90.1 FUGITIVEDUST

### From OPENAREAsANDVACANTLOTS 90.1.1 Purpose: To limit the EMissioN of PARTIcuLATE MATTER into the AMBIENT AIR from OPENAREASANDVACANTLOTS. Applicability: The provisions ofthis Regulation shall apply to OPENAREAs AND VAcANT LOTS which are located in the PM, 0 N0NATrAINMEm- AREA (HYDR0GRAPHIc BASIN 212) and theApexValley (HYDR0GRAPHIcBAsINs 216 and 217). Nothing in Section 90 ofthese Regulations shall be construed to prevent enforcement of Section 40 (Prohibition ofNUISANCE Conditions) of these Regulations. The provisions of this Regulation shall not apply to Normal Farm Cultural Practices or the raising of fowl or animals. 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 ofa BACTdetermination. 90.1.3 Effective Date Of

### This Regulation: 90.1.3.1 Section 90, adopted bythe District Board ofHealth ofClark County on June 22, 2000, shall be effective in HYDR0GRAPHIc BAsIN 212 on January 1, 2001, exceptas otherwise provided herein. 90.1.3.2 Section 90 shall be effective in HYDR0GRAPHIc BASINS 216 and 217 onApril 1, 2002, exceptas otherwiseprovided herein. 90.2 Requirements: OPEN AREAs AND VACANT LOTS: If OPEN AREAS AND VACANT LOTS are 5,000 square feetorlarger and are disturbed by any means, including use • by MOTOR VEHICLES and/or OFF-RoAD MOTOR VEHICLES or material dumping, then the OWNER AND/OR OPERAToR of such OPEN AREAS AND VACANT LOTS shall implement one or more of the CONTROL MEASURES

V described in Subsection 90.2.1.1 of this Regulation within 30 calendar days following the initial discovery ofdisturbance or vehicle use on OPEN AREAs AND VACANT LOTS. The OWNERAND/OR OPERATOR shall implement all control measures necessary to limitthe disturbance ofopen areas and Revised 12117102 90-1 CCAirQualityRegulations DAQM, 500GrandCentrai-Pkwy 1 LV 89155 

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# //z SECTION 90- FUGITIVE DUST FROM OPEN AREAS AND VACANT LOTS

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vacant lots in accordance with the requirements of this regulation. Advisory Notice: In order to conserve water to the greatest extent practicable, the use ofRECLAIMEDWATER is highly encouraged. 90.2.1.1 CONTROLMEASURES: (a) Where there is evidence of soil disturbance by MOTOR VEHICLES and/or OFF-ROADVEHIcLE use, preventMOTORVEHICLE and/orOFFROAD VEHICLE trespassing, parking, and/or access, by installing barriers, curbs, fences, gates, posts, signs, shrubs, trees, or other effective traffic Control Measures. A stable surface area shall be established and maintained by using one of the CONTROL MEAsuREs set forth in Subsections 90.2.1.1(b) or (c) or by the effective application of water in compliance with the stabilization standards set forth in Subsection 90.2.1.2. Where measures to prevent vehiculartrespassing and movement are not effective, the application ofwaterwill notbe utilized for surface stabilization. For the purposes ofthis Subsection, use ofor parking on OPEN AREAs AND VACANT LOTS for noncommercial and non-institutional purposes by the OWNER AND/OR OPERATOR of such OPEN AREAs AND VACANT LOTS shall not be considered vehicle use under this Subsection. In addition, vehicle use related to landscaping maintenance shall not be considered vehicle use under this Subsection. For the purpose of this Regulation, landscape maintenance does not include grading, trenching, or any other mechanized surface disturbing activities performed to establish initial landscapes orto redesign existing landscapes; or (b) Where a DISTURBED SURFAcE AREA exists (including disturbed surfaces caused by MOTORVEHICLES), uniformly apply and maintain surface gravel or DUSTPALuATIvEs to all areas disturbed by MOTOR VEHIcLES in compliance with one of the stabilization standards described in Subsection 90.2.1.2 ofthis Regulation; or (c) Where a DISTuRBED SURFACE AREA exists (including disturbed surfaces caused by MOTOR VEHICLES and/orOFF-ROAD MOTOR VEHIcLEs), apply and maintain an alternative CONTROL MEASURE approved in writing by the CONTROL OFFICER and the Region IX ADMINIsTRAToRofthe Environmental Protection Agency (EPA). 90.2.1.2 Stabilization Standards: (a) A visible crust shall be established, as determined by Subsection 90.4.1.1 (The Drop Ball/Steel Ball Test) of these Regulations; or,

