scholarly journals Hotspot of glyoxal over the Pearl River delta seen from the OMI satellite instrument: implications for emissions of aromatic hydrocarbons

2016 ◽  
Vol 16 (7) ◽  
pp. 4631-4639 ◽  
Author(s):  
Christopher Chan Miller ◽  
Daniel J. Jacob ◽  
Gonzalo González Abad ◽  
Kelly Chance
Keyword(s):  
Pearl River Delta ◽  
Transport Model ◽  
Southern China ◽  
River Delta ◽  
Pearl River ◽  
Emission Inventories ◽  
Ozone Monitoring Instrument ◽  
The Pearl River Delta ◽  
Volatile Organic ◽  
The Pearl River

Abstract. The Pearl River delta (PRD) is a densely populated hub of industrial activity located in southern China. OMI (Ozone Monitoring Instrument) satellite observations reveal a large hotspot of glyoxal (CHOCHO) over the PRD that is almost twice as large as any other in Asia. Formaldehyde (HCHO) and NO2 observed by OMI are also high in the PRD but no more than in other urban/industrial areas of China. The CHOCHO hotspot over the PRD can be explained by industrial paint and solvent emissions of aromatic volatile organic compounds (VOCs), with toluene being a dominant contributor. By contrast, HCHO in the PRD originates mostly from VOCs emitted by combustion (principally vehicles). By applying a plume transport model to wind-segregated OMI data, we show that the CHOCHO and HCHO enhancements over the PRD observed by OMI are consistent with current VOC emission inventories. Prior work using CHOCHO retrievals from the SCIAMACHY satellite instrument suggested that emission inventories for aromatic VOCs in the PRD were too low by a factor of 10–20; we attribute this result in part to bias in the SCIAMACHY data and in part to underestimated CHOCHO yields from oxidation of aromatics. Our work points to the importance of better understanding CHOCHO yields from the oxidation of aromatics in order to interpret space-based CHOCHO observations in polluted environments.

scholarly journals Hotspot of Glyoxal Over the Pearl River Delta Seen from the OMI Satellite Instrument: Implications for Emissions of Aromatic Hydrocarbons

2016 ◽  
Author(s):  
Christopher Chan Miller ◽  
Daniel J. Jacob ◽  
Gonzalo González Abad ◽  
Kelly Chance
Keyword(s):  
Aromatic Hydrocarbons ◽  
Pearl River Delta ◽  
Transport Model ◽  
Southern China ◽  
River Delta ◽  
Pearl River ◽  
Emission Inventories ◽  
The Pearl River Delta ◽  
Volatile Organic ◽  
The Pearl River

Abstract. The Pearl River Delta (PRD) is a densely populated hub of industrial activity located in southern China. OMI satellite observations reveal a large hotspot of glyoxal (CHOCHO) over the PRD that is almost twice as large as any other in Asia. Formaldehyde (HCHO) and NO2 observed by OMI are also high in the PRD but no more than in other urban/industrial areas of China. The CHOCHO hotspot in the PRD can be explained by industrial paint and solvent emissions of aromatic volatile organic compounds (VOCs), with toluene being a dominant contributor. By contrast, HCHO in the PRD originates mostly from VOCs emitted by combustion (principally vehicles). By applying a plume transport model to wind-segregated OMI data, we show that the CHOCHO and HCHO enhancements over the PRD observed by OMI are consistent with current VOC emission inventories. Prior work using CHOCHO retrievals from the SCIAMACHY satellite instrument suggested that aromatic VOC emissions in the PRD were too low by a factor of 10-20; we attribute this result in part to bias in the SCIAMACHY data and in part to underestimated CHOCHO yields from oxidation of aromatics. Our work points to the importance of better understanding CHOCHO yields from the oxidation of aromatics in order to interpret CHOCHO observations from space.

scholarly journals Observation and modelling of OH and HO<sub>2</sub> concentrations in the Pearl River Delta 2006: a missing OH source in a VOC rich atmosphere

2011 ◽  
Vol 11 (4) ◽  
pp. 11311-11378 ◽  
Author(s):  
K. D. Lu ◽  
F. Rohrer ◽  
F. Holland ◽  
H. Fuchs ◽  
B. Bohn ◽  
...  
Keyword(s):  
Pearl River Delta ◽  
Southern China ◽  
River Delta ◽  
Rural Site ◽  
Pearl River ◽  
Recycling Process ◽  
Mixing Ratios ◽  
Suburban Areas ◽  
The Pearl River Delta ◽  
The Pearl River

Abstract. Ambient OH and HO2 concentrations were measured by laser induced fluorescence (LIF) during the PRIDE-PRD2006 (Program of Regional Integrated Experiments of Air Quality over the Pearl River Delta, 2006) campaign at a rural site downwind of the megacity of Guangzhou in Southern China. The observed OH concentrations reached daily peak values of (15–26) × 106 cm−3 which are among the highest values so far reported for urban and suburban areas. The observed OH shows a consistent high correlation with j(O1D) over a broad range of NOx conditions. The correlation cannot be reproduced by model simulations, indicating that OH stabilizing processes are missing in current models. The observed OH exhibited a weak dependence on NOx in contrast to model predictions. While modelled and measured OH agree well at NO mixing ratios above 1 ppb, a continuously increasing underprediction of the observed OH is found towards lower NO concentrations, reaching a factor of 8 at 0.02 ppb NO. A dependence of the modelled-to-measured OH ratio on isoprene cannot be concluded from the PRD data. However, the magnitude of the ratio fits into the isoprene dependent trend that was reported from other campaigns in forested regions. Hofzumahaus et al. (2009) proposed an unknown OH recycling process without NO, in order to explain the high OH levels at PRD in the presence of high VOC reactivity and low NO. Taking a recently discovered interference in the LIF measurement of HO2 into account, the need for an additional HO2 → OH recycling process persists, but the required source strength may be up to 20% larger than previously determined. Recently postulated isoprene mechanisms by Lelieveld et al. (2008) and Peeters and Müller (2010) lead to significant enhancements of OH expected for PRD, but an underprediction of the observed OH by a factor of two remains at low NO (0.1–0.2 ppb). If the photolysis of hydroperoxy aldehydes from isoprene is as efficient as proposed by Peeters and Müller (2010), the corresponding OH formation at PRD would be more important than the primary OH production from ozone and HONO. While the new isoprene mechanisms need to be confirmed by laboratory experiments, there is probably need for other, so far unidentified chemical processes to explain entirely the high OH levels observed in Southern China.

Bulk organic δ13C and C/N as indicators for sediment sources in the Pearl River delta and estuary, southern China

2010 ◽  
Vol 87 (4) ◽  
pp. 618-630 ◽  
Author(s):  
Fengling Yu ◽  
Yongqiang Zong ◽  
Jeremy M. Lloyd ◽  
Guangqing Huang ◽  
Melanie J. Leng ◽  
...  
Keyword(s):  
Pearl River Delta ◽  
Southern China ◽  
River Delta ◽  
Pearl River ◽  
Sediment Sources ◽  
The Pearl River Delta ◽  
The Pearl River
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