Editor’s choice
The WHO estimates that about 3.2 million deaths per year is linked to household air pollution. Recognizing the importance of indoor air quality, serves as a reminder of our shared need for collective action and responsibility aimed at enhancing air quality in both open environments and enclosed spaces, like our schools and homes.
It is not news that clean air plays an important part in our wellbeing, whether it is outdoors or indoors. Considering the amount of time we spend indoors and the increasing airtightness of our homes to keep out outdoor polluted air, there is a growing interest in indoor air quality (IAQ) which is more amplified following the Covid-19 pandemic. Though IAQ is influenced by our actions and behaviours in enclosed spaces, the penetration of outdoor pollutants into indoor environments also plays a role.
The essential but frequently disregarded need to maintain good IAQ is important for ensuring a healthy atmosphere in residential, commercial, and other enclosed settings. The 2022 indoor air quality report to the UK Department for Environment, Food and Rural Affairs (DEFRA), considers indoor air quality a complex phenomenon, which has received less attention than air quality outdoors, however it emphasizes that indoor behaviours and activities greatly contribute to indoor air quality. This includes emissions from furnishing, cooking, and the use of consumer products such as household cleaning and hygiene products. While indoor air quality can be, to an extent, controlled by a person’s actions, outdoor air quality requires collective societal actions to address emissions.
The report also underscored that although there has been considerable improvement in outdoor air quality in the past three decades, enhanced energy efficiency measures have resulted in higher levels of airtightness and reduced rates of building ventilation. This situation has the potential to negatively impact indoor air quality.
Failure to address IAQ can result in exposure to high concentrations of air pollutants, which can lead to various health complications such as stroke and heart disease.
Addressing these IAQ challenges demands a concerted, holistic effort involving governments, the private sector, nonprofits, and individuals, much like how the UK and the world collectively address public health challenges like pandemics.
To understand more about this issue, we consulted experts from the INGENIOUS project—a team of IAQ scientists from four universities led by the University of York—to shed light on what it takes for the UK to ensure high IAQ standards. The INGENIOUS project’s primary objective is to understand indoor air pollutants’ sources in UK homes and to deliver practical interventions to mitigate IAQ issues. The experts share their prime concern on IAQ.
In the INGENIOUS project, one of our key objectives is to study the pollutants that are emitted from different indoor activities such as cooking and cleaning, and how occupant behaviour can impact these emissions. For example, though we are yet to conclude our research, our initial findings show that during cooking, pollutants called volatile organic compounds (VOCs) are emitted in very large quantities. The amount of VOCs (and particulates) emitted is further worsened during frying and the use of spices. Furthermore, these VOCs can easily oxidize in an enclosed space and form harmful secondary pollutants like formaldehyde, acetaldehyde, and secondary organic aerosols and affect indoor air quality.
Another key source of indoor VOCs is the use of household cleaning and personal care products (such as perfumes, deodorants and air fresheners), which are enriched in compounds called monoterpenoids that give them their wonderful aromas. These compounds, while harmless on their own, can undergo rapid chemical changes when they interact with indoor oxidants such as ozone and radicals, to form secondary pollutants and affect IAQ.
By employing various instrumentation and modelling techniques, we are trying to assess the different ways pollution sources and processes can be limited.
Currently, there are no commitments from manufacturers to include emission labelling on their products and this could be a good start for ensuring transparency and enabling consumers to make informed decisions about the products they buy and use.
To improve IAQ, there are three main areas we need to understand: individuals, the policy environment, and the science. It is vital that we take into account people’s lived experiences relating to indoor air quality, and consider how their behaviours impact indoor air quality. We also need to consider the legislative environment: how do laws and policies impact indoor air quality, for example, what is the impact of controlling the use of certain products indoors or nudging people towards lower emission products (e.g. electric cars, heat pumps instead of gas boilers), and restricting traffic into areas.
The third area is the science. Findings from research projects like INGENIOUS help us better understand the sources of pollutants in homes and the actions that can be taken to improve air quality. These findings need to be combined with understandings of the policy environment, including how businesses and individuals react to policies, in order to develop new and effective evidence-based policies.
One aspect that I believe is missing is the public’s awareness component of indoor air quality. We have spent so much time focusing on outdoor air quality, which is a crucial concern, with lesser attention to indoor air quality safety. Over 90% of our lives are spent indoors, where we are exposed to pollutants, some of which may originate from outdoor sources. As outdoor air pollution decreases in a number of environments, indoor air pollution will become a greater opportunity for health improvement. Clearly, reducing emissions of harmful pollutants is the wisest course of action.
Campaigns led by local councils and NGOs (in partnership with researchers) can raise public awareness and inform people about how their day-to-day behaviour might be affecting the IAQ at their homes and offices and what changes they can make.
While air quality studies have traditionally segregated indoor and outdoor environments, they are, in fact, inseparable. Even on a jet plane, the air is withdrawn from the outside, filtered before being circulated in the cabin, and recycled or discharged outside, affecting the air quality of Earth’s lowest layer of atmosphere.
In our daily lives, indoor pollution can carry outside and affect outdoor air quality, and vice versa. Activities indoors produce gases and particles, which can accumulate significantly over time. Furthermore, closing windows or ventilation, which is generally considered reasonable to eliminate outdoor pollution, can exacerbate indoor pollution. When these indoor gases and particles are transported outside, they mix with the outdoor pollutants and environmental elements (i.e., sunlight, humidity, temperature) and undergo physical and chemical alterations. This sequence also occurs in reverse, where outdoor pollutants penetrate indoor environments, react with indoor pollutants, and affect IAQ.
All stakeholders need to think and approach air quality issues holistically while at the same time focusing on solving a specific problem. Researchers have approached the IAQ problems holistically, as demonstrated by the INGENIOUS project. Policymakers should focus on regulating and advising on activities and products that produce large amounts of pollutants, such as domestic biomass burning, which pollutes indoors and outdoors. The industry needs to be more transparent and think about the products’ content and potential atmospheric impacts.
Lastly, we should be more aware of the activities that can pollute the indoor environment and ways to minimize pollution. Through research dissemination, policy and regulation, and citizen science, we can widely increase awareness of indoor and outdoor AQ issues.
Project / This project investigates air pollutants inside homes in the city of Bradford, UK: their sources, interactions and health effects on those living there.
Project / A citizen science project monitoring indoor air, created with and for UK schools.
Project / SEI works with research institutes to assess the impact of pollutants, besides CO₂, that drive climate change, and to develop climate change mitigation options.
Perspective / Collective action is needed to improve air quality in Latin American and the Caribbean. This perspective highlights trends and priorities for the region.
Feature / The 2023 edition, with the theme, “Together for Clean Air", emphasizes the urgent need for stronger partnerships and shared responsibility.
Past event / SEI was at the 3rd International Forum on Transboundary Air Pollution on data science for air policies in Northeast Asia on UN Clean Air Day, 2023.
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