Odour Impact Research Articles

Electronic Noses and Their Applications for Sensory and Analytical Measurements in the Waste Management Plants-A Review.

Waste management plants are one of the most important sources of odorants that may cause odor nuisance. The monitoring of processes involved in the waste treatment and disposal as well as the assessment of odor impact in the vicinity of this type of facilities require two different but complementary approaches: analytical and sensory. The purpose of this work is to present these two approaches. Among sensory techniques dynamic and field olfactometry are considered, whereas analytical methodologies are represented by gas chromatography–mass spectrometry (GC-MS), single gas sensors and electronic noses (EN). The latter are the core of this paper and are discussed in details. Since the design of multi-sensor arrays and the development of machine learning algorithms are the most challenging parts of the EN construction a special attention is given to the recent advancements in the sensitive layers development and current challenges in data processing. The review takes also into account relatively new EN systems based on mass spectrometry and flash gas chromatography technologies. Numerous examples of applications of the EN devices to the sensory and analytical measurements in the waste management plants are given in order to summarize efforts of scientists on development of these instruments for constant monitoring of chosen waste treatment processes (composting, anaerobic digestion, biofiltration) and assessment of odor nuisance associated with these facilities.

Performance of wet scrubbers to remove VOCs from rubber emissions

Poor performance of wet scrubbers in rubber processing plants due to breakthrough of specific volatile organic compounds (VOCs) causes odour impact events. The performance of wet scrubbers in the rubber drying process to remove VOCs was investigated in order to determine the responsible odorants. VOC emissions originating at the inlet and outlet of wet scrubbers were quantified using gas chromatography-mass spectrometry/olfactometry (GC-MS/O). Critical VOCs were identified alongside seasonal and daily variations of those VOCs. Altogether, 80 VOCs were detected in rubber emissions with 16 classified as critical VOCs based on their chemical concentration, high odour activity value (OAV) and unpleasant odour. Volatile fatty acids (VFAs) were the dominant VOCs with seasonal variations affecting emission composition. Results demonstrated the ineffectiveness of the wet scrubbers to mitigate odorous VOCs whereas the removal of some VOCs could be improved based on their polarity and solubility. It was found that there is a correlation between the wet scrubber performance and VFAs concentration in the emissions. The findings demonstrated that combining quantitative and sensory analyses improved accuracy in identifying odorous VOCs, which can cause odour annoyance from rubber processing. A VOC identification framework was proposed using both analyses approaches.

Exposure-response Relationship and Chemical Characteristics of Atmospheric Odor Pollution from a Cigarette Factory

Odor pollution is one of the most complained environmental problems in China. At present, the odor control is mainly aimed at municipal facilities. There is a lack of reports on the atmospheric odor pollution produced by some special industrial emissions. This paper studied the odor impact of a cigarette factory on surrounding residents in order to obtain the exposure-response relationship, which can provide a scientific basis for odor control of cigarette production. Exhaust emission measurement, sample collection and laboratory analysis, as well as community survey were carried out. The air dispersion model Aermod was used to simulate the olfactory odor concentrations in surrounding residential areas. Face-to-face questionnaire was used to collect the information of residential responses to the cigarette odor. The exposure-response relationship between the percentage of highly annoyed people (%) and the 98th percentile of odor concentrations was analyzed using the univariate binomial logistic model. In addition, the typical odor pollutants were found by odor activity value. The results showed that the proportion of highly annoyed people in the residential area was ranged from 5% to 64%, and the acceptable level of exposure odor concentration was 4 OU m–3 at the 98th percentile. The main odor substances of the cigarette factory were oxygenated organic substances including esters, fatty acids and ketones. Based on the chemical composition and the odor character of each substance, the odor wheel of cigarette factory was established for the first time.

Odour Impact Simulation of a Large Urban Wastewater Treatment Plant Through the Numerical Solution of an Eulerian Model

Odour Impact Simulation of a Large Urban Wastewater Treatment Plant Through the Numerical Solution of an Eulerian Model

Volatile Profile of Dry and Wet Aged Beef Loin and Its Relationship with Consumer Flavour Liking.

