Characterization of Primary Organic Aerosol Emissions from Meat Cooking, Trash Burning, and Motor Vehicles with High-Resolution Aerosol Mass Spectrometry and Comparison with Ambient and Chamber Observations

Abstract

Organic aerosol (OA) emissions from motor vehicles, meat-cooking and trash burning are analyzed here using a high-resolution aerosol mass spectrometer (AMS). High resolution data show that aerosols emitted by combustion engines and plastic burning are dominated by hydrocarbon-like organic compounds. Meat cooking and especially paper burning emissions contain significant fractions of oxygenated organic compounds; however, their unit-resolution mass spectral signatures are very similar to those from ambient hydrocarbon-like OA, and very different from the mass spectra of ambient secondary or oxygenated OA (OOA). Thus, primary OA from these sources is unlikelyto be a significant direct source of ambient OOA. There are significant differences in high-resolution tracer m/zs that may be useful for differentiating some of these sources. Unlike in most ambient spectra, all of these sources have low total m/z 44 and this signal is not dominated by the CO2+ ion. All sources have high m/z 57, which is low during high OOA ambient periods. Spectra from paper burning are similar to some types of biomass burning OA, with elevated m/z 60. Meat cooking aerosols also have slightly elevated m/z 60, whereas motor vehicle emissions have very low signal at this m/z.

Characteristics and sources of submicron aerosols above the urban canopy (260 m) in Beijing, China, during the 2014 APEC summit

“…4a). The HOA spectrum showed a higher m/z 55/57 ratio compared with that of exhaust aerosols from diesel trucks and gasoline vehicles (Mohr et al, 2009), yet it had characteristics similar to those resolved in urban Beijing (Sun et al, , 2012a. The high m/z 55/57 ratio and the two visible peaks at meal times in diurnal variations (Fig.…”

Variations in the OM/OC ratio of urban organic aerosol next to a major roadway

“…For example, Mexico City and Riverside summertime average OM/OC ratios were around 1.8 (Williams et al, 2010;Aiken et al, 2008), and the ratio can be even higher at rural sites, such as 2.3 in rural British Columbia (Sun et al, 2009), and 1.9 at rural Midwestern sites (Bae et al, 2006). The average ratio of 1.54 is typical of relatively fresh vehicle or other emissions, such as those generated in laboratory settings (Chirico et al, 2010;Mohr et al, 2009). In Las Vegas during the summertime, the OM/OC ratio would likely be higher, as increased photochemistry would lead to higher oxygen content and higher OM/OC ratios.…”

“…Work has also been done in chemical aging chambers to assess the initial OM/ OC ratio of vehicular and other emissions and the process by which they may change over time in a controlled environment Mohr et al, 2009;Chhabra, et al, 2010;Tkacik et al, 2012), but little work has been done to characterize the OM/OC ratio of vehicular emissions in the near-roadway environment. In the short time from the emission of organic aerosol and semivolatile vapors from the tailpipe to their impact at a nearby receptor, nucleation, dilution, condensation, evaporation, and oxidation all affect the gas/aerosol organic mixture and its phase partitioning.…”

A case study of aerosol processing and evolution in summer in New York City

“…It's interesting to note that the photo-oxidation processes during this period (06:00-18:00) appear to involve a continuum of evolution from the freshly oxidized and semivolatile species to highly oxidized and low volatility species, illustrated by the continuous increase of the O/C ratio of OA from ∼0.1, a value close to those of primary aerosols (e.g. diesel/gasoline and cooking) Mohr et al, 2009;He et al, 2010) to above 0.5 (Fig. 1g).…”