Particle number size distributions in a street canyon and their transformation into the urban-air background: measurements and a simple model study

Wehner, B.; Birmili, W.; Gnauk, T.; Wiedensohler, Alfred

doi:10.1016/s1352-2310(02)00174-7

Cited by 247 publications

(158 citation statements)

References 25 publications

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“…Figure 6 shows that both distributions were dominated by small, probably nucleation originated particles with a peak size of approximately 20 nm. Similar observation was also reported by Wehner and Wiedensohler (2003) and Ketzel et al (2004). Multimodal lognormal distribution was fitted to the measured distributions to enable the particle density calculation procedure described above.…”

Section: Characteristics Of Road-side Distributionssupporting

confidence: 53%

“…In the winter time the concentration peaking was a bit stronger during the morning rush hours than during evening rush hours. Williams et al (2000), Molnár et al (2002), Wehner et al (2002), Charron and Harrison (2003), and Janhäll et al (2004) observed stronger concentration peaks during the morning rush hour. Wehner et al associated the higher morning concentrations with the higher truck traffic rate.…”

Section: Correlation Of Particle Emissions and Traffic Ratementioning

confidence: 92%

“…Ketzel et al (2004) found that the traffic related distributions peaked at 22 nm in the centre of Copenhagen. In addition, Wehner and Wiedensohler (2003) reported the peak in the urban number size distribution around 20 nm. They also found the additional mode peaking at 10-15 nm during the summer time.…”

Section: Characteristics Of Road-side Distributionsmentioning

confidence: 99%

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Winter and summer time size distributions and densities of traffic-related aerosol particles at a busy highway in Helsinki

et al. 2006

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Abstract. Number concentrations and size distributions of traffic related aerosol particles were measured at a roadside in Helsinki during two winter campaigns (10-26 February 2003, 28 January-12 February 2004 and two summer campaigns (12-27 August 2003, 6-20 August 2004. The measurements were performed simultaneously at distances of 9 m and 65 m from the highway. Total number concentrations were measured by a condensation particle counter (CPC) and particle size distributions by a scanning mobility particle sizer (SMPS) and an electrical low pressure impactor (ELPI). This study concentrates on data that were measured when the wind direction was from the road to the measurement site. The total concentrations in the wintertime were 2-3 times higher than in the summertime and the concentrations were dominated by nucleation mode particles. The particles smaller than 63 nm (aerodynamic diameter) constituted ∼90% of all particles in the wintertime and ∼80% of particles in the summer time. The particle total concentration increased with increasing traffic rate. The effect of traffic rate on particles smaller than 63 nm was stronger than on the larger particles. The particle distributions at the roadside consisted of two distinguishable modes. The geometric mean diameter (GMD) of nucleation mode (Mode 1) was 20.3 nm in summer and 18.9 nm in winter. The GMD of the larger mode consisting mostly of traffic related soot particles (Mode 2) was 72.0 nm in summer and 75.1 nm in winter. The GMD values of the modes did not depend on the traffic rate. The average particle density for each mode was determined by a parallel density fitting method based on the size distribution measurement made by ELPI and SMPS. The average density value for Mode 1 particles Correspondence to: A. Virtanen (annele.virtanen@tut.fi) was 1.0±0.13 g/cm 3 and 1.0±0.07 g/cm 3 both in summer and winter respectively, while the average density value for Mode 2 was 1.5±0.1 g/cm 3 and 1.8±0.3 g/cm 3 for summer and winter, respectively.

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Section: Characteristics Of Road-side Distributionssupporting

confidence: 53%

Section: Correlation Of Particle Emissions and Traffic Ratementioning

confidence: 92%

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Winter and summer time size distributions and densities of traffic-related aerosol particles at a busy highway in Helsinki

et al. 2006

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“…The average was lower than that of 418/Mm measured in winter 2004 in Guangzhou (Andreae et al, 2008), and also lower than that of 473/Mm observed at an urban site in Guangzhou during fall 2009 (Tao et al, 2014b), probably due to a large amount of ultrafine/fine particle from vehicles in the urban areas (Wehner et al, 2002;Dai et al, 2015;Zhang et al, 2015). Average b sp values also were revealed to be relatively higher in China's densely populated city clusters, such as 312/Mm over a rural area near the Beijing mega-city in 2006 (Pan et al, 2009), 456/Mm during winter 2010 in Shanghai in the Yangtze River Delta region (Xu et al, 2012), and 293/Mm in 2011 in Chengdu, a mega-city in southwest China (Tao et al, 2014a).…”

Section: Visibility and Pm 25 Mass Concentrationscontrasting

confidence: 62%

Changes in visibility with PM2.5 composition and relative humidity at a background site in the Pearl River Delta region

Wang

et al. 2016

Journal of Environmental Sciences

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“…Wehner et al 67 measured UFPM in a street canyon in Leipzig, Germany, with TDMA and CPC instruments. They found ambient concentrations in excess of 10 5 cm…”

Section: Evolution Of Ufpm In the Atmospherementioning

confidence: 99%

Current Understanding of Ultrafine Particulate Matter Emitted from Mobile Sources

Seigneur

2009

Journal of the Air & Waste Management Association

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The physics and chemistry of ultrafine particulate matter (UFPM) associated with mobile source emissions is reviewed. UFPM includes those particles that are less than 0.1 m in diameter. Measurements of UFPM emitted from mobile sources have been conducted in the laboratory, on roadways, and downwind of roadways. In addition, UFPM formation and evolution have been modeled and the modeling results have been compared with available measurements. The results of those measurement programs and modeling studies are synthesized into a coherent description of the formation of UFPM in mobile source emissions and its subsequent evolution in the ambient atmosphere. Recommendations are provided to address the gaps in our current understanding of the processes leading to the formation of UFPM, its chemical composition, and its evolution in the atmosphere.

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Particle number size distributions in a street canyon and their transformation into the urban-air background: measurements and a simple model study

Cited by 247 publications

References 25 publications

Winter and summer time size distributions and densities of traffic-related aerosol particles at a busy highway in Helsinki

Winter and summer time size distributions and densities of traffic-related aerosol particles at a busy highway in Helsinki

Changes in visibility with PM2.5 composition and relative humidity at a background site in the Pearl River Delta region

Current Understanding of Ultrafine Particulate Matter Emitted from Mobile Sources

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