This is a summary of the linked shallow cause investigation done by Natalie Kiilu and John Anyanwu as a research project as Impact Academy fellows. We spent 8-13 weeks working on this project which was inspired by a similar exploration report by Rethink Priorities. Neither of us had prior experience with the proposed intervention.

We would like to extend our sincere gratitude to Peter Babigumira and the Impact Academy team for their support throughout the process. We also received the second prize award from  Impact Academy. 

All mistakes are the authors'. 

Summary

The argument

"Some people believe we’re going to look back on this era, one of commonly endured airborne infections, as a case of antiquarian barbarism, a bunch of needless suffering that we accepted because we didn’t know any better." (excerpt from Dylan Matthews's article)

Problems related to poor indoor air quality (IAQ) do not always produce easily recognisable impacts on human health or wellbeing. Yet, airborne illnesses pose a significant challenge to global public health systems, whether they appear as seasonal illnesses or in pandemic forms. With over 90 percent of transmissions of airborne respiratory illnesses and exposures to air pollutants occurring indoors, improving IAQ is expected to reduce the frequency of airborne disease exposure and potentially ‘strangle the next COVID in the crib’.

This study is motivated by the comprehensive cause exploration of IAQ improvement in high-income countries conducted by Kraprayoo and colleagues at Rethink Priorities. However, this study’s focus will be on the sub-Saharan region for several reasons. In particular, I contend that improving IAQ should be prioritised in the region because: a. poor IAQ contributes to high rates of morbidity and mortality in sub-Saharan Africa; b. poor IAQ poses a significant barrier to pandemic preparedness efforts, jeopardising the lives of the millions of near- and far-future generations across Africa and beyond; c. there are tractable ways to improve IAQ in the region; and lastly, d. this cause may be more suitable for hits-based donors who typically embrace higher risk tolerance levels. Furthermore, we also recognise some of the reasons why improving IAQ in sub-Saharan Africa may not be a sufficiently worthwhile cause, including concerns over feasibility and tractability, inadequate real-world data on its promises, enforcement and compliance challenges in the region, and concern over exacerbating the climate crisis.

Poor IAQ contributes to high rates of mortality and morbidity in sub-Saharan Africa 

Africa’s children are ‘silently suffocating’ as air quality in the region worsens. Given the inadequate data on the status of air pollution in the region, it is likely that even this dire analysis of the situation is an underestimate of the severity of harm brought about by poor air quality in the region. In 2019, half of the over 671,900 children under 5 years old who died from acute lower respiratory infections came from sub-Saharan Africa. Lower tract respiratory illnesses were also a leading cause of death in all sub-Saharan African countries, and combined with tuberculosis cost a staggering 60.7 million DALYs in 2019 alone. In addition to children, the elderly, and those suffering from respiratory complications are also especially vulnerable to poor IAQ. Furthermore, factors contributing to the prevalence of acute lower respiratory illnesses, including poverty, malnutrition, HIV, poor ventilation, household air pollution, and limited access to healthcare, are pervasive in the region.^, Comorbidities such as HIV infection and tuberculosis, which remain endemic in the region, further exacerbate the severity and mortality rates of respiratory illnesses. Exposure to poor IAQ also contributes to cognitive impairment and reduced worker productivity, leading to significant economic costs. 

With a population of about 1.2 billion people, the scale of the problem is large in terms of the numbers of people affected as well as the severity of harm they endure, including death and life-long chronic illnesses. This is set to worsen should the status quo persist as projections show that between 2017 and 2050, the population in 26 African countries will double, and that by 2100, the entire region’s population will have tripled. Therefore, improving IAQ could greatly easen the burden on the already overburdened healthcare systems in sub-Saharan Africa, save lives, and improve the overall health and wellbeing of hundreds of thousands of people each year. In sum, improving IAQ in this region may be a particularly promising intervention with other multiplier effects other than reducing the rate of morbidities and mortalities in the region.

