Safety resource 15 / 15

Wildfire Smoke and Outdoor Air Quality

When wildfire smoke drifts over a jobsite, the Air Quality Index for fine particulate (PM2.5) decides what protection is required and whether work moves.

Four smoke thresholds to recognize

Quick-reference overview. The actual project scope, site conditions, qualified evaluations and applicable requirements control.

Tap a number

GoodModerateSensitivegroupsUnhealthyVeryunhealthyHazardousBeyond500050100150200300500 PM2.5 AQI reading 151: rule applies N95s provided Required Indoors
Check PM2.5

Check the current AQI for PM2.5 before work and as conditions change, on AirNow or South Coast AQMD. The rule uses the PM2.5 reading, not ozone.

151: the rule applies

From an AQI of 151 for PM2.5, wildfire smoke protections start wherever smoke exposure is expected.

151 to 500: N95s provided

N95 respirators are handed out for voluntary use, with training on fit and limits, and workers are encouraged to wear them.

Over 500: respirators required

Respirators become mandatory under a full program with fit testing and medical evaluation.

Cut the exposure

Move work indoors with filtered air, shift hours, lighten the work and take breaks in an enclosed space or vehicle.

Project planning snapshot

  1. KnowAQI forecast, fire locations and wind direction.
  2. VerifyCurrent AQI for PM2.5 each shift, respirator supply and training.
  3. ControlRelocate or reschedule work, enclosed breaks, lighter work and N95s.
  4. RecordAQI readings, training, schedule changes and owner notices.

Fun facts

Three details worth remembering

  1. The trigger is PM2.5 only

    The 151 threshold refers to the PM2.5 reading, not an overall AQI driven by ozone.

  2. Smoke and heat arrive together

    Santa Ana wind fire weather often brings both, so heat and smoke plans run at the same time.

  3. Voluntary use still needs instruction

    Workers who wear N95s by choice get information on fit, use and limits.

Read the detailed planning guidanceConcise, source-grounded project considerations

Check the AQI before and during the shift

Check the current AQI for PM2.5 before work and as conditions change, using AirNow or South Coast AQMD readings. Tell the crew the reading and the protection in place in a language they understand, and make clear anyone can report symptoms without reprisal.

Reduce exposure

Move work into enclosed buildings with filtered air where the scope allows, or shift it to hours or areas with better air. Reduce work intensity, add rest breaks and give the crew an enclosed space or vehicle with recirculated air for breaks.

Provide respirators

Between an AQI of 151 and 500, provide N95 respirators for voluntary use and encourage workers to wear them. Above 500, respirators are required under a full respiratory protection program with fit testing and medical evaluation.

Train the crew and protect the schedule

Wildfire smoke training is part of the IIPP: health effects, how to get the AQI, the employer’s controls and respirator use. When smoke forces a schedule change, notify the owner early and in writing so schedule rights are preserved.

Primary references

Requirements can depend on the task, employer, location, project documents and actual field conditions.

SoCal Removal is a licensed demolition and environmental contractor—not an industrial hygienist, testing laboratory, engineer, attorney or regulatory agency.

Smoke season on the schedule? Plan the contingency.

Knowing which work can move indoors or shift hours keeps a smoke day from becoming a lost week.

Send us

  • Schedule and milestone dates
  • Outdoor and indoor scope
  • Owner notice requirements

We review

  • Work that can shift indoors
  • Resequencing options
  • Schedule-impact notices
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