Shift or Drift

The urgent need to align our built environment and human health becomes more apparent with every pandemic, wildfire, and the resulting boom and bust of air quality. Unmasking air quality ignorance is essential amid the noise and need for consistent definitions of clean and fresh air, healthy buildings, and sustainable living.

If the health and well-being of city inhabitants is the main intent of building cities, then urban development should have a human-centric foundation. The myopia of focusing only on providing thermal comfort for conventional buildings and their envelopes neglects the intricate connections between the built environment and how it is designed, constructed, and operated.

In today's rapidly urbanizing world, it is evident that human-centric and healthfocused architecture is the essence of enabling sustainable living. Ultimately, worsened urban and indoor air quality

Changing Mindsets to Transform Cities into Health-Focused Hubs of Sustainable Architecture

Filtered with Clean and Fresh Air

Dr. Iyad Al-Attar

necessitates dynamic governance to mitigate potential health implications due to wildfires, sandstorms, pandemics, weather inversions, industrial accidents, and other environmental disasters. Therefore, policies and politics must govern through technological innovations to navigate the emerging climate change challenges impacting cities and businesses worldwide.

The World Health Organization (WHO) (2014) has identified air pollution as the most significant environmental threat to health, leading to respiratory and cardiovascular conditions. In 2019, greenhouse gas (GHG) emissions from transport and buildings accounted for 15% and 16%, respectively1. Immediate action is needed to steer our planet towards a sustainable trajectory by retooling businesses with sustainable models that embrace purpose and profit. Countries and communities must tap into an ethical shift in how we live, commute, consume resources, generate, and use power. Cities can substantially reduce their emissions by promoting efficient industrial processes, healthy and energy-efficient buildings while reducing reliance on motorized transport and fossil fuel combustion.

The Filtration Myopia

It may seem utopian to tackle urban air quality issues and filtration challenges to improve human health and well-being through reinvigorated urban design. Striving for the highest living standards must go beyond constructing buildings that focus on pleasing aesthetics, structural integrity, and thermal comfort. Incorporating air quality into urban design standards ensures that buildings contribute to, rather than detract from, urban air quality, providing healthy indoor environments for occupants. The premise of understanding the interconnectedness of urban planning lies in addressing the intricate correlation of air quality with other factors such as transportation, energy use, waste management, and land use. Therefore, a holistic approach integrating air quality into these elements gives a starting point for creating cleaner, greener, and more sustainable cities.

Exposure to Urban Pollutants

Application-focused solutions are necessary to address the insights needed to reduce air pollution and filter out harmful particles that can enter our buildings and respiratory systems. Most aerosols contain a range of particle types and sizes, and to appropriately select air filters, their concentrations and size distributions must be considered. Airborne pollutants such as particulate matter (PM) (Figures 1, 2, and 3), gases, and bioaerosols represent a major health risk to city inhabitants indoors and outdoors. In urban environments, outdoor pollutants emitted from automobile exhaust, power stations, and industries can inundate installed air filters in HVAC systems and infiltrate buildings through structural openings or porous surfaces. Examples of these emissions can range from PM to nitrogen and sulfur oxides, ammonia, radon, volatile organic compounds (VOCs), and microbial volatile organic compounds (MVOCs), which are only a few examples of gaseous pollutants that can negatively impact urban air quality. When outdoor air is brought indoors through HVAC systems, it can contain high concentrations of contaminants (Figure 4) depending on their geographic location, potentially leading to premature clogging of air filters (Figure 5). Higher concentrations of gaseous pollutants require deep beds of chemical filtration for complete removal, necessitating more space and energy for installation and operation, respectively.

Thinking Beyond Particle Capture

Capturing various contaminants can be technically and economically challenging in light of increasing anthropogenic emissions, and sustainable operation of multistage filtration can be energy-intensive. Therefore, the challenge of urban air filtration for city dwellers – from outdoor to indoor settings – involves addressing complex exposure to multiple pollutants with different physical and chemical characteristics. From a health perspective, a comprehensive understanding of the staggering complexity of multiple pollutants exposure and their impact on HVAC systems and air filter performance is essential.