This study investigated the effect of ageing method and ageing time on the volatile profiles of grilled beef striploins (Longissimus thoracis et lumborum) and their relationship with consumer flavour liking. Volatiles were measured in grilled steaks subjected to 35 days of dry ageing, 35 days of wet ageing, 56 days of dry ageing or 56 days of wet ageing, using headspace-solid-phase microextraction followed by gas chromatography-mass spectrometry. Gas chromatography-olfactometry-mass spectrometry was also conducted on 35-day wet and dry aged samples to identify volatiles with high odour impact. The concentration of many odour impact volatiles, e.g., 3-hydroxy-2-butanone, 2-acetyl-2-thiazoline, and various alkyl-pyrazines, was significantly higher in dry aged beef compared to wet aged beef (p < 0.05). Several odour impact volatiles, e.g., 2-acetyl-1-pyrroline, and alkyl-pyrazines, decreased significantly with ageing time (p < 0.05), while volatile products of lipid oxidation and microbial metabolism increased with ageing time. Partial least-squares regression analysis showed that the higher consumer flavour liking for 35-day dry aged beef was associated with higher concentrations of desirable odour-active volatiles.

Odour dispersion modelling, impact criteria, and setback distances for an oil refinery plant

Odour dispersion modelling is considered to be the most effective approach in evaluating odour impact of various air emission sources as field odour measurements are associated with several difficulties. Using odour impact criteria (OIC), odour dispersion modelling could provide a comprehensive map of impact for current and future sources, along with providing time and cost savings, yet there was very little research on odour dispersion modelling for oil refineries. The OIC are source-specific but OIC for oil refineries has not been well studied. This study investigated odour impact of a conventional oil refinery in Western Canada using the AERMOD model. Odour intensities (OIs) were measured at 62 spots downwind from 70 m to 6.7 km from the plant. Peak to Mean factors (PMF) were generated for the model. The measured OIs were converted to odour concentrations (OC) using OI-OC correlation. Comparison of modelled and measured data indicated that AERMOD predicted the OC satisfactorily (r = 0.67). The model was then used to predict odour impact for this area based on 5-year meteorological data. Comparing dispersion modelling results with the general OIC of the region and odour complaint data, a new set of OIC for the oil refinery was proposed, and the resultant appropriate setback distances for different land uses were predicted by AERMOD. The OIC proposed by this study may be applicable for other refineries yet potential differences in odour acceptance levels of other communities should be considered. The resultant setbacks from this study may not be applicable for sites with different topographic and meteorological conditions.

Dispersion modelling of environmental odours using hourly-resolved emission scenarios: Implications for impact assessments

Regarding air quality, odours have been repeatedly ranked as the number one reason for public complaints to authorities. The most widely used method for assessing odour impacts is dispersion modelling. However, the entire impact assessment chain is permeated with uncertainty, and the role of different sources of uncertainty is not well understood. A critical component of this chain is the emission, the focus of this work. Here we develop modelling analyses for examining the influence of variable emissions against constant emissions on the outcomes of impact assessments. The analyses are built upon six hourly-resolved emission scenarios and one time-invariant scenario applied for the fattening phase of pig production systems. All seven scenarios are configured to treat total emissions due to a mechanically ventilated shed as coming from an elevated point source with an unobstructed vertical release. A total of 378 impact maps from three sites in two countries (Austria and the U.S.) over relatively flat terrain are scrutinised. The influence and relevance of accounting for variability in odour emissions over time depend strongly on the nature of the emissions (e.g., temporal pattern, presence of stochastic and deterministic components) as well as other factors such as building downwash, odour impact criterion and stack height. Altogether, the results suggest that using hourly odour emission rates can improve the confidence in impact assessments compared with the simulations driven by constant emissions. For odour impact criteria based on high-end percentiles, the assumption of constant emissions can be more easily compromised. In contrast, lower percentiles are found to be more robust in offsetting the source emission variability. Results also indicate that the variability in odour emissions might become less of an issue for releases under the influence of downwash than those without obstacle effects. This systematic work is the largest investigation to date on the consequences of incorporating variable emissions when modelling odour impacts. Our findings demonstrate that the emission scenario used as input to dispersion models can play a central role in dictating the conclusions of odour impact assessments. • Modelling analyses were developed to produce 378 odour impact maps for the investigation. • Assuming constant emissions brings a risk of biased impact estimates. • Releases under building downwash effects were less sensitive to the source emission variability. • The ultimate influence of variable emissions hangs upon the prescribed percentile of impact criteria. • More faithful representations of time-varying emissions are needed to ameliorate odour exposure calculations.

