Detailed Calculations of Construction Dust Emission Factors

 

Construction Activity	:	(1)	Materials Handling
		(2)	Rock Breaking
		(3)	Excavation
		(4)	Vehicle Movements on Unpaved Site Roads
		(5)	Wind Erosion

 

Calculations of Emission Factors for Various Construction Activities

 

(1)        Materials Handling (Based on USEPA AP-42 Vol. 1 5^th Edition, Section 13.2.4.3)

 

 

where   E     =   emission factor in kilograms per Megagram (Mg)

            k     =   particle size multiplier

            u     =   wind speed in metres per second

            M    =   material moisture content in percent

 

Assumptions :   (i)    k = 0.74 for TSP

                        (ii)   moisture content of 4.8%

                        (iii)  daily handling = 164m³

                        (iv)  density of spoil = 1800 kg/m³

                        (v)   10 working hours per day

                        (vi)  mean wind speed = 4 m/s

 

 

   = 7.56 x 10^-4 kg/Mg

 

  

 

  

 

  

 

(2)        Rock Breaking (Based on USEPA AP-42 Vol. 1 5^th Edition, Table 11.9-2, Equation (1))

 

E (in kg/blast) = 0.00022 x (A)^1.5

 

where  A     =   Horizontal area (m²), with blasting depth ≤ 21m not for vertical face of a  bench

           

            E (in kg/vol. of produced material) =       0.00022 x (V/21)^1.5/V   

 

            E (in kg/hr)        =          [0.00022 x (V/21)^1.5/V (kg/vol. of produced material)] x V/H

 

            H    =   10 working hours per day

 

Assumption : V (Typical volume of material produced from rock breaking per day (m³) = 51

 

E = 0.00022 x (51/21)^1.5 x (1/10) kg/hr

 

   = 8.32 x 10^-5 x 1000/(60x60) g/s

 

   = 2.3 x 10^-5 g/s

 

(3)        Excavation (Based on USEPA AP-42 Vol. 1 5^th Edition, Section 13.2.4.3)

 

 

where   E     =   emission factor in kilograms per Megagram (Mg)

            k     =   particle size multiplier

            u     =   wind speed in metres per second

            M    =   material moisture content in percent

 

Assumptions :   (i)    k = 0.74 for TSP

                        (ii)   moisture content of 4.8%

                        (iii)  mean wind speed = 4 m/s

                        (iv)  max. excavation rate = 75 Mg/hr/excavator

                        (v)   no. of excavator involved = 1

 

 

   = 7.56 x 10^-4 kg/Mg

 

   = 7.56 x 10^-4 kg/Mg x 75 Mg/hr/excavator x 1000 x 1/3600 x 1

 

   = 0.01575 g/s

 

 

 

(4)        Vehicle movements on unpaved site roads  (Based on USEPA AP-42 Vol. 1 5^th Edition, Section 13.2.2)

 

 

where   E     =   Size-specific emission factor (lb/VMT)

            S     =   surface material silt content (%)

            W    =   mean vehicle weight (tons)

            M    =   surface material moisture content (%)

 

Assumptions:    (i)    k = 10, a = 0.8, b = 0.5, c= 0.4 for TSP

            (ii)        surface material silt content of 4.3%      (mean value from AP-42 Table 11.9-3 for haul truck)

                        (iii)  surface material moisture content of 2.4%     (mean value from AP-42 Table 11.9-3 for haul truck)

                        (iv)  mean vehicle weight = 24 tons

                        (v)   truck flow = 8 veh/hr

                        (vi)  average one-way travel distance within site = 0.1km

                        (vii)1 lb/VMT = 281.9g/VKT

                        (viii) mean vehicle speed = 5 mph

 

 

     =  4.61 lb/VMT

 

    

 

     = 0.096 g/s

 

 

(5)                   Wind Erosion (Based on USEPA AP-42 Vol. 1 5^th Edition, Table 11.9-4)

 

 E = 0.85 Megagrams/hectare/year

 

where             E = emission factor in Megagram per hectare per year

 

 

    = 2.695 x10^-6 g/m²/s

 

B.1                  Stream Diversion

 

B.1.1.      Unmitigated Scenario - Dust Emission Factor for Works Site for Stream Diversion

 

Total Site Area = 6200m²

 

(I)      Total daytime TSP emissions   = + (5)

 

                                                       =  + 2.695 x 10^-6

 

                                                       = 6.6 x 10^-5 g/m²/s

 

(II)     Nighttime TSP emissions = 2.695x10^-6 g/m²/s

 

Assumption : 30% of the entire site as close to the nearest receptor to be exposed active works area