Workspace Air Quality Calculator: CO₂ Ventilation Planner
Office wellbeing tool
Workspace Air Quality & Ventilation Planner
Use a CO₂ monitor reading and your workspace set-up to create a simple fresh-air plan for meetings, home offices and shared rooms. This page does not calculate an exact fall in mental performance or diagnose an air-quality problem.
Check your workspace reading
Use a properly positioned indoor CO₂ monitor. Do not place it directly beside a person, open window, vent or cooker.
CO₂ monitor guide for UK workspaces
| Reading | Planning response |
|---|---|
| Up to 800 ppm | Generally a reassuring reading in an occupied room. Keep the current ventilation approach and re-check if occupancy changes. |
| 801–1,000 ppm | Use a refresh break: open windows/doors where appropriate, reduce crowding for a while, or check that mechanical systems are running. |
| 1,001–1,500 ppm | Improve fresh-air flow promptly and re-check after the change. Consider shorter meetings, fewer occupants or another room. |
| Over 1,500 ppm | Take practical steps now and raise a persistent issue with the person responsible for the workplace or building ventilation. |
These are practical interpretation bands, not medical thresholds. The HSE advises using CO₂ monitors to identify poorly ventilated occupied spaces and taking action when readings remain high.
Why a workspace ventilation planner is useful
Stuffy rooms are common in home offices, shared workspaces and small meeting rooms. People often notice the effect before they know the cause: a room feels warm, stale or hard to concentrate in. A CO₂ monitor can make the problem visible, particularly where rooms become busy or windows stay closed in colder weather.
This calculator deliberately avoids pretending that a reading can translate into a fixed percentage loss of focus. Concentration, fatigue and decision-making are influenced by sleep, workload, temperature, noise, lighting, stress, food, illness and many other factors. What a reading can do is help you make a sensible environmental change: more outdoor air, fewer people in the room, a shorter meeting, or a check of a mechanical ventilation system.
For employers, ventilation sits alongside wider workplace controls. If readings are repeatedly high in an occupied room, or people report headaches, dizziness, breathing difficulty, fumes, unusual odours or persistent damp, do not rely on this tool alone. Report the issue through the normal workplace route. Anyone with severe symptoms or a suspected gas or carbon-monoxide risk should leave the area and follow urgent safety advice.
Workspace air quality FAQs
Can a cheap CO₂ monitor measure all air pollution?
No. It is mainly a ventilation indicator. It does not replace a carbon-monoxide alarm, a mould assessment, or testing for particulate pollution and chemicals.
What should I do if my CO₂ reading rises during a meeting?
Where safe, increase outdoor-air flow, reduce the number of people or move to a better-ventilated room. Re-check after making the change rather than assuming it worked.
Does opening a window always solve it?
Not always. The effect depends on window size, wind, room layout, outdoor conditions and how many people are inside. Mechanical ventilation may need inspection if readings remain high.
Last reviewed: September 2026. Sources: HSE: using CO₂ monitors to identify poorly ventilated areas; GOV.UK ventilation guidance. Educational information only; not occupational-health or medical advice.
