Analysis of Atmospheric Mercury Speciation at HEDO Station

Analysis of Atmospheric Mercury Speciation at HEDO Station, Okinawa Eric Prestbo Ph. D. (ericp@frontiergeosciences. com)

Beijing Shanghai Hong Kong Eric Prestbo Ph. D. (ericp@frontiergeosciences. com)

Eric Prestbo Ph. D. (ericp@frontiergeosciences. com)

Anthropogenic Sources of Hg in 1995 Pacyna et al. - 2003 LRT Workshop Hg 0 – Ton/yr Hg(II) – Ton/yr PHg – Ton/yr Eric Prestbo Ph. D. (ericp@frontiergeosciences. com)

Atmospheric Mercury Nomenclature • Hg 0 or GEM - Gaseous Elemental Mercury • PHg – Particulate Bound Hg (2. 5 um) • RGM - Reactive Gaseous Mercury - Hg. Cl 2? Eric Prestbo Ph. D. (ericp@frontiergeosciences. com)

Instrument Description: Atmospheric Mercury Speciation Eric Prestbo Ph. D. (ericp@frontiergeosciences. com)

Eric Prestbo Ph. D. (ericp@frontiergeosciences. com)

Measurement vs Model Hedo Mean Hg 0 = 2. 04 ng/m 3 Hedo Max Hg 0 = 5. 47 ng/m 3 Seignuer et al. , 2004 ES&T 38: 555 Eric Prestbo Ph. D. (ericp@frontiergeosciences. com)

Measurement vs Model Hedo Mean Hg 0 = 2. 04 ng/m 3 Hedo Max Hg 0 = 5. 47 ng/m 3 Dastoor and Larocque. , 2004 Atmos. Env. 38: 147 Eric Prestbo Ph. D. (ericp@frontiergeosciences. com)

Measurement vs Model Hedo RGM Mean = 4. 51 pg/m 3 Hedo RGM Max = 32. 5 pg/ m 3 Seignuer et al. , 2004 ES&T 38: 555 Eric Prestbo Ph. D. (ericp@frontiergeosciences. com)

Measurement vs Model Hedo PHg Mean = 3. 05 pg/m 3 Hedo PHg Max = 16. 5 pg/ m 3 Seignuer et al. , 2004 ES&T 38: 555 Eric Prestbo Ph. D. (ericp@frontiergeosciences. com)

Comparison of Model and Observation of Hg 0 Seignuer et al. , 2004 ES&T 38: 555 Location W. Korea Date Spring 2001 Model (ng/m 3) Obs 3. 72 2. 13 Seoul, Korea Sept-97 May-98 3. 43 -3. 94 2. 03; 2. 12 Kyushu, Japan Beijing, China 1996 Jan, Feb, Sept 98 10. 8 6. 2 – 24. 7 1. 70 2. 26; 2. 38 HEDO, Okinawa Spr-2004 1. 7 -1. 9 Changchun, China Jul-Jan 0. 02 -2 (PHg) 2000 **PHg** Eric Prestbo Ph. D. (ericp@frontiergeosciences. com) 2. 04 0. 06 -2

Beijing - China Eric Prestbo Ph. D. (ericp@frontiergeosciences. com)

Eric Prestbo Ph. D. (ericp@frontiergeosciences. com)

Eric Prestbo Ph. D. (ericp@frontiergeosciences. com)

Eric Prestbo Ph. D. (ericp@frontiergeosciences. com)

Eric Prestbo Ph. D. (ericp@frontiergeosciences. com)

Eric Prestbo Ph. D. (ericp@frontiergeosciences. com)

Eric Prestbo Ph. D. (ericp@frontiergeosciences. com)

LOCAL? Eric Prestbo Ph. D. (ericp@frontiergeosciences. com)

Eric Prestbo Ph. D. (ericp@frontiergeosciences. com)

Eric Prestbo Ph. D. (ericp@frontiergeosciences. com)

Eric Prestbo Ph. D. (ericp@frontiergeosciences. com)

Eric Prestbo Ph. D. (ericp@frontiergeosciences. com)

Eric Prestbo Ph. D. (ericp@frontiergeosciences. com)

Eric Prestbo Ph. D. (ericp@frontiergeosciences. com)

High Hg 0 and CO often begins with rainfall note also SO 4 washout Eric Prestbo Ph. D. (ericp@frontiergeosciences. com)

Evidence for Biomass Signal? Organic Rich – Sulfate Low Eric Prestbo Ph. D. (ericp@frontiergeosciences. com)

Evidence for Biomass Signal? Organic Rich – Sulfate Low Eric Prestbo Ph. D. (ericp@frontiergeosciences. com)

NAAPS Forecast Smoke SO 4 Eric Prestbo Ph. D. (ericp@frontiergeosciences. com)

No clear observation of a dust event Eric Prestbo Ph. D. (ericp@frontiergeosciences. com)

NAAPS Forecast – over predicts SO 4 Dust Eric Prestbo Ph. D. (ericp@frontiergeosciences. com)

Eric Prestbo Ph. D. (ericp@frontiergeosciences. com)

Eric Prestbo Ph. D. (ericp@frontiergeosciences. com)

Low-Level RGM and PHg Emissions results in faster local removal by Dry Deposition? < 50 Meter Total Hg Emissions (tons/yr) >150 Meter Total Hg Emissions (tons/yr) Pacyna et al. - 2003 LRT Workshop Eric Prestbo Ph. D. (ericp@frontiergeosciences. com)

Why are RGM values lower than models and uncorrelated with pollution compounds? Hypothesis – RGM from anthropogenic emissions are preferentially reduced to Hg 0 via the complex chemistry of S 02 > S 03 > S 04 during cloud droplet formation and evaporation Eric Prestbo Ph. D. (ericp@frontiergeosciences. com)

What controls [RGM] – Photochemistry? Eric Prestbo Ph. D. (ericp@frontiergeosciences. com)

Hg 0 Eric Prestbo Ph. D. (ericp@frontiergeosciences. com)

Future Data Interpretation • More refined analysis of each event with respect to AMS and meteorology • Support hypothesis that SO 3 is preferentially converting emitted Hg(II) to Hg 0 during cloud water processing (formation/evaporation) • Rule out local impacts Eric Prestbo Ph. D. (ericp@frontiergeosciences. com)

Future: Need Hg Deposition Data! • Inventories coupled to models predict high deposition in NW Pacific due to RGM and PHg emissions • Measurements needed to confirm at HEDO and elsewhere • Should be event based – at least for intensive study periods • What Hg deposition data is currently being collected or published? Eric Prestbo Ph. D. (ericp@frontiergeosciences. com)

Continuous Mercury Speciation at HEDO • Depending on support-level we can do complete Automated Hg speciation system – or only total gaseous Hg with select intensive studies Eric Prestbo Ph. D. (ericp@frontiergeosciences. com)