How does a fly find its way to that mouldy banana lying concealed in a kitchen cupboard? A question of that order was posed by researchers at the University of Nevada. The answer seemingly offers clues as to how robotic systems might be trained to find the source of chemical leaks or odours, as explained in a study published in the journal Current Biology.

“We don’t currently have robotic systems to track odour or chemical plumes,” said co-author Professor Floris van Breugel. “We don’t know how to efficiently find the source of a wind-borne chemical. But insects are remarkably good at tracking chemical plumes, and if we really understood how they do it, maybe we could train inexpensive drones to use a similar process to find the source of chemicals and chemical leaks.”

A fundamental challenge in understanding how insects track chemical plumes is that wind and odours can’t be independently manipulated.

To address this challenge, van Breugel and co-author S. David Stupski used a new approach that makes it possible to remotely control neurons—specifically those associated with smell— on the antennae of flying fruit flies by genetically introducing light-sensitive proteins, an approach called optogenetics. These experiments, part of a $450,000 project funded through the Air Force Office of Scientific Research, made it possible to give flies identical virtual smell experiences in different wind conditions.

What van Breugel and Stupski wanted to know: how do flies find an odour when there’s no wind to carry it? This is, after all, likely the wind experience of a fly looking for a banana in your kitchen. The answer is in the Current Biology article, “Wind Gates Olfaction Driven Search States in Free Flight.” The print version will appear in the Sept. 9 issue.

Flies use environmental cues to detect and respond to air currents and wind direction to find their food sources, according to van Breugel. In the presence of wind, those cues trigger an automatic “cast and surge” behavior, in which the fly surges into the wind after encountering a chemical plume (indicating food) and then casts — moves side to side — when it loses the scent. Cast-and-surge behavior long has been understood by scientists but, according to van Breugel, it was fundamentally unknown how insects searched for a scent in still air.

Through their work, van Breugel and Stupski uncovered another automatic behavior: sink and circle, which involves lowering altitude and making repetitive, rapid turns in a consistent direction. Flies perform this innate movement consistently and repetitively, even more so than cast-and-surge behavior.

According to van Breugel, the most exciting aspect of this discovery is that it shows flying flies are clearly able to assess the conditions of the wind—its presence, and direction—before deploying a strategy that works well under these conditions. The fact that they can do this is actually quite surprising—can you tell if there is a gentle breeze if you stick your head out of the window of a moving car? Flies aren’t just reacting to an odour with the same preprogrammed response every time like a simple robot, they are responding in context-appropriate manner. This knowledge potentially could be applied to train more sophisticated algorithms for scent-detecting drones to find the source of chemical leaks.

University of British Columbia researchers say they have uncovered surprising insights into the Vancouver region’s “smellscape” using data from the Smell Vancouver app. Analyzing 549 reports from one year of app data, they discovered that “rotten” and “chemical” odours dominated, making up about 65 per cent of submissions. These unpleasant smells were linked to self-reported health issues like headaches and anxiety, leading some residents to change their behaviours, like closing windows even in stifling-hot weather.

“The reports illustrate how odours can be more than just a nuisance—they can impact physical and mental health, well-being, and quality of life,” said Dr. Amanda Giang, senior study author and assistant professor in UBC’s department of mechanical engineering and the Institute for Resources, Environment and Sustainability.

The app identified major sources of urban odours, including waste management and industrial activities. Four municipalities—City of Vancouver, Delta, Burnaby and Richmond—emerged as hotspots, each with its own distinct smell profiles and associated symptoms. Reports from Vancouver overwhelmingly focused on animal processing, while Delta saw higher complaints about garbage and compost, farming and cannabis.

Crowdsourcing science
With more than 3,500 reports logged, the app showcases the power of “crowdsourced science” in offering a more detailed view of urban air quality.

“Traditional air quality measurements are limited by their fixed locations and set sampling intervals, often missing the rapid onsets and impacts of odours,” explained Dr. Sahil Bhandari, co-author and former postdoctoral researcher in UBC’s faculty of applied science. “In addition, smell experiences are highly personal—what’s unpleasant to some people may be acceptable to others – and often occur in areas where monitors aren’t located. All this creates information gaps that traditional systems can’t address.”

