Towards traceable particle number concentration standard: Single charged aerosol reference (SCAR)

Yli-Ojanperä, Jaakko; Mäkelä, Jyrki M.; Marjamäki, Marko; Rostedt, Antti; Keskinen, Jorma

doi:10.1016/j.jaerosci.2010.04.012

Cited by 39 publications

(20 citation statements)

References 26 publications

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“…S4A, both the PSM and the CPC measured rather high concentrations, ∼10 6 /cm 3 at maximum. The actual counting instruments, CPC models 3775 and 3776, were concentration-calibrated in the laboratory after the field campaign based on the single charged aerosol reference (38). The calibration results were applied in the data analysis.…”

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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209

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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

209

132

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“…Thus, this increased extinction may cause overestimation of the imaginary part of the retrieved complex RI. These potential artifacts and consequent errors may be hindered by nebulizing lower bulk solution concentrations that produce narrower size distributions of particles with smaller size mode diameter, instruments designed for decreasing multiply charged particles concentration (Gupta et al 1989;Uin et al 2009;Yli-Ojanperä et al 2010), or by calculating the artifacts due to multiply charged particles and correcting the measured Q ext values as briefly described in the next section. Alternatively, reliable CRD-AS measurements can be conducted by generating a high concentration of larger particles (400-800 nm in diameter) as the fraction of multiply charged particles at these sizes is minimal because the formed aerosols do not usually contain many larger particles that would lead to doubly charged particles.…”

Section: Approachmentioning

confidence: 99%

An Approach for Faster Retrieval of Aerosols’ Complex Refractive Index Using Cavity Ring-Down Spectroscopy

Bluvshtein

Flores

Riziq

et al. 2012

Aerosol Science and Technology

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Cavity ring-down spectroscopy (CRD-S) is widely adapted for studying light extinction by aerosol in laboratory and field studies. The complex refractive index (RI) of an aerosol can be retrieved by finding the theoretical Mie theory curve that best fits the measured extinction efficiency for as many aerosol diameters as possible. In this study, we introduce a new retrieval approach for the complex RI of aerosols using extinction measurements at only two carefully selected size parameters. We show that for three model substances measured (ammonium sulfate, Suwannee river fulvic acid, and nigrosin) and for 22 other reanalyzed datasets, the "2-points" measurement approach enables the retrieval of complex refractive indices with comparable uncertainty to the traditional measurement and retrieval procedure. The advantages and disadvantages of the new approach are discussed.

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“…Above this, the multiple charging limits the precision. However, there are methods to limit this issue, for instance, an additional aerodynamic size selection (Romay-Novas and Pui 1988; Hillamo and Kauppinen 1991;Owen et al 2012) or modifications of the La Mer generator (Sinclair and La Mer 1948), which produce singly charged particles (Uin et al 2009;Yli-Ojanper€ a et al 2010;Yli-Ojanper€ a et al 2012). In 2012, Yli-Ojanper€ a et al successfully applied a modified La Mer generator and a DMA for producing singly charged calibration aerosol and for conducting a FCAE-based number concentration calibration up to 1 mm.…”

Section: Introductionmentioning

confidence: 99%

Extending the Faraday cup aerosol electrometer based calibration method up to 5 µm

Järvinen

Keskinen

Yli-Ojanperä

2018

Aerosol Science and Technology

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A Faraday cup aerosol electrometer based electrical aerosol instrument calibration setup from nanometers up to micrometers has been designed, constructed, and characterized. The setup utilizes singly charged seed particles, which are grown to the desired size by condensation of diethylhexyl sebacate. The calibration particle size is further selected with a Differential Mobility Analyzer (DMA). For micrometer sizes, a large DMA was designed, constructed, and characterized. The DMA electrical mobility resolution was found to be 7.95 for 20 L/min sheath and 2 L/min sample flows. The calibration is based on comparing the instrument's response against the concentration measured with a reference Faraday cup aerosol electrometer. The setup produces relatively high concentrations in the micrometer size range (more than 2500 1/cm 3 at 5.3 mm). A low bias flow mixing and splitting between the reference and the instrument was constructed from a modified, large-sized mixer and a four-port flow splitter. It was characterized at different flow rates and as a function of the particle size. Using two of the four outlet ports at equal 1.5 L/min flow rates, the particle concentration bias of the flow splitting was found to be less than ±1% in the size range of 3.6 nm-5.3 mm. The developed calibration setup was used to define the detection efficiency of a condensation particle counter from 3.6 nm to 5.3 mm with an expanded measurement uncertainty (k ¼ 2) of less than 4% over the entire size range and less than 2% for most of the measurement points.

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Towards traceable particle number concentration standard: Single charged aerosol reference (SCAR)

Cited by 39 publications

References 26 publications

Traffic is a major source of atmospheric nanocluster aerosol

Traffic is a major source of atmospheric nanocluster aerosol

An Approach for Faster Retrieval of Aerosols’ Complex Refractive Index Using Cavity Ring-Down Spectroscopy

Extending the Faraday cup aerosol electrometer based calibration method up to 5 µm

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