Tyre wear calculation methodology. The total emissions from tire wear in [mg] are given by the following equation:

Transcription

1 Tyre wear calculation methodology The total emissions from tire wear in [mg] are given by the following equation: where TE Tij = N j M j f Ti (EF T TSP ) j S T (V) i = TSP, PM 10, PM 2.5, PM 1, PM 0.1 depending on the fraction used in the equation each time. N = the number of vehicles. M = the mileage per vehicle for the period considered [km]. f Ti = the fraction of TSP that can be classified as TSP, PM 10, PM 2.5, PM 1 or PM 0.1. (EF T TSP ) j = the TSP emission rate in [mg/vkm] at a speed of 80 km/h for vehicle category j = PC (passenger car), LDV (light duty vehicle), HDV (heavy duty vehicle) or MC (motorcycle). S T (V) = the speed correction factor which depends on the mean vehicle velocity. Speed correction factor In case that the mean trip speed is known, S T (V) factor can be obtained from the following diagram: 1,6 speed correction factor [S(V)] 1,4 1,2 1 0,8 0, mean trip speed [V] (km/h)

2 V < 40km/h: S T (V) = 1,39 40km/h V 90km/h: S T (V) = -0,00974 V + 1,78 V > 90km/h: S T (V) = 0,902 Note that S T (V) = 1, when mean trip speed is 80 km/h. Emission factors Note: The complete procedure that was followed in order to conclude to the emission factors proposed here is presented in the annex. The emission factors proposed for the different vehicle categories j are given below: 1. Passenger Cars Using the values shown in Table 1 (Annex) and the procedure described there, we have concluded to an (EF T TSP ) PC range and an (EF T TSP ) PC value. Proposed (EF T TSP ) PC range : 6,7-16,2 [mg/vkm] Proposed (EF T TSP ) PC value : 10,7 [mg/vkm] 2. Light Duty Vehicles Using the values shown in Table 3 (Annex) and the procedure described there, we have concluded to an (EF T TSP ) LDV range and an (EF T TSP ) LDV value. Proposed (EF T TSP ) LDV range : 8,8-21,7 [mg/vkm] Proposed (EF T TSP ) LDV value : 16,9 [mg/vkm] It appears that the TSP emission factor from tyre wear for light duty vehicles (16,9 mg/vkm) is approximately 60% greater than the respective emission factor for passenger cars (10,7 mg/vkm), a fact which was expected due to the increased LDV s weight and its larger tyres. 3. Heavy Duty Vehicles Using the values shown in Table 4 (Annex), we have concluded to an (EF T TSP ) HDV range. Proposed (EF T TSP ) HDV range : 22,7-89,8 [mg/vkm] For reasons mentioned in the Annex, the following equation is proposed for the calculation of the emission factor from tyre wear for HDV s: (EF T TSP ) HDV (EFT TSP ) PC = N axle LCF (eq. 1) 2

3 where N axle = the number of the heavy vehicle s axles. (EF T TSP ) PC = the TSP emission factor for passenger cars. LCF = the load correction factor, which can be obtained from the following diagram. Load factor (LF) needs to be estimated on the average truck s load basis. If the truck is completely empty or fully loaded, the load factor should be 0(%) and 100(%) respectively. 3 2,795 Load Correction Factor 2 1 1,414 LCF = 0,01381LF+1, Load Factor (%) In case that there is no available information for the parameters N axle and LF, an average (EF T TSP ) HDV value for N axle =4 and LF=50 LCF=2,1 (half-loaded truck) is proposed: Proposed (EF T TSP ) HDV value if N axle and LF are unknown: 45 [mg/vkm] 4. Motorcycles Using the values shown in Table 2 (Annex) and the procedure described there, we have concluded to an (EF T TSP ) MC range and an (EF T TSP ) MC value. Proposed (EF T TSP ) MC range : 4,2-5,3 [mg/vkm] Proposed (EF T TSP ) MC value : 4,6 [mg/vkm] As expected, the TSP emission factor from tyre wear for motorcycles (4,6 mg/vkm) is approximately 40% smaller than the respective emission factor for passenger cars (10,7 mg/vkm). This is due to the two wheels and the lighter weight per wheel for a motorcycle.