Dr. Bhandari highlighted an instance where the app detected a strong foul odour from a refinery incident ahead of official reports, underscoring its potential for timely public awareness and emergency response.

Broader and more diverse participation
Despite these insights, more public participation is needed – for example, the app mainly attracted white women aged 30 to 49 without chronic health conditions and men from the highest income bracket. The researchers’ future studies will aim for more representative reports to provide a fuller picture of urban smells and their impacts.

Dr. Naomi Zimmerman, co-author and assistant professor of mechanical engineering at UBC said: “Integrating crowdsourced data into urban planning and policy can enhance responses to unpleasant smells. The SmellVan project underscores the need for policies that address odour sources, their broader health impacts and the importance of including diverse community demographics and perspectives.”

The study was published in July in the journal Environmental Research: Health.

A green technology for eliminating odorous volatile organic compounds (VOCs) and their by-products has been developed by a group from the Korea Institute of Industrial Technology (KITECH).

The research introduces a fuel-free technology for removing VOCs, thereby replacing incineration methods like thermal oxidizers and regenerative thermal oxidizers. This technology merges non-thermal plasma (NTP) with a wet scrubber (WS) system. Specifically, it employs atmospheric non-thermal plasma (ANTP) to enhance the scrubber’s VOC removal efficiency from 33% to 99.9% while minimizing the ozone generation typically produced by plasma, according to the group.

“NTP treatment stands out as a highly effective method for addressing odorous VOCs due to the production of high-energy electrons. These electrons destroy the structures of odorous gases and generate abundant radicals, which can be oxidized to CO2 and H2O, thereby increasing the reaction rate,” said the researchers.

WS systems are frequently used to remove odorous gases due to their relatively low cost and ease of handling. They have also been the subject of extensive research aimed at improving the economics of this kind of odour treatment.

This latest research introduces a process technology for removing VOCs that does not burn fuel, such as LNG, unlike conventional methods. As a result, it does not emit carbon dioxide through incineration. When deployed in industrial exhaust gas treatment facilities, both installation and operating costs are lower compared to those of the incineration method.

Compared to the separate use of NTP and WS, integrating a WS after NTP alters the kinetic characteristics and distribution of active particles, thereby improving the degradation efficiency of odorous VOCs. Additionally, the combined NTP and WS system can minimize or eliminate secondary air pollution by capturing ozone and other gaseous intermediate organics, which are by-products of the NTP process.

Because the NTP and WS system does not rely on chemicals or catalysts and eliminates the need for additional equipment to remove ozone, the total cost of the system, covering both installation and operation, can be reduced.

Dr Suhan Kim of KITECH said: “Our observations indicate that the removal efficiency within the NTP and WS system exceeds the VOC concentrations usually present in process gases from chemical facilities.”

He said he believed the combined NTP and WS system could be implemented in many industries as an effective gas treatment method, with the advantage that it does not produce ozone and is sparing of energy consumption.

Seemingly significant strides with the miniaturisation and performance of olfactory sensors have been reported by researchers at the Hong Kong University of Science and Technology (HKUST), with an approach said to mimic human olfaction. Commentary from the group places such developments at the outset of a prospective revolution enabled by the digitization of odour.

The digitization of visual information has been a transformative technology, an omnipresent feature of everyday life, and central to consumer products such as phones. A similar revolution might be starting to take place in the realm of odour, driven by the availability of miniature sensors.

HKUST’s latest publication demonstrates the use of innovative chip technology to address the long-standing challenge of creating artificial olfactory sensors with arrays of diverse high-performance gas sensors. Their newly developed biomimetic olfactory chips (BOC) are able to integrate nanotube sensor arrays on nanoporous substrates with up to 10,000 individually addressable gas sensors per chip, a configuration that is similar to how olfaction works for humans and other animals.

