Home NEWS Features The Silent Threat: Air pollution from Kiamaiko slaughterhouses

The Silent Threat: Air pollution from Kiamaiko slaughterhouses


In the early morning hours, Nairobi’s Kiamaiko area springs to life with a vibrant of activity at the local slaughterhouses.

As I make my way through the busy streets, the distant sound of bleating goats grows louder. Trucks and lorries arrive in succession, each transporting a load of goats destined for the slaughter. The animals, alert and restless, are guided off the vehicles into holding areas. The air around carries more than the sounds of bustling markets and neighborhood life. The air hangs heavy with the residue of organic decay producing a nauseating stench especially pronounced after the recent rains, which acted as a catalyst for the production of this pervasive odor. Solid waste from condemned meat, skins, and fecal matter mingles with liquid effluents—blood and bodily fluids—that flow untreated into the Nairobi River.

One worker, unable to escape the onslaught of pollutants, involuntarily spat at the doorstep, a gut reminder of the toll exacted by this silent threat. Ali Mohammed, the seasoned worker at one of Kiamaiko’s slaughterhouses for the past 15 years, has grown accustomed to these odors. Over the

years he has suffered from persistent headaches and recurring colds that he once attributed to mere occupational hazards. It never occurred to him that these ailments could be linked to the very air he breathes day in and day out. “It’s just part of the job,” Ali says in a weary tone. “After all, everyone around me complains of the same symptoms. We all get these things from time to time. This is our source of income. You learn to live with it” he asserts.

Dr. Paul Njogu, Chair of the N-AIR Research and Data Committee, underscores the long-term respiratory health effects of prolonged exposure to these pollutants from the slaughterhouses on both workers and nearby residents. He stresses the importance of proper ventilation systems to ensure adequate air exchange and dilution of gases within the facility. Regular maintenance and cleaning of holding areas, waste disposal sites, and sewer systems are essential measures to minimize the buildup of organic matter and subsequent gas emissions.

Ali and his co-workers at the Kiamaiko slaughterhouse don’t wear masks as part of their protective gear. Instead, they rely on dustcoats and gumboots to avoid getting stained during the operations. For them, it’s more about practicality than safety. In this demanding environment, even those who handle the intestines and other visceral parts of the animals, working in close proximity to airborne particles, go without masks. They have adapted to the challenges. The collective assumption is that they’ve built up a tolerance over the years. They don’t believe their health could take a toll, even though the air they breathe is heavy with odors and contaminants.

On 8th March of this year, National Environment Management Authority (NEMA) led a multiagency effort to suspend government services to Kiamaiko slaughterhouses, including meat inspection, public health services, and permit issuance by Nairobi City County and Nairobi water and sewerage company.

“The decision to enforce closure stems from longstanding concerns regarding the handling of blood and offal, as well as the improper treatment of wastewater discharge, as outlined in the Water Quality Regulations of 2006,” said NEMA.

The multi-agency emphasized that the intention behind these enforcement measures wasn’t aimed at impeding the legitimate trade of meat or the operation of butcheries. “Rather, the focus is squarely on addressing the specific deficiencies observed within the slaughterhouse facilities themselves which degrade the environment.”

Dr. Njogu, highlights the impact of animal waste on air quality within Kiamako slaughterhouses. He explains that as animal waste, including blood, urine, and fecal matter, is released during processing, it contains bacteria that continue to break down if left exposed. “This decomposition process releases microbial contaminants like bacteria, viruses, and fungi, which can become aerosolized during various operations. Improper disposal of slaughterhouse waste into sewer systems without adequate pretreatment further exacerbates the issue” he further notes. Dr. Njogu emphasizes that the decomposition of organic matter in wastewater releases significant amounts of methane, contributing to air pollution.

Right behind the slaughterhouses, in a dimly lit storage space, I spoke with a worker, who sought to remain anonymous, who handles goat skins in these unsanitary conditions. The space is cramped, with piles of discarded skins stacked against the walls. As he sorts through stacks of goat skins in the poorly ventilated storage area, he is keenly aware of the musty odor that hangs in the air. “These skins can accumulate here for as long as thirty days depending on how fast they sell. Moisture from blood and other bodily fluids, combined with the warm, humid environment, creates the perfect breeding ground for mold and fungi. Inhaling this air makes every breath heavy” he explains.

