Soilworks products are the industry’s top standard due to our insistence on creating high performance soil stabilization and dust control products that stand up to rigorous testing – both in the lab and in the field. Our commitment to quality and performance has led to our involvement and testing in hundreds of real-world situations. The following library of reports, presentations, specifications, approvals and other similar documents provide you, our customer, the transparency and dependable assurance that is expected from Soilworks.
Fugitive dust control, PM10 reduction, construction site stabilization, trackout prevention, unpaved haul road management, open storage pile control, and disturbed soil stabilization are central priorities for contractors, site superintendents, utility crews, bulk material handlers, landscapers, demolition teams, and operations managers working in dust-generating environments. Soilworks solutions help meet these challenges by supporting proactive dust control plans, continuous site stabilization, and reliable suppression for disturbed surfaces, unpaved roads, parking areas, staging areas, access routes, stockpiles, weed abatement zones, and inactive construction phases.
For long-lasting dust control in high-traffic areas, Durasoil provides durable, non-water-dependent suppression for unpaved roads, haul routes, parking lots, and bulk material yards. For soil stabilization, crust formation, and erosion control on disturbed or inactive areas, Soiltac and Gorilla-Snot help bind loose soils, reduce wind-blown dust, support surface stability, and improve site readiness where dust suppressants are needed beyond routine watering. Project managers, engineers, environmental specialists, and operations leaders can contact Soilworks for guidance on selecting the right product strategy for fugitive dust emissions, trackout control support, exposed soil stabilization, and compliant dust abatement planning.
February 2026
Dust Abatement Handbook
Maricopa County
Air Quality Department
Compliance and Enforcement Division
Maricopa County Air Quality Department’s (MCAQD’s) Rule 310-Fugitive Dust from Dust Generating Operations (Adopted Rules | Maricopa County, AZ) is a comprehensive set of regulations that, when properly implemented, dramatically reduce dust emissions and improve air quality. The need for improved air quality for dust (PM10) is urgently important in Maricopa County.
Rule 310 is a critical element in Maricopa County’s strategy to achieve improved air quality and compliance with the rule’s provisions is essential. MCAQD has instituted a comprehensive program to monitor compliance with Rule 310 and strict enforcement is leading to reduced dust emissions.
The purpose of this handbook is to provide a practical guide offering a comprehensive overview of MCAQD’s policies and interpretations of Rule 310. The handbook is organized to respond to topical questions and is structured to provide answers to the most encountered compliance challenges.
MCAQD has also produced the Dust Abatement Field Guide for the construction industry as a pocket-sized, quick reference designed to provide information about how to comply with Rule 310 in the field. While not as comprehensive as this handbook, the field guide is a durable, reliable, and brief summary of the most important points that designated site representatives and workers in the field should know about Rule 310.
This Dust Abatement Handbook and the related field guide are provided to assist in better understanding the provisions of MCAQD’s Rule 310. The contents of this handbook and the field guide should not be viewed as the definite statement of the rule and how to achieve compliance. Where the clear language of Rule 310 and any formally issued policy related to Rule 310 conflicts with this handbook or the field guide, Rule 310 and the policy will prevail.
This handbook is not intended to serve as an alternative to Rule 310 which is, by itself, the definite statement of dust control requirements.
ADEQ Arizona Department of Environmental Quality
A.R.S. Arizona Revised Statutes
ASTM American Society for Testing and Materials
cm/second centimeters per second
CMP A code preceding a subcontractor’s registration number; previously “SC”
EPA U.S. Environmental Protection Agency
ft2 Square feet
Facility ID A sequence of letters and numbers used to identify a facility in MCAQD’s database
MCAQD Maricopa County Air Quality Department
mm millimeters
mph miles per hour
NESHAP National Emission Standards for Hazardous Air Pollutants
oz/ft2 Ounces per square foot
PM10 Particulate matter less than or equal to 10 microns in diameter
SC Subcontractor
TFV Threshold friction velocity
yd3 Cubic yards
Contents
Introduction……………………………………………….. 2
About This Handbook……………………… 2
Commonly Used Dust Abatement Acronyms…………………………………… 3
SECTION 1: BEFORE STARTING WORK…………………………………. 3
Why Rule 310?………………………………………………………….. 3
Coverage of Rule 310……………………………….. 3
What’s Not Covered?…………………………………………. 3
Does Rule 310 Apply?………………………………… 4
Is a Dust Control Permit Required?………………………. 6
Before Starting Work………………………………………. 6
While Your Permit is Active………………………… 8
As Your Project Nears Completion…………………………… 8
What Activities Are Covered by Rule 310?…………………………….. 9
What is Considered a Dust-Generating Activity?……………………….. 10
What is Required Before Commencing Work at a Project Site?……………… 10
What Do I Do When My Permit is Close to Expiring?…………………….. 11
Understand Your Obligations…………………………….. 11
SECTION 2: DUST CONTROL PERMIT……………. 11
Applying for a Permit……………………. 11
What Do I Do if I Have Questions or Need Assistance?…………………. 12
Block Permit Information……………………….. 12
Block Permits and Utility Responsibilities……………………. 13
Activity Occurring at Locations Not in the Block Permit…………….. 13
Enforcement and Utility Responsibilities…………………………………. 14
Accelerated Dust Control Permit Processing…………… 14
Receiving Your Permit………………………….. 14
What to Do When Your Permit is About to Expire…………………….. 14
Permitting Administrative Process……………………………. 15
The Dust Control Plan……………………………….. 15
Updating the Dust Control Plan…………………………. 15
Changes Initiated by the Permit Holder……………… 16
Changes Required by MCAQD………………………… 16
How is the Approved Dust Control Plan Used?……………… 16
Primary Control Measure………………………….. 17
Contingency Control Measure………………………… 17
SECTION 3: APPROVED DUST CONTROL TRAINING……………….. 17
What Training is Required?…………………………… 17