For decades, researchers worldwide have been developing artificial olfaction and electronic noses (e-noses) with the aim of emulating the intricate mechanism of the biological olfactory system to effectively discern complex odourant mixtures. Yet, major challenges with their development reside with the difficulty of miniaturizing the system and increasing its recognition capabilities in determining the exact gas species and their concentrations within complex odorant mixtures.

To tackle these issues, the research team used an engineered material composition that allows for wide arrays of diverse sensors on one small nanostructured chip. Leveraging the power of AI, their biomimetic olfactory chips are reported to exhibit exceptional sensitivity to various gases with excellent distinguishability for mixed gases and 24 distinct odours. With a vision to expand their olfactory chip’s applications, the team also integrated the chips with vision sensors on a robot dog, creating a combined olfactory and visual system that can accurately identify objects in blind boxes.

The group says the work will both improve the existing applications of e-noses in food, environmental, medical and industrial process control, while also opening up new possibilities with intelligent systems such as advanced robots and portable smart devices, for applications in security patrols and rescue operations.

For example, in real-time monitoring and quality control, the chips might be used to detect and analyze specific odours or volatile compounds associated with different stages of industrial processes to ensure safety. Or they might be used to detect abnormal or hazardous gases in environmental monitoring, or to identify leakage in pipes to facilitate timely repair.

The technology is claim as a pivotal breakthrough in the realm of odour digitization. As the scientific community witnesses the emerging preeminence of visual information digitization, facilitated by modern imaging sensing technologies, the realm of scent-based information has remained untapped due to the absence of advanced odour sensors.

The work conducted by the team led by Prof. FAN Zhiyong of HKUST has – says the group – helped pave the way for developing biomimetic odour sensors.

With further advancements, these sensors could find widespread utilization, akin to the ubiquitous presence of miniaturized cameras in cell phones and portable electronics.

A researcher in interdisciplinary materials science and engineering, Prof. Fan has worked on biomimetic sensory systems for more than two decades, including developing the world’s first spherical artificial eye with 3D retina in 2020.

“In the future, with the development of suitable bio-compatible materials, we hope that the biomimetic olfactory chip can also be placed on [the] human body to allow us to smell odour that normally cannot be smelled. It can also monitor the abnormalities in volatile organic molecules in our breath and emitted by our skin, to warn us [of] potential diseases,” he said.

The research work, carried out in collaboration with Tsinghua University, Jilin University and Prof. Fan’s start-up company Ai-Sensing Co. Ltd., was recently published in Nature Electronics.

A mathematical model that maps the relationship between the molecular structure of odorous substances and how they are perceived is claimed to have an edge over human experts, when it comes to identifying smells correctly.

A central undertaking of neuroscience is learning how our senses translate light into sight, sound into hearing, food into taste, and texture into touch. Smell is where these sensory relationships get more complex and perplexing.

To address this question, a research team from the Monell Chemical Senses Centre and start-up firm Osmo – a spinout from machine learning work undertaken at Google Research – are investigating how airborne chemicals connect to odour perception in the brain. They report that a machine-learning model has achieved human-level proficiency at describing, in words, how chemicals might smell. The research appeared in the 1 September issue of Science.

“The model addresses age-old gaps in the scientific understanding of the sense of smell,” said senior co-author Joel Mainland.

This collaboration moves the world closer to digitizing odours, which can be recorded and reproduced. It also may identify new odours for the fragrance and flavour industry that could decrease dependence on endangered plants, and identify new functional scents for things like mosquito repellent.

Brain-to-nose connection
Humans have about 400 functional olfactory receptors. These are proteins at the end of olfactory nerves that connect with airborne molecules to transmit an electrical signal to the olfactory bulb. The number of olfactory receptors is much more than we use for colour vision – four – or even taste – about 40.

“In olfaction research, however, the question of what physical properties make an airborne molecule smell the way it does to the brain has remained an enigma,” said Mainland. “But if a computer can discern the relationship between how molecules are shaped and how we ultimately perceive their odours, scientists could use that knowledge to advance the understanding of how our brains and noses work together.”