Poor IAQ is a significant barrier to pandemic preparedness efforts

The practice of fire control in high-income countries can serve as a useful analogy for pandemic preparedness efforts. Williamson highlights the usefulness of lessons learnt from fire control, observing that fires in those countries have become less destructive due to the deliberate reengineering of their urban environments around preventing the spread of fire. Pandemics, while less overt, yield significantly more devastating effects than fire. Hence, Williamson makes the case for the pursuit of multiple strategies under pandemic preparedness, ranging from preventive and detection strategies, to passive and active protection strategies, instead of limiting our focus to the development of new pharmaceuticals. 

In the context of pandemic preparedness, a highly promising passive protection strategy would be the mass implementation of more and better air cleansing systems in high-risk buildings. Curbing airborne transmission is key to conferring passive protection because infectious bioaerosols, and especially viruses, are easy to spread and difficult to combat. When a pandemic outbreak occurs, it results in mass deaths, economic crises, and the exacerbation of existing structural inequalities, all of which tend to have long-lasting and far-reaching effects, especially on the most vulnerable members of the community.^, 

Multiple issues, especially when taken together, make poor IAQ a particularly pressing issue with regards to pandemic preparedness globally as well as in sub-Saharan Africa. Firstly, there is good reason to believe that the next deadly pandemic will be caused by an airborne viral pathogen. Secondly, there has been a steady increase in the number and kinds of novel pathogens, as well as higher incidences of zoonotic transmission. Moreover, this region may be more vulnerable to spill-over events meaning that as a potential origin point, it would be an instrumental first line of defense. Thirdly, pandemics and GCBR events, by definition, are transnational and require global efforts to attain any level of security against such outbreaks; crises cannot be confined within borders. Lastly, the fact that sub-Saharan Africa’s population will make up 35 percent of the global population by 2100 exponentially increases the scale of the problem even if an outbreak remains confined to the region. Thus, there is a need for urgent action in order to mitigate the multifaceted risks posed by pandemics and safeguard future generations of Africans. 

There are tractable ways to address poor IAQ in sub-Saharan Africa

Infection control involves the blocking of any stage of the infection pathway. Similarly, pandemic preparedness involves the pursuit of different strategies, including preventive actions, detection, passive protection, and active protection, to safeguard against dire outcomes from such outbreaks. By some estimates, the annual cost of significantly reducing the transmission of novel diseases from tropical forests globally falls between 22.2 and 30.7 billion USD, markedly lower than the staggering total costs of COVID-19, estimated at 8.1 and 15.8 trillion USD, which is 500 times more expensive.  

Fortunately, similar to how improved sanitation has effectively addressed waterborne diseases, airborne diseases can also be mitigated. Techniques such as disinfecting the air to kill present pathogens, ventilation, and filtration would be useful for these purposes.^, Yet, current building codes, even when inclusive of some mandates to promote good IAQ, are not developed with the aim of controlling airborne infection in mind. Implementing engineering controls such as ventilation, filtration, and disinfection, alongside other non-pharmaceutical interventions during outbreaks, could be highly effective in reducing transmission, thus serving as a critical layer of biodefense.^, Notably, these measures circumvent the challenges faced in the pursuit of other non-pharmaceutical interventions as they do not rely on individual compliance and public acceptability, such as mask mandates during outbreaks. Consequently, we discuss interventions, ranging from the engineering controls necessary to improve IAQ to policy advocacy measures that would bring forth relevant regulation to urge the mass implementation of those controls in high-risk, high-traffic public buildings.

