Comparison of the SCAQS tunnel study with other on-road vehicle emission data. [Southern California Air Quality Study (SCAQS)]

Journal Article · Thu Nov 01 04:00:00 EST 1990 · Journal of the Air and Waste Management Association; (United States)

DOI:https://doi.org/10.1080/10473289.1990.10466799· OSTI ID:6102680

Pierson, W R; Gertler, A W ^[1]; Bradow, R L

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1. Desert Research Inst., Reno, NV (United States)

The Van Nuys Tunnel experiment conducted in 1987 by Ingalls et al. (see A and WMA Paper 89-137.3), to verify automotive emission inventories as part of the Southern California Air Quality Study (SCAQS), gave higher Co and HC emission-rate values than expected on the basis of automotive-emission models - by factors of approximately 3 and 4, respectively. The CO/NO{sub x} and HC/NO{sub x} emission-rate ratios moreover were higher than expected - by similar factors (NO{sub x} emission rates were about as expected). The purpose of the present paper is to review the literature on dynamometer and on-road (in tunnels and along roadways) testing of in-use vehicles, and on urban-air CO/HC/NO{sub x} concentration ratios, to see whether the Van Nuys Tunnel results are reasonable in terms of previous experience. The conclusions are that (1) on-road CO and HC emissions higher than expected have been reported before, (2) on-road CO and HC emissions consistent with the Van Nuys Tunnel results have been reported before, and (3) on-road CO/NO{sub x} and HC/NO{sub x} emission-rate ratios higher than expected have been reported before. The Van Nuys Tunnel NO{sub x} results actually are lower than in other on-road experiments, and the CO/NO{sub x} and HC/NO{sub x} ratios consequently are higher. The higher-than-predicted CO/NO{sub x} and HC/NO{sub x} ratios at Van Nuys and other on-road sites suggest richer operation on-road than predicted or than observed in the in-use-vehicle dynamometer tests which serve as the model inputs. Support for these suggestions and conclusions is found in comparison of urban-air and emission-inventory HC/NO{sub x} ratios.

• OSTI ID: 6102680
• Journal Information: Journal of the Air and Waste Management Association; (United States), Journal Name: Journal of the Air and Waste Management Association; (United States) Vol. 40:11; ISSN JAWAE; ISSN 1047-3289
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540120* -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (1990-)
AIR POLLUTION MONITORING
AIR QUALITY
CALIFORNIA
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
DEVELOPED COUNTRIES
ENVIRONMENTAL QUALITY
EXHAUST GASES
FEDERAL REGION IX
FLUIDS
GASEOUS WASTES
GASES
HYDROCARBONS
MONITORING
NITROGEN COMPOUNDS
NITROGEN OXIDES
NORTH AMERICA
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
TUNNELS
UNDERGROUND FACILITIES
URBAN AREAS
USA
VEHICLES
WASTES