[ COUNTY AIR QUALITYZZEMENZRD

AIR QUALITY REGULATIONS

SECTION 91 - FUGITIVE DUST FROM UNPAVED ROADS, UNPAVED

ALLEYS, AND UNPAVED EASEMENT ROADS

91 .1 FuGITIvE DUST From Unpaved Roads, Unpaved Alleys, and Unpaved

EASEMENT Roads

91.1.1 Purpose: To limit the Emission of PARTIcuLATE MATTER into the

AMBIENT AIR from unpaved roads, unpaved alleys, unpaved ROAD

EASEMENTS and unpaved access roads for utilities and railroads.

91.1.2 Applicability: The provisions of this Regulation shall apply to

unpaved roads, which includes unpaved alleys, unpaved ROAD

EASEMENTS and unpaved access roads for utilities and railroads which are

located in the PMio N0N-ATIAINMENT AREA (HYDR0GRAPHIc BASIN 212)

and the Apex Valley (HYDR0GRAPHIc BAsINs 216 and 21 7). Nothing in

Subsections 91 .1 through 91 .3 of these Regulations shall be construed

to prevent enforcement of Section 40 (Prohibition of NUISANCE

Conditions) of these Regulations. The provisions of this Regulation shall

not apply to non-commercial and non-institutional private driveways and

shall not apply to horse trails, hiking paths, bicycle paths, or other

similar paths that have been officially designated by a governing body

for exclusive use for purposes other than travel by motor vehicles. The

provisions of this Regulation shall not apply to STATIONARY SOURCES as

defined in Section 0, except that these control measures shall be

considered as part of a BACT determination.

91 .1 .3 Effective Date Of This Regulation:

91.1.3.1 Regulations 91.1 through 91.3 shall be effective in HYDR0GRAPHIc BASIN

212 on their adoption by the District Board of Health of Clark County on

June 22, 2000.

91.1.3.2 Regulations 91.1 through 91.3 shall be effective in HYDR0GRAPH1c

BAsINs 216 and 217 on April 1, 2002.

91 .2 Requirements:

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91 .2.1 Unpaved Roads: An OWNER AND/OR OPERATOR of an unpaved road in

the PMio NON-ATTAINMENT AREA, shall implement one of the CONTROL

MEASURES set forth in Subsection 91 .2.1 .3 of this Regulation, except as

set forth in Subsection 91 .2.1 .1 of this Regulation. For the purpose of

this Regulation, the CONTROL MEASURES shall be considered effectively

implemented when the unpaved roadway complies with the

stabilization standards set forth in Subsection 91 .2.1 .4 of this

Regulation. Advisory Notice: In order to conserve water to the

greatest extent practicable, the use of RECLAIMED WATER is highly

encouraged.

91 .2.1.1 Implementation Of CONTROL MEASURES For Existing Unpaved Roads:

91 .2.1 .1 .1 OWNERS AND/OR OPERATORS of existing unpaved roads that were

constructed prior to June 22, 2000 in HYDROGRAPHIC BASIN 21 2 shall

implement one of the CONTROL MEASURES set forth Subsection

91 .2.1 .3 of this Regulation according to the following schedule:

(a) CONTROL MEASURES shall be implemented for one third (1/3) of

the total miles of unpaved roads having vehicular traffic of 1 50

vehicles or more per day in accordance with Subsection

91.2.1.3 (CONTROL MEASURES) of this Regulation by

June 1, 2001.

91 CONTROL MEASURES shall be implemented for two thirds (2/3) of

the total miles of unpaved roads having vehicular traffic of 1 50

vehicles or more per day in accordance with Subsection

91.2.1.3 (CONTRoL MEAsuREs) of this Regulation by June 1,

2002.

(c) CONTROL MEASURES shall be implemented for all unpaved roads

having vehicular traffic of 1 50 vehicles or more per day in

accordance with Subsection 91.2.1.3 (CONTRoL MEASURES) of

this Regulation by June 1, 2003.

