Why it matters
CO₂ is produced continuously by occupants and, indoors, it is the most practical single indicator of whether fresh air is actually reaching people. Dubai’s sealed, heavily air-conditioned buildings are designed to keep heat out, which means the same envelope keeps stale air in whenever fresh-air dampers are throttled to save energy.
CO₂ itself is not the hazard at office concentrations. It is a proxy. Where CO₂ climbs, every other occupant-generated contaminant is climbing with it.
World standards
ASHRAE Standard 62.1 sets minimum outdoor air rates per person and per unit floor area rather than a CO₂ number, on the basis that ventilation rate is the thing you control and CO₂ is the thing you observe.
Reference: ASHRAE Standard 62.1, Ventilation and Acceptable Indoor Air Quality.
UAE standards
- CO₂: 800 ppm as an 8-hour average, or 700 ppm above outdoor air levels
- Threshold limit value, ceiling: 5000 ppm
- Carbon monoxide, for comparison: 9 ppm over 8 hours, 25 ppm over 1 hour
A reading persistently above 800 ppm means the fresh-air damper is closed, the intake is blocked, or the space now holds more people than it was designed for. Buildings tested against 1000 ppm can still fail a DM assessment.
Reference: DM-HSD-GU119-IAQ Version 3 (2024), Table 2.
Impact on health
Elevated CO₂ is linked to headache, drowsiness, difficulty concentrating and measurable declines in decision-making performance. Under-ventilated spaces also concentrate airborne pathogens, allergens and VOCs, so the same fault that raises CO₂ raises everything else.
How to fix a building that fails
- Have the fresh-air rate measured against the design specification rather than assumed. DM lists a minimum fresh-air damper opening of around 15% as a check point
- Confirm the outdoor air intake is not blocked, not shielded shut against sandstorms and left that way, and not sited next to a car park exhaust or cooling tower
- Rebalance the air distribution where occupancy has grown since fit-out. DM requires rebalancing after any layout change affecting the HVAC system
- Place monitors in the breathing zone, 1 to 2 m above floor level, away from diffusers and away from anyone’s exhaled breath
- Set the audible alarm at 800 ppm rather than 1000 ppm, so you are warned before the compliance limit rather than after it
Need this equipment serviced?
Inspection first, fixed written price before any work begins, and a photo report on completion.