Revised 12117102 90-2 CCAirQualityRegulations DAQM-5OOGrandCentralPkwy LV89155(b) A percent cover that is equal to or greater than 20% for non erodible elements shall be established, as determined by Subsection 90.4.1.2 (RockTestMethod) ofthese Regulations; or, (c) A threshold friction velocity, corrected for non-erodible elements of 100 cm/second or higher, shall be established, as determined by Subsection 90.4.1.3 (Determination OfThreshold Friction Velocity) ofthis Regulation; or, (d) An alternative test method approved in writing by the CONTROL OFFIcER and the Region IXADMINIsTRAToR ofthe EPA. 90.2.2 Dust Mitigation Plans Required: Any OWNER ANDIOR OPERATOR of OPEN AREAs AND VACANT LOTS having a cumulative area of 101000 acres or greater must submit a dust mitigation plan to the Department of Air Quality Management for approval by March 31, 2003, in a format prescribed bythe CONTROLOFFICER. 90.2.3 Mechanized Weed Abatement andlorTrash Removal: If machinery is

V used to clear weeds or trash from OPEN AREAs AND VACANT LOTS of 5,000 square feet or larger, then the following Control Measures set forth in Subsection 90.2.3.1 shall be applied. Advisory Notice: In order to conserve water

## to the greatest extent practicable, the use of REcLAIMED WATER is highly encouraged. 90.2.3.1 CoNTRoLMEASURES

V (a) Pre-wet surface soils before mechanized weed abatement and/or trash removal occurs; and, (b) Maintain dust control measures while mechanized weed abatement and/ortrash removal is occurring; and, (c) PAVE, apply gravel, apply water, or apply a suitable DUST PALLIATIVE, in compliance with the stabilization standards set forth in Subsection 90.2.1.2 of this Regulation, after mechanized weed abatement and/ortrash removal occurs. 90.3 Record Keeping Requirements 90.3.1 Record Keeping: Any PERSON subject to the requirements of this Regulation shall compile and retain records that provide evidence of CONTROLMEAsuRE application, by indicating type oftreatment or CONTROL MEAsuRE, extent of coverage, and date applied. The records and

