The short answer: Rule 403 is a performance rule backed by operating controls
Within South Coast AQMD jurisdiction, Rule 403 applies to any activity or man-made condition capable of generating fugitive dust. Demolition and grading must use the applicable best available control measures, prevent prohibited visible emissions and vehicle dust, control track-out, and meet added egress or large-operation duties when thresholds are reached. The field plan must cover actual dust sources, not simply list “water as needed.”
Numbered guide: connect each dust source to a field control and record
The eight markers match the illustration above. They move from jurisdiction and planning through work methods, wind response, stockpiles, haul roads, site exits, observations, corrective action, and documentation.
Return to the numbered illustration above
- 1
Jurisdiction and planningConfirm the air district, current Rule 403 and any supplemental rule, site acreage, daily earth movement, import or export volume, permit conditions, dust sources, sensitive boundaries, responsible party, water supply, and contingency resources.
- 2
Water and work methodsPrecondition material and apply water or another authorized control at demolition, excavation, grading, loading, unloading, crushing, and traffic points without creating unsafe saturation, runoff, or uncontrolled slurry.
- 3
Wind responseMeasure or otherwise document conditions as required, monitor exposed work and boundaries, deploy contingency measures early, reduce the active area or production, and pause operations that cannot meet the applicable standard.
- 4
Stockpile and haul-road controlsLimit drop height, stabilize or cover piles, maintain haul routes, control vehicle speed, phase disturbed areas, and protect inactive surfaces so dust is not recreated between active shifts.
- 5
Track-out preventionUse the required stabilized egress, gravel pad, paved apron, wheel shaker, wheel wash, or approved equivalent as applicable. Prevent spillage and remove track-out before it reaches the rule limit and at the end of the shift.
- 6
Field observationsAssign trained personnel to observe active sources, property lines, roadways, wind, water coverage, equipment speeds, stockpiles, vehicle loads, and complaints on the frequency required by the rule, plan, or permit.
- 7
Corrective actionGive the field lead authority and resources to add water, change the method, repair an exit control, sweep with suitable equipment, reduce traffic, cover material, stabilize surfaces, or suspend the source promptly.
- 8
Records and handoffRecord the active areas, controls, inspections or observations, wind conditions when relevant, deficiencies, corrections, track-out cleanup, equipment and water issues, notifications, supervisor coverage, and end-of-phase stabilization.
Rule 403 starts below the large-operation threshold
Rule 403 applies to active operations, open storage piles, disturbed surfaces, and vehicle movement capable of producing fugitive dust. No person may allow dust from an active operation, open storage pile, or disturbed surface to remain visible beyond the source property line. Vehicle-generated dust may not exceed 20 percent opacity. Applicable Table 1 best available control measures must be used for each source type.
Track-out may not extend 25 feet or more in cumulative length from its point of origin, and all track-out must be removed at the end of each workday or evening shift. These are performance duties for covered activities; they do not disappear because a site is smaller than five or fifty acres.
Jurisdiction checkpoint Confirm the exact project location and current air-district rules. Coachella Valley work may have supplemental Rule 403.1 requirements, and projects outside South Coast AQMD are governed by another California air district.
Build the dust-control plan around the production sequence
List each dust-capable operation by phase: interior strip-out, structural demolition, debris sizing, slab or pavement breaking, excavation, mass grading, trenching, loading, unloading, crushing, stockpiling, haul-road travel, track-out, cleanup, and inactive disturbed surfaces. For each source, identify the primary control, contingency control, inspection point, trigger for correction, responsible field lead, and record.
Water is often central, but the estimate must address source, meter or hydrant approval, storage, hose and truck capacity, refill time, distribution, freeze or heat conditions, equipment conflict, runoff, slippery access, sediment, and after-hours coverage. Chemical stabilizers, coverings, barriers, paving, gravel, sweeping, and phasing may require separate approvals or environmental controls.