RHINOS: A lightweight portable electronic nose for real-time odor quantification in wastewater treatment plants

SummaryQuantification of odor emissions in wastewater treatment plants (WWTPs) is key to minimize odor impact to surrounding communities. Odor measurements in WWTPs are usually performed via either expensive and discontinuous olfactometry hydrogen sulfide detectors or via fixed electronic noses. We propose a portable lightweight electronic nose specially designed for real-time odor monitoring in WWTPs using small drones. The so-called RHINOS e-nose allows odor measurements with high spatial resolution, and its accuracy is only slightly worse than that of dynamic olfactometry. The device has been calibrated using odor samples collected in a WWTP in Spain over a period of six months and validated in the same WWTP three weeks after calibration. The promising results obtained support the suitability of the proposed instrument to identify the odor sources having the highest emissions, which may give a useful indication to the plant managers as regards odor control and abatement.

Gaseous pollutants from a small-scale aerobic biological treatment facility: odor and health risk assessment

BackgroundBiological treatment technology is good for the recovery of resources and energy from municipal solid waste (MSW) and cutting down biodegradable components in landfill waste. Recently, the aerobic biological treatment of MSW has increased in rural areas of China. These facilities are usually open setup and close to nearby residents, and complaints tend to be received regarding odorous gases. A semi-in-vessel setup facility was built in recent years, and its impact on the environment and personnel is not clear.ResultsAmmonia was the predominant compound released from the windrow and its concentration was one order of magnitude higher than those of other compounds. Terpenes and reduced sulfur compounds (RSCs) persisted throughout the entire active fermentation process, with only slight decreases. The biofilter pool had a greater odor impact on the surrounding neighborhood than the waste unloading and sorting operation. The concentrations of most compounds were reduced by the biofilter pool. Ten major substances that caused odors at the facility were analyzed, where most comprised RSCs. The odor impact of the facility was low, but it was associated with a carcinogenic risk to the operators, thereby indicating the need to improve personal protection.ConclusionsLarge amounts of ammonia and volatile organic compounds were released from the composting units, but they had a low odor impact on the environment because of the semi-in-vessel setup. The odor impact of the facility was low but it was associated with a carcinogenic risk to the operators. This technology can be popularized in rural areas.

Chemical Composition and Sensory Evaluation of Saffron.

The quality and economic value of saffron, one of the most counterfeited spices, are based on three key substances that are relatively easy to measure: crocines (colour); picrocrocines (bitter); safranal (odour impact). Despite being well-known, as their concentration is correlated to sensory intensity, a detailed sensory evaluation, performed by a trained panel, supported by advanced analytical approaches, may better show the relationships between saffron composition and sensory perception. Three saffron samples of different Italian origins (Sardinia and Tuscany) were evaluated by a trained sensory panel and their chemical composition was determined by HPLC (High Performance Liquid Chromatography) and spectrophotometry. Safranal concentration and the perceived odour intensity were positively correlated while relationships between picrocrocine and bitter perception were more complex to detect. By correlating (Multiple Factor Analysis) saffron sensorial and chemical profiles, this work aims at improving saffron characterisation while providing better information on the quality of this valuable spice.

Effect of ageing time on the volatile compounds from cooked horse meat

Volatile compounds from cooked and aged (0, 7, 14, 21 days) Hispano-Bretón horse meat (loin) were analyzed by solid-phase microextraction coupled to gas chromatography–mass spectrometry. A total of 77 volatile compounds were found, from which aldehydes were the predominant family. Most of the identified compounds had their origin in the degradation of lipids, with a negligible contribution of Maillard derived products. Odour impact ratios were calculated and used as indicators of the contribution of each compound to the total aroma and aldehydes were, in general, the major contributors to cooked horse meat aroma. Results revealed that ageing affected 15 of the volatile compounds detected. From them, hexadecanal and 2- and 3-methylbutanal significantly increased during ageing, presumably affecting the cooked meat odour as these have considerable odorant impact. Under the present study conditions, periods longer than 14 days would be necessary for significant changes in the volatile profile of cooked horse meat.

