Once considered a background environmental issue, Indoor Air Quality (IAQ) is recognised as a fundamental determinant of public health. Studies link indoor pollutants and ventilation efficiency to wellbeing and infection control ⁵M. Jantunen, E. Oliveira Fernandes, P. Carrer, S. Kephalopoulos, and European Commission, Eds., Promoting actions for healthy indoor air (IAIAQ). Luxembourg: European Commission, 2011. doi: 10.2772/61352..
In a recent past, the COVID-19 pandemic had the side effect in accelerating awareness and interest in IAQ research and sensor technologies. The need for real-time risk assessment led to the adoption of CO₂ as a proxy for ventilation performance ⁶L. Morawska et al., “How can airborne transmission of COVID-19 indoors be minimised?,” Environment International, vol. 142, p. 105832, Sept. 2020, doi: 10.1016/j.envint.2020.105832., and reframed indoor environments as measurable health systems ⁷J. G. Allen, Healthy Buildings: How Indoor Spaces Drive Performance and Productivity. Cambridge: Harvard University Press, 2020.⁸J. G. Allen and J. Macomber, Healthy buildings: how indoor spaces can make you sick or – keep you well. Cambridge, Massachusetts; London, England: Harvard University Press, 2022..

Studies have focused on different exposure contexts. At home, on pollutant levels from cooking, heating, and cleaning and the unseen need for ventilation ⁹S. Vardoulakis et al., “Indoor Exposure to Selected Air Pollutants in the Home Environment: A Systematic Review,” IJERPH, 17(23):8972, Dec. 2020, doi: 10.3390/ijerph17238972.. In workplaces, CO₂ and ventilation data became productivity and safety metrics for the healthier office ¹⁰J. G. Allen and J. Macomber, Healthy buildings: how indoor spaces can make you sick or – keep you well. Cambridge, Massachusetts; London, England: Harvard University Press, 2022..
In schools, both European SINPHONIE ¹¹European Commission JRC IHCP; DG Health and Consumers; Regional Environmental Centre for CEE, SINPHONIE: Schools Indoor Pollution & Health Observatory Network in Europe: final report. LU: Publications Office, 2014. Accessed: Oct. 23, 2025. https://data.europa.eu/doi/10.2788/99220¹²R. M. Baloch et al., “Indoor air pollution, physical and comfort parameters related to schoolchildren’s health: Data from the European SINPHONIE study,” Science of The Total Environment, 739:139870, Oct. 2020, doi: 10.1016/j.scitotenv.2020.139870. and Portuguese studies ¹³J. Madureira et al., “Children’s Health and Indoor Air Quality in Primary Schools and Homes in Portugal—Study Design,” J Toxicol Environ Health A, 78(13–14):915–930, July 2015, doi: 10.1080/15287394.2015.1048926., have been looking at the impact of CO₂ concentrations on student cognition and attention. Similar trends in hospitals and transport systems, looking at ventilation and crowding effects on airborne disease transmission ¹⁴M. Beaussier et al., “Aerodynamic analysis of hospital ventilation according to seasonal variations…,” Environment International, 158:106872, Jan. 2022, doi: 10.1016/j.envint.2021.106872.¹⁵L. Morawska et al., “A paradigm shift to combat indoor respiratory infection,” Science, 372(6543):689–691, May 2021, doi: 10.1126/science.abg2025..

As people spend nearly 90 % of their lives indoors ¹⁶J. G. Allen, Healthy Buildings: How Indoor Spaces Drive Performance and Productivity. Cambridge: Harvard University Press, 2020., often in the same space, is important to check possible chronic exposure to CO₂, PM₂.₅, PM₁₀, formaldehyde, and VOCs, as it is associated with respiratory and cardiovascular disease, cognitive decline, and premature mortality ¹⁷J. Duchesne et al., “Exposure to ambient air pollution and cognitive decline: Results of the prospective Three-City cohort study,” Environment International, 161:107118, Mar. 2022, doi: 10.1016/j.envint.2022.107118.¹⁸A. Yuan et al., “Lifetime air pollution exposure, cognitive deficits, and brain imaging outcomes: A systematic review,” NeuroToxicology, 96:69–80, May 2023, doi: 10.1016/j.neuro.2023.03.006.. Firefly can help to identify when air renewal or longer term building adjustments are necessary. It also translates complex standards, such as those outlined in Portuguese law ¹⁹República Portuguesa, Portaria n.º 138-G/2021, de 1 de julho. 2021., WELL Building Standard ²⁰International WELL Building Institute, “WELL Building Standard v2,” IWBI, 2020. https://www.wellcertified.com/certification/v2/, RESET ²¹GIGA, “RESET Air Standard for Commercial Interiors (2.0),” 2018. https://reset.build/standards/air/, WHO ²²World Health Organization, WHO Global Air Quality Guidelines: Particulate Matter (PM2.5 and PM10), Ozone, Nitrogen Dioxide, Sulfur Dioxide and Carbon Monoxide, 1st ed., Geneva: WHO, 2021., and EU directives ²³M. Jantunen et al., Promoting actions for healthy indoor air (IAIAQ). European Commission, 2011. — into easy-to-read visual indicators, color codes, dashboard analysis, historical data, and alerts.