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# 1/13/03 supporting documentation shall be made available to the CONTROL OFFIcERwithin 24 hours ofawritten request. 90.3.2 Record Retention: Copies ofthe records required by Subsection 90.3.1 (Record Keeping Requirements) ofthis Regulation shall be retained for at leastone year. 90.4 TestMethods 90.4.1 Stabilization Standards For OPEN AREAS AND VACANT LOTS: The test methods described in Subsections 90.4.1.1 through Subsections 90.4.1.3 of this Regulation shall be used to determine whether an OPEN AREA or a VAcANT LOT has a stabilized surface. Should a disturbed OPEN AREA or VACANT LOT contain more than one type of disturbance, soil, or other characteristics which are visibly distinguishable, each representative surface must be tested separately for stability in an area that represents a random portion ofthe overall disturbed conditions ofthe site, utilizing the appropriate test methods in Subsections 90.4.1.1 through Subsections 90.4.1.3 ofthis Regulation. Depending upon test method results, include oreliminate each representative surface from the total size assessment of the DIsTURBED SURFACEAREA(S). 90.4.1.1 Soil Crust Determination (The Drop Ball Test): Drop a steel ball with a diameter of 15.9 millimeters (0.625 inches) and a mass ranging from 16- 17 grams from a distance of 30 centimeters (one foot) directly above the soil surface. Ifblowsand is present, clearthe blowsand from the surfaces on which the soil crusttest method is conducted. Blowsand is defined as thin deposits of loose uncombined grains Covering less than 50% of an OPEN AREA or VACANT LOT which have not originated from the representative OPENAREA orVACANTLOT surface being tested. Ifmaterial covers a visible cwst, which is not blowsand, apply the test method in Subsection 90.4.1.3 (Determination OfThreshold Friction Velocity) ofthis Regulation to the loose material to determine whether the surface is stabilized. (a) A sufficient crust is defined underthe following conditions: once a ball has been dropped according to Subsection 90.4.1.1 of this Regulation, the ball does not sink into the surface, so that it is partially or fully surrounded by loose grains and, upon removal of the ball, the surface upon which it fell has not been pulverized, so thatloose grains are visible. (b) Randomly select each representative DIsTURBED SURFACE for the drop ball test by using a blind “over the shoulder” toss of a throwable object (for example, a metal weight with survey tape

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attached). Using the point of fall as the lower left hand corner, measure a 1-foot square area. Drop the ball three times within the 1-foot by 1-foot square survey area, using a consistent pattern across the survey area. The survey area shall be considered to have passedthe Soil Crust Determination Test ifat leasttwo ofthe three times the ball was dropped, the results met the criteria in Subsection 90.4.1.1(a) ofthis Regulation. Select at least

### two other survey areas that represent a random portion of the overall disturbed conditions ofthe site, and repeat this procedure. If the results meetthe criteriaofSubsection 90.4.1 .1(a) ofthis Regulation for all ofthe survey areas tested, then the site shall be considered to have passed the Soil Crust Determination Test and shall be considered sufficiently crusted. (c) At any given site, the existence of a sufficient crust covering one portion of the site may not represent the existerice or protectiveness ofa cruston anotherportion ofthe site. Repeatthe soil crusttest asoften as necessary on each portion ofthe overall conditions ofthe site using the random selection method set forth in Subsection 90.4.1.1(b) of this Regulation for an accurate assessment. 90.4.1.2 Rock Test Method: The Rock Test Method, which is similar to Subsection 90.4.1.3 (Determination OfThreshold Friction Velocity) ofthis Regulation, examines the wind-resistance effects ofrocks and other non erodible elements on disturbed surfaces. Non-erodible elements are objects larger than 1 centimeter (cm) in diameter that remain firmly in place even on windy days. Typically, non-erodible elements include rocks, stones, glass fragments, and hardpacked clumps ofsoil lying on or embedded in the surface. Vegetation does not count as a non-erodible element in this method. Thepurpose ofthis testmethod is to estimatethe 

### percent càverofnon-erodibleelements on a given surfaceto see whether such elements take up enough space to offer protection against windblown dust. For simplification, the following test method refers to all non-erodible elements as “rocks.” (a) Randomly select a 1 meter by 1 meter survey area within an area that represents the general rock distribution on the surface (a I meter by 1 meter area is slightly greater than a 3 foot by 3 foot area). Use a blind “over the shoulder toss of a throwable object (for example, a metal weight with survey tape attached) to select the survey surface and using the pointoffall as the lower lefthand corner, measure a 1 meter by 1 meter survey area. Mark-offthe survey area by tracing a straight, visible line in the dirt along the edge ofa measuring tape or by placing short ropes, yard sticks, or otherstraightobjects in a square around the 

### survey area. Revised 12117102 90-5 CCAirQualityRegulations DAQM, 500 GrandCenfràlPkwy, LV89155(b) Without moving any of the rocks, or other elements, examine the survey area. Since rocks greaterthan 3/8 inch (1 cm) in diameter are ofinterest, measure the diameter ofsome ofthe smallerrocks to a geta sense ofwhich rocks needto be considered. (c) Mentallygroup the rocks greaterthan 3/8 inch (1cm) diameterlying 