To address this, Osmo created a model that learned how to match the prose descriptions of a molecule’s odour with molecular structure. The resulting map of these interactions is essentially groupings of similarly smelling odours, like floral and candy sweets. “Computers have been able to digitize vision and hearing, but not smell – our deepest and oldest sense,” said Wiltschko. “This study proposes and validates a novel data-driven map of human olfaction, matching chemical structure to odour perception.”

What is the smell of garlic or of ozone?
The model was trained using an industry dataset that included the molecular structures and odour qualities of 5,000 known odourants. Data input is the shape of a molecule, and the output is a prediction of which odour words best describe its smell.

To ascertain the efficacy of the model, researchers conducted a blind validation procedure in which a panel of trained participants described new molecules, and then compared their answers with the model’s description. The 15 panelists were each given 400 odourants as well as trained to use a set of 55 words – from mint to musty – to describe each molecule.

In comparing the model’s performance to that of individual panelists, the model achieved better predictions of the average of the group’s odour ratings than any single panelist in the study, impurities aside. Specifically, the model performed better than the average panelist for 53% of the molecules tested.

“The most surprising result, however, is that the model succeeded at olfactory tasks it was not trained to do,” said Mainland. “The eye-opener was that we never trained it to learn odour strength, but it could nonetheless make accurate predictions.”

The model was able to identify dozens of pairs of structurally dissimilar molecules that had counter-intuitively similar smells, and characterize a wide variety of odour properties, such as odour strength, for 500,000 potential scent molecules.

A “lab-on-a-drone” system has been used to monitor hydrogen sulphide gas from the air above a wastewater treatment plant in Brazil, in a project that has been written up in the American Chemical Society publication Analytical Chemistry.

Hydrogen sulphide (H2S) – well known for its putrid, rotten-egg odour – is a problem pollutant associated with petroleum refineries and wastewater treatment plants. The gas is an irritant, and in high enough amounts, it can be toxic. Most methods to quantify H2S and other pollutants rely on ground-based instruments, and expensive devices such as satellites are required to collect measurements at higher altitudes. Unmanned drones have been used by researchers to gather samples in mid-air, but analyses still had to be performed on the ground with traditional instruments. So, João Flávio da Silveira Petruci and colleagues wanted to create an inexpensive “lab-on-a-drone” that could sample and analyze H2S gas while in the air and report the results in real time — seemingly a first for devices of its kind.

Using a 3D printer, the team manufactured a custom device that was mounted to the bottom of a commercially available quadcopter drone. It took advantage of a unique chemical reaction between H2S and a green-glowing fluorescein mercuric acetate molecule. When excited by an onboard blue LED light, the interaction caused a decrease in the green fluorescence intensity, which was detected and quantified. This reaction is highly selective and was not affected by other, interfering gaseous air pollutants.

The team took their drone to a wastewater treatment plant, where it sampled air on the ground, then at around 30 and 65 feet in the air at three different times throughout the day. The detection device transmitted its results via Bluetooth to a smartphone, allowing for real-time monitoring. In the evening, there was a clear increase in H2S concentration as the drone increased altitude, though it never exceeded the acceptable ambient level. The researchers say that this system could be adapted to detect other pollutants in the future.

The authors acknowledge funding from the Coordination for the Improvement of Higher Education Personnel, the Research Support Foundation of the State of Minas Gerais, and the National Council for Scientific and Technological Development.

Our MonashellTM and CrumRubberTM are patented sustainable technologies which use recovered materials as the critical filtration component. The unique properties of these materials enhance capture and treatment. They not only remove harmful atmospheric pollutants but also provide multiple environmental benefits in terms of circular economy, and carbon footprint (low water and energy requirement and no consumables).