Identification of volatile sulfur odorants emitted from ageing wastewater biosolids

Volatile sulfur compounds (VSCs) are important sources of unpleasant odours in biosolid emissions. However, the study of VSCs may be limited by complications in their gas phase measurements due to reactivity, transformations and varying reported odour detection thresholds. A range of methods were used to quantitatively analyse VSCs in wastewater biosolid emissions. VSCs were identified in aged biosolid emissions by gas chromatography (GC) with a sulfur chemiluminescence detector (SCD) and mass spectrometry coupled with olfactory detection port (MS/O). In total, 10 VSC's were identified with two volatile organic sulfur compounds (VOSCs), allyl methyl sulfide and methyl propyl sulfide being reported for the first time in biosolid emissions. The emission patterns of different VSCs varied as the biosolids aged. Initially, the median concentrations of H2S, dimethyl sulfide (DMS), dimethyl trisulfide (DMTS), methanethiol (MeSH) and ethanethiol (EtSH) were orders of magnitude greater than their reported odour detection threshold, suggesting they would contribute to the odorous impact of the biosolids. The maximum H2S value was equal to 59.9 × 103 μg/m3 and was at least one magnitude higher compared to VOSCs, such as dimethyl disulfide (DMDS) (3.8×103 μg/m3), DMS (4.53 × 103 μg/m3), EtSH (2.83 × 103 μg/m3) and MeSH (3.25 × 103 μg/m3). Among the identified VSCs, H2S was the prominent odorant in terms of the magnitude and the frequency of detection, both initially as well as throughout storage. However, DMTS should be considered as a high priority or key odorant due to its odour activity value (OAV) and frequency of detection (sensorially detected in more than 75% of samples, with an OAVs higher than 1).

Odour Impact Assessment in a Changing Climate

(1) Background: The impact of odour sources as stock farms on neighbouring residential areas might increase in the future because the relevant climatic parameters will be modified due to climate change. (2) Methodology: Separation distances are calculated for two Central European sites with considerable livestock activity influenced by different orographic and climatic conditions. Furthermore, two climate scenarios are considered, namely, the time period 1981–2010 (present climate) and the period 2036–2065 (future climate). Based on the provided climatic parameters, stability classes are derived as input for local-scale air pollution modelling. The separation distances are determined using the Lagrangian particle diffusion model LASAT. (3) Results: Main findings comprise the changes of stability classes between the present and the future climate and the resulting changes in the modelled odour impact. Model results based on different schemes for stability classification are compared. With respect to the selected climate scenarios and the variety of the stability schemes, a bandwidth of affected separation distances results. (4) Conclusions: The investigation reveals to what extent livestock husbandry will have to adapt to climate change, e.g., with impacts on today’s licensing processes.

An innovative biofilter technology for reducing environmental spreading of emerging pollutants and odour emissions during municipal sewage treatment

Wastewater treatment plants (WWTPs) are known sources of contaminants of emerging concern (CECs) spreading into the environment, as well as, of unpleasant odors. CECs represent a potential hazard for human health and the environment being pharmaceutical or biologically active compounds and they are acquiring relevance in European directives. Similarly, the public concern about odour emissions from WWTPs is also increasing due to the decreasing distance between WWTP and residential areas. This study focuses on the effectiveness of the recently developed MULESL technology (MUch LEss SLudge; WO2019097463) in removing CECs and limiting odour emissions from WWTPs. MULESL technology has been developed for its ability to reduce up to 80% the sludge production from WWTPs. However, it is ought to evaluate if the benefits coming from sludge production reduction do not invalidate CECs removal or negatively affect odour emissions. Thus, the performances of a MULESL and a conventional WWTP (flow rate of 375 m3/d and 3600 m3/d, respectively) were compared while treating the same municipal sewage.Whereas both plants succeeded in removing the traditional gross parameters characterizing wastewaters (e.g. chemical oxygen demand, nitrogen), the MULESL was much more effective than the conventional one in terms of CECs removal for about 60% of the identified compounds showing, however, the same or lower effectiveness for about 30% and 10% of them, respectively. This result was attributed to the high sludge retention time and biomass concentration in the MULESL (enabling enrichment of slow growing microorganisms and forcing biomass to use unusual substrates, respectively), and to the biomass feature to grow in the form of biofilm and granules (favoring micropollutants absorption on biomass).Furthermore, odour impact analysis has shown that the MULESL was characterized by a much lower impact, i.e. 45% lower than that of primary and secondary treatments of the conventional WWTP.

