h i g h l i g h t s Emissions evaluation from ethanol and iso-butanol GDI and PFI vehicles. THC, CO, and NO x did not show strong trends with ethanol and blends. PM mass, number, and black carbon emissions were higher for the GDI vehicles. Increasing ethanol and butanol content reduced PM and number emissions. Butanol blends enhanced the formation of butyraldehyde emissions.

We assessed the emissions response of a fleet of seven light-duty gasoline vehicles for gasoline fuel aromatic content while operating over the LA92 driving cycle. The test fleet consisted of model year 2012 vehicles equipped with spark-ignition (SI) and either port fuel injection (PFI) or direct injection (DI) technology. Three gasoline fuels were blended to meet a range of total aromatics targets (15%, 25%, and 35% by volume) while holding other fuel properties relatively constant within specified ranges, and a fourth fuel was formulated to meet a 35% by volume total aromatics target but with a higher octane number. Our results showed statistically significant increases in carbon monoxide, nonmethane hydrocarbon, particulate matter (PM) mass, particle number, and black carbon emissions with increasing aromatics content for all seven vehicles tested. Only one vehicle showed a statistically significant increase in total hydrocarbon emissions. The monoaromatic hydrocarbon species that were evaluated showed increases with increasing aromatic content in the fuel. Changes in fuel composition had no statistically significant effect on the emissions of nitrogen oxides (NOx), formaldehyde, or acetaldehyde. A good correlation was also found between the PM index and PM mass and number emissions for all vehicle/fuel combinations with the total aromatics group being a significant contributor to the total PM index followed by naphthalenes and indenes.

a b s t r a c tWe examined the effects of different ethanol and iso-butanol blends on the gaseous and particulate emissions from two passenger cars equipped with spark ignition direct injection engines and with one spray-guided and one wall-guided configuration. Both vehicles were tested over triplicate FTP (Federal Test Procedure) and UC (Unified Cycles) using a chassis dynamometer. Emissions of THC (total hydrocarbons), NMHC (non-methane hydrocarbons), and CO (carbon monoxide) reduced with increasing oxygen content in the blend for some of the vehicle/fuel combinations, whereas NO x (nitrogen oxide) emissions did not show strong fuel effects. Formaldehyde and acetaldehyde were the main carbonyls in the exhaust, with the higher ethanol blends showing higher acetaldehyde emissions during the coldstart. For butyraldehyde emissions, both vehicles showed some increases with different butanol blends when compared to ethanol blends, but not for all cases. The higher ethanol and butanol blends showed reductions in PM (particulate mass), number, and soot mass emissions. Particulate emissions were significantly affected by the fuel injection design, with the wall-guided vehicle producing higher mass and number emissions compared to the spray-guided vehicle. Particle size was influenced by ethanol and iso-butanol content, with higher alcohol blends showing lower accumulation mode particles than the baseline fuel.

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Abstract. Aliphatic amines can form secondary aerosol via oxidation with atmospheric radicals (e.g., hydroxyl radical and nitrate radical). The particle can contain both secondary organic aerosol (SOA) and inorganic salts. The ratio of organic to inorganic materials in the particulate phase influences aerosol hygroscopicity and cloud condensation nuclei (CCN) activity. SOA formed from trimethylamine (TMA) and butylamine (BA) reactions with hydroxyl radical (OH) is composed of organic material of low hygroscopicity (single hygroscopicity parameter, κ, ≤ 0.25). Secondary aerosol formed from the tertiary aliphatic amine (TMA) with N 2 O 5 (source of nitrate radical, NO 3 ) contains less volatile compounds than the primary aliphatic amine (BA) aerosol. As relative humidity (RH) increases, inorganic amine salts are formed as a result of acid-base reactions. The CCN activity of the humid TMA-N 2 O 5 aerosol obeys Zdanovskii, Stokes, and Robinson (ZSR) ideal mixing rules. The humid BA + N 2 O 5 aerosol products were found to be very sensitive to the temperature at which the measurements were made within the streamwise continuous-flow thermal gradient CCN counter; κ ranges from 0.4 to 0.7 dependent on the instrument supersaturation (ss) settings. The variance of the measured aerosol κ values indicates that simple ZSR rules cannot be applied to the CCN results from the primary aliphatic amine system. Overall, aliphatic amine aerosol systems' κ ranges within 0.2 < κ < 0.7. This work indicates that aerosols formed via nighttime reactions with amines are likely to produce hygroscopic and volatile aerosol, whereas photochemical reactions with OH produce secondary organic aerosol of lower CCN activity. The contributions of semivolatile secondary organic and inorganic material from aliphatic amines must be considered for accurate hygroscopicity and CCN predictions from aliphatic amine systems.