Who Can Provide Training?…………………… 18
Certifications……………………………….. 18
Basic Certification…………………………………… 19
Comprehensive Certification………………………. 19
Visible Emission Certification…………………….. 19
Dust Control Coordinators………………………… 19
Authority to Direct Activities to Comply with Rule 310……………. 20
SECTION 4: PERMIT SIGNAGE AND RECORDKEEPING………………….. 21
Project Information Signs………………….. 21
Information to Include……………………………… 21
When to Update the Sign………………………… 22
Where to Post the Sign…………………………. 22
Recordkeeping – What Records Are Required?………………… 23
Document Retention…………………………………. 23
SECTION 5: ACCESSIBLE AREAS…………………….. 24
Areas that are Accessible to the Public……….. 24
SECTION 6: WORKING ON OTHER SITES……………………….. 25
Subcontractor Registration………………………………. 25
Displaying Subcontractor Registration Numbers……………….. 25
Subcontractors are Subject to Enforcement……………… 26
Subcontractor registration is not required for the following activities…….. 27
SECTION 7: TRACKOUT………………….. 27
Trackout Clean-Up Requirements…………………. 27
The Difference Between Trackout and Staining……………………. 28
Measuring Trackout……………………………… 28
Trackout Control Devices……………………….. 29
Controlling and Changing Exits During Construction Phases……………….. 29
SECTION 8: STABILIZING YOUR SITE……………………………….. 30
Control Measures on Disturbed Areas (No Activity for 30 Days or Longe) …….. 31
SECTION 9: VISIBLE EMISSIONS……………………… 32
On-Site Visible Emissions Opacity Limits……………… 32
Visible Emissions Beyond the Property Line………………… 32
Visible Emissions Guide…………………………….. 33
High Wind Conditions and Visible Emissions……………… 34
Visible Emissions Originating from Adjacent Lands………… 34
SECTION 10: ON-SITE OPERATIONS……………….. 35
Unpaved Parking Lots……………….. 35
Unpaved Haul and Access Roads…………….. 36
Trackout Control Devices……………………. 38
Hauling Bulk Materials………………………….. 39
Moving Bulk Materials………………………. 39
Haul Truck Load Cross Section: Proper Loading…………… 40
Storage Piles, Bulk Material Stacking, Loading, and Unloading…………… 40
SECTION 11: PERMIT ADMINISTRATION………………………. 42
SECTION 12: INSPECTIONS…………………….. 43
Compliance Warning Signs………………………. 43
Inspection Rights…………………………. 44
Inspection Rights Form………………………………… 44
Once an Inspection Begins, What Do Inspectors Look For?……………………. 46
Subcontractors………………………………. 46
Site Conditions………………………………. 47
Courtesy Site Visits…………………………. 47
SECTION 13: ENFORCEMENT……………………….. 47
SECTION 14: TEST METHODS………………….. 48
Determining the Presence of Visible Emissions Crossing a Property Line………… 48
Determining Opacity of Fugitive Emissions…………………. 49
Determining Stabilization………………….. 49
Determining Silt Content Using ASTM Method C136-06………………. 50
Threshold Friction Velocity……………………….. 50
APPENDIX A: MORE HELPFUL HINTS………………….. 51
APPENDIX B: RESOURCES…………….. 52
MCAQD’s Rule 310 (Fugitive Dust from Dust-Generating Operations), was developed as part of a comprehensive program to control dust (PM10) and achieve compliance with air quality standards for PM10 air pollution in the greater metropolitan Phoenix area.
Rule 310 is a county-wide rule and can be enforced in any portion of Maricopa County. Rule 310 applies to any activity that results in soil disturbance. While a few activities are exempt, a good rule of thumb is to assume that the activity you are planning is covered by Rule 310 until you confirm otherwise.
The following activities are covered:
Although tribal communities are found within the borders of Maricopa County, MCAQD has no jurisdiction over them because they are legally considered sovereign nations. Check with tribal governments, as some have their own dust control requirements.
Normal farm cultural practices are all activities conducted on any facility for the production of crops and/or nursery plants, including disturbance of the field surface caused by turning under stalks, tilling, leveling, planting, fertilizing, or harvesting.
Normal farm cultural practices are under the jurisdiction of the Arizona Department of Environmental Quality (ADEQ), not Maricopa County. However, construction activities that take place on agricultural lands are subject to Rule 310. For example, construction of a new food processing warehouse on farmland would be regulated by Rule 310 and a permit would be required, if the surface area that will be disturbed is equal to or greater than 0.1 acre (4,356 square feet (ft2)).
Trackout originating from agricultural lands is regulated by Rule 310. See also MCAQD’s substantive policy statement SPS-2018-001-Trackout from Normal Farm Cultural Practices for the requirements for cleaning up trackout from a facility where normal farm cultural practices occur.
In addition, if trucks are exiting agricultural lands, the load must be covered by a tarp.
If you are engaged in a dust-generating activity covered by Rule 310, the rule requirements apply at all times (24/7), even during inactive periods. Even if you are not required to have a permit, the dust control provisions of Rule 310 still apply to your project.
At facilities with a Title V or a Non-Title V permit, dust-generating operations that are conducted as part of the primary operations of the facility must be performed under the existing permit and dust control plan.
At facilities with an Authority to Operate (ATO) under a Stationary Dust-Generating Source General permit, the following dust-generating operations apply:
If a facility has obtained a permit from MCAQD for nonmetallic mineral processing and/or related operations and the permit contains fugitive dust control requirements from Maricopa County Air Pollution Control Regulations, Rule 316 (Nonmetallic Mineral Processing) (Adopted Rules | Maricopa County, AZ), the facility does not need to obtain a dust control permit before commencing construction, demolition, grading, overburden removal, and other dust-generating operations. Instead, the facility must submit a revised dust control plan and comply with the requirements of Rule 316. The permit holder is ultimately responsible for ensuring that all operations and activities conducted under the permit are in compliance with applicable requirements.
If a contractor will be hired to complete a demolition or construction project, the project contractor should obtain a dust control permit before any dust-generating operations associated with the project commence. The area that is covered by the dust control permit will be subject to Rule 310 and the dust control permit holder will be responsible for compliance.