Influence of Yeast Strain on Odor-Active Compounds in Fiano Wine

The type of yeast strain used for wine alcoholic fermentation dramatically affects its final volatile composition and, therefore, its sensory properties. In this study, the influence of four oenological Saccharomyces strains (three S. cerevisiae and one S. bayanus) on wine volatile composition was determined on the Fiano variety, a typical cultivar from the Campania region (Italy), fermented in oak barrique. Fiano wines were analyzed by means of gas chromatography/mass spectrometry (GC/MS) and gas chromatography/olfactometry (GC/O). The results showed that the four selected yeast strains had a significant impact on the majority of volatile compounds as shown by the concentration of volatile compounds and based on the Aroma Extract Dilution Analysis (AEDA) values for many of the odor volatile compounds. This resulted in a dramatic change of the odor impact of the wines, such as the “fruity” attribute, which was higher compared to the control, and caused some changes of other odor attributes, particularly “floral”, “phenolic” and “honey”. This research demonstrates the potential of using these selected yeast strains and this technological approach of oak fermentation for this typical white wine grape variety.

Impact of odour with high annoyance potential on human feeling, activity, and mood in odorimetric studies

Introduction. It is known that an extraneous odour can cause an adverse emotional reaction of a person and, as a result, reduce the quality of life, which is most likely the reason for a large number of complaints of air pollution from the population. The converse statement about the influence of a person’s emotional state on his/her perception of a smell can also be true. An assessment of the relationship between odour characteristics and emotional state of a person can be investigated in a laboratory olfactory-odorimetric study with the participation of specially trained investigators. The aim of this study was to analyze in laboratory conditions the impact of odour with high annoyance potential on human feeling, activity, and mood. Materials and methods. Ten 26-71-years healthy investigators of both genders, who have been psychologically tested with a block of standard psychological questionnaires to evaluate emotional stress expression and quality of life, took part in 2 series of odorimetric studies on the ECOMA T08 olfactometer. During this study, they assessed the odour intensity and annoying effect of multicomponent odorant with isopropyl mercaptan, ethyl mercaptan, and 2-butanethiol largest contribution (unpleasant odour). The influence of the odour on investigators’ feeling, activity, and mood before, during, and after odorimetry was determined using a FAM (feeling, activity, and mood) test card. The study results showed the perception of unpleasant smell to be connected with investigators’ age, emotional state at the time of odorimetry, and some indices of the life quality. It is established that the perception of the smell in its tangible concentrations can lead to increased activity and improved mood. At the same time, exposure to the odour in higher concentrations, in most cases, was associated with decreased activity and mood, as well as - for some investigators - with decrease of feelings regardless of age. The given work results comparison with data obtained in the only similar study of odour emissions of chewing gum production carried out with a common methodic approach and on the same equipment, demonstrated a qualitative similarity in the perception of an extraneous odour of different hedonic tone: a connection with age, background emotional state, and quality of life indicators. Moreover, it was revealed odours of different hedonic tones to influenced in the same way on investigators’ activity and mood indices. Conclusion. Although the obtained results do not allow us to unambiguously conclude which odour strength (concentration of odorous substances) is an unacceptable value for all investigators, the similar research implementation is necessary to study the odour impact on the human adaptation systems. In addition, the data obtained allow us to conclude that all complaints of the presence of an extraneous odour of any character and hedonic tone, are most often justified, deserve careful attention and a quick response from the sanitary services.

Influence of packing material on the biofiltration of butyric acid: A comparative study from a physico-chemical, olfactometric and microbiological perspective

The influence of bed material on the odor removal performance of a biofilter was studied. A compost-wood biofilter and a wood biofilter were treated with a gaseous stream contaminated with butyric acid and comparatively evaluated at pilot scale using olfactometric, physico-chemical and microbiological approaches. The variables analyzed in both biofilters were correlated with specific families of their microbiota composition. In addition to a higher nutrients content (nitrogen and phosphorus), the compost-wood biofilter registered maximum values in number of aerobic microorganisms (3.6·108 CFU/g) and in aerobic microbiological activity (≈40 mg O2/g VS of cumulative oxygen demand at 20 h). This may explain the higher performance of this biofilter compared to the wood biofilter, withstanding odor loads of up to 1450 ouE/m2·s with odor removal efficiencies close to 100%. The analysis of the microbial community showed that Actinobacteria, particularly the mostly aerobic Microbacteriaceae family, might play an important role in butyric acid degradation and hence reduce odor impact. The multidisciplinary analysis carried out in this work could be a very useful strategy for the optimal design of biofiltration operations.

