Characterization of ozone precursors in the Pearl River Delta by time series observation of non-methane hydrocarbons Atmospheric Environment 42 (2008) 6233–6246 Jia-Lin Wanga, Chieh-Heng Wanga, Cheng-Hsun Laia, Chih-Chu ng Changb, Ying Liuc, Yuanhang Zhangc, Shaw Liub, Min Shao
Characterization of ozone precursors in the Pearl River Delta by time series observation of non-methane hydrocarbons. Atmospheric Environment 42 (2008) 6233–6246 Jia-Lin Wanga, Chieh-Heng Wanga, Cheng-Hsun Laia, Chih-Chung Changb, Ying Liuc, Yuanhang Zhangc, Shaw Liub, Min Shao. - PowerPoint PPT Presentation
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Characterization of ozone precursors in the Pearl River Delta by time series observation
Guangzhou (urban) and Xinken (rural) in the Pearl River Delta, China.
Site description
From 16 October to 5 November in 2004
Guangzhou
• urban center of Guangzhou city
• about 55m above ground
• wind direction : NNE and NNW
Xinken
• rural area
• about 10m height
• wind direction : NE and N
※ ES sea breeze was observed in late afternoon.
Instrumentation
Guangzhou : Time-series observation of propane, toluene, isoprene
Guangzhou : Time-series observation of VOC (TVOC), CO, and NO
Xinken: Time-series observation of propane, toluene, isoprene
Xinken: Time-series observation of VOC (TVOC), CO, and NO
Surface windflow patterns andPBL heights (m) over the PRD
Guangzhou & Xinken
Top 10 NMHCs ranked by their concentration ranges (ppbv)
isoprene versus 3-methylpentane
hourly averaged concentration of three categories of NMHCs
Composition of NMHCs
• LPG-related species : propane, n-butane, and iso-butane
• Guangzhou
• 58% of total alkanes , 35% of total VOC
• Xinken
• 42% of total alkanes , 22% of total VOC
Car exhaustFuel/solvent evaporation
ethylbenzene versus m,p-xylene
conclusion
• Diurnal patterns and correlation between the concentrations of NMHCs, NO, and CO suggest that vehicle exhaust is the dominant source of ozone precursors in Guangzhou.
• A large portion of NMHCs in Guangzhou is found to be related to LPG used as fuel for motor vehicles.
• The use of PCA and E/X as age indicator reveals that the air masses observed in Xinken are well aged and photochemically processed, which explains the high level of ozone frequently observed in the coastal areas of PRD such as Xinken.