In addition, the demolition or construction project could be subject to the National Emission Standard for Hazardous Air Pollutants (Asbestos NESHAP) and Maricopa County Air Pollution Control Regulations, Rule 370 (Federal Hazardous Air Pollutant Program) (Adopted Rules | Maricopa County, AZ).
If a facility stores or handles bulk materials, especially biodegradable materials, a permit is required when:
PM10 per year.
The threshold for a dust control permit is based on the amount of surface area disturbed by a project. If the area disturbed will meet or exceed 0.1 acre (4,356 ft2), a permit is required. A tenth of an acre (0.1 acre or 4,356 ft2) is a relatively small amount of land and is roughly the size of a basketball court.
What do you need to do to ensure that a project is in compliance? The following list of important “Do’s and Don’ts” are intended to provide a snapshot of some of the most significant provisions of Rule 310. This handbook provides more expansive discussions on each of these provisions in later sections.
Know when your permit expires and place the expiration date on your calendar. Should you require a new permit, remember that MCAQD has up to 14 days to process your complete application. If the application is not complete or errors are present, additional time will be required to resolve any issue. A dust control permit that expires while a dust control permit application is pending will be subject to immediate enforcement for operating without a permit.
If you are engaged in dust-generating operations, no matter how small, you must control fugitive dust emissions and comply with Rule 310. If you are disturbing 0.1 acre (4,356 ft2) or more, you must comply with Rule 310 and obtain a dust control permit.
Rule 310 applies to all activities that may result in fugitive dust emissions but mainly regulates dust emissions associated with construction activities. Generally, if the surface of the ground is disturbed in some manner, or if bulk materials are moved from one location to another or stockpiled, the potential exists for fugitive dust emissions.
In Rule 310, Maricopa County defines “disturbance” as “a portion of the earth’s surface or material placed on the earth’s surface that has been physically moved, uncovered, destabilized, or otherwise modified from its undisturbed native condition if the potential for the emission of fugitive dust is increased by the movement, destabilization, or modification.”
Examples of activities that can disturb 0.1 acre (4,356 ft2) or more and would require a dust control permit include:
A primary dust-generating activity is any operation capable of generating fugitive dust, including but not limited to, the following:
Remember: Disturbed surfaces do not have to be contiguous (connected to or adjacent to each other).
MCAQD utilizes the Dust and Miscellaneous Portal for dust permit applications. Dust permit applications submitted by email will not be processed and will be returned. The portal is designed to provide a user-friendly interface for industry representatives to submit the required information to process a dust permit application. Users have the ability to:
First time users must begin by creating an account. Once an account is created, you will be able to begin the application process.
The Dust and Miscellaneous Portal also features a public database containing all dust permit applications submitted to MCAQD. The use of this feature does not require an account.
Call 602-506-6010 or email AQPermits@maricopa.gov.
Basic fees for a dust control permit (permit valid for one year) are calculated on the basis of the total disturbed acreage. Fees are established according to the following schedule:
| $570 | 0.1 to less than one acre |
| $1,130 | One acre to less than ten acres |
| $4,120 | Ten acres to less than 50 acres |
| $6,870 | 50 acres to less than 100 acres |
$10,310 100 acres to less than 500 acres
$16,490 500 acres or greater
A late fee of $100 is required for any application submitted in response to a violation.
If paying by electronic check, make checks payable to “Maricopa County Air Quality Department” or “MCAQD” and reference the permit application number on the check.
The block permit fee is $2,000. Block permits are only issued to municipalities, government agencies, or utilities for one or more of the following projects that occur in multiple, small areas scattered throughout Maricopa County:
The purpose of the block permit is to allow municipalities, governmental agencies, and utilities to conduct similar activities at multiple sites across the county. Covered activities include routine operation and maintenance of urban infrastructure, as well as the expansion or extension of that infrastructure such as roads, utilities (e.g., pipelines and electric substations), and other public rights-of-way.
Use the Dust and Miscellaneous Portal to submit a “Block Permit Application”, a “Block Permit Site List Attachment or Update”, and a “Block Permit Subcontractor List Update”.
A block permit can only be issued to municipalities, governmental agencies, or utilities. However, when municipalities, government agencies, or utilities don’t have the resources to conduct these projects themselves, they find it necessary to hire contractors.
MCAQD’s substantive policy statement SPS-2018-009-Block Permits and Contractors explains the applicability of block permits to contractors who are hired by municipalities, government agencies, or utilities, and the responsibilities of the contractor and municipalities, government agencies, and utilities (the block permit holder). While the permit is held by the authorized block permit holder, subcontractors to the authorized permit holder may operate under the cover of the permit as would the employees of the permit holder.
The block permit is applicable to those locations that are listed in the “Block Permit Site List Attachment or Update”. To conduct work at a location other than those locations, the block permit holder must notify MCAQD of the intent to work in a new location at least three days in advance of the planned activity. The notice must include information describing the location and the anticipated start date of the work. This requirement does not apply to emergency activities conducted by utility or government agencies in order to prevent public injury or to restore critical utilities to functional status.
New infrastructure construction that is not an extension of an existing system must be covered under a new dust control permit.
For any project not listed in the dust control block permit application, the applicant is required to notify MCAQD at least three working days in advance of initiating the activity.
Similarly, at new subdivisions or commercial developments, a utility will operate under its block permit and is required to notify MCAQD of its intention to work on a specific property. As with other areas, a block permit holder is required to provide MCAQD with notification of its intent to operate at a location not previously identified in its block permit. Notification must be provided in writing within a minimum of three working days.
The permit holder retains responsibility for all work conducted within the area covered by the dust control permit. However, if a utility causes an instance of non-compliance, the utility can be cited in accordance with Rule 310. This includes the obligation to ensure that areas disturbed during utility work are adequately stabilized. A utility is obligated to meet minimum stabilization requirements of Rule 310.
