UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

REGION IX AIR DIVISION

Technical Support Document

EPA’s Proposed Rulemaking

For the

Pinal County Air Quality Control District

Chapter 4, Article 1, West Pinal PM10 Moderate Nonattainment Area Fugitive Dust

Prepared by: Christine Vineyard

March 2016
RULE IDENTIFICATION 

Agency Pinal County Air Quality Control District

Subject of this 

TSD

Rule: Chapter 4, Article 1 – West Pinal PM10 Moderate 

 Nonattainment Area Fugitive Dust

Adopted – October 28, 2015

Submitted – December 21, 2015

Completeness 

Finding

March 21, 2016

RULE SUMMARY

Applicability – the purpose of the Article is to control fugitive dust from open 

areas/vacant lots, unpaved roads, unpaved lots and paved public roadways by requiring 

measures to prevent, reduce or mitigate fugitive dust emissions.

Exemptions

The standards and requirements of this Article shall not apply to:

1. Legitimate vehicle test and development facilities and operations conducted by or 

for equipment manufacturers where dust is required to test and validate the 

design integrity, product quality and/or commercial acceptance.

2. Sudden and unforeseeable emergency response activities that may disturb the 

soil conducted by any utility or government agency in order to prevent public 

injury or to restore critical utilities to functional status. 

3. Normal farm cultural practices.

4. Dust generating operations subject to the standards and/or requirements 

described in Chapter 4, Article 3 – Construction Sites – Fugitive Dust.

5. The establishment of initial landscape without the use of mechanized equipment, 

conducting landscape maintenance without the use of mechanized equipment, 

and playing on or maintaining a field used for non-motorized sports; and shall not 

include grading, or trenching, performed to establish initial landscapes or to 

redesign existing landscapes.

Definitions

Applicable definitions are included to add clarity to the rule.

Standards

General – the owner and/or operator of open areas/vacant lots, unpaved lots, unpaved 

roads and paved public roadways must implement control measures to meet the visible 

emissions requirements, stabilization requirements and compliance determinations for 

each applicable category. Failure to implement control measures as required by this 

rule shall be deemed a violation of this rule.
Open Areas/Vacant Lots:

A. The owner and/or operator of open areas/vacant lots shall not cause, suffer, 

allow, or permit fugitive dust emissions which exceed twenty percent (20%) 

opacity.

B. Upon evidence of trespass, an owner/operator shall install and maintain no 

trespassing signs and physical barriers such as curbs, fences, gates, posts, 

shrubs, trees, or other effective control measures.

C. Owners and/or operators of open areas/vacant lots 1.0 acre (43,560 ft2) or 

larger and have a cumulative of 0.5 acre (21,780 ft2) or more disturbed 

surface area in addition to the general requirements shall implement an 

additional control measure listed in this section.

D. Open area/vacant lots 1.0 acre (43,560 ft2) or larger and have a cumulative of 

0.5 acre (21,780 ft2) or more disturbed area, shall sign up to receive the Pinal 

County dust control forecast within 30 calendar days following the initial 

discovery of the disturbed surface area. In addition, the owner and/or 

operator shall ensure the open area/vacant lot is stabilized the day leading up 

to and the day that is forecast to be high risk for dust emissions.

E. No person shall use blading, disking, plowing under or any other means to 

remove vegetation from any open area/vacant lots without implementing all 

the required control measures.

F. A list of stabilization requirements compliance methods are included.

Unpaved Lots

A. The owner and/or operator of an unpaved lot greater than 5,000 ft2 shall not:

i. Cause or allow visible fugitive dust emissions to exceed 20% opacity;

ii. Allow silt loading equal to or greater than 0.33 oz./ft2 as determined by 

the referenced test method. If silt loading is equal to or greater than 0.33 

oz./ft2, the owner and/or operator shall not allow the silt content to 

exceed 8%;

iii. In addition to the opacity and silt requirements, the owner and/or 

operator shall pave; or apply and maintain dust suppressants to maintain 

a stabilized surface; or apply and maintain surface gravel uniformly; or 

an alternative control measure approved by the Control Officer and EPA.

B. Control measures shall be considered effectively implemented when the 

unpaved lot meets the visible emissions and stabilization requirements.

Unpaved Roads

A. The owner and/or operator of unpaved roads with average daily trips (ADT) 

greater than 150 shall not:

1. Cause or allow visible fugitive dust emissions to exceed 20% opacity;

2. Allow silt loading equal to or greater than 0.33 oz./ft2 as determined by the 

referenced test method. If silt loading is equal to or greater than 0.33 

oz./ft2, the owner and/or operator shall not allow the silt content to exceed 

6%;
3. In addition to the opacity and silt requirements, the owner and/or operator 

shall pave; or apply and maintain dust suppressants other than water; or 

uniformly apply and maintain surface gravel.

B. The control measures listed in A. are considered implemented when:

i. One of the control measures is annually implemented on 15 miles per year 

of unpaved roads having ADT of 150 or more under the listed 

circumstances.

ii. For year 2019 and beyond, control measures applied on unpaved roads 

with less than 150 ADT can be used for compliance with this Section

through use of the equivalency conversion table included in the rule.

Paved Public Roadway

A. The owner and/or operator of the property from which trackout or erosioncased deposition came from upon discovery of mud/dirt that extends 50 feet 

or more from the nearest unpaved surface exit onto the paved public roadway 

shall:

i. Within 24 hours of discovery, remove the mud/dirt from roadway by:

- Manually sweeping and picking up; or

- Operating a rotary brush or broom accompanied or preceded by 

sufficient wetting to limit opacity to 20% or less; or

- Operating a PM10 efficient street sweeper; or

- Flushing with water, if curb and gutters are not present and the 

use of water will not result in adverse impacts or violate of any 

permit programs.

