Impact of Ambient Temperatures and Driving Conditions on the Chemical Composition of Particulate Matter Emissions from Non-Smoking Gasoline-Powered Motor Vehicles

Abstract

The detailed chemical composition of particulate matter emissions from four non-smoking gasoline powered motor vehicles were measured using three different driving conditions: a cold-cold start Unified Driving Cycle (UDC), a hot UDC, and a steady state cruise driving cycle. The cold-cold start UDC tests were performed with a cold-cold start temperature of 0• C, which is significantly lower than the 24• C cold start temperature widely used for motor vehicle testing. Each vehicle was operated over three cold-cold UDC cycles, three hot UDC cycles, and a steady state driving cycle comprised of 2 hours at 100 kilometers per hour (kph) plus 1 hour at 50 kph. Particulate matter emissions were characterized for elemental carbon (EC), organic carbon (OC), sulfate ions, nitrate ions, ammonium ions, and organic compounds using gas chromatography mass spectrometry (GCMS). Mass emissions rates for the test vehicles using both the hot UDC and steady state driving cycles ranged from <0.1 to 1.3 mg km −1 , while the average cold-cold UDC cycle emissions ranged from 1.0 to 7.1 mg km −1 for the four vehicles. The cold-cold start UDC emissions averaged 5-30 times higher than the hot start UDC emissions. EC was an important contributor to the particulate matter emissions for the cold-cold start UDC emissions. Speciation of the organic compounds in the particulate matter emissions demonstrates differences in the composition of the organic aerosol emissions for the different driving cycles. The results of the present study demonstrate the important impact of cold-cold start temperature and driving conditions.

Real-Time Black Carbon Emission Factor Measurements from Light Duty Vehicles

“…The BC/TC ratios observed here are consistent with some previous dynamometer studies, 8,16,17 but not with others 6,15,20 ( this. The comparably large BC/TC ratio observed here could result from the relatively high dilution ratios used here, although the similarity of the SDS (total dilution factor ~60) and CVS (dilution factor ~12) EC/TC suggests this is not the case.…”

“…The average ERBC values for all vehicles from this study compare reasonably well with results obtained from the majority of previous dynamometer studies, both for individual phases and averaged over the entire cycle 6,8,15,16,30 ( is between the high and low emitters tested here. However, the ERBC's from high and low emitters are lower than those reported in Schauer et al, 16 likely because their vehicles started at lower cold start temperatures.…”

“…Average ERBC's for LEVs are much lower during the steady state test than during either the cold start or hot stabilized phases of the UC, consistent with Schauer et al, 16 and likely as a result of vehicles operating at stoichiometry (i.e. low load) during steady-state operation even at high speeds.…”

“…However, the ERBC's from high and low emitters are lower than those reported in Schauer et al, 16 likely because their vehicles started at lower cold start temperatures.…”

Review of Recent Advances in Detection of Organic Markers in Fine Particulate Matter and Their Use for Source Apportionment

“…Studies of the effects of ambient temperature, cold-start, and driving conditions have also been reported. 186 Although driving conditions and cold starts can have significant impacts on the measured source profiles, general agreement was found between controlled conditions and ambient results. The source contribution input data should be validated to show they are consistent with the analysis of direct emissions that are specific to the location studied.…”