Utility access by a block permit holder onto areas covered by a dust control permit may pose a special challenge. While the block permit holder is obligated to comply with all dust control measures implemented under the dust control permit, the dust control permit holder is accountable for all site conditions. A block permit holder can be held accountable for instances of non-compliance, if a block permit holder does not restore a disturbed area to its former stabilized condition.
You may request accelerated permit processing of a dust control permit application for a fee of two times the basic fee amount. Applications submitted with an accelerated permit fee will be processed by the end of the next business day.
Once issued, the completed permit will be sent to the applicant’s email address. Allow up to 14 days for permit processing, unless you requested accelerated dust control permit processing, which will be completed by the end of the next business day after submittal.
Apply for a new dust permit, using MCAQD’s Dust and Miscellaneous Portal, well before your current permit is due to expire. Remember to allow up to 14 days for MCAQD to review the complete application. If the application is not complete or errors are present, additional time will be required to resolve any issue. A dust control permit that expires while a dust control
permit application is pending will be subject to immediate enforcement for operating without a permit.
Step 1: Using the Dust and Miscellaneous Portal, the applicant completes the dust permit application, including the dust control plan, and submits the application with the appropriate fee payment.
Step 2: MCAQD receives the application, confirms fee payment, and determines if the application is complete.
Step 3: MCAQD conducts a technical review of the application and dust control plan within 14 days after submittal.
Step 4: The Control Officer approves the permit and MCAQD emails the approved permit and dust control plan to the permit applicant. Or The Control Officer rejects the application and MCAQD contacts the permit applicant with instructions. Return to Step 3.
Step 5: The approved permit and dust control plan are received at the project site and approved dust-generating activities can begin.
The dust control plan is submitted as part of the permit application. MCAQD reviews each dust control plan for completeness and technical accuracy.
The approved dust control plan can be revised by the permit holder or as directed by MCAQD.
Revisions to the dust control plan are not effective at time of submittal; they must be approved by MCAQD before becoming effective. Changes to the dust control plan required by MCAQD must be submitted within three working days of receipt of the MCAQD’s directive.
The permit holder may request changes to the dust control plan through the Dust and Miscellaneous Portal for the reasons listed below.
At times, dust emissions may continue to occur even if the control measures contained in the dust control plan are followed. When this occurs, MCAQD will issue a notice to the permit holder requiring revisions to the dust control plan. The permit holder must submit required revisions within three working days of receipt of the notice. If more than three working days are needed, the permit holder can request an extension. MCAQD will evaluate the request, but keep in mind that granting of an extension is not guaranteed. In any event, compliance with Rule 310 is expected immediately.
A primary control measure if the first action you implement to control dust emissions.
A contingency control measure is the backup strategy to be used when the primary control measure is not effectively controlling dust emissions.
Rule 310 requires certain personnel at a permitted site to receive training on dust control and emission reduction strategies. The level of required training and which personnel must be trained depends on the amount of acreage disturbed within the permitted area. The table below shows who must be trained and the level of training required by size of the disturbed area.
MCAQD provides online Rule 310 training classes. MCAQD’s online training system, mcaqd.learningcart.com, allows users to purchase and access training classes without having to contact MCAQD in order to sign-up and pay for classes. Participants have immediate access to the class upon payment, and companies have the ability to purchase multiple seats and receive registration codes.
Training class fees:
Basic Class: $50 Comprehensive Class: $125
Just as there are two levels of dust training (basic and comprehensive), there are two levels of certification: basic and comprehensive.
When you successfully complete dust training, you will receive a certification card via email. All dust control certifications are valid for three years from the date of issuance. Register for dust training before certification expires to avoid any lapse in compliance.
Newly hired employees will be granted 30 days from their date of hire to complete training.
To earn basic certification, individuals must complete the three-hour training course. Water truck and water-pull drivers are required to earn basic certification.
For projects that disturb one acre or more, the permit holder must designate a site representative who has earned basic certification (i.e., site superintendent, plant manager, or foreman).
In addition, a dust control block permit holder is required to have at least one individual who has received the basic certification for those sites on which there is one acre of surface disturbance.
Employees required to have the basic certification must renew their training certification once every three years.
Rule 310 comprehensive training covers dust control measures in detail. Individuals who complete this training earn comprehensive certification and may be designated as a Dust Control Coordinator.
On projects that disturb five or more acres, the permit holder must identify a certified Dust Control Coordinator, who must be present at all times during primary dust-generating activities.
A Dust Control Coordinator must renew their training certification once every three years. Note: Comprehensive certification includes basic certification.
Visible emissions certification is not required but is strongly recommended, especially for Dust Control Coordinators.
To receive a dust control permit, the permit holder must name a site representative or Dust Control Coordinator, who has the level of training required based on the area disturbed by the project. If a site representative or Dust Control Coordinator is required based on the size of the project, he or she must be given the authority by the permit holder to control dust. This means the site representative or Dust Control Coordinator must be able to direct actions within an area covered by a permit to ensure compliance with Rule 310, including ceasing operations, if necessary, to ensure that dust is not generated.
A Dust Control Coordinator is required whenever the disturbed area reaches or exceeds five acres. In some instances, there may be fewer than five acres of disturbed surface remaining in one phase of the project but there are additional permitted, yet undisturbed, areas of the project waiting to be developed. In this scenario, a Dust Control Coordinator would be required on site.
The only time a Dust Control Coordinator would not be required on site would be if the undisturbed phases were clearly identified in the dust control permit and in the dust control plan and the undisturbed area on the project site was clearly marked with access restricted.
When fewer than five acres of land (in all phases of the project) remain to be disturbed, previously disturbed areas have been stabilized, and notice of stabilization has been provided to MCAQD, the Dust Control Coordinator requirement would no longer apply.
The purpose of the project information sign is to provide the public with information about the permit status of the project and who to contact if there are dust complaints.
The requirement for a project information sign is based on the acreage of the permit. For all sites with a dust control permit that are five acres or larger, except for routine maintenance and repair done under a dust control block permit, the owner and/or operator shall erect and maintain a project information sign at the main entrance such that members of the public can easily view and read the sign at all times.