(d) CONTROL MEASURES set forth in Subsection 91 .2.1 .3 shall be

implemented for existing unpaved roads on which vehicular

traffic is equal to or greater than 1 50 vehicles per day that

develops after June 1, 2003. CONTROL MEASURES shall be

implemented within 365 calendar days following the initial

discovery that vehicular traffic equals or exceeds 1 50 vehicles

per day and that the road surface does not comply with the

stabilization standards set forth in Subsection 91.2.1.4 of this

Regulation. The CONTROL OFFIcER may require short-term

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stabilization of any unpaved road subject to Subsection

91.2.1.1(d).

(e) Non-federal Requirement: CONTROL MEASURES set forth in

Subsection 91 .2.1 .3 shall be implemented for existing unpaved

roads having vehicular traffic of less than 1 50 vehicles per day

within 365 calendar days following the initial discovery that the

road surface does not comply with the stabilization standards

set forth in Section 91.2.1.4 of this Regulation. The

requirements of this Subsection (91.2.1.1 (e) shall not

constitute applicable State Implementation Plan requirements

pursuant to Section 189 of the federal Clean Air Act. The

CONTROL OFFICER may require short-term stabilization of any

unpaved road subject to Subsection 91 .2.1 .1 (e)). For the

purpose of this Subsection, the CONTROL MEASURES shall be

considered effectively implemented when the unpaved road

complies with the stabilization standards set forth in Subsection

91.2.1.4 of this Regulation.

91.2.1.1.2 OwNERS AND/OR OPERATORS of existing unpaved roads that were

constructed prior to April 1, 2002 in HYDR0GRAPHIC BASINS 216 and

217_shall implement one of the CONTROL MEASURES set forth

Subsection 91.2.1.3 of this Regulation according to the following

schedule:

(a) CoNTROL MEASURES shall be implemented for one third (113) of

the total miles of unpaved roads having vehicular traffic of 1 50

vehicles or more per day in accordance with Subsection

91.2.1 .3 (CoNTRoL MEASURES) of this Regulation by

April 1, 2003.

(b) CoNTROL MEASURES shall be implemented for two thirds (2/3) of

the total miles of unpaved roads having vehicular traffic of 1 50

vehicles or more per day in accordance with Subsection

91 .2.1 .3 (CONTROL MEASURES) of this Regulation by April 1,

2004.

(c) CONTROL MEASURES shall be implemented for all unpaved roads

having vehicular traffic of 1 50 vehicles or more per day in

accordance with Subsection 91.2.1 .3 (CoNTROL MEASURES) of

this Regulation by April 1, 2005.

(d) CoNTRoL MEASURES set forth in Subsection 91 .2.1 .3 shall be

implemented for existing unpaved roads on which vehicular

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traffic is equal to or greater than 1 50 vehicles per day that

develops after April 1, 2005. CoNTRoL MEASURES shall be

implemented within 365 calendar days following the initial

discovery that vehicular traffic equals or exceeds 1 50 vehicles

per day and that the road surface does not comply with the

stabilization standards set forth in Subsection 91 .2.1 .4 of this

Regulation. The CONTRoL OFFICER may require short-term

stabilization of any unpaved road subject to Subsection

91.2.1.1(d).

Ce) Non-federal Requirement: CONTROL MEASURES set forth in

Subsection 91 .2.1.3 shall be implemented for existing unpaved

roads having vehicular traffic of less than 1 50 vehicles per day

within 365 calendar days following the initial discovery that the

road surface does not comply with the stabilization standards

set forth in Section 91 .2.1 .4 of this Regulation. The

requirements of this Subsection (91.2.1.1 Ce) shall not

constitute applicable State Implementation Plan requirements

pursuant to Section 189 of the federal Clean Air Act. The

CONTROL OFFICER may require short-term stabilization of any

unpaved road subject to Subsection 91 .2.1 .1 (e)). For the

purpose of this Subsection, the CONTRoL MEAsuREs shall be

considered effectively implemented when the unpaved road

complies with the stabilization standards set forth in Subsection

91.2.1.4 of this Regulation.

