Productivity and air quality

The business case for investing in indoor air quality has matured from "soft" to "load-bearing." Satish et al. (LBNL, 2012) ran controlled exposures in a real office and found decision-making performance fell measurably at 1,000 ppm CO₂ and substantially at 2,500 ppm. Allen et al. at the Harvard T.H. Chan School replicated and extended the work, showing decrements across nine cognitive function domains.

Fisk's review of school ventilation finds that classrooms often get far less outdoor air than standards require, and that more ventilation goes with better student performance and fewer absences, at a net cost of a few dollars to about $10 per person per year. For offices, MacNaughton, Allen and colleagues estimated that doubling ventilation above the ASHRAE minimum costs less than $40 per person per year in energy, while the same change was linked to an 8% gain in worker performance, worth about $6,500 per person per year.

Particles matter too. In a 12-month study of 302 office workers in six countries, Cedeño Laurent et al. found that each 8.8 µg/m³ rise in indoor PM_2.5 went with slightly slower, less accurate work on cognitive tests: responses about 1% slower, and about 1.5% fewer correct answers per minute on an arithmetic test. During outdoor pollution events such as wildfire smoke, a HEPA purifier sized for the space is the usual way to keep indoor PM_2.5 down.

For facility managers, the useful numbers are how often each room climbs past a chosen CO₂ level, how CO₂ follows occupancy through the day, and how quickly a room recovers after a meeting. The point is not to micromanage employees, but to give facility managers the data to make the building work better. Terrestream's Facilities workspace keeps a per-room history of CO₂, temperature, and humidity and flags rooms whose estimated air-change rate is low, so those rooms can be checked for more ventilation first.