Mercury (Hg) is an important global neurotoxin that is present throughout the environment. A post-doctoral position is currently available in our group to develop new methods for the measurement of mercury.


A post doctoral position is available in the Jaffe Research Group to develop new instrumental methods for atmospheric mercury measurements

Mercury (Hg) is an neurotoxin that is important due to its methylation and bioaccumulation in the food chain. Atmospheric cycling plays a critical role in delivering anthropogenic mercury to the food chain, however, there are large gaps in our understanding. New measurement approaches are critically needed to test our understanding of the sources and sinks, to evaluate chemical transport models and ultimately to develop good policies around control and regulation of mercury emissions. The Jaffe Research Group has been a national leader in research on global transport of mercury (see publications).

We seek an outstanding atmospheric chemist to lead the development of new methods to measure gaseous Hg0 and Hg+2. The selected scientist will also work with others in our team to coordinate between ground and airborne observations of mercury, including or ongoing measurements at the Mt. Bachelor Observatory. Candidates must have a PhD in chemistry, physics, atmospheric sciences, environmental engineering or a closely related field and prior experience with mercury instrumentation, mass spec and/or other state of the art methods. We are looking for an outstanding scientist who has the ability to think creatively about instrumentation and the global mercury issue. The selected candidate must have a good publication record and be dedicated to outstanding communication of their scientific work in both written and oral presentations. Finally, the selected candidate must be a good team player and have the ability to work with other scientists at a variety of levels. A PhD and previous experience with mercury instrumentation, mass spec methods and/or other instrumentation are required. The initial appointment is for one year, renewable. The salary range is $3800-$4200 per month.

A new article by David Reidmiller recently published in Atmospheric Chemistry and Physics (Vol. 9, p. 5027-5042) incorporates observations from EPA’s CASTNet sites and results from 16 global chemical transport models as part of the Hemispheric Transport of Air Pollution (www.htap.org) project. Each model conducted an array of sensitivity simulations in which anthropogenic O3 precursor emissions were reduced by 20% in four Northern Hemispheric regions. The figure shown here illustrates the decline in maximum daily 8-hr average (MDA8) O3 during spring for 9 regions across the U.S. attributable to emissions reductions in three foreign source regions.



Large concentrations of particulate mercury (PHg) were observed in 15 events at the the Mount Bachelor Observatory from 2005-2007. Using a combination of air-mass back-trajectories and chemical tracer data, we conclude that these events were due to regional wildfires. Based on the observed PHg/CO ratio, we calculate that global wildfires are a source of PHg comparable to anthropogenic sources. These results are presented in a new paper accepted for publication in Atmospheric Environment.



An article by Phil Swartzendruber, Dan Jaffe, and Brandon Finley on the development of a higher time resolution technique for measuring gaseous oxidized mercury (RGM), published in Environmental Science & Technology. Two existing approaches, speciation by difference and direct collection on denuders, are combined to allow for 2.5 minute resolution for higher RGM concentrations, and direct collection on denuders for lower concentrations. The system was flown in the Pacific Northwest northwest in five test flights and detected several pockets of air with enhanced RGM, consistent with previous observations at Mt. Bachelor.


This figure shows the vertical distribution of gaseous elemental mercury (GEM), total airborne mercury (THg), reactive (oxidized) gaseous mercury (RGM), and ozone, on Aug 23, 2008. High levels of oxidized mercury are observed above 850 mb with low and moderate ozone.

A new article published in the Journal of Geophysical Research by Emily Fischer, Dan Jaffe, David Reidmiller, and Lyatt Jaeglé

This paper will focus on sprintime 2008 observations of peroxyacetyl nitrate (PAN) at Mount Bachelor. During this period, PAN mixing ratios ranged from below detection limit to 527 pptv, with a campaign mean of 119 pptv. Our analysis indicates that the variability in PAN was predominantly a function of synoptic scale processes. Three plumes containing elevated PAN were analyzed in detail. Two of these plumes were of Asian origin, and one was associated with North American sources.

Fischer, E. V., D. A. Jaffe, D. R. Reidmiller, and L. Jaeglé (2010), Meteorological controls on observed peroxyacetyl nitrate at Mount Bachelor during the spring of 2008, J. Geophys. Res., 115, D03302, doi:10.1029/2009JD012776.

A new article by Emily Fischer, Dan Jaffe, N. A. Marley, J. S. Gaffney, and A. Marchany-Rivera.

This paper will discuss the first set of multi-wavelength measurements of aerosol optical properties at Mount Bachelor. Observations of low RH sub –micron aerosol scattering and absorption were made with an integrating nephelometer and a particle soot absorption photometer during spring 2008 and 2009. Using a combination of in-situ observations, trajectory calculations and satellite observations, we identified 7 plumes of Asian origin. These plumes included many of the highest aerosol scattering (34.8 Mm-1) and aerosol absorption (5.7 Mm-1) hourly average values observed at MBO over the 2008 and 2009 campaigns. This paper addresses 1) whether the intensive optical properties differed between these 7 plumes, 2) whether these differences can be linked to differences in composition, and 3) whether the intensive optical properties changed during transpacific transport.

Fischer, E.V., D. A. Jaffe, N. A. Marley, J. S. Gaffney, and A. Marchany-Rivera (2010), Optical properties of aged Asian aerosols observed over the U.S. Pacific Northwest, J. Geophys. Res., doi:10.1029/2010JD013943, in press.


A new article published in Atmospheric Chemistry and Physics by David Reidmiller, Dan Jaffe, Emily Fischer and Brandon Finley.