The project information sign must contain the information shown below (using text size of at least four inches). The sign must be placed at the main entrance of the site. Once the project information sign is required and is installed, it must remain throughout the life of the project, even if the project is reduced to less than five acres.
Dust Complaints?
Call Maricopa County Air Quality Department 602-372-2703
You must change your project information sign to reflect changes to the dust control permit or dust control plan, such as:
Post the sign in a location most prominently visible to the public, typically the main entrance to the site. As a project expands, an additional main entrance should be established, and an additional sign must be posted there.
Each day there are dust-generating operations occurring, a self-inspection by the permit holder must be conducted with notes taken to document observations. This is an important document and can be used to show that site conditions have been carefully controlled.
Critical information required by Rule 310 includes:
Records must be retained consistent with the following time frames and whichever is longer will apply:
The definition of “areas accessible to the public” is “any paved parking lot or paved roadway that can be entered or used for public travel primarily for purposes unrelated to the dust generating operation.” To determine whether an area meets this definition, consider the following:
The use of signs, barricades, ropes, or fences can help to define a controlled area and distinguish between areas that are under construction and areas that are accessible to the public. While the use of yellow rope or tape to separate the area is not required, it has practical value in ensuring that the area is visible and understood to be separate from other areas where the public has ready access.
Subcontractors are hired by a permit holder to perform various tasks on a construction site. MCAQD requires that subcontractors accessing sites covered by a dust control permit obtain registration. This applies to any subcontractor engaged in dust-generating activities (e.g., driving on roads, landscaping, and doing carpentry).
Registrations are valid for one year from the date the registration is approved/issued.
While the permit holder is responsible for all site activities that may result in a violation of the provisions of Rule 310, subcontractors may, under certain circumstances, also be held accountable. A permit holder cannot delegate primary obligations to a subcontractor to avoid compliance responsibility.
A utility is not considered to be a subcontractor when operating under its own block permit.
The subcontractor registration number must be displayed on a jobsite. Subcontractor registration numbers used to begin with “SC” but now begin with “CMP”. If the previous subcontractor registration number beginning with “SC” is displayed on trucks and equipment, this will be acceptable provided the source renews the dust control permit annually.
Methods of displaying the subcontractor registration number may include:
While a subcontractor will be held responsible for their compliance with Rule 310, the responsibility of the permit holder and the actions of a subcontractor can be difficult to separate. Factors that will be taken into account when determining which party is responsible include, but are not limited to, whether the:
MCAQD’s Substantive Policy Statement SPS-2018-010-Inspection and Inspection Report Policy issued August 26, 2019, states the following regarding subcontractors: The responsible party is typically the recipient of an inspection report. However, alleged violation(s) of applicable Code of Federal Regulations, air quality control statutes, rules, and/or permit conditions may occur as a result of the actions of subcontractors working on behalf of the responsible party or by persons not associated with the responsible party. An inspection report may be issued to a person other than the responsible party where:
Trackout is one of the most frequently cited instances of non-compliance by MCAQD’s inspectors. Controlling trackout must be a priority. In Rule 310, trackout is defined as:
“Any and all bulk materials that adhere to and agglomerate on the surfaces of motor vehicles, haul trucks, and/or equipment (including tires) and that have fallen or been deposited onto an area accessible to the public.”
A trackout control device is required at work sites with two or more acres of disturbed surface area or when hauling 100 yd3 or more of bulk materials on- or off-site per day regardless of the amount of disturbed surface area on the site.
Trackout must be removed immediately when the length of the trackout totals 25 feet or more, when measured from one, more than one, or all the project site’s exits. An inspection report that documents instances of non-compliance will be issued when the length of the trackout extends 25 feet or more, even if the removal of the trackout is occurring at the time of the determination. The term “immediately” is viewed as when the trackout occurs. The expectation is that trackout that extends 25 feet or more will be cleaned up immediately following deposition on the roadway.
Trackout extending less than 25 cumulative feet from the project site’s exits must be cleaned-up prior to the end of the workday. Fugitive dust emissions resulting from the trackout being driven over may result in an inspection report that documents instances of non-compliance, because opacity may exceed the 20% limit.
Trackout is the presence of material deposited on a road surface. Trackout can become airborne particulate matter when vehicles pass over and entrain the material into the air. In contrast, staining on a road surface is not considered to be trackout (if it is not deposited on top but in the crevices of the road). While staining may indicate that trackout may have been present at some time in the past, staining itself is not considered trackout under Rule 310 and will not result in an inspection report that documents an instance of non-compliance.
The distance of individual trackout paths originating from a permitted facility are combined to determine compliance. When trackout reaches a cumulative distance of 25 feet it must be cleaned up immediately. Trackout is measured from an exit onto a paved surface and along the path of trackout to the point where it ends. This may follow the actual curved path of trackout or the horizontal distance may be used instead (especially where traffic/safety is a concern). Line C on the diagram below is an example. Trackout on sidewalks and gutters are included in determining the total amount of trackout present.
A trackout control device is required at work sites with two or more acres of disturbed surface area or when hauling 100 yd3 or more of bulk materials on site or off site per day regardless of the amount of disturbed surface area on the site.
Several options are available for trackout control devices. At least one of the following controls must be in-place at all exits onto paved areas accessible to the public:
New technology for controlling trackout, like the “egg carton” trackout control device, may be allowed, as long as the device prevents trackout and is approved by the Control Officer.
Managing the flow of traffic entering and exiting a permitted area is one of the primary challenges for a work site that is trying to ensure dust control measures are being utilized. For some, it is tempting to exit at the nearest convenient paved area rather than travel over the designated trackout control device; however, this is considered non-compliance. In addition, vehicles circumventing a trackout control device by not travelling over the full length of the device or by using an undesignated exit is considered non-compliance, regardless of the presence or not of trackout on the area accessible to the public.
Place trackout control devices at all designated exits from the permitted area onto an area accessible to the public if:
Ensuring that disturbed areas within a permitted area are stabilized is a primary requirement of Rule 310. The disturbed area of a site must be stabilized at all times, including holidays, nights, and weekends. Rule 310 has separate stabilization requirements and test methods in place for disturbed areas, where dust-generating operations are occurring and for inactive disturbed areas. A project site may contain both active and inactive disturbed area at the same time.