During the past number of years along with parent company Anua Clean Air International and Italian sister company Air Clean SRL we have been very active in the UK, Ireland and in overseas markets including Italy, France, the Middle East, China and the US. International projects include Dual Pass Monashell installations in Riyadh, Jeddah, Laguna Lake in the Philippines, Coimbatore in India, and Sindos in Greece. CrumRubber technology has been installed in the Canary Islands, China, Oman, UK and Ireland. We are also very excited to be currently working with Air Clean USA on the delivery of a number of new installations in Massachusetts, Connecticut, Maine and Rhode Island, Anua Clean Air International also specialises in equipment health checks and process upgrades as well as optimisation and media replacement services. We have performed system health checks and media replacement services on many hundreds of worldwide biological air treatment installations.

www.anuacleanair.co.uk

Odour management expert Silsoe Odours explores how to understand, handle and prevent odour complaints.

Unpleasant odours can impact the health and well-being of those who live and work nearby. Facilities that emit odours will often have an odour condition in their operating permit. Your permit may specify acceptable levels of odour emissions, as well as protocols for responding to odour complaints. It is important to know how to handle these complaints, so that you can maintain a safe and comfortable environment for everyone. Doing so will also help you to meet your statutory obligations. As a result, you may avoid potential fines and legal consequences.

This article goes into detail about common sources of odour complaints, as well as practical solutions to prevent and manage them. By following these tips, you can be better prepared to handle odour complaints and protect the well-being of those around you.

Common sources of odour complaints
There are many industries which emit odours as part of their operations. The most common causes of complaints include;

• wastewater treatment plants
• food processing facilities
• waste management, landfills and composting sites
• agricultural operations
• chemical manufacturing plants
• commercial and restaurant kitchens.

Operators in these industries need to get the proper permits and comply with environmental regulations. Councils must look into odour complaints that could be a statutory nuisance.

Why is it important to address odour complaints?
If your site does anything that emits odours, you might get the odd complaint from people who live or work nearby. Even if it is just one complaint, it is important to investigate. If it is a valid problem and you don’t do anything about it, things could get worse. Failing to address odour issues can lead to several potential consequences. For instance, odours can affect people’s health and quality of life, which can hurt your relationship with the community. In turn, this can damage your site’s reputation. Additionally, violating your operating permit could result in fines and legal repercussions. All these things can take up a lot of time and money.

For every odour complaint you receive, there could be more than 250 negative contact points.

The consequences of failing to control odour: an example
In 2023, A North East company was fined almost £26,000 for failing to control odour and violating its environmental permit. The company faced legal action from the Environment Agency after receiving odour complaints from the public. This case highlights the importance of having a strong odour management strategy in place, as well as being equipped with the knowledge and tools necessary to prevent and address odour complaints.

Challenges in validating complaints
It can sometimes be difficult to address odour complaints because odours are subjective. The perception of an unpleasant odour can vary from person to person. Also, it can be hard to identify the source of an odour. Usually, this happens if there are a few different possible sources, or if the odour occurs over a large area. It can also be difficult to pinpoint the source of sporadic odour emissions. Sometimes, investigating an odour complaint can take a lot of time and resources. Even so, it is imperative to address complaints to avoid permit restrictions and legal consequences.

Your first step is to conduct odour sampling and surveys. This type of investigation will help you to understand the nature of the emissions. At Silsoe Odours, our odour consultants will help you figure out the best way to solve the problem. We will guide you on the best approach for your needs.

HANDLING ODOUR COMPLAINTS
Appoint appropriate personnel
Having a consistent person or team to manage odour complaints offers several advantages. For instance, they will know the details of previous complaints. This gives them a better understanding of possible issues, as well as effective methods to resolve them. A consistent liaison person also fosters trust within the local community. A recognisable face demonstrates accountability, prevents misunderstandings and helps build positive relationships. Furthermore, a centralised team is better equipped to maintain complaint-handling records. This is helpful if you need to show your actions to the regulator or in court.

Objectives when handling complaints
When you receive an odour complaint, you should have three main objectives. Firstly, you must assure the complainant that you are taking the issue seriously. Doing so can help you maintain positive community relationships. Secondly, investigate the complaint to determine its legitimacy. Finally, if you find the complaint to be valid, you should take prompt corrective action to address the issue. Your specific actions will depend on your site. That said, we have outlined a simple and effective approach you can follow.

