A5.3.6.2  Methodology - Wind Erosion  The second major source of PM emissions from sand and salt piles is  wind erosion  of the piles.  A detailed methodology for calculating wind erosion emissions is given in Chapter 13.2.5,  Industrial Wind Erosion 37 , of EPA’s AP -42. The methodology calculates the  PM emissions  generated by wind erosion of open storage piles by applying an “erosion potential function” to  each surface of the pile. Because the  methodology is too complex to be reduced into a single  equation, this section  mainly focuses on the critical data inputs needed to compute these  emissions.  The data inputs required to estimate PM emissions from wind erosion of storage  piles are  summarized in  Table A5-11  ( Data Inputs for Wind Erosion ).  Table A5-11. Data Inputs for Wind Erosion  37  EPA, AP-42,  Chapter 13.2.5, Industrial Wind Erosion ,  http://www.epa.gov/ttnchie1/ap42/ch13/final/c13s0205.pdf.  Data Inputs  Description  Source  Quantity of Material  Stored in Pile  The quantity should be expressed in  tons used/stored per a given time  period.  This information should be obtained from maintenance operator of the pile.  Moisture Content of  Stored Material  The moisture content of the material of  the pile is typically expressed in  percentages (%).  This information can be obtained by sampling of the piles, or from the maintenanc operator pile. If data is unava Chapter 13.2.5 of EPA’s AP -42 provide information on the moisture content of material  types by industry.  Silt Content of Stored  Material  Silt content is a measure o f the  percentage of material that p asses  through a No. 200 sieve.  This can be obtained by  direct sampling of the  pile or the maintenance operator of the pile. data is unavailable, Chapter 13.2.5 of EPA’s AP- 42 provides the silt content of a sand pile stored  at a municipal landfill: 2.6%. This value may be  used as a default if silt content of  piles located  on the site is not available.  Frequency of  Loading/Unloading  Events  Wind erosion is a factor of the number  of times the surface of the pil e is  disturbed through loading or unloading  events in a given time period.  Information on the  frequency of loading a unloading events should be obtained from maintenance operator of the pile.  Percentage of Pile  Surface Disturbed in  Loading/Unloading  Events  An estimate of the percentage of the  pile surface disturbed in each ev ent  must be calculated.  This information is based on the throughput rate and pile size, or if possible, from  information  supplied  by  the  main operator of the pile. Chapter 13.2.5 of AP-42 describes the specific requirements needed for these calculations.  Physical Dimensions of  the Pile  Required dimensions include overall  pile shape description (flat, conical, o r  oval flat- topped), as well as pile height  and diameter, expressed in meters.  This information is available through observation or from the maintenance operator of  the pile.  APPENDIX A5$_{ }$ 44$_{ }$