Before starting work, conduct site preparation: pre-water the site or phase work so that the disturbed area created is minimized. If phasing is being used as a control measure, then project phases should be clearly identified in the dust control plan.
Within a permitted area, there may be several defined areas (representing project phases). One phase may be active with ongoing surface disturbance while another phase may not be disturbed. Ensure that areas not yet disturbed are clearly demarcated, identified in the dust control plan, and not accessible.
When phasing work, it is important to meet the stabilization requirements of Rule 310 for areas that have been disturbed but are not being actively worked.
When a disturbed area will remain in its current disturbed state with no further work taking place for a period of 30 days or longer, achieve one or more of the following:
stabilization standard should be achieved within 10 days following the completion of the dust-generating operation.
While a permit is still effective, the permit holder is responsible for any disturbance that occurs as a result of illegal trespass. If an area is disturbed after final stabilization and the permit is still in effect, the permit holder is obligated to ensure that stabilization is restored. If disturbed areas that are not stable are identified during an inspection, an inspection report that documents instances of non-compliance can be issued. It may be in the best interest of the permit holder to restrict access to the site during non-working hours. Trespassing can lead to unstable, disturbed areas and trackout, which are considered non-compliance. Issues resulting from trespassing are considered the responsibility of the permit holder. When the project has been completed and the permitted area has been properly stabilized, the permit holder must request a permit cancellation through the Dust and Miscellaneous Portal.
Essentially, Rule 310 focuses on ensuring dust (particulate) emissions are minimized. Emissions are subject to two separate standards, depending on whether the emissions are observed on site or off site.
Within the boundary of the area covered by the permit, visible emissions can never exceed 20% opacity.
The method used to determine whether visible emissions exceed 20% opacity is found in Maricopa County Air Pollution Control Regulations, Appendix C (Adopted Rules | Maricopa County, AZ). This method consists of the average of 12 observations of five seconds each taken over a period not longer than one hour. As a practical matter, the 12 observations will most likely be completed over the period of a few minutes.
In the figure above, the brown area is covered by a dust control permit. Surrounding this, the grey area is owned by the dust control permit holder but is not covered by a dust control permit. Visible emissions from the permitted area are allowed onto this adjacent area, since the property is owned by the permit holder and the emissions do not cross a property line.
Should the emissions extend further and onto the property designated as a private home or onto the forested area, the emissions are crossing a property line and are not allowed.
In the photo below, dust emissions are clearly visible crossing the property line. Although visible emissions are allowed beyond the property line, they cannot exceed 20% opacity. Also, in this instance, a serious public safety hazard is created by impairing visibility in a traffic lane.
High wind conditions have the potential to dramatically degrade air quality and can lead to emissions even when appropriate controls are implemented. The property line emission requirement and the 20% fugitive dust opacity standard do not apply to wind-blown dust if the emissions cannot be prevented by better application, operation, or maintenance of control measures. To demonstrate that the emission limits do not apply, the following actions must be taken:
Conditions may arise where winds will drive dust from one property (e.g., a vacant field) across another. Normally, visible emissions seen crossing the property line will constitute a violation. If visible emissions are created from a location outside of the permitted facility, it is important to document the occurrence in the facility’s records and even photograph or record the occurrence. This way, if an opacity violation is issued or discussed by an inspector, the facility will have proper documentation to show the inspector and/or the Business Assistance Unit. If visible dust emissions are seen passing over a permitted area and no additional dust emissions from the permitted area were added to such visible dust emissions, the permitted facility is not in violation of the property line opacity standard.
Unpaved parking lot is defined in Rule 310 as: “Any area that is not paved and that is designated for parking in the dust control plan or that is used for parking, maneuvering, material handling, or storing motor vehicles and equipment. An unpaved parking lot includes, but is not limited to, automobile impound yards, wrecking yards, automobile dismantling yards, salvage yards, material handling yards, and storage yards. For the purpose of this rule, maneuvering shall not include military maneuvers or exercises conducted on federal facilities.”
While the use of an area for staging or for material storage may be clearly evident, an isolated instance of such use will not cause the area to be designated as an unpaved parking lot.
An unpaved parking lot, as defined by Rule 310, is present when the use of an area by vehicles goes beyond what can be considered to be incidental use.
An area used as an unpaved parking lot should normally be designated in the dust control plan. However, identifying an unpaved parking lot in the dust control plan is not required for an inspector to determine that one is present based on the observed use.
To determine that a disturbed area is an unpaved parking lot requires observations of activities that reflect actual use of the property for an activity similar in scope to those examples provided in the definition.
The definition of “unpaved parking lot” refers to the term “maneuvering.” After-the-fact observation of tire tracks alone on an otherwise empty lot is not sufficient to classify an area as an unpaved parking lot without some supporting evidence that the area has been used in the manner contemplated by the definition. “Maneuver” means to direct any type of motorized vehicle through a series of movements or controlled series of changes in course or movement towards an objective. While one or two tire marks on an unpaved area constitutes incidental use and does not identify an area as an unpaved parking lot, multiple tire marks in varied directions identify that maneuvering occurred on the lot.
The following activities constitute incidental use and are not sufficient to determine that an area is being used as an unpaved parking lot:
Unpaved parking lots must meet a specified soil stability standard (silt loading cannot equal or exceed 0.33 oz/ft2) and operations on the lot cannot generate dust emissions greater than 20% opacity. If silt loading is equal to or exceeds 0.33 oz/ft2, then the silt content may not exceed 8%. (Note: As a practical matter, there is very little difference between the two values).
Whether an area is considered an unpaved parking lot or an otherwise disturbed area, stabilization is always required.
Whether marked or unmarked, an unpaved haul or access road is a road within a permitted area that is used to move material, equipment, or people from one point to another. These roads are likely to change location frequently and meeting the stabilization requirements is likely to require close attention.
