U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
202-366-4000
Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations
REPORT |
This report is an archived publication and may contain dated technical, contact, and link information |
|
Publication Number: FHWA-HRT-12-054 Date: December 2012 |
Publication Number: FHWA-HRT-12-054 Date: December 2012 |
This appendix describes the computations for pollutant emissions. The pollutants discussed are provided in table 34 .
Table 34. Pollutant index identification.
Pollutant | Pollutant Index Identification |
---|---|
Volatile organic compound (VOC) | PO = 1 |
Sulfur dioxide (SO2) | PO = 2 |
Oxides of nitrogen (NOX) | PO = 3 |
Particles of 2.5 micrometers or less (PM 2.5) | PO = 4 |
Particles of 10 micrometers or less (PM 10) | PO = 5 |
1 = 0.039 mil
The emission data in this appendix were provided by FHWA using the MOVES model.(31)
Emission
rates in terms of grams per VMT are typically relatively low at high speeds
(e.g., 75 mi/h). The rates reduce somewhat as speed decreases and then increase
significantly as speed continues to decrease. Emissions for each pollutant for
5-min time periods are modeled
by
figure 71.
Figure 71. Equation. Emissions.
Where:
POL = Emissions.
PO = Pollutant.
ER = Emission rate.
The emission rate for each pollutant as a function of speed for years 2011 and 2016 is provided in table 35 and table 36.
Table 35. Emission rates for 2011.
Speed (mi/h) |
Emission Rate (g/mi) | ||||
---|---|---|---|---|---|
NOX | SO2 | VOC | PM 2.5 | PM 10 | |
75 | 1.062 | 0.00768 | 0.1021 | 0.0261 | 0.0275 |
70 | 1.014 | 0.00731 | 0.0934 | 0.0247 | 0.0260 |
65 | 0.959 | 0.00705 | 0.0893 | 0.0235 | 0.0247 |
60 | 0.922 | 0.00696 | 0.0899 | 0.0228 | 0.0239 |
55 | 0.915 | 0.00698 | 0.0930 | 0.0236 | 0.0248 |
50 | 0.917 | 0.00707 | 0.0976 | 0.0256 | 0.0268 |
45 | 0.923 | 0.00722 | 0.1043 | 0.0274 | 0.0288 |
40 | 0.935 | 0.00742 | 0.1137 | 0.0288 | 0.0302 |
35 | 0.955 | 0.00770 | 0.1265 | 0.0306 | 0.0321 |
30 | 1.028 | 0.00821 | 0.1434 | 0.0370 | 0.0387 |
25 | 1.105 | 0.00913 | 0.1638 | 0.0395 | 0.0413 |
20 | 1.187 | 0.0102 | 0.1918 | 0.0454 | 0.04766 |
15 | 1.294 | 0.0118 | 0.2306 | 0.0511 | 0.0536 |
10 | 1.472 | 0.0148 | 0.3025 | 0.0582 | 0.0609 |
5 | 2.131 | 0.0240 | 0.5198 | 0.0905 | 0.0945 |
2.5 | 3.652 | 0.0427 | 0.9618 | 0.1665 | 0.1734 |
Table 36. Emission rates for 2016.
Speed (mi/h) |
Emission Rate (g/mi) | ||||
---|---|---|---|---|---|
NOX | SO2 | VOC | PM 2.5 | PM 10 | |
75 | 0.621 | 0.00646 | 0.0596 | 0.0172 | 0.0182 |
70 | 0.591 | 0.00615 | 0.0523 | 0.0159 | 0.0169 |
65 | 0.557 | 0.00593 | 0.0491 | 0.0151 | 0.0160 |
60 | 0.536 | 0.00585 | 0.0488 | 0.0146 | 0.0155 |
55 | 0.532 | 0.00587 | 0.0504 | 0.0150 | 0.0159 |
50 | 0.532 | 0.00595 | 0.0530 | 0.0161 | 0.0169 |
45 | 0.534 | 0.00608 | 0.0569 | 0.0171 | 0.0180 |
40 | 0.540 | 0.00625 | 0.0626 | 0.0179 | 0.0188 |
35 | 0.549 | 0.00648 | 0.0703 | 0.0190 | 0.0200 |
30 | 0.589 | 0.00691 | 0.0804 | 0.0226 | 0.0238 |
25 | 0.628 | 0.00768 | 0.0910 | 0.0243 | 0.0255 |
20 | 0.677 | 0.00857 | 0.1067 | 0.0280 | 0.0294 |
15 | 0.741 | 0.00990 | 0.1271 | 0.0315 | 0.0331 |
10 | 0.847 | 0.01243 | 0.1637 | 0.0360 | 0.0378 |
5 | 1.237 | 0.02028 | 0.2746 | 0.0553 | 0.0581 |
2.5 | 2.143 | 0.03617 | 0.5019 | 0.1003 | 0.1050 |
To
obtain the appropriate emissions rate, interpolation for both speed and the
evaluation year should be performed.
Signal delay includes the deceleration and acceleration periods associated with a stop for a traffic signal. Since the emission rates associated with these moving periods are somewhat higher than for the idling period, the use of the idling emissions rate to represent the emissions during signal delay period provides a low estimate for the emissions generated during these periods. The relationship for 15-min-period emission levels is provided in figure 72.
Figure 72. Equation. Arterial pollutant emission.
Where:
POLA = Arterial pollutant emission (g).
PO = Pollutant identification.
LI = Intersection ID.
LG = Traffic signal lane group.
PA = Idling emissions generation rate (g/h).
V = Volume (v/h).
LCD = Control delay for the lane group
for a vehicle.
Table 37 provides the values for the idling emission rates.
Table 37. Idling emission rates.
Pollutant | 2011 Emission Rate (g/h) | 2016 Emission Rate (g/h) |
---|---|---|
NOX | 5.858 | 3.500 |
SO2 | 0.0708 | 0.0669 |
VOC | 3.404 | 1.642 |
PM 2.5 | 0.305 | 0.213 |
PM 10 | 0.318 | 0.222 |