4 Fractions For the calculation of mass emission from different particle sizes, the following fractions f Ti are suggested: i f Ti TSP 1 PM 10 0,6 PM 2.5 0,42 PM 1 0,06 PM 0.1 0,048 As it is shown in the table above, the fraction of TSP that can be classified as PM 10 is 0,6. Examples for each category The next chart provides PM 10 emission factors as a function of speed for different vehicle categories. Smaller particle sizes are calculated on the basis of this. Correlation between emission factors and mean trip speed 60 EF for PM PC LDV HDV, 4 axles, LF=20% HDV, 4 axles, LF=100% Motorcycles mean speed (km/h)

5 ANNEX: TSP emission rates from tyre wear for passenger cars, light duty vehicles, heavy duty vehicles and motorcycles - Methodology verification. In order to estimate a final value of the TSP emission factor for each vehicle category, all values found in the literature were collected (and shown in the tables below), some of them were taken into consideration and others were rejected. Table 1: Wear rates, PM 10 emission factors and TSP emission factors from tyre wear for passenger cars found in the literature Source Wear rate EF for PM 10 EF for TSP Kolliousis (2000) 40,0 4,0 6,7 Gebbe (1997) 53,0 5,3 8,8 Garben (1997) 64,0 6,4 10,7 Lee (1997) 64,0 6,4 10,7 Legret (1999a) 68,0 6,8 11,3 Baumann (1997) 80,0 8,0 13,3 Warner (2002) 97,0 9,7 16,2 CARB (1993) 120,0 12,0 20,0 G ttle (1979) 120,0 12,0 20,0 Malmqvist (1983) 120,0 12,0 20,0 BUWAL (1998) 135,0 13,5 22,5 SENCO (1999) 163,0 16,3 27,2 Baekken (1993) 200,0 20,0 33,3 Dannis (1974), Clark (1988) 300,0 30,0 50,0 Cadle (1979) 400,0 2,4 4,0 USEPA (1995) 50,0 5,0 8,3 Rauterberg-Wulff(1999) 61,0 6,1 10,2 The values shown with red color have been estimated or calculated in surveys, while the ones shown with black color are derived using the equations: EF PM = 0, 1 WearRate 10 EF = EF TSP PM10 0,6 It is found in the literature that 1-10% of a tyre s wear is emitted as PM 10. The factor 0,1 is the upper limit of this range. The factor 0,6, which is used for transformation of PM 10 to TSP, is also obtained from the literature (Miguel et al. 1999). The proposed value for each vehicle category is calculated as the average of the values shown in blue color in each table. Also, the min and max values in blue color form the proposed range. The values that are not shown in blue in the column EF for TSP were excluded from the proposed range and the calculation of the proposed

6 value, because they were either out-dated or providing values which were much higher than expected. Therefore, using information from Table 1, the proposed TSP emission factors and ranges from tyre wear for passenger cars respectively are: Proposed (EF T TSP ) PC range : 6,7-16,2mg/vkm Proposed (EF T TSP ) PC value : 10,7mg/vkm Similarly, proposed emission rates for motorcycles, light duty vehicles and heavy duty vehicles can be obtained. Table 2: Wear rates, PM 10 emission factors and TSP emission factors from tyre wear for motorcycles found in the literature Source Wear rate EF for PM 10 EF for TSP Gebbe (1997) 26,4 2,6 4,4 Garben (1997) 32,0 3,2 5,3 Env. Austral. (2000) 2,5 4,2 EMPA (2000) 7,0 11,7 As before, using information from Table 2, the proposed TSP emission factor and range from tyre wear for motorcycles are derived from the values shown in blue: Proposed (EF T TSP ) MC range : 4,2-5,3mg/vkm Proposed (EF T TSP ) MC value : 4,6mg/vkm Table 3: Wear rates, PM 10 emission factors and TSP emission factors from tyre wear for light duty vehicles found in the literature Source Wear rate EF for PM 10 EF for TSP EMPA (2000) 53,0 5,3 8,8 Gebbe (1997) 110,0 11,0 18,3 Garben (1997) 112,0 11,2 18,7 EMPA (2000) 13,0 21,7 Similarly, the proposed LDV TSP emission factor and range from tyre wear are derived using information from Table 3: Proposed (EF T TSP ) LDV range : 8,8-21,7mg/vkm Proposed (EF T TSP ) LDV value : 16,9mg/vkm

