Sampling Method for Particle Measurements of Vehicle Exhaust

Mikkanen, Pirita; Moisio, M.; Keskinen, Jorma; Ristimäki, Jyrki; Marjamäki, Marko

doi:10.4271/2001-01-0219

Cited by 53 publications

(34 citation statements)

References 11 publications

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“…Real-world nanoparticle formation was mimicked using an exhaust sampling system (40) that has been reported to mimic exhaust nucleation mode particle formation relatively well (29,41). With this sampling system, a portion of exhaust was sampled directly from the tailpipe and further diluted immediately using a porous tube-type primary diluter (42), led through a residence time chamber with a residence time of 2.6 s, and finally diluted by an ejector secondary dilution unit. In the primary diluter, the dilution air temperature was kept at 30°C and the dilution ratio, calculated from CO 2 data for undiluted and diluted exhaust, was maintained at 12.…”

Section: Methodsmentioning

confidence: 99%

Traffic is a major source of atmospheric nanocluster aerosol

Rönkkö

Kuuluvainen

Karjalainen

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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203

132

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In densely populated areas, traffic is a significant source of atmospheric aerosol particles. Owing to their small size and complicated chemical and physical characteristics, atmospheric particles resulting from traffic emissions pose a significant risk to human health and also contribute to anthropogenic forcing of climate. Previous research has established that vehicles directly emit primary aerosol particles and also contribute to secondary aerosol particle formation by emitting aerosol precursors. Here, we extend the urban atmospheric aerosol characterization to cover nanocluster aerosol (NCA) particles and show that a major fraction of particles emitted by road transportation are in a previously unmeasured size range of 1.3-3.0 nm. For instance, in a semiurban roadside environment, the NCA represented 20-54% of the total particle concentration in ambient air. The observed NCA concentrations varied significantly depending on the traffic rate and wind direction. The emission factors of NCA for traffic were 2.4·10 15 (kg fuel ) −1 in a roadside environment, 2.6·10 15 (kg fuel ) −1 in a street canyon, and 2.9·10 15 (kg fuel ) −1 in an on-road study throughout Europe. Interestingly, these emissions were not associated with all vehicles. In engine laboratory experiments, the emission factor of exhaust NCA varied from a relatively low value of 1.6·10 12 (kg fuel ) −1 to a high value of 4.3·10 15 (kg fuel ) −1 . These NCA emissions directly affect particle concentrations and human exposure to nanosized aerosol in urban areas, and potentially may act as nanosized condensation nuclei for the condensation of atmospheric low-volatile organic compounds.nanocluster aerosol | atmospheric aerosol | combustion-derived nanoparticles | air pollution | traffic emission D etailed characterization of aerosol sources is required to understand climate impacts and health effects of atmospheric aerosols, as well as to develop technologies and policies capable of mitigating air pollution in urbanized areas. In densely populated areas, one of the most significant source of particles is traffic (1, 2). Owing to their small size and complicated chemical and physical characteristics (3-6), atmospheric particles resulting from traffic emissions pose a significant risk to human health (7-12), and also contribute to anthropogenic forcing of climate (13,14). Previous research on vehicular emissions has demonstrated the presence of soot and ash (3, 15) and solid sub-10-nm core particles (4-6) in primary emissions from vehicles and engines and their variation, depending on vehicle technologies (4, 6), the properties of fuels and lubricant oils (15, 16), and driving conditions (15-17). In addition to particles, exhaust typically contains species that reside in the gaseous phase in the undiluted high-temperature exhaust (5, 18, 19) but condense or even nucleate to the particle phase immediately after the exhaust is released to the atmosphere. Here, we term such aerosols delayed primary aerosols, because particle precursors exist already in the u...

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Section: Methodsmentioning

confidence: 99%

Traffic is a major source of atmospheric nanocluster aerosol

Rönkkö

Kuuluvainen

Karjalainen

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

203

132

View full text Add to dashboard Cite

show abstract

“…combustion process, but also by physical nucleation and condensation of gaseous hydrocarbons and sulfates during exhaust dilution. Recently, Mikkanen et al 8 and Wei et al 9,10 have discussed dilution strategies that specifically address nuclei mode formation.…”

Section: Introductionmentioning

confidence: 99%

A Constant-Volume Rapid Exhaust Dilution System for Motor Vehicle Particulate Matter Number and Mass Measurements

Maricq

Chase

et al. 2003

Journal of the Air & Waste Management Association

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“…The primary dilution of the exhaust was accomplished inside a porous tube (Dekati prototype), which was inserted directly into the tailpipe to minimize sampling losses. Detailed information about the diluter can be found in Mikkanen et al (2001). By controlling the temperature of the dilution air by means of a vortex cooler, the sample temperatures (T) were in the range of 34.7 • C±0.5 • C or 44.5 • C±0.5 • C, respectively.…”

Section: Samplingmentioning

confidence: 99%

Effect of organic compounds on nanoparticle formation in diluted diesel exhaust

2004

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Abstract. The nucleation of nanoparticles in the exhaust of a modern light-duty diesel vehicle was investigated on a chassis dynamometer. This laboratory study is focused on the influence of volatile organic compounds (VOCs) on nucleation of volatile nanoparticles. Different organic compounds were added to the dilution air of the particle sampling under different sampling conditions. Sample temperature and relative sample humidity were varied in a wide range. The number size distribution of the particles was measured with a scanning mobility particle sizer (SMPS) and showed significant differences in response to the added organic compounds. While the nucleation mode particles showed a large variation in concentration, the accumulation mode particles remained unchanged for all compounds. Depending on the functional group, organic compounds were capable of initiating and increasing (alcohols and toluene) or decreasing (acetone, aniline, and methyl tert-butyl ether (MTBE)) nucleation mode particles. Short volatile aliphatic hydrocarbons (hexane and cyclohexane) turned out to be without effect on nucleation of nanoparticles. Possible reasons for the differences are discussed.

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Sampling Method for Particle Measurements of Vehicle Exhaust

Cited by 53 publications

References 11 publications

Traffic is a major source of atmospheric nanocluster aerosol

Traffic is a major source of atmospheric nanocluster aerosol

A Constant-Volume Rapid Exhaust Dilution System for Motor Vehicle Particulate Matter Number and Mass Measurements

Effect of organic compounds on nanoparticle formation in diluted diesel exhaust

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