By definition, an unpaved haul or access road represents a permanent or semi-permanent disturbed area that will require stabilization on an ongoing basis. At all times, visible emissions from unpaved haul or access roads must remain below 20% opacity. Additionally, Rule 310 sets silt loading and silt content levels that must never be exceeded. These levels are:
An unpaved road is any road, including an “equipment path”, used by motorized vehicles. An unpaved road is different from an unpaved haul/access road only by its designated use.
While an unpaved road is, by definition, different from an unpaved haul/access road, control and stabilization of the disturbed area is still expected.
At a minimum, visible emissions from an unpaved road cannot exceed 20% opacity. The road surface must be kept visibly moist or a crust must be maintained on the surface.
A trackout control device is required at work sites with two or more acres of disturbed surface area or when hauling 100 yd3 or more of bulk materials on site or off site per day regardless of the amount of disturbed surface area on the site.
Several options are available for trackout control devices. At least one of the following controls must be in-place at all exits onto paved areas accessible to the public:
New technology for controlling trackout, like the “egg carton” trackout control device, may be allowed, as long as the device prevents trackout and is approved by the Control Officer.
The use of haul trucks to move bulk materials from or within a site is regulated. A haul truck can be any number of different types of vehicles (e.g., a small pick-up, a flatbed truck, an 18-wheeler, a paddle-wheel scraper, a front-end loader, or a trailer towed by a motor vehicle). The purpose for which the vehicle is used is the determining factor, not the inherent nature or size of the vehicle.
If bulk materials are being moved out of an area covered by a dust control permit and onto a paved area accessible to the public, a trackout control device must be installed; there is no lower acreage limit that applies when off-site hauling bulk materials. In addition, the following requirements apply:
If bulk materials are moved within an area covered by a dust control permit but do not cross a paved area accessible to the public, the following requirements apply:
If bulk materials are moved within an area covered by a dust control permit and a paved area accessible to the public is used for a short distance to travel from one portion of a permitted area to another, the load must be tarped.
Be aware that spillage and visible emissions from a tarped load while driving on a highway constitute instances of non-compliance.
Using any portion of an area accessible to the public (other than simply crossing the road) will require the load to be tarped. There is no minimum threshold distance to travel.
Bulk materials encompass a wide array of materials including earth, rock, sand, gravel, soil, aggregate less than two inches in length or diameter, and demolition debris among many others. When handled, bulk materials are capable of producing fugitive dust emissions. Prior to and while conducting loading, unloading, and excavating operations, spray material with water or other dust suppressant as necessary to comply with the 20% opacity standard.
The establishment of cottonseed stockpiles is not considered a dust-generating operation.
Open Storage Pile: Any pile of bulk material with silt content of 5% or more, with a surface area greater than or equal to 150 ft2 and reaching a height of three feet (at any point). An open storage pile is presumed to have a silt content of 5% or more; however, a permit holder has the option to show that the silt content is less than 5% using ASTM C136-06.
Permanent Areas of a Facility: Areas that remain in place for 180 days or more in 12 consecutive months (e.g., exits, office areas, and warehouses)
After an open storage pile has been created, when material is not being added or removed, use one of the following control measures:
Prior to stacking, loading, and unloading: Mix the material with water or mix with a dust suppressant other than water.
While stacking, loading, and unloading: Apply water or apply a dust suppressant other than water.
Where vacant land is being disced, scraped, or bladed to control weeds, control measures must be applied. These include:
After weed abatement is completed, the area that has been disced, scraped, or bladed must be stabilized in one of the following ways:
MCAQD has a Dust and Miscellaneous Portal for the following dust control permit modifications and revisions:
Dust control permit modifications and revisions are required for any one of the following circumstances:
A dust control permit is not “renewed”. A dust control permit is valid for a one-year period. If the dust-generating operation continues beyond one year, a dust control permit application must be submitted at least 14 days prior to the expiration of the permit. A dust control permit that expires while a dust control permit application is pending will be subject to immediate enforcement for operating without a permit.
Apply for a new permit at least 14 calendar days prior to expiration. The Dust and Miscellaneous Portal allows you to copy most of the existing permit information into the dust control permit application. Keep in mind:
All projects covered by a dust control permit are expected to be fully compliant with Rule 310 at all times. While all inspectors are assigned to conduct specific inspections, they may, in the course of their duties, observe locations that exhibit “tell-tale” signs (e.g., the presence of trackout or visible emissions), that suggest not only that an inspection is necessary, but that the site may not be in compliance.
Paying attention to indicators of potential non-compliance is important. Identifying problems and correcting them is key to avoiding instances of non-compliance.
As a prelude to an inspection, the inspector will present a copy of your inspection rights and ask that the facility representative sign the document acknowledging that they were informed of their rights.
A permit holder who receives a violation may request an independent and objective case review by the Business Assistance Unit. This opportunity is described in the notice of inspection rights.
Maricopa County Air Quality Department (MCAQD) is conducting this inspection pursuant to Arizona Revised Statutes (A.R.S.) Sections 49-473, 49-474, 49-488, and/or the inspection and entry provisions in an Air Quality Permit or conditional order. There are no direct fees for this inspection.
I understand the following:
When an inspector arrives, there are several areas that will be inspected and reviewed. The list below highlights key points that an inspector will be reviewing.
Is the dust control permit on site and accessible? Has it expired?
Records should be clear and meet the basic requirements. Are copies of all training certificates on site?
Is the dust control plan on site? Are the control measure commitments being followed?
Based on the size of your project, a Dust Control Coordinator may be required to be on site during primary dust-generating activities; however, if the only activity for the day is house painting and no one is disturbing soil, the Dust Control Coordinator may not be required that day.
Be able to document that water is being used in sufficient quantities to meet operational requirements.
Is a hospital, school, or long-term care facility nearby? Is there the potential for vulnerable populations to be exposed to dust from disturbed areas?
In circumstances where a site representative believes that a subcontractor is directly responsible for conditions that may result in an instance of non-compliance, the site representative may request that the inspector confer with the subcontractor to determine whether the subcontractor should be cited for the instance of non-compliance.
cleaning-up trackout?
