P. Cicerofernandez et al., EFFECTS OF GRADES AND OTHER LOADS ON ON-ROAD EMISSIONS OF HYDROCARBONS AND CARBON-MONOXIDE, Journal of the Air & Waste Management Association [1995], 47(8), 1997, pp. 898-904
This project was developed to assess driving patterns that promote hig
h emissions episodes, also known as emission excursions, particularly
while driving on roads with grade. An instrumented vehicle was equippe
d to record driving conditions such as speed and grade, as well as mea
sure emission rates of total hydrocarbons and carbon monoxide. Control
led runs with predetermined cruise speeds between 35 and 55 mph and ac
celerations less than 3.3 mph/second were conducted on flat terrain an
d on hills with grades ranging from 0 to 7%. The hills were located in
metropolitan Los Angeles, both along freeways and arterial roads. For
hydrocarbons, the increase in emissions was about 0.04 g/mile for eac
h 1% grade increment. For carbon monoxide (GO), the increase was more
dramatic: 3.0 g/mile for each 1% grade increment. For a fully occupied
vehicle with four passengers on a 4.5% grade, emissions increased by
0.07 g/mile for hydrocarbons and 10.2 g/mile for CO. Air conditioning
operation, at full setting, further increased emissions while driving
on hills (4.5 and 6.7% grades) by 0.07 g/mile for hydrocarbons and 31.
9 g/mile for CO.