7 Table 4: Wear rates, PM 10 emission factors and TSP emission factors from tyre wear for heavy duty vehicles found in the literature Source Wear rate EF for PM 10 EF for TSP Legret (1999a) 136,0 13,6 22,7 Baumann (1997) 189,0 18,9 31,5 Baumann (1997) 192,0 19,2 32,0 Baumann (1997) 234,0 23,4 39,0 Gebbe (1997) 539,0 53,9 89,8 Garben (1997) 768,0 76,8 128,0 SENCO (1999) 1403,0 140,3 233,8 EMPA (2000) 798,0 200,0 333,3 Rauterberg (1999) 32,0 53,3 The proposed TSP emission range from tyre wear for heavy duty vehicles is: Proposed (EF T TSP ) HDV range: 22,7-89,8mg/vkm However, the category of heavy duty vehicles is characterized by the variability of the number of axles and by the wide range of a truck s load. Therefore, the number of axles and the load factor need to be taken under consideration for the calculation of HDV emissions from tyre wear. In order to develop an equation that calculates these emissions, it was assumed that the lower limit of the proposed range corresponds to a HDV with 3 axles (N axle =3) and no load (LF=0%), while the upper limit corresponds to a HDV with 6 axles and full load (LF=100%). The equation proposed is the following: (EF T TSP ) HDV (EFT TSP ) PC = N axle LCF (eq. 1) 2 Note that the average (EF T TSP ) PC is used. Also, the parameter N axle used in the equation ranges from 3 to 6. For example, although it is likely that a part of the fleet of the HDVs has only 2 axles or more than 6, the minimum value of 3 and the maximum value of 6 for the parameter N axle must be respectively used in this case. The following figures 1 and 2 represent the dispersion of the values that appear in the tables shown above.

8 PC, LDV and motorbikes TSP EFs 50,0 50,0 40,0 PC-Values derived from wear rate/not used for calculating the proposed value PC-Values derived from wear rate/used PC-Values derived from PM10 EF/used PC-Value found in the literature/not used 33,3 PC-Proposed value 30,0 LDV-Values derived from wear rate/used TSP 27,2 LDV-Value derived from PM10 EF/used LDV-Proposed value 22,5 21,7 motorbikes-values derived from wear rate/used 20,0 20,0 20,0 20,0 18,7 18,3 motorbikes-value derived from PM10 EF/used 16,2 16,9 motorbikes-value derived from PM10 EF/not used 13,3 motorbikes-proposed value 10,0 10,7 8,8 11,3 10,7 10,2 8,3 10,7 8,8 11,7 6,7 5,3 4,0 4,6 4,4 4,2 0,0 PC LDV Motor Figure 1: Dispersion of the TSP emission factors from tyre wear for PCs, LDVs and MCs

9 HDV TSP EFs 350,0 333,3 300,0 250,0 233,8 HDV-Values derived from wear rates/used HDV-Value derived from wear rate/not used TSP 200,0 150,0 128,0 HDV-Value derived from PM10 EF/not used HDV-Value derived from PM10 EF/used HDV-Value derived from methodology for Naxle=6 and LF=50% HDV-Proposed value 100,0 89,8 50,0 44,7 32,0 53,3 50,3 39,0 31,5 22,7 0,0 Figure 2: Dispersion of the TSP emission factors from tyre wear for HDVs