Dust sourceField-control approachPlanning detail to document
Demolition and debris handling Pre-wet, apply water at the point of disturbance, limit drop height, control debris piles, and stop uncontrolled visible emissions Water reach and pressure, occupied boundaries, asbestos or lead controls, debris route, equipment sequence, and runoff protection
Earthmoving and grading Precondition soil, water during work, phase the active area, stabilize completed areas, and control equipment speed Soil moisture, acreage, cut/fill balance, daily cubic yards, wind exposure, watering capacity, and shutdown criteria
Stockpiles and inactive surfaces Apply water, cover, crust, barrier, vegetation, or another applicable stabilization method Pile dimensions, planned idle time, cover anchorage, inspection frequency, and who maintains controls after a phase ends
Haul routes and loads Maintain roads, control speed, prevent load loss, use required load controls, and clean spilled material promptly Truck count, route length, pavement interface, load condition, speed limit, sweeper availability, and responsibility beyond the gate
Site exits and public road Use required egress controls, inspect throughout the shift, and remove track-out with suitable equipment Threshold, exit count, pad or wash dimensions, water recovery, street-sweeping method, traffic control, and disposal of collected material
Do not confuse the egress threshold with the large-operation threshold
An active operation with five or more acres of disturbed surface, or 100 cubic yards or more of daily bulk-material import or export, must use at least one of the egress measures specified in Rule 403(d)(5) at each vehicle exit to a paved public road. That added exit requirement is not the definition of a large operation.
A large operation is an active operation on property containing at least 50 acres of disturbed surface, or an earthmoving operation reaching at least 5,000 cubic yards of daily earth movement or throughput three times during the most recent 365-day period. Unless a specific exemption or approved-plan pathway applies, large-operation duties include the applicable Table 2 and 3 actions, notification, daily records, signage, a qualified dust-control supervisor, annual resubmittal, and completion notice.
- Submit a fully executed Form 403N within seven days after qualifying as a large operation, unless an applicable approved-plan or exemption provision controls.
- Maintain daily large-operation dust-control records for at least three years and make them available when requested.
- Install required project contact signage before earthmoving begins.
- Identify a certified dust-control supervisor who is onsite or available onsite within 30 minutes during working hours and has authority to act.
- Resubmit an accepted notification annually when required and notify South Coast AQMD in writing within 30 days after the site no longer qualifies.
TriggerAdded field or administrative duty
Any dust-capable activity Meet Rule 403 performance standards and use the applicable Table 1 best available control measures
At least 5 disturbed acres or 100 cubic yards per day of bulk-material import/export Use at least one specified Rule 403(d)(5) control at every active vehicle egress to a paved public road
At least 50 disturbed acres or 5,000 cubic yards on three days in the most recent 365 days Evaluate large-operation notification, Table 2 and 3 actions, signage, supervisor, monitoring or observations, recordkeeping, resubmittal, and completion duties
High wind is a contingency condition, not a blanket permission slip
Rule 403 defines high-wind conditions as instantaneous wind speeds above 25 miles per hour. Its high-wind provision is limited: the exemption addresses specified performance paragraphs only when the required Table 3 contingency measures are implemented and records are maintained. Applicable control measures, track-out, egress duties, safety requirements, project permits, and other environmental rules still require separate compliance.
The contract should assign initial and ongoing water, temporary shutdown stabilization, weekend or post-phase maintenance, public-road cleanup, complaints, monitoring equipment, notification, certified-supervisor coverage, and the date responsibility transfers from demolition or grading to the owner or next contractor. A schedule handoff does not stabilize an exposed site.
Separate compliance systems Rule 403 fugitive-dust control does not replace South Coast AQMD Rule 1403 asbestos requirements, Cal/OSHA silica controls, hazardous-soil rules, stormwater BMPs, local permits, or an owner’s project-specific environmental plan.
Rule 403 dust-control questions
These answers provide project-planning context. Current rules, approved plans, project specifications, retained qualified parties, permits, facility criteria, and written project direction control the actual work.
Does Rule 403 apply only to large construction sites?
No. Rule 403 applies to any activity or man-made condition capable of generating fugitive dust. Large projects have added duties, but smaller demolition, grading, stockpile, hauling, and vehicle operations still must control dust and meet the rule’s performance standards.
When do added Rule 403 construction requirements apply?
Projects with at least 5 acres of disturbed surface area, or at least 100 cubic yards per day of bulk-material import or export, must use a specified track-out control at each vehicle egress from the site to a paved public road. A large operation has at least 50 disturbed acres or daily earthmoving or throughput of at least 5,000 cubic yards three times in the most recent 365-day period and carries additional notification, supervisor, signage, monitoring, and recordkeeping duties.
Does high wind automatically exempt demolition or grading from Rule 403?
No. Rule 403 has a limited high-wind exemption when specified wind conditions and control measures are met. It is not blanket permission to continue an uncontrolled operation, and other air-quality, safety, silica, and project requirements still apply.
