Yi-Shiu Jen 1, Chung-Shin Yuan 1, Yuan-Chung Lin 1, Chang-Gai Lee 2. Institute of Environmental Engineering, National Sun Yat-sen University 2

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1 Tempospatial Partition of Gaseous Elemental Mercury (GEM) and Particulate Mercury (PM) at Background and Heavily Polluted Urban Sites in Kaohsiung City Yi-Shiu Jen 1, Chung-Shin Yuan 1, Yuan-Chung Lin 1, Chang-Gai Lee 2 1, 2 Department of Environmental Resource Management, Tajen University A&WMA International Specialty Conference May 10-14, 2010, Xi an, China 1

2 Introduction (1/2) Atmospheric mercury has been claimed by UNEP as the second global environmental issue followed greenhouse gases (GHGs), thus many countries are becoming increasingly concerned about atmospheric mercury pollution recently. The emission of mercury from natural sources is about 2,000 tons/yr; while the emission of mercury from anthropogenic sources, mainly coal-fired power plants and waste incinerators, accounts for approximately 4,000 tons/yr (UNEP, 2003). Mercury and its compounds are produced from two major sources, including natural and anthropogenic sources. Major form of mercury is gaseous elemental mercury (GEM), particulate mercury (PM), reactive gaseous mercury (RGM), and gaseous methyl-mercury are relatively low. 2

3 Introduction (2/2) Hg 0 has high volatility, low chemical reactivity, and low solubility in water, which accounts for more than 95% of total gaseous mercury (TGM) and has a yr residence time in the atmosphere, while Hg 2+ is abundant in the particulate and aqueous phases, and is also known as reactive mercury. Mercury is an important global pollutant, which is recorded as a persistent and bio-accumulated toxic pollutant by UNEP and EU. It causes permanent injuries mainly on the brain and the nerve system. Very few literatures have quantitatively addressed the issue of atmospheric mercury pollution in Taiwan, particularly for such a highly polluted region as in metro Kaohsiung. 3

4 Global Mercury Cycle 4

5 Biogeochemical Mercury Cycle 5

6 Global Mercury Emission Map (ton) 6

7 Asia Mercury Emission Map (2008) 7

8 Global Anthropogenic Mercury Emission in the Year of 2003 Continent Stationary combustion Non-ferrous metal production Pig iron and steel production Cement production Waste disposal Total Europe Africa Asia North America South America Australia and Oceania Total

9 Global Anthropogenic Mercury Emission from Different Sectors Sector Coal consumption (10 4 ton) Hg into atmosphere (ton) Hg into cinder (ton) Farming, forestry, animal husbandry, fishery Industry Mining mineral products Manufacturing Nonmetal mineral products Smelting and pressing of ferrous metal Raw chemical materials and products Other manufacturing Electric power Construction Transportation, postal, & elecommunications Wholesale, retail trade, and catering services Others Residential consumption Total consumption

10 Concentration and Speciation of Atmospheric Mercury in USA Sampling Sites GEM (ng/m 3 ) RGM (pg/m 3 ) PM (pg/m 3 ) CBL, Maryland Curtis Creek, Maryland Hart-Miller Island, Maryland Northern Chesapeake Bay, Maryland Science Center, Maryland Stillpond, Maryland Tennessee N.A. Indiana N.A. Northern Wisconsin N.A Florida N.A Detroit, Michigan N.A. N.A Rural Michigan N.A. N.A

11 Objectives Conduct the field sampling and chemical analysis of atmospheric mercury in Kaohsiung City. Investigate the tempospatial variation and partition of GEM and PM concentrations for background, urban, and polluted sites, respectively. Compare the concentration of GEM and PM in Kaohsiung City with other Asian cities. 11

12 Methodologies 12

13 Sampling Sites of Atmospheric Mercury in Kaohsiung City B1: National Kaohsiung First University B2: National Sun Yet-sen University U1: Chein-chin air quality monitoring station U2: Hsiao-kang air quality monitoring station P1: Ren-wu high school P2: Guan-yin elementary school P3: Deng-fa elementary school 13

14 Sampling Method of Atmospheric Mercury (NIEA A304.10C) Atmospheric mercury was continuously sampled by NIEA A304.10C (Taiwan), similar to USEPA Method IO-5, at each sampling site for 24 hours in the spring and winter of 2008, the most polluted seasons, in Kaohsiung City. Gaseous mercury was captured onto the surface of goldcoated sands through the amalgamation with a constant air flow of 0.3 L/min. Particulate mercury was collected on the filters with a constant air flow of 30 L/min. 14

15 Sampling Apparatus of Atmospheric Mercury Gaseous Hg sampling Particulate Hg sampling Q=0.3 L/min Q=30 L/min 15

16 Gold-coated Sand Trap Heater (30-40 ) Gold-coated sand (Second) Air in Air out Gold-coated sand (First) 16

17 Analysis of Atmospheric Mercury (CVAFS) After sampling, the adsorbed GEM on gold-coated sands was initially desorbed at and further measured with a cold vapor atomic fluorescence spectrometer (CVAFS). PM collected on the filters was initially digested by oxidizing mercury to Hg 2+ with BrCl and further reducing to Hg 0 with SnCl 2. Finally, the solution was purged with Ar (g) and Hg 0 was captured onto the surface of gold-coated sands and further measured with the CVAFS. CVAFS 17

