The employer must determine the current PM_2.5 for worksites covered by WAC 296-820-805 through 296-820-860 periodically as needed. The employer may use any of the following methods to determine employee exposures such that they are able to comply with the requirements in WAC 296-820-805 through 296-820-860:

1. (1) Check PM_2.5 forecasts and the current PM_2.5 from any of the following:

   1. (a) Washington department of ecology website;
   2. (b) Air Quality WA mobile app;
   3. (c) Washington smoke information website;
   4. (d) U.S. EPA Fire and Smoke Map;
   5. (e) U.S. EPA AirNow website;
   6. (f) U.S. EPA AirNow mobile app;
   7. (g) U.S. Forest Service AirFire website; or
   8. (h) Local clean air agency website.
2. (2) Obtain PM_2.5 forecasts and the current PM_2.5 directly from the Washington state department of ecology, U.S. EPA, U.S. EPA EnviroFlash.info, or local clean air agency by telephone, email, text, or other effective method; or

3. (3) Measure current PM_2.5 levels at the work location in accordance with WAC 296-820-845.

   The following table indicates the NowCast AQI values that may be used from the Washington state department of ecology, local clean air agency, or EPA to comply with this section:

   CURRENT PM2.5	NOWCAST AIR QUALITY INDEX FOR PM2.5 (AQI)
   20.5 μg/m3	72
   35.5 μg/m3	101
   250.5 μg/m3	351
   500.4 μg/m3	849
   555 μg/m3	957

   Notes:	• The current PM2.5 is updated hourly.
   	• Employers are not responsible for tracking employee exposures outside of working hours.

[Statutory Authority: RCW 49.17.010, 49.17.040, 49.17.050, 49.17.060, and chapter 49.17 RCW. WSR 25-09-064, s 296-820-815, filed 4/15/25, effective 5/16/25; WSR 24-01-070, § 296-820-815, filed 12/14/23, effective 1/15/24.]