Outcomes of a Citizen Science Methodology and Traditional Odour Impact Evaluation Techniques Applied in a Chilean Pilot Study

The EU Horizon 2020 call ‘’Science with & for Society’’ funded the D-NOSES project (Distributed Network for Odour Sensing, Empowerment and Sustainability), which aims to develop a methodology based on participatory strategies and collaboration among different stakeholders using an extreme citizen science approach. This paper presents the findings of this approach applied to a Chilean case study concerning a small community impacted by a municipal wastewater treatment plant. Results of odour observations gathered by citizens during a three-month period are compared with the traditional odour impact evaluation techniques such as field inspections. An adapted odour annoyance index showed a better accuracy for each assessment square compared to the odour impact characteristics. It also points out challenges of citizen participation and opportunities of combining both approaches.

Improving the Impact of Odour Nuisance in Thessaloniki: a Stakeholder Engagement Approach

Nowadays, it is widely acknowledged that the problem of odour pollution is extremely important and requires immediate action. The problem is high also at European Union’s political agenda, which highlights the issue of odours at European level and seeks to apply innovative tools, such as direct citizen participation and education, modelling and mapping tools, in order to tackle the problem and propose a related legislative framework and establish rules for controlling and reducing odour disturbances.In this context, a key feature is the creation of an exchange of views to inform and understand the nature of odour incidents, with the joint involvement of authorities, citizens, universities and odour producers, with the aim of exploring mutually acceptable solutions.To the best of our knowledge, there are very few studies that deal with the issue of odour nuisance, even less that focus on the western part of the city of Thessaloniki. The treatment of odour annoyance associated with industrial and other activities in the area of Dendropotamos, Menemeni, Kalochori is considered as an appropriate case for the implementation of this study. The combination of the odour issue and at the same time the environmental impact on the area make this case extremely interesting.The current study aims at proposing a methodology that is based on Citizen Science and stakeholder engagement, which provides for active participation in scientific endeavours that generate new knowledge or perceptions. The proposed approach is part of the methodology initiated by the European Commission Horizon 2020 Project D-NOSES. The main objective of the study is to understand the problem and through stakeholder engagement and the active involvement of as many parties as possible, who are affected by the problem, to improve the impact of odours in the area. Training seminars, bilateral interviews and discussions assisted in developing a common understanding and goals, while an electronic application, the Odour Collect, developed for this purpose can report 'real-time' odour incidents and give them qualitative features. The results from the case study of Thessaloniki are presented in this paper and could further assist decision makers and key player to propose measures for improving the current situation.Key words: Odour Nuisance; Odour; Citizen Science; Stakeholder Engagement; Stakeholders Consultation; Participatory Approach; Statistical Analysis; Thessal

Short Introduction to the Summary and Evaluation of the Odour Regulations Worldwide

When it comes to air pollution complaints, odours are often the most significant contributor. Sources of odour emissions range from natural to anthropogenic. Mitigation of odour can be challenging, multifaceted, site-specific, and is often confounded by its complexity—defined by existing (or non-existing) environmental laws, public ordinances, and socio-economic considerations. The objective of this paper is to review and summarize odour legislation in selected European countries (France, Germany, Austria, Hungary, United Kingdom, Spain, The Netherlands, Italy, Belgium), North America (USA and Canada), South America (Chile and Colombia), as well as Oceania (Australia and New Zealand) and Asia (Japan, China). Many countries have incorporated odour controls into their legislation. However, odour-related assessment criteria tend to be highly variable between countries, individual states, provinces and even counties and towns. Legislation ranges from (1) no specific mention in environmental legislation that regulates pollutants which are known to have an odour impact to (2) extensive details about odour source testing, odour dispersion modeling, ambient odour monitoring, (3) setback distances, (4) process operations, and (5) odour control technologies and procedures. Agricultural operations are one specific source of odour emissions in rural and suburban areas and a model example of such complexities. Management of agricultural odour emissions is important because of the dense consolidation of animal feeding operations and the advance of housing development into rural areas. Overall, there is a need for continued survey, review, development, and adjustment of odour legislation that considers sustainable development, environmental stewardship, and socio-economic realities, all of which are amenable to a just, site-specific, and sector-specific application.