The Vertical Distribution and Stratification of VOC in the Atmosphere at Kaohsiung Area

1. 2012 International Conference on Environmental Quality Concern, Control and Conservation (EQC 2012) National Kaohsiung Marine University Department of Marine Environmental Engineering The Vertical Distribution and Stratification of VOC in the Atmosphere at Kaohsiung Area Chia-Chun Cheng1*, Ying-Hui Kao1, Chitsan Lin2, Chung-Hsin Yuan3, Chung-Hsuan Hung4 1Graduate Student of the Department of Marine Environmental Engineering, National Kaohsiung Marine University, Kaohsiung 81157, Taiwan. 2Professor of the Department of Marine Environmental Engineering, National Kaohsiung Marine University, Kaohsiung 81157, Taiwan. 3Professor of the Institute of Environmental Engineering, National Sun Yat-sen University, Kaohsiung 80424, Taiwan. 4Assistant Professor of the Department of Safety Health and Environmental Engineering, Kaohsiung First University of Science and Technology, Kaohsiung 81164, Taiwan. May, 25-26 2011 1

2. Outline 2

3. Introduction • Many factories were crowded in Kaohsiung, such as refinery,industrial zones andexport processing zones...etc. Moreover, manychimneysandburning towers result in serious VOCsemissions and might harmful for nearby residential area. The VOCsis not easy to proliferate. This cause air pollutants to accumulate in specific weather conditions. • TheVOCswill harm the human health. When it release to the atmosphere by photochemical reactions, which produce highly toxic secondary pollutants, for exampleozone,peroxyacetylnitrate (PAN) andphotochemical smog. 3

4. Currently, all ozone air qualityimprovement strategies always takeair quality model (AQM) as standard, the atmosphere of VOCs was assumed by the AQM which in the vertical height is uniformly mixed. But in recently, some researchers have shows layered distribution of VOCs in the atmosphere. • The VOCs concentration distribution and stratification in the atmosphere will be affected by weather conditions (such as mixing layer height variation orinversion layer form),season,time,space,vertical height...etc. 4

5. Purpose In this study, we would investigate vertical distribution of volatile organic compounds to Kaohsiung area. • To prove the stratification of VOC exists and exploration the stratification period and height. • To prove the VOCs species of photochemical reacts in different high level, Maximum Incremental Reactivity (MIR). 5

6. Sampling Site • Material and method Sampling time：August, 2010 (summer) and February, 2011 (winter) 12:00, 18:00, 00:00, 06:00 Sampling height：Ground, 100, 200, 300, 400, 500, 600, 700 and 800m. NKMU WFES Sampling Location 6

7. Sampling Method The tethered balloon collected the VOCs samples from the atmosphere. A pump was connected to a 10 L sampling bag. The samples were immediately transferred into a stainless canister to ensure the accuracy of the data. 7

8. Analysis Method Mass Spectrometry Detector (MSD) HP 5973 Auto sampler Entech 7016 Pre-concentrated Entech 7100 Gas-chromatography (GC) HP 6890 Urban Air Toxics (UAT)and Photochemical Assessment Monitoring System(PAMS) Taiwan EPA NIEA A715.13B 8

9. Standard gas patterns Can be analysis 101 kinds of compounds. UAT PAMS 9

10. The definition ofstratification • Results and discussions Relationship between vertical VOCs and stratification Occurrence periods of stratification Ozone Formation Potential 10

11. The definition ofstratification Height Conc. stratification non- stratification The stratification means concentration of pollutants increase or decrease suddenly in high altitude. However the concentration of pollutants with stable change is non-stratification. 11

12. Relationship between vertical VOCs and stratification Summer Winter Height (m) Height (m) Conc. (ppbv) Conc. (ppbv) • In summer, the pollutants are accumulating in 100m, 400m and 700m. • Especially, ground with high conc. at 18:00.With increasing height and decreasing, but there are lower conc. at 300m and 800m. • In winter, the pollutants are accumulating between 400m to 600m. • There are lowest conc. at 300 and 700m, but it was increased over 800m. 12

13. NKMU WFES Height (m) Height (m) Conc. (ppbv) Conc. (ppbv) • In NKMU station, pollutants almost accumulate at 400m to 500m, and it was decrease at 600m. • Ground conc. is higher than other time in 18:00. • In WFESstation, there is not observable stratification at 12:00. • Almost conc. are decrease at 700m, but it was increased over 800m. 13

14. Occurrence periods of stratification 87.5% Summer • The probability of stratification is 87.5% in summer. • The occur time in summer is 12:00 and height at 700m. 14

15. 75% Winter • The probability of stratification is 75% in winter. • The occur time in winter is 00:00 and height at 400m. 15

16. 75% NKMU 50% WFES • From different stations, NKMU probability of occur stratification around 75% at 400-500m, occurrence time are 12:00 and 00:00. • WFES probability of occur stratification around 50% under 200m, occurrence time is 00:00. 16

17. Ozone Formation Potential Thus, we going to discussing if stratification occurs will cause ozone formation. • This study follow as the Carter (1994) MIR photochemical reactivity index, and select a higher detection rate of compounds to estimate the ozone formation potential in various periods. • Alkanes：Hexane, Isopentane, Undecane, Dodecane • Alkene：Propene, 1-Butene, Styrene • Aromatic hydrocarbon：Benzene, Toluene, Ethylbenzene, m/p-Xylene, 1,3,5-Trimethylbenzene, 1,2,4-Trimethylbenzene • Aldehydes and ketones：Acetone 17

18. Ozone Formation Potential of different season and time. • Summer with highest ozone formation potential at 18:00, and main compounds are 1,3,5-Trimethylbenzeneand m/p-Xylene. • Winter with highest ozone formation potential at 12:00, and main compounds are Toluene and m/p-Xylene. 18

19. Ozone Formation Potential of different season and height. • Summer with highest ozone formation potential at 400m and 700m, the main compounds are 1,3,5-Trimethylbenzeneand m/p-Xylene. • Winter with highest ozone formation potential at ground and 500m, the main compounds are Tolueneand m/p-Xylene. 19

20. From the vertical variation of VOCs conc. shows there exist stratification in atmosphere certainly. • In summer, most pollutants were accumulate about 100m and 700m.And accumulate from 400m to 600m in winter. • The probabilities of stratification are 87.5% in summer and 70% in winter. • The occur time is 12:00 at the height of 700m in summer, and in winter is 00:00 at the height of 400m. • Conclusions • From different stations, NKMU probability of occur stratification around 75% at 400-500m, occurrence time are 12:00 and 00:00. • WFES probability of occur stratification around 50% under 200m, occurrence time is 00:00. 20

21. With photochemical reactivates, the highest ozone formation potential in 18:00 at summer and in 12:00 at winter, the main compound is 1,3,5-Trimethylbenzene. • The highest ozone formation potential at 400m and 700m in summer with ground and 500m in winter, the main compound is m/p-Xylene. • Our study indicates the occurrence of stratification at lower height in summer and at 500m in winter with highest ozone formation potential. • Therefore, we suspect occurrence of stratification usually accompany the ozone formation. But we need further research to confirm. 21

22. 2012 International Conference on Environmental Quality Concern, Control and Conservation (EQC 2012) National Kaohsiung Marine University Department of Marine Environmental Engineering Thanks for your attention