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Student : Shen-Feng Chang Advisor : Yi-Chyun Hsu

Aircraft measurements of O 3 , NO x , CO, VOCs, and SO 2 in the Yangtze River Delta region. Student : Shen-Feng Chang Advisor : Yi-Chyun Hsu. Atmospheric Environment 43 (2009) 584–593 journal homepage: www.elsevier.com/locate/atmosenv. Introduction Description of the measurements

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Student : Shen-Feng Chang Advisor : Yi-Chyun Hsu

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  1. Aircraft measurements of O3, NOx, CO, VOCs, and SO2 in the Yangtze River Delta region Student : Shen-Feng Chang Advisor :Yi-Chyun Hsu Atmospheric Environment 43 (2009) 584–593 journal homepage: www.elsevier.com/locate/atmosenv

  2. Introduction • Descriptionofthemeasurements • Analysisoftheresult

  3. Introduction (1/3) • The Yangtze River Delta (YRD) region located in • east China (with longitude from 120°E to 121°E, • and latitude from 30.5°N to 31.5°N) is highly • urbanized with a cluster of large cities (including • Shanghai, Hangzhou, Shuzhou, Wuxi, etc.). • Among these large cities, Shanghai has the highest • population in China (about 20 millions). • During the past 20 years, this region is undergoing • a rapid increase in economical development.

  4. Introduction (2/3) • The GDP has increased by 500% from 1996 • to 2006, accounting for more than 5% of the • total GDP in China. • The rapid urbanization causes wide-ranging • potential consequences for weather and climate • related to urban environments, such as air • pollutions. • Like other large cities in east China, Shanghai • is suffering severe air pollution problems, such • as high particular matter (PM) concentrations • and poor visibility.

  5. Introduction (3/3) • As industrial activities and the number of • automobiles increase together with the changes • in natural activities (such as vegetation and • forest), emission of VOCs and NOx will • significantly increase in the YRD region. • Both VOCs and NOx play critical roles during • O3 formation in the troposphere. • Several studies regarding the air quality in the • YRD region have been conducted.

  6. Descriptionofthemeasurements (1/2) • Fig. 1 displays the horizontal routes for several • representative flights. • It shows that the flight routes are located in west • side of the megacity (Shanghai) with several large • cities, such as Suzhou, Wuxi and Jiading. • In addition, there are several large power plants • in this region. For example, the Changshou • power plant generates 1200MW per year.

  7. Descriptionofthemeasurements (2/2) • There are totally five flights between • September/30 and October/11 (flight-1 on • September/30, flight-2 on October/2, flight-3 • on October/5, flight-4 on October/9, and • flight-5 on October/11), which are analyzed • in this study. • There are also several inter-state high ways, • and high density of small towns and villages. • As a result, the local emissions of air pollutants • from automobiles, and area and point sources • are intensive.

  8. Analysisoftheresult (1/2) • Both the O3 mean values are generally lower • than the US national standard values (84 ppbv), • suggesting that the O3 values are modest in the • YRD region. • The NOx concentrations have large variability, • ranging from 3 to 40 ppbv. • The highest concentrations of NOx are observed • normally in the NCITY case, ranging from 10 • to 40 ppbv.

  9. Analysisoftheresult (2/2) • The SO2 concentrations also have a large • variability, ranging from 1 to 35 ppbv. • The highest concentrations of SO2 are measured • in the NCITY case, ranging from 7 to 35 ppbv. • The CO concentrations are relatively high, • and have smaller variability compared to • NOx and SO2, ranging from 3 to 7 ppmv.

  10. The results are summarized in the follows: • (1) The measured O3 concentrations range from 20 • to 60 ppbv. • These values are normally below the US national • standard (84 ppbv), suggesting that at the present, • the O3 pollutions are modest in this region. • The NOx concentrations have a large variability, • ranging from 3 to 40 ppbv. • The SO2 concentrations have very large variability, • ranging from 1 to 35 ppbv.

  11. The CO concentrations are relatively high, and • have less variability, ranging from 3 to 7 ppmv. • The concentrations of VOCs are relatively small, • with the total VOC concentration of 6 ppbv. • Among the total VOCs, alkanes have highest • values (2.8 ppbv). • (2) The relatively small VOC concentrations and • large NOx concentrations indicate that the O3 • chemical formation is under “VOC-limited” • regime in the YRD region.

  12. The measured O3 and NOx concentrations are • strongly anti-correlated, suggesting that • enhancements in NOx concentrations lead to • decrease in O3 concentrations. • (3) The O3 concentrations are more sensitive to • NOx concentrations in the rural PBL region • than in the city region. • This result suggests that changes in NOx emissions • could have strong effects on O3 concentrations in • rural areas of the YRD region.

  13. (4) The O3-isopleth diagram study shows • that the O3 concentrations could increase • rapidly with increase in VOC concentrations • in the YRD region. • For example, if the VOC concentrations • increase to 75 ppbC in the future, O3 • concentrations could exceed to 84 ppbv, • which is normally considered as the • national standard for human’s health.

  14. Thank you for your attention!

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