This is a legacy version of the WELL Building Standard. Please check the latest version here.

Air quality monitoring and feedback

Building performance, such as ventilation and infiltration rates, is highly variable and has a direct effect on indoor air quality. To maintain ideal performance metrics, projects must continuously gather data on building performance. Collecting this data allows individuals to be aware of and promptly fix any deviations in indoor quality metrics.

Part 1: Indoor Air Monitoring

Monitors measure 2 of the following pollutants in a regularly occupied or common space (minimum one per floor) within the building, at intervals no longer than once an hour, and results are annually transmitted to the IWBI:

a. Particle count (resolution 35,000 counts per m³ [1,000 counts per ft³] or finer) or particle mass (resolution 10 μg/m³ or finer).
b.1 Carbon dioxide (resolution 25 ppm or finer).
c. Ozone (resolution 10 ppb or finer).
Part 2: Air Data Record Keeping and Response

In an effort to consistently meet the WELL parameters, projects provide a written policy specifying:

a. Detailed enforcement strategies for monitoring and record-keeping of parameters listed in the Air Quality Standards Feature.
b. Records are to be kept for a minimum of 3 years, including full data from field inspectors or laboratory results where appropriate.
c. Detailed plan for action and remediation of unacceptable conditions.
Part 3: Environmental Measures Display

Real-time display of the following indoor environmental parameters are made available per 930 m² [10,000 ft²] of regularly occupied space on a screen no smaller than 15 cm [5.9 inches] by 13 cm [5.1 inches]:

a. Temperature.
b. Humidity.
c. Carbon dioxide concentration.

Applicability Matrix

Core & Shell New & Existing Buildings New & Existing Interiors
Part 1: Indoor Air Monitoring - O O
Part 2: Air Data Record Keeping and Response - O O
Part 3: Environmental Measures Display - O O
Commercial Kitchen Education Multifamily Residential Restaurant Retail
Part 1: Indoor Air Monitoring O O O O O
Part 2: Air Data Record Keeping and Response O O O O O
Part 3: Environmental Measures Display O O O O O

Verification Methods Matrix

Letters of Assurance Annotated Documents On-Site Checks
PART 1 (Design)
Indoor Air Monitoring
MEP Spot Check
PART 2 (Protocol)
Air Data Record Keeping and Response
Operations Schedule
PART 3 (Design)
Environmental Measures Display
Visual Inspection

U.S. Green Building Council. LEED v4: Reference Guide for Building Design and Construction. Washington D.C.: U.S. Green Building Council; 2013: 37, 43-44, 541-552, 567, 605, 623, 645-53, 658-61, 682-3, 685-6, 723-4.


USGBC's LEED v4 EQ prerequisite: Minimum Indoor Quality Performance requires carbon dioxide monitoring within each thermal zone for mechanically ventilated spaces.