How to respond to odour complaints

• Acknowledge and Understand the Complaint. Begin by acknowledging the complainant’s concerns and assure them that you will investigate the manner. Gather information about the time, location and nature of the odour. This will help you to identify the potential problem. If the Environment Agency becomes involved, they will also follow similar steps. You may find the Odour Complaint Report form in their H4 Odour Guidance helpful.
• Investigate. Investigate the complaint promptly and thoroughly. Conduct odour sampling and surveys to determine the source and nature of your odour emissions. You can also use the results to confirm whether your odour abatement equipment is working as it should be. We recommend seeking support from an experienced odour consultancy to ensure your investigation is effective. You can contact Silsoe Odours for guidance.
• Communicate the Findings. Communicate the findings of the investigation to the complainant. Explain how you plan to resolve the issue and the expected timeframes. By demonstrating transparency and accountability, you can build trust and positivity. In some cases, you may also be required to do this as part of your permit stipulations.
• Resolve the Issue. Take action to fix the problem. For example, you might need to change some of your processes and operating practices. You could also install or update odour control equipment and ventilation systems. Put in place best practices to maintain and check the changes made. You should have an Odour Management Plan which outlines how you manage odours on your site. This will form part of your ongoing permit compliance actions.
• Close the Complaint. Lastly, you can take steps to close the complaint. Let the complainant know that the issue has been resolved. You may find it helpful to ask them for feedback on how you handled the issue. This can provide valuable insights for possible improvements. Update your records to show that you have resolved the complaint and archive related documentation. Remember, it is important to keep detailed records of all complaints.

PREVENTING ODOUR COMPLAINTS
The importance of regular monitoring and maintenance
One of the most effective ways to prevent odour complaints is to make sure your odour management practices are in tip-top shape. Designing effective odour control systems and processes is important. But, one of the most common mistakes operators make is to not track these systems once they are in place. Regular odour monitoring allows you to spot when things start to go wrong. This means that you can rectify them before they cause major problems. With this in mind, establish regular maintenance and cleaning procedures to ensure all your odour control equipment is working. You should also develop an odour management plan that includes best practices for managing emissions. For example, regular sniff surveys and odour sampling can be valuable tools.

Community engagement
We have outlined the importance of effective communication with complainants. You can also enhance your relationship with the wider community by creating an open dialogue. Publicise any changes to processes or systems that may affect odour emissions. When there are problems, provide updates on how you have solved them. Give details of the person or team responsible for odour complaints. You should also make sure that they are easy to contact. By being transparent and accessible, you may even receive informal reports of odour issues before they escalate into formal complaints.

It is crucial to understand, handle and prevent complaints. If you follow the practical solutions we have outlined in this article, you can:

• manage and prevent odour issues
• protect the well-being of your community
• comply with your statutory obligations.

For more advice from our experienced team of odour consultants, call 01525 860222, email info@silsoeodours.co.uk, or visit our website.

A waste to energy (WtE) plant in northern Paris, known as the ‘L’étoile Verte’ or ‘Green Star’ waste recovery facility, which was originally built in an industrial area, is now surrounded by residential development. This has presented a number of challenges; not least of which is odour. The company ELLONA has therefore been contracted to establish a smart continuous odour and gas monitoring network, so that the sources of odour can be identified, and improvement measures can be underpinned by scientific data.

“The ELLONA monitoring network was established for a number of reasons,” says Claire Bara, Syctom Director of Urban Ecology and Environmental Regulation. “Firstly, it was clear that we would need continuous monitoring to be able to identify odour events. Secondly, air quality monitoring alone would be insufficient because of the complexity involved with odour detection and perception. Thirdly, the identification of peaks would enable us to correlate odours with specific processes and locations within the plant. So, by identifying the main sources of odour, we would be able to implement improvements that would also be monitored by the ELLONA network.

“Classical modelling tools would not be able to accommodate the complexities of the urban environment, so one of the main aims of the tool was to be able to identify every odour source – both on-site and in the surrounding neighbourhood,” Claire explains.