However, in the sub-Saharan African context, solving the problem of poor IAQ also faces several challenges. For one, we anticipate that even in the event that appropriate regulation is put in place, there will be serious compliance and enforcement challenges. Given that the region is almost entirely made up of low- and middle-income countries, getting government actors to allocate the necessary funds to combat poor IAQ may also prove to be challenging. Moreover, as improving IAQ cannot by itself eliminate the risk of pandemics, other interventions such as improving water, sanitation, and hygiene services, supporting vaccination programmes, and improving health facilities, may take precedence in the region due to their relevance for multiple other problems including pandemic outbreaks. However, where national governments and traditional donors may not go, hits-based philanthropic donors, willing to take on some risk for potentially huge gains, may significantly contribute to furthering existential security for the world and promoting everyday health and wellbeing for the billions of people living in sub-Saharan Africa.

The case against the prioritisation of improving IAQ

Gaps in present scientific knowledge

There are significant gaps in our scientific knowledge on IAQ, its contribution to poor health outcomes, and the efficacy of IAQ improvement in alleviating health risks. In a report by Rethink Priorities, Kraprayoon and colleagues highlight several limitations with research in this field, including ‘confounding variables and pervasive errors in medical literature that are significant enough to obviate the results of some studies’. The debate over the exact modes of transmission of illnesses such as influenza and SARS also remains unsettled. Furthermore, it is also unclear how best to determine pathogen load in the air, especially because using carbon dioxide as a surrogate parameter for infection risk is somewhat controversial. For one, the concentration of carbon dioxide in a room plateaus after some time, while the number of infectious bioaerosols particles inhaled by a person in that room increases over time even if the concentration of particles in the room remains unchanged. Equally unclear is the relationship between pathogen load and infection cases with regards to indoor air, significantly limiting our ability to predict infection risk.

Regarding the proposed engineering control measures, there is a paucity of research supporting their use and evaluation in influencing human infection and health implications. Presently, there is concern over the safety of far UVC use and uncertainty over whether there are reliable ways to test the efficacy of these interventions before their mass deployment. It is also probable that these interventions may prove to be less effective than desired since it remains unclear whether reducing pathogen loads in the air will necessarily reduce transmission and infection rates. On the flip side, there is also concern that the success of these interventions could lead to a reduction in population immunity, making even common colds more destructive than they currently are. Compounding these challenges is the lack of reliable data from sub-Saharan Africa on the actual burden of respiratory illnesses, which impedes effective scientific study. Nonetheless, these existing knowledge gaps present an opportunity for hits-based donors to support work in this field, advancing our collective scientific understanding and potentially yielding significant breakthroughs.

Feasibility concerns

Globally, engineering controls for good IAQ can be quite costly to install and maintain.^, For example, currently, installing UVGI devices in all locations is infeasible, although their installation can be more cost-effective within larger systems. Expectedly, this is a significant obstacle in sub-Saharan Africa, a region that is significantly resource-constrained. To illustrate, even though there is widespread acknowledgement of the dangers of outdoor air pollution, air quality in the region remains largely unmonitored due to the high costs of acquiring and running standard air pollution monitoring stations. Similarly constrained are efforts to reduce HAP, despite the pressing nature of the problem. 

Nevertheless, there exist opportunities for non-governmental entities from industry and philanthropic communities to fill these gaps, inadvertently creating employment opportunities, fostering innovation, and even promoting a shift to clean energy in the region. Multinational corporations, for instance, could play a leading role in raising public awareness and shifting public perceptions by prioritising the highest IAQ standards in their buildings as well as collaborating with various governmental agencies to support similar efforts through their corporate social responsibility initiatives. 

Inadequacy as a stand-alone intervention

Improving IAQ is insufficient to minimise threats; rather, it must be incorporated into a comprehensive strategy for reducing GCBR or controlling pandemic transmission.^, To guarantee the effectiveness of the proposed engineering control measures, universal implementation, not selective, is imperative, thus making the implementation process quite demanding. These passive protection measures could also be circumvented by malicious actors who could incorporate IAQ interventions into their bioterrorism plans, rendering these measures ineffective even in the event of an airborne pandemic outbreak. These challenges, in addition to the lack of sufficient evidence on viral infection risk reduction in indoor settings and the resource constraints plaguing sub-Saharan Africa, other relevant and well-established but underfunded public health interventions such as those focused on water, sanitation and hygiene (WASH) improvement could be more meritorious. 

