Cleared for Fresh Air: Understanding and Achieving WELL Certification Credit for Particulate Matter Control

“Air is the invisible fuel for our bodies, and when it is pure, it fuels us best.” – Jane Burston.

This quote underscores the significance of air quality in our day-to-day lives and our workplaces, the place where we spend a substantial portion of our lives. To highlight this often-overlooked aspect of green building design, this blog will delve into the WELL certification credit A01.1: Meeting Thresholds for Particulate Matter.

WELL certification places a premium on air quality, with a specific focus on Particulate Matter (PM). PM, including PM2.5 and PM10, is a mixture of solid particles and liquid droplets found in the air. PM2.5 refers to fine particles with diameters that are 2.5 micrometers and smaller, while PM10 includes particles with diameters of 10 micrometers and smaller.

The credit aims at maintaining PM levels within acceptable thresholds, ensuring the health and wellbeing of occupants. To comply with this credit, there are several options that adjust according to regional pollution levels.

Option 1: Acceptable thresholds
The first option requires the following thresholds to be met in occupiable spaces:

PM2.5: 15 µg/m³ or lower
PM10: 50 µg/m³ or lower

Option 2: Modified thresholds in polluted regions
If the annual average outdoor PM2.5 level is 35 µg/m3 or higher, the building needs to meet the following modified thresholds:

PM2.5: 25 µg/m³ or lower
PM10: 50 µg/m3 or lower

Option 3: Dynamic thresholds in polluted regions
This option applies to buildings where the annual average outdoor PM2.5 level is 35 µg/m3 or higher. The thresholds to be met are:

PM2.5 less than or equal to 30% of the 24- or 48-hour average of outdoor levels on the day(s) of performance testing.
PM10 less than or equal to 30% of the 24- or 48-hour average of outdoor levels on the day(s) of performance testing.

Data Requirement
To calculate the PM2.5 and PM10 levels in your building, indoor air quality monitoring equipment that accurately measures the concentration of these particles is essential. Regular monitoring, at least annually, is necessary for performance testing and the data collected forms the basis of the sample calculation.

Sample Calculation
A building has an annual average outdoor PM2.5 level of 40 µg/m³. According to Option 3, the indoor PM2.5 level should be less than or equal to 30% of the 24-hour average of outdoor levels. If the outdoor PM2.5 level was 40 µg/m³ on the day of testing, the indoor level should be 12 µg/m³ or less.

Compliance Examples

About Firstgreen Consulting

At Firstgreen Consulting, we understand the importance of air quality for health and wellbeing. As a leading green building consulting firm, we provide comprehensive support and guidance to meet WELL certification requirements. Our team can help assess current air quality levels, suggest and implement air quality improvement measures, and provide ongoing monitoring to ensure compliance with the WELL standards. We believe in creating healthier, more productive indoor environments that benefit both occupants and the environment, fostering a future where workspaces are a foundation for wellness and sustainability.