91.2.1.2 No unpaved roads or alleys may be constructed in public thoroughfares

in HYDROGRAPHIC BASIN 212 after June 22, 2000, or in HYDR0GRAPHIC

BAsINs 216 and 217 after April 1,2002, unless the unpaved road is an

interim component of an active paving project.

91.2.1.3 CoNTROL MEASURES:

(a) PAVE, or

(b) Apply DUST PALLIATIVES, in compliance with the stabilization

standards set forth in Subsection 91 .2.1 .4 of this Regulation, or

Cc) Apply and maintain and alternative CoNTROL MEASURE approved

in writing by the CONTROL OFFICER and the Region IX

Administrator of the EPA.

91.2.1.4 Stabilization Standards: For the purpose of this rule, CONTROL

MEASURES shall be considered effectively implemented when

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stabilization observations for FUGITIVE Dust EMISSIONS from unpaved

roads and unpaved alleys do not exceed 20% OPAcITY and do not

equal or exceed 0.33 oz/ft 2 sift loading, or do not exceed 6% silt

content, as determined by Subsection 91 .4.1 of these Regulations.

91.3 Record Keeping Requirements

91 .3.1 Record Keeping: Any person subject to the requirements of this

Regulation shall compile and retain records that provide evidence of

CONTROL MEASURE application, by indicating type of treatment or

CONTROL MEAsuRE, extent of coverage, and date applied. The records

and supporting documentation shall be made available to the CoNTRoL

OFFICER within 24 hours from written or verbal request.

91 .3.2 Records Retention: Copies of the records required by Subsection

91.3.1 (Record Keeping Requirements) of this Regulation shall be

retained for at least one year.

91 .3.3 Reports Required: In addition to complying with the record keeping

requirements specified in Subsection 91 .3.1, OwNERs of unpaved

roads shall be subject to the requirements set forth in Subsection

91.2.1.1, and shall prepare and submit a written report to the CONTROL

OFFICER documenting compliance with the provisions •of

Subsection 91 .2.1 .1. This report shall be prepared for the years

2001, 2002, and 2003 for OwNERs of unpaved roads in HYDR0GRAPHIC

BASIN 212, for the years 2003, 2004, and 2005 for OWNERS of

unpaved roads in HYDR0GRAPHIc BASINS 216 and 217, and shall be

submitted to the CONTROL OFFICER no later than October first of each

year and shall include:

91 .3.3.1 The total miles of unpaved roads under the jurisdiction of the OWNER

and the miles PAVED during the reporting period subject to the

requirements of Subsection 91.2.1.1. Miles of PAvING for roads

subject to Subsections 91.2.1.1.1(a), 91.2.1.1.1(b), and

91.2.1.1.1(c) must be listed separately from paving of roads found to

be subject Subsection 91 .2.1 .1 .1 (d). Miles of PAVING for roads

subject to Subsections 91 .2.1 .1 .2(a), 91 .2.1 .1 .2(b), and

91.2.1.1.2(c) must be listed separately from paving of roads found to

be subject Subsection 91.2.1.1.2(d).

91 .4 Test Methods

91 .4.1 Stabilization Test Methods For Unpaved Roads And Unpaved

Alleys:

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91.4.1.1 OPACITY Test Method: The purpose of this test method is to estimate

the percent OPACITY of FuGITIvE DUST plumes caused by vehicle

movement on unpaved roads, unpaved alleys, and unpaved EAsEMENTs.

This method can only be conducted by an individual who has received

certification as a qualified Visible EMISSIONS Evaluator,

(a) Step 1: Stand at least 1 6.5 feet from the FUGITIVE DUST source

in order to provide a clear view of the EMISSIONS with the sun

oriented in the 140-degree sector to the back, Following the

above requirements, make OPACITY observations so that the line

of vision is approximately perpendicular to the dust plume and

wind direction. If multiple plumes are involved, do not include

more than one plume in the line of sight at one time.

