The invisible threat of indoor air pollution

IAQ in action.

According to the World Health Organisation Air Pollution - both indoor and out -  is responsible for about one in every nine deaths annually and this will only get worse unless we take action to mitigate the risks. What is to be done? Sutart Smith of Zehnder has suggestions.  

Air pollution, both outdoor and indoor, is the most significant environmental health risk around today. According to the World Health Organisation it is responsible for about one in every nine deaths annually and this will only get worse unless we take action to mitigate the risks.

Although air quality has gradually improved in recent times, air pollutant concentrations “still exceed the 2005 WHO air quality guideline levels in many areas*” – meaning they are over the air quality guideline levels that are associated with important risks to public health.

Indoor air pollution is often overshadowed by its outdoor counterpart, with well-known figureheads leading the charge on climate change and environmental concerns, but it demands equal attention. It is widely known that indoor air can contain concentrations of pollutants up to five times higher than those found outdoors, so with almost 90% of our time spent inside, we need to highlight the risks and educate harder on how we protect ourselves from this invisible threat.

In a recent Zehnder study, which explored people’s attitudes towards air pollution both inside and out as well as assumptions about hidden air pollutants inside, we found that four in ten people living in the UK are still unaware that indoor air pollution could be harming their health.

A quarter of people polled say they have always assumed that the air inside is safe, with 41 percent disagreeing that outdoor air pollution affects indoor air quality. Yet the majority questioned (83 percent) wish they knew more about air pollution, opening the door for us to provide better signposting and information about levels of indoor air quality (IAQ). 

Modern methods of construction aren’t helping either. In our efforts to reach net zero targets and build more sustainably, buildings are becoming more airtight. This is a great thing for energy efficiency - using triple glazing, insulation and providing a more robust, sealed up building envelope to conserve energy - but without effective ventilation, buildings lock in polluted air and put occupants at severe risk. Yet adequate ventilation is still being considered as a secondary priority in the construction process.

Tiny particles, big problems

When it comes to air quality, we predominantly focus on measuring particulate matter (microscopic particles of solid matter suspended in the air) of PM 10 and PM 2.5 in size. These particulates are known as Fine Particulate Matter (FPM) and, even at this diameter, can get into the lungs and cause health problems.

While the larger particles, PM 10 and PM 2.5, are well-researched within the industry and levels within ‘safe’ guidelines are benchmarked by WHO, by only looking at FPM we aren’t seeing the bigger – and more frightening – picture. 

More recent studies have found that Ultra-Fine Particulate Matter (UFP), like PM1, are considered even more dangerous due to its extremely small size. A typical PM1 particle has a larger physical surface area, despite its smaller diameter, than other fine particulates and this makes PM1 more likely to carry heavy metals, chemicals, and volatile organic compounds (airborne chemicals) on its surface and cause even greater harm when inhaled.

Once in the lungs, PM1 can get into the bloodstream and travel through the body and cause serious health problems with regular exposure. Chronic exposure has been associated with respiratory diseases and aggravating existing conditions like asthma - and these pollutants can also lead to cardiovascular diseases. Prolonged exposure to PM1 can affect the heart and blood vessels too, causing inflammation and oxidative stress, which could potentially lead to heart disease, stroke, and high blood pressure.

The majority of airborne PM1 originates from human activity like emissions from factories and other industrial activity, vehicle exhaust, tire particles from vehicles and types of smoke. It’s because of this that densely populated urban areas, especially those with busy roadways or industrial facilities, are especially prone to PM1 pollution as well as other types of particle pollution.

While there are less studies and knowledge around the harm UFP cause, the very make-up of the particles underscores the latent risks to public health and the urgent need for comprehensive mitigation strategies.


Industry's Role in Improving Air Quality

Whatever their size, airborne pollutants are dangerous to human health and are present inside our buildings, often in built up concentrations. Businesses and industries have a significant role to play in removing them through effective ventilation and as a result improving the IAQ for occupants inside.

Commercial ventilation is a crucial part of managing indoor air quality in mass-occupied spaces and helps reduce the concentration of VOCs and particulate matter, including PM1, in the air.

But hitting the minimum requirements isn’t enough. Part F of the UK Building Regulations mandates the performance of ventilation systems to achieve the desired inflow of fresh air and outflow of pollutants within buildings. At present, however, Part F only sets minimum requirements for the rate of fresh airflow into a building – to ensure there is a sufficient supply of fresh air to push out pollutants. It does not stipulate requirements for how that fresh air is circulated once it is within the building envelope.

Although this is not a major issue for smaller buildings, it becomes more problematic the more extensive the internal space and the greater the area supplied by a given ventilation system. Imagine, for example, a spacious office where individuals seated close to a ventilation terminal enjoy an optimal flow of fresh air, precisely as per system design. But, in contrast, those located at the far end of the office may encounter a diminished circulation of fresh air, as it must traverse through their colleagues before reaching them.

This complexity is further compounded when alterations are made to a building's layout, be it through expansion or refurbishment. What may have once constituted an effective method of air circulation during the initial construction may no longer prove suitable. For example, when an internal structure of an office is modified due to a change of use or increase in personnel.

Adjusting the ventilation system to address these modifications isn't always a feasible option and, in these cases, systems will need renewed consultation to assess the requirement and maintenance going forward.

A ventilation system must also be serviced properly to ensure it functions as intended. Regular maintenance of these systems is crucial - such as changing filters annually and ensuring extract fans are in operation.

Furthermore, businesses should consider investing in air quality monitoring devices. These tools provide real-time data on air quality, allowing for immediate responses when pollutant levels exceed safe thresholds.

The Future of Indoor Air Quality Management

IAQ deserves to be a top priority for businesses and individuals alike. Though the challenge is considerable, proactive steps, such as improving ventilation, monitoring air quality, and reducing pollutant sources, can lead to safer and healthier indoor environments. As we strive to understand and mitigate these invisible threats, our efforts will contribute to a healthier and more sustainable future for everyone.

The future of IAQ management is expected to be more dynamic and integrated. Advancements in technology, like more smart devices capable of detecting and responding to changes in indoor air quality in real time, will be key to further education.

Added development in AI and IoT could also revolutionise indoor air quality management by automating responses, like adjusting ventilation rates or air filtration based on real-time pollutant levels. This blend of advanced technology and a proactive approach to indoor air quality will usher in a new era of healthier, safer indoor environments.

*World Health Organisation European Health Report 2021

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