18 Calibration Curves of GEM and PM GEM PM Integral Area (PAU) y = 8E+06x R = Integral Area (PAU) y = 3E+07x R = Standard of Mercury Concentration (ng) Standard of Mercury Concentration (ng) For vapor phase mercury, samples can be analyzed in duplicate. Repeated injections of vapor phase mercury standards can be used to assess the analytical precision which should be less than 5% for the methods described. Particle-phase mercury should be less than 10%. The correlation coefficient (r) should be or better and each of the points on the curve should be predicted by the slope within 5 % of their actual value. 18

19 Results and Discussion 19

20 Atmospheric Mercury Concentrations in Spring and Winter (1/4) Seasons Mercury concentration B1 B2 U1 U2 P1 P2 P3 GEM (ng/m 3 ) Spring PM (ng/m 3 ) GEM/(GEM+PM) (%) GEM (ng/m 3 ) Winter PM (ng/m 3 ) GEM/(GEM+PM) (%) B: background sites; U: urban sites; P: polluted sites 20

21 Comparison of GEM and PM in Spring and Winter (2/4) Spring Winter Spring Winter GEM (ng/m3) 10 PM (ng/m3) B1 B2 U1 U2 P1 P2 P3 0.0 B1 B2 U1 U2 P1 P2 P3 21

22 Atmospheric Mercury Concentrations in Spring and Winter (3/4) Among these sites, site B2 is a coastal background site which are far away from pollution sources, thus their concentrations of GEM and PM were relatively lower than other sites. Sites P1 and P2 are downwind sites adjacent to municipal waste incinerator, thus their concentrations of GEM and PM were much higher than other sites. Moreover, the partition of PM at sites P1 and P2 were also higher. Site P1 was located at approximately 2 km downwind of the municipal solid waste incinerator, resulting in the highest atmospheric mercury concentration. 22

23 Atmospheric Mercury Concentrations in Spring and Winter (4/4) Sites B1 and P3 were only partially influenced by the stack plume emitted from the municipal solid waste incinerator, which make these two sites lower mercury concentration compared to sites P1 and P2. Major partition of mercury at the heavily polluted metropolitan area was GEM ranging form to 99.16% in spring, and from 94.38% to in winter. However, adjacent to the polluted area, the partition of PM would be higher. 23

24 Concentration Contour of GEM+PM Spring Winter During the sampling period of atmospheric mercury in both spring and winter in metro Kaohsiung, the maximum concentration of GAM+PM were located closely adjacent to the municipal solid waste incinerator, which was approximately times higher than that at the background area. 24

25 Comparison of Atmospheric Mercury with Other Asian Cities (1/2) Seasons Mercury concentration Sichuan, China Beijing, China Tokyo, Japan Kang-Hwa Island, Korea Kaohsiung, Taiwan Spring Gaseous (ng/m 3 ) Particulate (ng/m 3 ) ± ±0.37 Winter Gaseous (ng/m 3 ) Particulate (ng/m 3 ) ± ±0.38 The concentrations of atmospheric mercury in metro Kaohsiung was close to Kang-Hwa Island (Korea), lower than Beijing (China), and higher than Sichuan (China) and Tokyo (Japan), and the concentrations of atmospheric mercury in winter had similar trend as in spring. Gaseous and particulate mercury concentrations in winter were higher than those in spring, for both highly polluted metropolitan area and background area. 25

26 Comparison of Atmospheric Mercury with Other Asian Cities (2/2) 100 Gaseous Mercury Particulate Mercury Spring 100 Gaseous Mercury Particulate Mercury Winter % of GEM+PM % of GEM+PM Sichuan Beijing Tokyo Kang Hwa Island Kaohsiung 0 Sichuan Beijing Tokyo Kang Hwa Island Kaohsiung In metro Kaohsiung, the partition of gaseous mercury was 94.9% and 94.2% in spring and winter, respectively. Similarly, gaseous mercury was abundant for atmospheric mercury in major Asian cities ( %), and particulate mercury accounted for the rest of %. 26

27 Conclusions (1/2) GEM and PM concentrations in heavily polluted metropolitan sites were times higher than those in background areas. GEM and PM concentrations were relatively higher in winter than those in spring, for both heavily polluted metropolitan sites and background site. The partition of PM at the locations adjacent to the polluted areas (P1-P3) was higher than background areas (B1 and B2) and urban areas (U1 and U2). 27

28 Conclusions (2/2) In both spring and winter in metro Kaohsiung, the maximum concentration of atmospheric mercury (GEM+PM) was observed at site P1, that is closely adjacent to the municipal solid waste incinerator. The concentrations of atmospheric mercury (GEM+PM) in metro Kaohsiung was close to Kang-Hwa Island (Korea), lower than Beijing (China), and higher than Sichuan (China) and Tokyo (Japan). 28

29 Thanks for Your Attention 29