### in the survey area into small, medium, and large size categories. If the rocks are all approximatelythe same size, simply select a rock of average size and typical shape. Without removing any of the rocks from the ground, count the number of rocks 

### in the survey area

### in each group andwrite down the resulting number. (d) Without removing rocks, select one or two average-size rocks in each group and measure the length and width. Use either metric units or standard units. Using a calculator, multiplythe length times thewidth ofthe rocks to getthe average dimensions ofthe rocks in each group. Writedownthe results foreach rockgroup. (e) Foreach rock group, multiplythe average dimensions (length times width) by the number of rocks counted in the group. Add the results from each rock group to get the total rock area within the survey area. (f) Divide the total rock area, calculated in Subsection 90.4.1.2(e) of this Regulation, by 

### two (to get frontal area). Divide the resulting number by the size of the survey area (make sure the units of measurement match), and multiply by 100 for percent rock cover. Forexample, thetotal rockarea is 1,400 square centimeters, divide 1,400 by 2 to get 700. Divide 700 by 10,000 (the survey area is 1 meter by 1 meter, which is 100 centimeters by 100 centimeters or 10,000 centimeters) and multiply by 100. The result is 7% rock cover. If rock measurements are made in inches, convert the survey areafrom metersto inches (1 inch 2.54 centimeters). (g) Select and mark-off 

### two additional survey areas and repeat the procedures described in Subsection 90.4.1.2(a) through Subsection 90.4.1.2(f) ofthis Regulation. Make sure the additional survey areas also represent the general rock distribution on the site. Average the percent coverresults from all three survey areas to estimatethe average percentofrockcover. (h) If the average rock cover is greater than or equal to 20%, the surface is stable. Ifthe average rockcoveris less than 20%, follow the procedures in Subsection 90.4.1.2(i) ofthis Regulation.
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(i) Ifthe average rock cover is less than 20%, the surface may ormay not be stable. Follow the procedures in Subsection 90.4.1.3 (Determination Of Threshold Friction Velocity) of this Regulation and use the results from the rocktest method as a correction (le., multiplication) factor. If the rock cover is at least 1%, such rock cover helps to limit windblown dust. However, depending on the soil’s ability to release fine dust particles into the air, the percent rock cover may or may not be sufficient enough to stabilize the surface. It is also possible that the soil itself has a high enough Threshold Friction Velocity (TFV) to be stable without accounting forrock cover. (j) Aftercompleting the procedures described in Subsection 90.4.1.2(i) of this Regulation, use Table 2 of this Regulation to identify the appropriate correction factorto the TFV, depending on the percent rock cover. Multiply the correction factor by the TFV value for a final TFVestimatethat is correctedfornon-erodible elements. 90.4.1.3 Determination Of Threshold Friction Velocity (TFV): For DIsmRBED SURFACE AREAS that are not crusted or vegetated, determine TFV according to the following sieving field procedure (based on a 1952 laboratory procedure published byW. S. Chepil). (a) Obtain and stack a set of sieves with the following openings: 4 millimeters (mm), 2 mm, 1 mm, 0.5 mm, and 0.25 mm, or obtain and stack a set ofstandard/commonly available sieves. Place the sieves in order according to size openings, beginning with the largest size opening at the top. Place a collector pan underneath the bottom (0.25 mm) sieve. Collect a sample of loose surface material from an area at least 30 cm by 30 cm in size, to a depth of approximately 1 cm using a brush and dustpan or other similar device. Only collect soil samples from dry surfaces (i.e., when the surface is not damp to the touch). Remove any rocks largerthan I cm in diameter from the sample. Pour the sample into the top sieve (4 mm opening) and coverthe sieve/collectorpan unitwith a lid. Minimize escape of particles into the air when transferring surface soil into the sieve/collector pan unit. Move the covered sieve/collectorpan unit by hand using a broad, circular arm motion in the horizontal plane. Complete 