“I have developed chest allergies, but work has to be done.” As the discarded skins sit in the storage areas, any residual organic matter begins to decompose. The presence of moisture from the salted skins can accelerate this process. The decomposition of organic materials releases gases such as methane and hydrogen sulfide into the air. These gases contribute to the foul odors and pollution within the storage spaces. Limited ventilation in these storage areas allows these gases to accumulate, creating a stagnant and polluted atmosphere. Despite the evident risks, Ali and his coworkers are convinced that their health can withstand the daily onslaught.

According to Gideon Lubisia, an air quality expert at Airqo, untreated waste releases air pollutants whose chemical composition has great amounts of hazardous elements such as metals and organic carbon that prolonged exposure causes damage to human health. As effluents are disposed of without pretreatment, the air becomes heavy with odors and contaminants. “Pollutants surrounding the slaughterhouses such as particulate matter, ammonia, sulphur oxides among others should be monitored for the health of the people living close or working in the slaughterhouses,” he notes.

Air is said to be polluted when it is contaminated as a result of alteration of its natural composition. Contaminants such as dust, fumes gas, mist, odors, smoke or vapor could be present in the polluted atmosphere in such quantities, and for such period of time that make them injurious to human, plant or animal life. According to the State of Global Air 2020 report, air pollution contributed to 6.67 million deaths in 2019 globally while in Kenya more than 28,000 deaths were linked to air pollution. In addition, the National Economic Survey 2017 estimated that 19.9 million Kenyans suffer from respiratory ailments that are exacerbated by poor air quality.

Click here to see Percentage of Cause-specific deaths linked to air pollution

Globally, slaughterhouses are recognized as significant contributors to air pollution. The extent of their impact on air quality ranges from minor to major, depending on the implementation of control measures. Failure to address emissions can result in environmental nuisances and pose threats to public health.

Pathways of air emissions from the slaughterhouses

Speaking during an interview, Dr Njogu goes ahead and explains the production of the pollutants during the slaughterhouse operations. As animals are processed within slaughterhouses, a complex interplay of gases emerges, each with its origins and implications. Carbon dioxide (CO2), a natural byproduct of animal respiration and metabolism, is released as livestock are herded into slaughter lines.

In the interior of slaughterhouses, methane (CH4) emerges as a consequence of organic decay. The decomposition of animal waste, discarded tissues, and offal in holding areas generates methane gas. Anaerobic digestion of organic materials in wastewater treatment systems within slaughterhouses also releases methane into the atmosphere.

Ammonia (NH3), one of the most potent gases encountered in slaughterhouses, originates from the breakdown of urea in animal urine and feces. Bacterial decomposition of animal waste releases ammonia vapors into the air, alongside ammonia-based cleaning agents used for sanitation purposes.

Hydrogen sulfide (H2S) is produced during the decomposition of sulfur-containing amino acids in organic matter within slaughterhouses. This gas can be released during organic breakdown in anaerobic conditions, contributing further to the air pollution burden.

Impacts on Air Quality and Public Health

The continuous release of these gases creates a potent mix that affects both indoor and outdoor air quality around slaughterhouse facilities. High concentrations of these pollutants pose various health associated risks to humans. Ammonia and hydrogen sulfide irritate the respiratory system, causing symptoms such as coughing, wheezing, and throat irritation. Volatile organic compounds (VOCs) from organic waste decomposition exacerbate respiratory issues and may contribute to asthma and other respiratory conditions.

Methane displaces oxygen in the air, potentially causing asphyxiation in confined spaces which can lead to suffocation or unconsciousness due to lack of air. Fine particulate matter (PM2.5) from animal waste adds to the air pollution burden, posing risks to respiratory health and overall well-being.  Long-term exposures to air pollution contribute to increased risk of illness and death from ischemic heart disease, lung cancer, chronic obstructive pulmonary disease (COPD), lower-respiratory infections (e.g., pneumonia), stroke, type 2 diabetes, and, more recently, adverse birth outcomes.

