2015-12-16_GENERAL DOCUMENTS - C1981035 ‎(2)‎

• Permit No: C1981035
• IBM Index Class Name: General Documents
• Doc Date: 12/16/2015
• Doc Name: Air Quality Modeling Analysis by McVehil-Monnett /EPA Brocure EPA Fax Sheet on Particle Pollution
• From: Luke Danielson
• To: DRMS
• Permit Index Doc Type: General Correspondence
• Email Name: RAR
• Email Name: DIH
• Media Type: D
• Archive: No

Substituting these values into Equation 1 above, the PMIo emission factor for this traffic level is
0.116 lb/VMT. The following equation is then used to calculate daily PMIo emissions on the
paved section of the road:
PMIo emissions (lb/day) = daily trips * road length (miles) * PMIo emission factor (lb/VMT)
Multiplying the number of daily trips (539) by the length of the paved section (2.554 miles) and
the PMIo emission factor (0.116 lb/VMT) yields 159 lb/day of PMIo emitted from the paved
road.
Peak Trafflc Level
Silt loading for this traffic level is also conservatively estimated at 4 g/m2. Average vehicle
weight is calculated as:
312 transport truck trips @ 30 tons
15 delivery truck trips @ 10 tons
334 employee vehicle trips n, 2.5 tons
661 total trips @ 15.65 tons average
Using Equation 1, the PMIo emission factor is calculated as 0.128 lb/VMT. Daily, paved road
PMIo emissions are further calculated at 217 lb/day for this traffic level.
Unpaved Section of County Road 120
The quantity of PMIo generated from vehicle travel on publicly accessible unpaved roads is
estimated by the following equation:
E (PMIo) = 1.8 (s/12) (S/30)05 / (M/0.5)0-2 <Equation 2>
where: E (PMIo) = uncontrolled PMIo emission factor (lb/VMT)
s = surface material silt content (%)
S = average vehicle speed (miles per hour [mph])
M = surface material moisture content (%)
Year 2014 Traffic Level
In the absence of site-specific surface material silt and moisture contents, default values are used
for these parameters. The default silt content used in Equation 2 is 8.4%. This is a typical value
for haul roads as presented in AP -42 Table 13.2.2-1. A default moisture content of 0.5% (from
AP -42) is used in Equation 2. The average vehicle speed is calculated as:
225 transport truck trips @ 25 mph
11 delivery truck trips @ 35 mph
303 employee vehicle trips n, 35 mph
539 total trips @ 30.83 mph average
9250 East Costilla Avenue 1 Suite 630 1 Greenwood Village, Colorado 80112 6
303/790-1332 1 Fax [phone]
www.mevehil-monnett.com