Evidence Domain

Indoor Air Quality

What it studies

The composition and movement of indoor air: ventilation rates, CO2, particulates, volatile organic compounds, humidity and pathogen transmission. It connects building services engineering to health and cognitive outcomes — with an evidence base that strengthened dramatically through pandemic-era research.

Why it matters

IAQ carries some of the strongest environmental-performance evidence in the workplace canon: ventilation and CO2 levels show measurable associations with cognitive performance and sickness absence in multiple studies, and airborne transmission research made ventilation a duty-of-care question. It is also invisible — the environmental variable occupants cannot see and buildings routinely under-deliver.

Questions it answers
  • What ventilation performance do occupied densities actually require?
  • What do CO2 and pollutant levels indicate about building operation?
  • What does the evidence support on air quality and cognitive performance?
  • How should IAQ be monitored and reported without inducing either complacency or alarm?
Evidence sources
  • Ventilation and cognition studies (Allen et al. and successors — promising, with replication and generalisation caveats)
  • Ventilation standards (EN 16798, ASHRAE 62.1)
  • Pandemic-era transmission and ventilation research
  • Continuous IAQ monitoring data
Design and policy implications

Ventilation specified against actual planned densities, not code minimums; continuous monitoring in occupied zones with transparent reporting; density decisions tested against ventilation capacity; IAQ as a standing recalibration variable, not a handover checkbox.

Related methods
Common misuse

Reporting cognitive-performance percentages from single studies as established fact, and monitoring theatre — sensors installed, dashboards displayed, ventilation never actually adjusted. The evidence supports taking IAQ seriously; it does not support the precise productivity arithmetic vendors quote.

Further research

Dose-response relationships between ventilation and cognition, and the long-run health economics of IAQ investment, are active and unsettled research areas.