Click here to see the Trends of Air Pollution Related Health Conditions in Nairobi

The detrimental health effects of slaughterhouse effluents are keenly felt by both workers within these facilities and residents living nearby. Despite its invisible nature, the impact of this pollution is evident, seeping into the lungs of workers with each breath drawn. These workers, often without adequate protective gear like masks, face increased risks of respiratory infections and other health issues due to prolonged exposure to slaughterhouse emissions.

A worker in one of the unsanitary goat skin storages

Residents living in proximity to these slaughterhouses corroborated these accounts, expressing their frustrations over the widespread emissions that infiltrate their homes. In a cruel irony, residential flats doubling as ground-level slaughterhouses contrast the daily routines of family life with the pungent realities of slaughterhouse effluents. The situation highlights a contradiction with Kenya Standards, which require slaughterhouses to be separated from residential or other non-processing buildings.

One of the Kiamaiko slaughterhouses sharing the same block with the residential houses

With the many slaughterhouses, butcheries and eateries occupying ground- and first-floor levels of high-rise blocks, environmental officials’ worries about slaughterhouse leakages and animal waste contaminating the air, nearby river and animal trading within designated residential areas.

“In Kiamaiko, we’re struggling with serious air pollution issues,” says Doreen Muthoni, a longstanding resident. She notes with concern that the air quality has been deteriorating, attributing much of the problem to the emissions and odors from nearby slaughterhouses. Doreen also contends with the dust generated by lorries transporting goats, which is dumped directly on the goat market site in Kiamaiko. These activities create significant dust clouds that contribute to air pollution in the area.

Doreen herself has experienced firsthand the health effects of this pollution. “The odors from the slaughterhouse effluents are something many of us have sadly gotten used to. I’ve suffered from respiratory issues due to the poor air quality,” she shares, recalling instances of coughing and difficulty breathing. These health challenges have compelled her to seek relief through over-the-counter painkillers from a nearby chemist, highlighting the limited options available to manage her symptoms. Doreen believes if the slaughterhouses could comply with the standards set, then maybe they would not have to suffer. “It’s about taking steps to protect our health, even if we can’t change everything overnight”.

Dr. Desire Ndayirukiye, a physician at Al-Basrah Hospital located near the slaughterhouses, has observed a significant number of workers presenting with chest problems and respiratory issues. Many of these complaints are linked to their exposure in the slaughterhouse environment. Dr. Ndayirukiye emphasizes the importance of wearing masks to minimize direct inhalation of harmful substances. He also advocates for implementing proper sanitation practices and effective waste treatment procedures within the slaughterhouses to reduce the health impacts on both workers and residents. These measures are essential for safeguarding respiratory health and improving overall well-being among workers in the area.

Unsurprisingly, slaughterhouses were cautious about our efforts to interview or film within them. Rumours abound that influential interests behind the slaughterhouses have managed to delay the authorities. Much remains uncertain about Kiamaiko’s future.

Solutions and mitigation efforts

According to Maurice Kavai, Deputy Director, Air quality and Climate Change for Nairobi county government, an estimated 33% of Nairobi’s air pollution is attributable to poor waste management. He however says that the city has recently taken major steps to manage air pollution. This includes the development of an Air Quality Action Plan which will implement and enforce improved policy and regulatory frameworks for air quality management.

With the regulatory oversight failures there is need to implement strict guidelines which must be enforced for the proper handling and disposal of solid waste. Liquid effluents containing blood, urine, and fecal matter must undergo thorough treatment before disposal into sewer systems or nearby water bodies. The law-specifically CAP 356 of the Meat Control Act and CAP 387 of the

Environmental Management Coordination Act states clearly the requirements of slaughterhouses in regards sanitation measures such as removal of blood, offals and garbage and control of effluent treatment and solid waste disposal systems.

Additionally, ventilation and air quality monitoring play vital roles in combating air pollution from slaughterhouses. Installing adequate ventilation systems within these facilities improves indoor air quality by reducing the concentration of airborne contaminants. Regular monitoring of air quality using appropriate equipment allows us to identify pollution hotspots and take timely corrective actions to mitigate the impacts.

Furthermore, promoting the use of personal protective equipment (PPE) among slaughterhouse workers is essential. Masks and respirators can help minimize direct exposure to airborne pollutants.

This story was produced with the support of Earth Journalism Network (EJN)

Soila Arasha
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