application. Several odor mitigation technologies have been suggested and evaluated including diet manipulation, solid-liquid separation, additives, aeration, anaerobic digestion, lagoon covers, biofilters, acid scrubbing, shelterbelts, and manure injection. The effectiveness of these mitigation technologies varied widely; however, diet manipulation, biofilters, shelterbelts, and direct injection of manure have shown advantages over other odor mitigation methods. Diet manipulation is the first line of defense for odor mitigation. Biofilters and shelterbelts provide solutions for treating the odorous air before releasing to atmosphere, whereas additives, lagoon covers, aeration, and anaerobic digestion reduce or control odor emissions during manure storage and treatment. Direct injection of manure provides ultimate disposal solution and can reduce odor significantly compared to surface application.

Odor and Odorous Chemical Emissions from Animal Buildings: Part 1. Project Overview, Collection Methods, and Quality Control

Livestock facilities have historically generated public concerns due to their emissions of odorous air and various chemical pollutants. Odor emission factors and identification of principal odorous chemicals are needed to better understand the problem. Applications of odor emission factors include inputs to odor setback models, while chemical emission factors may be compared with regulation thresholds as a means of demonstrating potential health impacts. Acompanion study of the National Air Emissions Monitoring Study (NAEMS) included measurements necessary for establishing odor and chemical emission factors for confined animal feeding operations. This additional investigation was conducted by the University of Minnesota, Iowa State University, West Texas A&M Agri-Life Center, and Purdue University. The objectives were to (1) determine odor emission rates across swine and dairy facilities and seasons using common protocols and standardized olfactometry methods, (2) develop a chemical library of the most significant odorants, and (3)correlate the chemical library with the olfactometry results. This document describes the sampling and quality assurance methods used in the measurement and evaluation of odor and chemical samples collected at two freestall dairy farms, one sow (gestation/farrowing) facility, and one finishing pig site. Odor samples were collected in Tedlar bags and chemical samples were collected in sorbent tubes at barn inlet and exhaust locations using the NAEMS multiple-location gas sampling systems. Quality assurance protocols included interlaboratory comparison tests, which were evaluated to identify variations between olfactometry labs. While differences were observed, the variations among the labs and samples appeared random and the collected odor data were considered reliable at a 0.5% level of statistical significance. Overall, the study took advantage of groundbreaking opportunities to collect and associate simultaneous odor and chemical information from swine and dairy buildings while maintaining accordance with standard methods and comparability across laboratories.

A Study on Characterization of Trace Odorants in Air by Gas Chromatography Using Preconcentration

A Study on Characterization of Trace Odorants in Air by Gas Chromatography Using Preconcentration

A case report of gas chromatographic determination of odorants in ambient air near of autoclaved light weight cellular concrete (ALC) factory

A case report of gas chromatographic determination of odorants in ambient air near of autoclaved light weight cellular concrete (ALC) factory

A salty-congruent odor enhances saltiness: functional magnetic resonance imaging study.

Excessive intake of dietary salt (sodium chloride) may increase the risk of chronic diseases. Accordingly, various strategies to reduce salt intake have been conducted. This study aimed to investigate whether a salty-congruent odor can enhance saltiness on the basis of psychophysical (Experiment 1) and neuroanatomical levels (Experiment 2). In Experiment 1, after receiving one of six stimulus conditions: three odor conditions (odorless air, congruent, or incongruent odor) by two concentrations (low or high) of either salty or sweet taste solution, participants were asked to rate taste intensity and pleasantness. In Experiment 2, participants received the same stimuli during the functional magnetic resonance imaging scan. In Experiment 1, compared with an incongruent odor and/or odorless air, a congruent odor enhanced not only taste intensity but also either pleasantness of sweetness or unpleasantness of saltiness. In Experiment 2, a salty-congruent combination of odor and taste produced significantly higher neuronal activations in brain regions associated with odor-taste integration (e.g., insula, frontal operculum, anterior cingulate cortex, and orbitofrontal cortex) than an incongruent combination and/or odorless air with taste solution. In addition, the congruent odor-induced saltiness enhancement was more pronounced in the low-concentrated tastant than in the high-concentrated one. In conclusion, this study demonstrates the congruent odor-induced saltiness enhancement on the basis of psychophysical and neuroanatomical results. These findings support an alternative strategy to reduce excessive salt intake by adding salty-congruent aroma to sodium reduced food. However, there are open questions regarding the salty-congruent odor-induced taste unpleasantness.

Swine Odor Analyzed by Odor Panels and Chemical Techniques

The National Research Council identified odors as a significant animal emission and highlighted the need to develop standardized protocols for sampling and analysis. The purpose of our study was to compare different odor sampling techniques for monitoring odors emitted from stored swine manure. In our study, odorous headspace air from swine manure holding tanks were analyzed by human panels and analytical techniques. Odorous air was analyzed by human panels using dynamic dilution olfactometry (DDO). Chemical analysis used acid traps for ammonia (NH₃), fluorescence for hydrogen sulfide (H₂S), and thermal desorption gas chromatography-mass spectrometry for volatile organic compounds (VOCs). Chemical analysis included the use of gas chromatography-olfactometry (GC-O) for determining key odorants. Chemical odorant concentrations were converted to odor activity values (OAVs) based on literature odor thresholds. The GC-O technique used was GC-SNIF. Dilution thresholds measured by different odor panels were significantly different by almost an order of magnitude even though the main odorous compound concentrations had not changed significantly. Only 5% of the key odorous VOCs total OAVs was recovered from the Tedlar bags used in DDO analysis. Ammonia was the only chemical odorant significantly correlated with DDO analysis in the fresh (1 wk) and aged manure. Chemical analysis showed that odor concentration stabilized after 5 to 7 wk and that HS was the most dominant odorant. In aged manure, neither volatile fatty acids (VFAs) nor HS was correlated with any other chemical odorant, but NH, phenols, and indoles were correlated, and phenols and indoles were highly correlated. Correlation of odorant concentration was closely associated with the origin of the odorant in the diet. Key odorants determined by chemical and GC-O included indoles, phenols, NH₃, and several VFAs (butanoic, 3-methylbutanoic, and pentanoic acids).

Development of a Livestock Odor Dispersion Model: Part I. Model Theory and Development

ABSTRACT A livestock odor dispersion model (LODM) was developed to predict mean odor concentration, odor frequency, instantaneous odor concentration, and peak odor concentration from livestock operations. This model is based on the Gaussian fluctuating plume model and has the ability to consider the instantaneous concentration fluctuations and the differences between odor and traditional air pollutants. It can predict odor frequency from the routine hourly meteorological data input and deal with different types of sources and multiple sources. Also, the relationship between odor intensity and odor concentration was incorporated into the model. IMPLICATION The LODM is a model developed especially for odor from livestock buildings and manure storage. It has the ability to consider short time odor fluctuations, which is important from research and management perspectives. The weighted odor-exceeding half-width method used in LODM to predict odor frequency is an improvement over past studies. The model can accept routine hourly meteorological input and deal with different and multiple sources. It can also consider the relationship between odor concentrations and intensity. These characteristics of LODM make it especially relevant for odor research and application.