Protecting Indoor Workers Exposed to Smoke

By Erica Vranak, TSI Product Marketing Manager

Wildfires are raging across the West Coast, leaving cities with apocalyptic orange skies and destroying over 3 million acres in California, more than a million acres in Oregon, and over 500,000 acres in Washington. By Sunday, smoke from the wildfires had blown thousands of miles away, into Canada and even upstate New York.

TSI’s headquarters in Shoreview, Minnesota—over 1,900 miles from San Francisco—was still showing good outdoor air quality levels of 21 AQI (Air Quality Index) as of Monday afternoon. However, the Minnesota Pollution Control Agency only forecasted “green” through Tuesday. According to airnow.gov, green indicates, "Air quality is satisfactory, and air pollution poses little or no risk."

What happens when the AQI numbers start to go up? At what point does exposure to wildfire smoke become harmful?

Under Cal/OSHA directive §5141.1 Protection from Wildfire Smoke, outdoor workers must be protected from breathing “unhealthy” smoke-filled air, which is defined as a current AQI of 151 or greater for PM2.5 particulates. On Monday, September 14, for example, the rule would have applied to San Francisco because the city had an AQI of 187.

Can unhealthy outdoor AQI affect indoor workers?

This regulation might be specific to outdoor workers, but employers should also consider AQI for indoor workers. Open windows and frequently opened doors can allow smoke from wildfires inside a building and it can become unsafe for indoor workers. You don’t even need to reach an AQI of 151—AQI over 101 can be unhealthy for sensitive groups.

Most buildings have a central ventilation system that filters air, but smoke can still make its way indoors. TSI’s AirAssure™ PM2.5 Indoor Air Quality IAQ Monitor can provide assurance to indoor workers during wildfires by providing real-time, reliably accurate measurement of indoor PM2.5 concentrations.

Ensuring reliable indoor air quality readings

The AirAssure™ IAQ Monitor is a mass concentration measuring device that mounts to a wall and continuously measures PM2.5 concentrations in indoor environments. Each AirAssure™ IAQ Monitor requires minimal maintenance and includes NIST traceable calibration. It is an easy-to-implement system for communicating wildfire smoke hazards in a form readily understandable by all individuals inside the building, helping create a safe working environment for everyone:

• Workers: A measurement they can trust, in an easy-to-read color coded, digital display.
• Building Managers: A low maintenance unit with patented measurement stability and a simple dashboard interface that enables convenient monitoring of multiple networked units.
• Building Owners/Employers: Accurate measurement and demonstrated indoor air quality helps to retain employees and improve occupancy rates with the promise of a safe, healthy indoor environment.

Workplace safety is not only important for the health and safety of workers, it also benefits the company when workers feel comfortable and confident by reducing absenteeism and turnover and increasing productivity.

While active wildfires continue to burn, unhealthy smoke can drift into neighboring communities. Employers in regions where wildfires are common—or long-lasting—should anticipate that their workers may have concerns about being exposed to wildfire smoke, even as they work indoors.