Standard
WELL is the leading global rating system focused exclusively on human health in the built environment. The Air concept sits at the centre of WELL v2 — and is the most performance-driven section of the standard.
Version
WELL v2
Concept
Air
Owner
IWBI
Features
14 air-related
WELL v2 organises the Air concept into preconditions (mandatory for any level of certification) and optimisations (points-based, contributing to Silver, Gold and Platinum). Together they cover particulates, VOCs, carbon monoxide, ozone, mould management, ventilation effectiveness, source control and continuous monitoring.
The standard rewards measured outcomes, not just specifications — every air feature requires verification through performance testing or continuous monitoring.
For continuous occupied spaces WELL v2 sets PM2.5 ≤15 µg/m³, PM10 ≤50 µg/m³, ozone ≤51 ppb, carbon monoxide ≤9 ppm, TVOC ≤500 µg/m³ and formaldehyde ≤27 µg/m³. CO₂ is benchmarked at ≤900 ppm for the highest tier with live display required.
UK projects routinely meet most thresholds with a well-commissioned MVHR system and MERV 13+ filtration — the harder ones are TVOC and formaldehyde, which depend on material specification rather than mechanical strategy.
WELL distinguishes itself from BREEAM through its requirement for continuous post-occupancy monitoring of key parameters — typically PM2.5, CO₂, TVOC, temperature and humidity — with live data displayed publicly to occupants. The display requirement creates a feedback loop that drives operational discipline. IAQ monitoring →
Several features address upstream causes: smoking and combustion prohibitions, low-emission material specifications (paints, adhesives, ceilings, flooring, insulation, furniture), entryway tracking management and pesticide management. These mirror BREEAM's material credits but with stricter compositional thresholds in some categories. Compare with BREEAM →
Most UK commercial fit-outs targeting WELL Gold pair the standard with BREEAM, since the material-emission and ventilation requirements overlap substantially. Plan the performance verification — chamber testing of materials, post-occupancy measurement and ongoing monitoring contracts — into the project programme from RIBA Stage 2, not as a final-stage add-on.