### twenty circular arm movements, ten clockwise and ten counterclockwise, at a speedjust necessary to achieve some relative horizontal motion between the sieves and the particles. Remove the lid from the sieve/collector pan unit and disassemble each sieve separately, beginning with the largest sieve. As each sieve is removed, examine it for loose particles. If loose particles have not been sifted to the finest sieve through which they can pass, reassemble and coverthe sieve/collector pan Revised 12117102 90-7 CCAirQualityRegu’ations DAQM5OOGrandCentra1Pkwy, LV89155

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unit and gently rotate it an additional ten times. Afterdisassembling the sieve/collector pan unit, slightly tilt and gently tap each sieve, and the collector pan, so that material aligns along one side. In doing so, minimize escape of particles into the air. Line up the sieves and collector pan in a row and visibly inspect the relative quantities of catch in order to determine which sieve (or whether the collector pan) contains the greatest volume of material. If a visual determination of relative volumes ofcatch among sieves is difficult, use a graduatedcylinderto measurethevolume. Estimate 

### TFV forthe sieve catch with the greatest volume using Table I of this Subsection, which provides a correlation between sieve opening size and TFV. Table 1. Determination OfThreshold FrictionVelocity TylerSieve No. ASTM 11 Opening TFV Sieve No. (mm) (cm/s)

5 5 4 135 9 10 2 100 16 18 1 76 32 35 0.5 58 60 60 0.25 43 CollectorPan 30 (b) Collect atleastthree soil samples which representrandom portions of the overall conditions of the site, repeat the above TFV test method for each sample and average the resulting TFVs together to determine the TFV uncorrected for non-erodible elements. Non erodible elements are distinct elements, in the random portion of the overall conditions of the site, that are larger than 1 cm in diameter, remain firmly in place during a wind episode, and inhibit soil loss by consuming part ofthe shear stress ofthe wind. Non erodible elements include stones and bulk surface material but do. not include flat or standing vegetation. For surfaces with non erodible elements, determine corrections to the TFV by identifying the fraction of the survey area, as viewed from directly overhead, that is occupied by non-erodible elements using the following procedure. For a more detailed description ofthis procedure, see Subsection 90.4.1.2 (RockTest Method) ofthis Regulation. Select

a survey area of, 1 meter by 1 meter that represents a random portion of the overall conditions of the site. Where many non erodible elements lie within the survey area, separate the non erodible elements into groups according to size. For each group, calculate the overhead area for the non-erodible elements according tothefollowing equations:

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Eq. 1: (Average length) x (Averagewidth) Average Dimensions. Eq. 2: (Average Dimensions) x (NumberofElements) = OverheadArea. Eq. 3: Overhead Area OfGroup 1 + Overhead Area Of Group 2 (etc.) = Total OverheadArea. Eq. 4: Total OverheadAreal2 =Total FrontalArea. Eq. 5: (Total Frontal Area/Survey Area) x 100 = Percent Cover Of Non Erodible Elements. Note: Ensure consistent units of measurement (e.g. square meters or square inches when calculating percentcover). Repeatthis procedure on an additional

### two distinct

### survey areas thatrepresent a random portion ofthe overall conditions ofthe site and average the results. Use Table 2 ofthis Subsection to identify the correction factorfor the percent cover of non-erodible elements. Multiply the TFV by the corresponding correctionfactorto calculatethe

### TFVcorrectedfornon-erodibleelements. Table2. Correction Factors ForThreshold FrictionVelocity

PercentCoverOfNon-Erodible Elements Correction Factor Greaterthan orequalto 10% 5 Greaterthan orequalto 5% and lessthan 10%3 Less than 5% and greaterthan orequal to 1% 2 Less than 1% None
History: Initial adoption: June 22, 2000 Amended: November20, 2001; December 17, 2002

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