(b) Step 2: Record the FUGITIVE DUST source location, source type,

method of control used, if any, observer’s name, certification

data and affiliation, and a sketch of the observer’s position

relative to the FUGITIVE DUST source. Also, record the time,

estimated distance to the FUGITIVE DusT source location,

approximate wind direction, estimated wind speed, description

of the sky condition (presence and color of clouds), observer’s

position to the FUGITIVE DUST source, and color of the plume and

type of background on the visible emission observation form

both when OPACITY readings are initiated and completed.

(c) Step 3: Make OPACITY observations, to the extent possible,

using a contrasting background that is perpendicular to the line

of vision. Make OPACITY observations approximately 1 meter

above the surface from which the plume is generated. Note that

the observation is to be made at only one visual point upon

generation of a plume, as opposed to visually tracking the entire

length of a dust plume as it is created along a surface. Make

two observations per vehicle, beginning with the first reading at

zero seconds and the second reading at five seconds. The

zero-second observation should begin immediately after a plume

has been created above the surface involved. Do not look

continuously at the plume but, instead, observe the plume

briefly at zero seconds and then again at five seconds.

(d) Step 4: Record the OPACITY observations to the nearest 5% on

an observational record sheet. Each momentary observation

recorded represents the average OPACITY of EMissioNs for a

5-second period. While it is not required by the test method,

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EPA recommends that the observer estimate the size of vehicles

which generate dust plumes for which readings are taken (e.g.

mid-size passenger car or heavy-duty truck) and the approximate

speeds the vehicles are traveling when readings are taken.

(e) Step 5: Repeat Step 3 (Subsection 91 .4.1 .1 (c) of this

Regulation) and Step 4 (Subsection 91.4.1 .1 (d) of this

Regulation) until you have recorded a total of 1 2 consecutive

OPACITY readings. This will occur once six vehicles have driven

on the source in your line of observation for which you are able

to take proper readings. The 1 2 consecutive readings must be

taken within the same period of observation but must not

exceed 1 hour. Observations immediately preceding and

following interrupted observations can be considered

consecutive.

(f) Step & Average the 1 2 OPAcITY readings together. If the

average OPAcITY reading equals 20% or lower, the source is in

compliance with the OPACITY standard described in Section 91

of these Regulations.

91.4.1.2 Silt Content Test Method: The purpose of this test method is to

estimate the silt content of the trafficked parts of unpaved roads,

unpaved alleys, and unpaved EAsEMENTs. The higher the silt content,

the greater the amount of fine dust particles that are entrained into the

atmosphere when cars and trucks drive on unpaved roads, unpaved

alleys, and unpaved EASEMENTS.

(a) Equipment:

(1) A set of sieves with the following openings: 4

millimeters (mm), 2 mm,”l mm, 0.5 mm and 0.25 mm, a

lid, and collector pan

(2) A small whiskbroom or paintbrush with stiff bristles and

dustpan 1 foot in width (the broom/brush should

preferably have one, thin row of bristles no longer than

1 .5 inches in length)

(3) A spatula without holes

(4) A small scale with half ounce increments (e.g., postal/

package scale)

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(5) A shallow, lightweight container (e.g., plastic storage

container)

(6) A sturdy cardboard box or other rigid object with a level

surface

(7) A calculator

(8) Cloth gloves (optional for handling metal sieves on hot,

sunny days)

(9) Sealable plastic bags (if sending samples to a laboratory)

(10) A pencil/pen and paper

(b) Step 1: Look for a routinely traveled surface, as evidenced by

tire tracks (only collect samples from surfaces that are not damp

due to precipitation or dew). This statement is not meant to be

a standard in itself for dampness where watering is being used

as a CONTROL MEAsuRE. It is only intended to ensure that surface

testing is done in a representative manner. Use caution when

taking samples to ensure personal safety with respect to

passing vehicles. Gently press the edge of a dustpan (1 foot in

width) into the surface four times to mark an area that is 1

square foot. Collect a sample of loose surface material using a

whiskbroom or brush and slowly sweep the material into the

dustpan, minimizing escape of dust particles. Use a spatula to

lift heavier elements such as gravel. Only collect dirt/gravel to

an approximate depth of 3/8 inch or 1 cm in the 1 square foot

area. If you reach a hard, underlying subsurface that is greater

than 3/8 inch in depth, do not continue collecting the sample by

digging into the hard surfacer In other words, you are only

collecting a surface sample of loose material down to 1 cm. In

order to confirm that samples are collected to 1 cm in depth, a

wooden dowel or other similar narrow object at least one foot in

length can be laid horizontally across the survey area while a

metric ruler is held perpendicular to the dowel.