Enforcement and compliance concerns 

Challenges related to enforcement and compliance are commonplace in sub-Saharan Africa, extending to building codes. Multiple studies conducted in Nigeria and Kenya reveal low adherence to building regulations, often intertwined with corruption during the construction process.^,,,,, Introducing new regulations requiring inspection or certification could inadvertently create opportunities for further corrupt practices, further hindering any chances of success. Moreover, instigating widespread change in regulations and public attitudes towards IAQ improvement may encounter resistance in communities, negatively impacting compliance and enforcement. This is a significant bottleneck, as the overwhelming uncertainty over whether regulations could actualize the necessary progress, even when successfully enacted, may weaken motivations for addressing this problem.  

There are also some technical concerns over the inadvertent effects of encouraging the adoption of filtration and upper-room UVC. Primarily, there is a worry that their mass implementation could lead to infrastructure lock-in, making the adoption of far UVC in public indoor spaces afterwards difficult. Inversely, poor implementation strategies in the present may lead to increased resistance to all other future strategies due to idea inoculation. Secondly, where the regulations are unclear as to the minimum requirements, developers may adopt UVGI at the expense of ventilation and filtration, which remain paramount to IAQ improvement especially with regards to all other pollutants other than infectious bioaerosols. 

All these challenges notwithstanding, pursuing advocacy campaigns to shift public opinions and institute legal change has been shown to have a decent likelihood of success in comparable contexts. For instance, in the past, Charity Entrepreneurship been open to supporting advocacy interventions for some their top recommended problems even when they estimated a 20–30 percent, or 48 percent chance of success for their proposed advocacy interventions. Moreover, as some countries in the region have higher rates of compliance and enforcement, further investigations into this could be useful in identifying where pilot programs should be launched.

Contribution to the climate crisis

The mass implementation of engineering controls to improve IAQ may inadvertently exacerbate the climate crisis as these controls may have high energy demands, which would lead to increased carbon emissions. For instance, increasing outdoor air ventilation rates using air filters typically comes with high energy penalties, which surge further during large outbreaks where these systems are required to run continuously for infection control purposes. Additionally, doubling the ventilation rates in some instances could build excessive pressure on electricity grids, leading to power shortages. 

The use of UVGI, while highly effective in deactivating infectious bioaerosols, would also produce harmful pollutants as UV can break down oxygen molecules into ozone, an air pollutant, worsening respiratory health and contributing to around 365,000 deaths annually. Additionally, ozone interacts with volatile organic compounds to create particulate matter, causing smog and potentially resulting in up to 6.6 million deaths annually. Despite these concerns, some argue that the benefits of disinfection outweigh the costs, especially in countries like Nigeria, as in most of the region, where tuberculosis claimed the lives of 125,000 individuals in 2021 alone. Notably, the ozone problem could be mitigated by simultaneously cleaning the air through better ventilation and filtration although this would also decrease the benefits of using far UVC. Ultimately, this concern could be addressed by conventional wisdom urging the continued use of ventilation even when air filtration and UVGI devices are deployed.

Conclusion 

Improving IAQ in sub-Saharan Africa could substantially eliminate a key source of morbidities and mortalities in the region and safeguard all future generations from extreme pandemics and GCBR events by conferring passive protection against such outbreaks. Even though the problem is highly neglected, there are numerous tractable ways to begin addressing it, as well as several ways to make progress on the problem despite the existence of some limitations. Hits-based donors seem particularly well suited to spearheading efforts in this direction, moving humanity from this age of ‘needless suffering’ and a glaring ‘biosecurity vulnerability’ to an age of increased global health and wellbeing and enhanced pandemic preparedness measures.