- If needed, restrict vehicles from traveling over mud/dirt until the 

material has been removed from the travel lanes of the paved 

public roadway.

ii. Remove mud/dirt in a manner that does not cause another source of 

fugitive dust.

iii. In the event unsafe travel conditions would result from restricting 

traffic, and removal of such material isn’t possible within 72 hours due 

to a weekend or holiday condition, the provisions of section A.i. above 

can be extended upon notification to and approval by the Control 

Officer.

B. Requirements the owner and/or operator of any existing paved public roadway 

shall comply with prior to, during and after work on unpaved road shoulder:

i. Apply dust suppressant to total disturbed area in sufficient quantity and 

frequency to maintain a stabilized surface.

ii. Prevent trackout by using one of the control measures in A.i. above. 

Recordkeeping

Any person subject to the requirements of this rule shall compile and retain records that 

provide evidence of control measure applications including the type of treatment or 

control measures, extent of coverage, and date applied. Records and supporting 
documentation shall be provided within 48 hours of Control Officers verbal or written 

request. 

Reporting Requirements

Any city, county, or state agency with primary responsibility for an existing paved public 

roadway and unpaved roads shall comply with the following:

A. By January 30 of each year provide the Air District with a list of all unpaved road 

in its jurisdiction (i.e. length, ADT, unpaved road segments).

B. By January 30 of each year submit to the Air District a list of unpaved roads

which were paved the previous year including the total number of unpaved roads 

miles, ADTs and the respective segments.

 

Records Retention

All required recordkeeping and reporting records shall be retained for at least 2 years.

Violations

Failure of any person to comply with the applicable requirements of this rule shall 

constitute a violation.

A. The opacity requirements shall not apply during:

i. Wind conditions that cause fugitive dust to exceed the opacity requirements 

if all applicable control measures are implemented, applied and maintained, 

and all dust contributing disturbed area are stabilized.

ii. Emergency maintenance of flood control channels and water retention 

basins if at least 1 applicable control measure is applied, and maintained.

Emission Reductions

If the attainment controls do not produce the expected emissions reductions, the control

measures in this rule will be implemented as expeditiously as practicable as a 

contingency to achieve the following additional reductions: 

Open Areas/Vacant Lots: 1,727.9 TPY

Unpaved Lots: 143.3 TPY

Unpaved Roads: 1142.7 TPY

Paved Public Roadway: 7.6 TPY

A detailed explanation on how these reductions will be achieved can be found in 

Appendix D – Pinal County PM10 Nonattainment Area, 2018 Attainment Demonstration 

and Controlled Emissions Inventories, Air Quality Division, December 21, 2015 – Final.

RULE EVALUATION
A. Rule Stringency - CAA Sections 172(c)(1) and 189(a)(1)(C) require that moderate 

nonattainment area SIP revisions include emissions reductions from existing 

sources of PM10 emissions, as may be obtained through RACM and reasonably 

available control technology (RACT). RACM and RACT must be implemented as 

“expeditiously as practicable” and “shall provide for the attainment of the NAAQS.” 

Additionally, if an area is classified as moderate, a State must implement RACM no 

later than four years after designation. However, RACM findings are generally made 

in context of an overall attainment demonstration. Consequently, our stringency 

evaluation primarily reviews the State’s comparison of these Pinal provisions with 

with analogous requirements in other areas. Specifically, the State provided a 

demonstration that the requirements in Article 1, West Pinal PM10 Moderate 

Nonattainment Area Fugitive Dust, are as stringent and in some areas more 

stringent than other Air Agency RACM measures (Appendix F – RACM analysis for 

the West Pinal County PM10 Nonattainment Area, Arizona Department of 

Environmental Quality, Final December 21, 2015).

B. Enforceability – CAA §110(a)(2)(A) requires that regulations submitted to EPA for 

SIP approval must be clear and legally enforceable. The rule requirements for open 

areas/vacant lots, unpaved lots, unpaved roads and paved public roadways to 

suppress fugitive dust emissions contain definitions, recordkeeping, reporting, 

control requirements and other provisions that are sufficiently clear and enforceable.

C. Anti-Backsliding - We propose to determine that our approval of the submitted rule 

would comply with CAA §110(l) because the West Pinal PM10 Moderate 

Nonattainment Area does not contain any control requirements for the control of 

fugitive dust emissions at open areas/vacant lots, unpaved lots, unpaved roads and 

paved public roadways, and our approval of Rule Chapter 4, Article 1 into the SIP 

only adds new SIP requirements and does not interfere with the on-going process 

for ensuring that requirements for RFP and attainment of the NAAQS are 

met. Section 193 of the Act does not apply to our proposed action because this is a 

new rule to the SIP and does not modify any SIP-approved control requirement in 

effect before November 15, 1990, in a nonattainment area.

EPA ACTION

The submitted Rule Chapter 4, Article 1, West Pinal PM10 Moderate Nonattainment 

Area Fugitive Dust, strengthens the SIP by restricting emissions from fugitive dust. The 

rule fulfils the relevant CAA §110 and part D requirements. Therefore, EPA staff 

recommends approval of Chapter 4, Article 1.

References:

1. “Issues Relating to VOC Regulation Cutpoints, Deficiencies, and Deviations,” 

(a.k.a., Bluebook) EPA OAQPS, May 25, 1988 
(http://www.epa.gov/ttn/naaqs/ozone/ozonetech/voc_bluebook.pdf).

2. Chapter 4, Article 1, West Pinal PM10 Moderate Nonattainment Area Fugitive 

Dust.