Importantly, ELLONA worked in partnership with the high-performance computing and modelling company NUMTECH to model the complex air flows that take place in the plant and in the surrounding urban environment.
Each of the nineteen ELLONA monitors (WT1) at Green Star features a comprehensive array of sensors measuring temperature, humidity, pressure, hydrogen sulphide, ammonia and VOCs. Other important variables are wind speed and direction, which have obvious effects on odours.

The WT1 units store measurements internally, but the data are also transferred to the Cloud every 10 seconds for processing. Data from the physical sensors and from the virtual sensors (created from the physical sensors’ data and mathematical models) provide information on air quality, odour identity, intensity and duration. The measurements and the derived odour information are provided in real-time to Syctom via a dedicated website, which also provides the ability to view historical data.

Looking forward, says the group, “odour nuisance will be reduced further by implementing and assessing mitigation measures. The constituents of household waste may change, but with the monitoring system in place, Syctom will be able to respond appropriately to any variations in odour generation.”

The Variable Monetary Penalty (VMP), the first in Scotland served by SEPA, was issued to Paterson’s of Greenoakhill Ltd due to offensive odour issues at the site between 8 and 15 June 2021. The company was also required to pay £1,156.35 of SEPA’s costs.

Odour from the landfill site has had an impact on the local community for many years, says SEPA, which has used a range of enforcement powers to try and tackle this.

Site visits by SEPA officers in March 2021 identified concerns with a new tipping area, known as the Cell 10 Extension, that was closer to Hamilton Road and nearby domestic properties. As the cell was close to the site boundary, SEPA advised that maximum controls would be required to manage odours.

In April 2021 the operator started depositing waste in the new area and this led to a change in the odours reported, with the main description being rotten waste/bin smell. SEPA repeated the advice about the need for adequate odour control measures.

Between 8 and 15 June 2021 the site breached its permit on five separate occasions causing detriment to the surrounding community – as evidenced by substantiated offensive odour assessments by SEPA officers. The incident occurred during a period of hot weather including evenings and weekends.

Witnesses described several impacts, including disruption to daily life – being unable to use gardens, cancelling social gatherings, sending children to stay with relatives and being unable to use the local park for exercise. While odour can be subjective, SEPA said its officers substantiated offensive odours on five separate occasions during that period and identified the source of those odours as the Paterson’s of Greenoakhill Ltd landfill site.

Pamela Armstrong, SEPA Greater Glasgow and Clyde Unit Manager, said:  “We tried to work with Paterson’s of Greenoakhill Ltd to address the issues and secure compliance but were unsuccessful. We believe a VMP is the appropriate course of action in this case.

“The eight-day period of odour the community had to deal with was significant and was due to a lack of reasonable care by the operator. It chose to dispose of waste in an area significantly closer to housing than previously, and continued to do so throughout the eight days, despite being notified by SEPA that offensive odours were being recorded off-site.

On 22 July 2021, SEPA served an Enforcement Notice which required, amongst other actions, the operator to cap the Cell 10 Extension. SEPA confirmed that this work was completed in December 2021 and odour assessments carried out by officers, along with a reduction in pollution reports, indicates that the capping material is providing improved odour control in this area. The new waste deposit area is further away from the nearby road and housing, and the operator has committed to undertaking daily off-site odour checks. The operator currently deploys odour neutraliser units near the waste deposit area to try and mask any strong odours, these are operational during office hours. The site has also started to engage with local community councils, which allows for a better understanding of the impacts site operations are having on those living nearby and enable earlier intervention to reduce the impact.

Throughout 2022 there has been a reduction in odour events at Paterson’s landfill site. However, there has been a rise in odour complaints over recent weeks. SEPA officers attended the site on 6 December and identified an area of the landfill which has started to produce landfill gas. The site has agreed to bring forward landfill gas infrastructure works which will aim to collect and treat the gas through the on-site landfill gas management system. These works were scheduled for completion by 18 December and Paterson’s will then undertake a gas survey of the landfill site to identify if there are any further sources of fugitive gas emissions.