Air quality can vary due to inconsistent filter performance, where filter capture efficiencies cannot be guaranteed amid fluctuating ambient conditions and urban air quality prompted by environmental events such as sandstorms and wildfires. Indeed, there is an emerging emphasis on widening the lens of air quality to think beyond filtration technologies when drafting and crafting our urban plans.

A comprehensive approach to air quality should entail filtration systems that address gaseous and bioaerosol pollutants, going beyond traditional particle-capture methods (Figure 6). Relying solely on mechanical air filters to capture all contaminants with different concentrations and size distributions is naive. Tackling gases and bioaerosols cannot be overlooked when considering the “freshness” and the “cleanliness” of outdoor and indoor air, considering appropriate filter media selection and their application sensitivity.

Indoor air quality (IAQ) is a critical determinant of health and well-being, especially considering that we spend up to 90% of our time indoors2. IAQ issues are interdependent and not entirely filtrationspecific, and continuing to assume that frequent filter replacement will exonerate facility managers from any IAQ deterioration is a fallacy. The first alignment is knowing what we are up against in terms of pollutant exposures. We can gather valuable data by monitoring the air quality throughout our daily activities, from waking up, taking the elevator, using public transport, working, and returning home.

Today’s air quality monitoring technologies provide reliable and affordable data collection, allowing us to understand what our respiratory systems are exposed to. Such knowledge underscores the importance of technology in monitoring and maintaining healthy air quality in urban environments.

Part of resolving IAQ issues is understanding emission sources from various modes of transportation, as well as industrial activities and power generation emissions. The urgency of this matter cannot be overstated, as urban transportation significantly impacts public health and well-being. To reduce vehicular emissions, policies and incentives must promote public transport on the one hand (Figure 7) and, on the other hand, reduce reliance on private transportation to minimize congestion while promoting physical activities such as cycling and walking. Vehicular emissions expose pedestrians and cyclists to higher pollutant concentrations and challenge cabin air filters installed in the micro-environment of vehicles. Such emissions are further exacerbated by ozone pollution, especially in humid, warm, and high-elevation geographies where cycling and walking may be less popular.

Building a System-Thinking Approach

Adopting a system-thinking approach by integrating air quality data into building management systems through feedback loops is essential to raising the bar of sustainable living. Real-time IAQ monitoring powered by artificial intelligence (AI) and facilitated by Internet of Things devices and data analysis can be used to identify a building's year-round IAQ challenges and indoor pollution profiles. As city inhabitants seek refuge in buildings for comfort and sustainable living, system-thinking methodologies will prove invaluable to how technologies and innovations shape and lead the future of the design and operation of built environments. The adaptability of well-designed, selected, and maintained HVAC systems is crucial for responding to changing IAQ dynamics by controlling moisture levels, pollutant concentration, and varying heat loads. Furthermore, identifying and characterizing pollutants that compromise IAQ is central to engineering sustainable air filter performance for the best air quality outcomes. Adaptive IAQ solutions should be based on data and scientific solutions rather than filtration quick fixes that usually fail.

Air Filtration Misconceptions

Unmasking air quality ignorance is essential amid the noise and need for consistent definitions of clean and fresh air, healthy buildings, and sustainable living. A common misconception is that air filter performance is linear to the air quality enhancement outcomes. It is often thought that increasing filtration will automatically result in better air quality. The limited rationality suggesting that cleaner air is directly proportional to higher filter efficiencies and additional stages can exacerbate the nonlinearities associated with unoptimized filter performance and airflow reduction. Failing to engineer filter requirements can result in misaligned building performance where IAQ interventions are misled by incorrect interpretation of building functions, deviating from sustainable and healthy living objectives. Appropriate filter selections must align with the physical and chemical characteristics of airborne pollutants challenging buildings and their occupants.

A Few More Realignments

Modern ventilation and filtration systems should have integrated, adaptive, dynamic, and evolutionary capabilities to maintain IAQ within specified conditions. However, it is critical to realize that what lacks definition lacks precision. Speaking the same “clean air” language requires being on the same “air quality” page; ultimately, we should define first what constitutes “clean air” before demanding its delivery. That is why it is essential, as the first step forward, to characterize our pollutants and seek certification prior to embarking on selecting appropriate IAQ solutions.

