PMID- 22624357
OWN - NLM
STAT- MEDLINE
DCOM- 20130809
LR  - 20181201
IS  - 0250-3301 (Print)
IS  - 0250-3301 (Linking)
VI  - 33
IP  - 3
DP  - 2012 Mar
TI  - [Particle number size distribution near a major road with different traffic 
      conditions].
PG  - 694-700
AB  - The profiles of number concentration of ambient particles at a roadside site in 
      Beijing were studied with different traffic conditions. A Scanning Mobility 
      Particle Sizer (SMPS) was utilized to measure the number concentrations of fine 
      and ultrafine (10-100 nm) particles in August 2008 and August 2009, which 
      represented the normal and Olympic traffic conditions, respectively. Size 
      distributions of particle number concentration were identified and their temporal 
      variations were also discussed. Results indicated that with normal traffic 
      pattern, the total number concentration of ultrafine and 10-478 nm particles were 
      (1.15 +/- 0.49) x 10(4) cm(-3) and (1.61 +/- 0.57) x 10(4) cm(-3), respectively. 
      While the concentrations were decreased to (0.55 +/- 0.14) x 10(4) cm(-3) and 
      (1.21 +/- 0.24) x 10(4) cm(-3), respectively, with special traffic condition 
      during the Beijing Olympic Games. Largest reduction of 52.2% was observed for 
      ultrafine particles among all size ranges. With normal traffic condition, bimodal 
      distribution was found with two peak values in number concentrations around 22.5 
      nm and 113.0 nm. During the Olympic period, nucleation mode particles were 
      significantly reduced due to a series of temporal control measures on motor 
      vehicles such as the removal of yellow-labeled vehicles from the roads and travel 
      restrictions based on odd-even license plate numbers. As a result, the peak in 
      particle number concentration at 22.5 nm disappeared. The temporal variation 
      indicated that significantly higher ultrafine particle number concentrations 
      occurred around 00 : 00-04 : 00, 11 : 00-13 : 00 and 17 : 00-20 : 00 with normal 
      traffic situation, which primarily attributed to the contributions of diesel 
      exhaust at night, secondary formation at noon and traffic jam in the evening, 
      respectively. However during the Olympic period, the temporal variation pattern 
      changed significantly. The gap in the number concentrations of ultrafine particle 
      between these three time periods and other time periods were narrowed, which 
      should be attributed to the reduction of traffic flow as well as the increase of 
      fleet speed during the Olympics.
FAU - Yang, Liu
AU  - Yang L
AD  - School of Environment, Tsinghua University, Beijing 100084, China. 
      yang-l@mails.tsinghua.edu.cn
FAU - Wu, Ye
AU  - Wu Y
FAU - Song, Shao-Jie
AU  - Song SJ
FAU - Hao, Ji-Ming
AU  - Hao JM
LA  - chi
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - China
TA  - Huan Jing Ke Xue
JT  - Huan jing ke xue= Huanjing kexue
JID - 8405344
RN  - 0 (Air Pollutants)
RN  - 0 (Particulate Matter)
RN  - 0 (Vehicle Emissions)
SB  - IM
MH  - Air Pollutants/*analysis
MH  - Air Pollution/prevention & control
MH  - Atmosphere
MH  - China
MH  - Cities
MH  - *Environmental Monitoring
MH  - Particle Size
MH  - Particulate Matter/*analysis
MH  - Sports
MH  - Vehicle Emissions/*analysis
EDAT- 2012/05/26 06:00
MHDA- 2013/08/10 06:00
CRDT- 2012/05/26 06:00
PHST- 2012/05/26 06:00 [entrez]
PHST- 2012/05/26 06:00 [pubmed]
PHST- 2013/08/10 06:00 [medline]
PST - ppublish
SO  - Huan Jing Ke Xue. 2012 Mar;33(3):694-700.