• At this point, you can choose to place the sample

collected into a plastic bag or container and take it to an

independent laboratory for silt content analysis. A

reference to the procedure the laboratory is required to

follow is at the end of this section.

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(c) Step 2: Place a scale on a level surface. Place a lightweight

container on the scale. Zero the scale with the weight of the

empty container on it. Transfer the entire sample collected in

the dustpan to the container, minimizing escape of dust

particles. Weigh the sample and record its weight.

(d) Step 3: Stack a set of sieves in order according to the size

openings specified above, beginning with the largest size

opening (4 mm) at the top. Place a collector pan underneath the

bottom (0.25 mm) sieve.

(a) Step 4: Carefully pour the sample into the sieve stack,

minimizing escape of dust particles by slowly brushing material

into the stack with a whiskbroom or brush (on windy days, use

the trunk or door of a car as a wind barricade). Cover the stack

with a lid. Lift up the sieve stack and shake it vigorously up,

down and sideways for at least 1 minute.

(f) Step 5: Remove the lid from the stack and disassemble each

sieve separately, beginning with the top sieve. As you remove

each sieve, examine it to make sure that all of the material has

been sifted to the finest sieve through which it can pass; e.g.

material in each sieve (besides the top sieve that captures a

range of larger elements) should look the same size. If this is

not the case, re-stack the sieves and collector pan, cover the

stack with the lid, and shake it again for at least 1 minute (you

only need to reassemble the sieve(s) that contain material,

which requires further sifting).

(g) Step 6: After disassembling the sieves and collector pan, slowly

sweep the material from the collector pan into the empty

container originally used to collect and weigh the entire sample.

Take care to minimize escape of dust particles. You do not

need to do anything withmaterial captured in the sieves; only

the collector pan. Weigh the container with the material from

the collector pan and record its weight.

(h) Step 7: If the source is an unpaved road, multiply the resulting

weight by 0.38. If the source is an UNPAVED PARKING LOT,

multiply the resulting weight by 0.55. The resulting number is

the estimated silt loading. Then, divide by the total weight of

the sample you recorded earlier in Step 2 (Subsection

91 .4.1.2(c) of this Regulation) and multiply by 100 to estimate

the percent silt content.

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(i) Step 8: Select another two routinely traveled portions of the

unpaved road or UNPAVED PARKING LOT and repeat this test

method. Once you have calculated the silt loading and percent

silt content of the 3 samples collected, average your results

together.

(j) Step 9: Examine Results. If the average silt loading is less than

0.33 oz/ft 2,the surface is stable. If the average silt loading is

greater than or equal to 0.33 oz/ft 2,then proceed to examine

the average percent silt content. If the source is an unpaved

road, unpaved alley, or unpaved EAsEMENT and the average

percent silt content is 6% or less, the surface is stable. If your

field test results are within 2% of the standard (for example,

4%-8% silt content on an unpaved road, alley, or EASEMENT), it

is recommended that you collect 3 additional samples from the

source according to Step 1 (Subsection 91 .4.1 .2(b) of this

Regulation) and take them to an independent laboratory for silt

content analysis.

(k) Independent Laboratory Analysis: You may choose to collect 3

samples from the source, according to Step 1 (Subsection

91 .4.1 .2(b) of this Regulation), and send them to an

independent laboratory for silt content analysis rather than

conduct the sieve field procedure. If so, the test method

the laboratory is required to use is:

“Procedures For Laboratory Analysis Of Surface/Bulk

Loading Samples”, (Fifth Edition, Volume I,

Appendix C.2.3 “Silt Analysis’, 1 995), AP-42,

Office of Air Quality Planning & Standards,

U.S. Environmental Protection Agency,

Research Triangle Park, North Carolina

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