Secondly, air filters must have their own filtration systems to meet and, ideally, exceed the filter and energy efficiency targets, not just be confined to small spaces in conventional air handling units.

Thirdly, IAQ goals should be reformulated based on changing feedback loops and new targets to achieve resilient performance. Installing a high-end air filter in a malfunctioning or contaminated HVAC system can worsen IAQ. Also, dealing with changes in filter loading conditions and time-dependent variations, such as reduced permeability affecting filter performance, presents challenges to achieving sustainable filter performance and should be further investigated.

Finally, air quality governance, a framework through which policies, regulations, and actions are coordinated to manage and improve air, is essential to ensuring compliance with clean air and fresh indoor air that protects public health and well-being. Poor air quality often disproportionately affects low-income communities, and good governance ensures that air quality policies are equitable and that all communities have access to clean air, regardless of socio-economic status.

Public awareness and advocacy are crucial to propel the cause of enhanced air quality. This task is compelling, especially in regions facing immediate crises, limited resources, lack of access to HVAC systems, and unreliable power supply. Governments may feel pressure to prioritize short-term economic gains over longterm environmental health in these areas to provide essential services. Amid these conflicting priorities, policies and politics play a central role in creating the necessary synergies to address climate change and improve air quality, which are closely linked but often very challenging to coordinate effectively.

Technological advancements and innovative solutions can empower us to understand the impact of climate conditions on buildings and their occupants. The early call for air quality inclusion in urban design is central to delivering clean air sustainably, avoiding leaving it as part of a retrofit backup plan. Fixing our relationship with the environment driven by a behavioral change that transitions to sustainable urban living necessitates substantial lifestyle and societal changes. Our collective accountability in acknowledging and addressing the imminent perils of climate change is a shared responsibility that cannot be overstated.

Shift or Drift

Embracing sustainability is not a zero-sum game; businesses can still do well by doing good. However, business models must shift towards conscientious consumption to avoid drifting into irreversible climate consequences. Achieving this objective is paramount; after all, humankind’s survival and prosperity depend on our ability to equitably access clean and fresh air. Communities, businesses, and governments must contribute their fair share to address the intergenerational challenge of climate change, of which air pollution lies at its core. Urban and indoor quality issues cannot tackled by conventional filter employment or delegated to the next generation; they are the current reality as they impact our health and well-being.

As Abraham Lincoln once said, “You cannot avoid tomorrow’s responsibilities by neglecting them today.” It reinforces the message that we must act now to secure a bright and sustainable future.

Dr. Al-Attar is a mechanical engineer and an independent air filtration consultant. He is a Visiting Academic Fellow in the School of Aerospace, Transport, and Manufacturing at Cranfield University, consulting for air quality and filter performance relevant to land-based gas turbines. Dr. Al-Attar is also the strategic director, instructor, and advisory board member of the Waterloo Filtration Institute. In 2020, Eurovent Middle East appointed Dr. Al-Attar as the first associated consultant for air filtration.

Recently, he became the Indoor Air Quality (IAQ) patron for EUROVENT. With engineering degrees (BSc, MSc, Ph.D.) from the University of Toronto (Canada), Kuwait University, and Loughborough University (UK), respectively, he is now reading for an MSc in sustainable urban development for air quality inclusion at the University of Oxford. His expertise is on the design/performance of high-efficiency filters for HVAC and land-based gas turbine applications, focusing on chemical and physical characterization of airborne pollutants.

1.IPCC (2022), Emissions Trends and Drivers. In IPCC, 2022: Climate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, UK and New York, NY, USA. doi: 10.1017/9781009157926.004

2. Nelson, W.C., Ott, W.R., Robinson, J.P., Tsang, A.M., Switzer, P., Behar, J.V., Hern, S.C. and Engelmann, W.H., 1994. The National Human Activity Pattern Survey (NHAPS).