Test methods are identified in Maricopa County Air Pollution Control Regulations, Appendix C (Adopted Rules | Maricopa County, AZ). This section provides information on these methods.
Visible emissions of dust (not requiring opacity measurements) are determined using EPA Reference Method 22. A certified observer is not required. In this method, emissions may not exceed 30 seconds in duration during any six-minute period. The 30-second provision is cumulative, meaning that emissions may be observed in discrete segments that are shorter than 30 seconds and which are then added together. If the combined total of observed emissions exceeds 30 seconds when collected during a six-minute period, non-compliance has been observed.
Opacity emissions of dust are determined using Appendix C, Sections 3 and 4. Observations made using Appendix C require the observer to be certified and to use very specific protocols to determine opacity values.
There are several distinct protocols for determining opacity based on the type of operation:
A simple test to determine if a soil crust is present is known as the drop ball test. A relatively small (15.9 millimeters (mm)) steel ball weighing between 0.56 and 0.6 ounces is dropped onto a one-foot square area from a distance of one foot above the surface. The ball is dropped three times within this one-foot square area.
If the observation of the dropped ball passes the test criteria two out of each three times the ball is dropped, the area is considered to have passed the test. The criteria for passing are: (1) the dropped ball must not sink into the surface such that it is partially or fully surrounded by loose grains of soil and (2) when the ball is removed, the surface upon which it fell must not be pulverized so that loose grains of soil are visible.
Yes. Each sample area selected at random by an inspector is considered to be representative of the soil type in the disturbed area in its entirety.
Determining soil moisture (12% as required in Rule 310) requires the use of a specific test procedure that is done using an oven under laboratory conditions. This method requires several hours for proper drying of the sample. A synopsis of the test method is provided on the ASTM website and the full test method is available through ASTM at astm.org/Standards/D2216.htm.
Silt content is determined using ASTM Method C136-06-Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates. The test is used to determine the compliance status of the resulting particle size distribution. Details on the sample analysis procedure can be found at astm.org/Standards/C136.htm.
Silt loading is determined using ASTM Method C136-06–Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates. The test is used to determine the compliance status of the resulting particle size distribution. Details on the sample analysis procedure can be found at astm.org/Standards/C136.htm. The main difference between silt loading and silt content is a mathematical factor.
Threshold Friction Velocity (TFV) is defined as the wind velocity necessary to initiate soil erosion. A test can be readily performed in the field by an inspector to determine whether soil conditions are susceptible to dust entrainment. The TFV value is specified in Rule 310. Soils that do not meet this value are not stable and a condition of non-compliance exists.
By passing a soil sample through a series of sieves, a distribution of particle sizes in a soil sample can be determined. This distribution is then compared to a table contained in the test methodology that allows the determination of a TFV value. The standard contained in Rule 310 is to maintain soil conditions such that the TFV value is 100 cm/sec or greater.
The details of this procedure are available for review at Maricopa.gov/DocumentCenter/View/5306.
The Rock Test Method examines the wind resistance effects of rocks and other non-erodible elements on disturbed surfaces. Non-erodible elements are objects larger than one centimeter in diameter that remain firmly in place, even on windy days. Typically, this includes rocks, stones, glass fragments, and hard-packed clumps of soil lying on or embedded in the surface. Vegetation does not count as a non-erodible element in this method. The purpose of this test is to estimate the percent cover of non-erodible elements on a given surface to determine whether they take up enough space to offer protection to diminish the wind’s ability to entrain dust. For details on this test visit Maricopa.gov/DocumentCenter/View/5306.
Have all site supervisors read and initial the approved dust control plan.
Establish subcontractor expectations. Review the approved dust control plan with subcontractors.
Keep the job site organized and presentable. Prominently post site rules for dust control. Restrict access to non-active areas.
Conduct frequent dust control tailgate meetings.
To better control trackout, monitor exits at least every 30 minutes.
Maintain records that provide a clear understanding of site operations. Recordkeeping should be conducted in tandem with site operations and be used to help trigger corrective action (e.g., an observation of trackout greater than 25 feet should be accompanied by notations of immediate action taken to control trackout).
Be aware of sensitive areas that surround your site. Anticipate complaints and inspections to investigate those complaints.
Restrict exits with fencing.
Park only in designated areas that are identified in the dust control plan or, at minimum, in areas that are posted.
If you are hauling off site, ask the permit holder to spray water over your load before tarping to ensure that dust emissions while driving are eliminated.
Applicable Rules – Maricopa.gov/1951
Courtesy Site Visits – Call 602-506-5102 or contact AQBusinessAssistance@maricopa.gov
Rule 310 Dust Control Recordkeeping Template in PDF – Business Assistance Resources | Maricopa County, AZ
Maricopa.gov/DocumentCenter/View/91338
Desk Duty Supervisor – Call 602-506-6734
Dust Abatement Field Guide – Maricopa.gov/9724
Dust Control Forms, Instructions, Information, and Samples – Maricopa.gov/5560
Dust Control Resources – Maricopa.gov/1814
Dust Permit Application via Dust and Miscellaneous Portal – Maricopa.gov/5560
Dust Sources, Control, and Training – Maricopa.gov/1913
Maricopa County Air Quality Department Website – Maricopa.gov/aq Location, Hours, and Other Contact Information – Maricopa.gov/1585 Public Records Request – Maricopa.gov/5847
Web Contact Form – Maricopa.gov/Air-Quality-Web-Contact-Form-75 Report a Violation – Call 602-372-2703 or visit Maricopa.gov/2132 Resources for the Regulated Community – Maricopa.gov/1814
Rule 310 Dust Control Permit Help Sheet – Business Assistance Resources | Maricopa County, AZ
Subcontractor Registration Information – Maricopa.gov/1823
Training – Maricopa.gov/1822 or Mcaqd.learningcart.com
Maricopa County Air Quality Department
Compliance and Enforcement Division Maricopa.gov/AQ