Nitrogen oxides in the boundary layer and free troposphere at the Mt. Bachelor Observatory

Using chairlift soundings, we devised a novel way of isolating free tropospheric (FT) air at the Mt. Bachelor Observatory (MBO). This allowed us to analyze the causes of interannual variability in FT springtime NOx at MBO (changes in trans-Pacific transport pathways and meteorological conditions). Furthermore, we characterized the synoptic regimes that facilitate sampling of enhnaced NOx in the FT during spring.

Reidmiller, D. R., D. A. Jaffe, E. V. Fischer and B. Finley: Nitrogen oxides in the boundary layer and free troposphere at the Mt. Bachelor Observatory, Atmos. Chem. Phys., 10, 6043-6062, 2010.

Nitrogen oxides in the boundary layer and free troposphere at the Mt. Bachelor Observatory, Atmos. Chem. Phys., 10, 6043-6062, 2010.

A new article submitted to Atmospheric Environment by Brandon Finley, Phil Swartzendruber, and Dan Jaffe shows that wildfires are a major source of particulate mercury (PHg) in the Pacific Northwest. Emissions of PHg were observed in 16 wildfire plumes sampled at the Mount Bachelor Observatory from 2005-2007. Wildfires were identified using back-trajectory analysis and MODIS fire data. Using the measured PHg/CO ratio and estimates of global CO produced from wildfires, we estimate that wildfire sources of PHg are comparable to anthropogenic sources.

Finley, B. D., Swartzendruber, P., & Jaffe, D. A. Large particulate mercury emissions from wildfires at the Mount Bachelor Observatory.

The interannual variability of long-range transport (LRT) of CO to the west coast of the U.S. was investigated with MBO and ESRL ground station data, MOPITT and TES satellite retrievals and GEOS-Chem model output. We reveal a significant enhancement in LRT of CO during spring 2005 vs. spring 2006. This was due to the combination of differing transport pathways, synoptic conditions over the NE Pacific and anomalously strong biomass burning in SE Asia during winter 2004 - spring 2005.

Reidmiller, D. R., D. A. Jaffe, D. Chand, P. Swartzendruber, S. Strode, G. M. Wolfe and J. A. Thornton, (2009), Interannual variability of long-range transport as seen at the Mt. Bachelor Observatory. Atmos. Chem. Phys., 9, 557 - 572.

A new article by Emily Fischer shows that dust from the Gobi and Taklimakan deserts in China and Mongolia is routinely present in the air over the western United States during spring months. The article was published this month in the journal Geophysical Research Letters.

Fischer, E. V., N. C. Hsu, D. A. Jaffe, M.-J. Jeong, and S. L. Gong (2009), A decade of dust: Asian dust and springtime aerosol load in the U.S. Pacific Northwest, Geophys. Res. Lett., 36, L03821, doi:10.1029/2008GL036467.

Zhang L., D. J. Jacob, K. F. Boersma, D. A. Jaffe, J. R. Olson, K. W. Bowman, J. R. Worden, A. M. Thompson, M. A. Avery, R. C. Cohen, J. E. Dibb, F. M. Flock, H. E. Fuelberg, L. G. Huey, W. W. McMillan, H. B. Singh, and A. J. Weinheimer. Transpacific transport of ozone pollution and the effect of recent Asian emission increases on air quality in North America: an integrated analysis using satellite, aircraft, ozonesonde, and surface observations. Atmos. Chem. Phys., 8, 6117-6136, 2008

Zhang 2008

The following article by Nicola Pirrone (Italy-UNEP) stresses the value
of the Mt. Bachelor observations.


"A network of mercury monitoring stations ideally would include background sites such as those in the WMO's Global Atmospheric Watch initiative, as well as strategic high altitude sites on known long range transport routes such as Mount Bachelor in Oregon (Jaffe and Strode, 2008) and Mauna Loa in Hawaii."

Atmos. Env.

Seattle is in violation of the new, tougher O3 standard.

Going over the legal limit for smog over the weekend means officials here will have to devise a plan to improve air quality in the region.

Read the article:

http://seattlepi.nwsource.com/local/375427_airpollution19.html

This figure shows the relationship between summer mean O3 measured at 9 NPS/CASTNET sites in the Western US along with summer area burned for 1989-2004. Large fire years, such as 1994, 1996, 2000 and 2002, have significantly more O3. The relationship is statistically robust. In the publication the impacts of fires on different scales around each monitoring site.


Influence of fires on air quality.

Interannual Variations in PM2.5 due to Wildfires in the Western United States. Dan Jaffe, William Hafner, Duli Chand, Anthony Westerling, and Dominick Spracklen. Environ. Sci. Technol., 42 (8), 2812–2818, 2008. 10.1021/es702755v
Environ. Sci. Technol.

Reactive and particulate mercury in the Asian atmospheric boundary layer, Chand D., Jaffe D., Prestbo E., Swartzendruber P.C., HafnerW., Weiss-Penzias P., Kato S., Takami A., Hatakeyama S., and Kajii Y.. Atmos.Envir. 42, Issue 34, 7988-7996, doi:10.1016/j.atmosenv.2008.06.048. 2008. Click here for PDF

Vertical Distribution of Mercury, CO, Ozone, and Aerosol Scatter in the Pacific Northwest During the Spring 2006 INTEX-B Campaign, Swartzendruber, P., D. Chand, D. Jaffe, J. Smith, D. Reidmiller, L. Gratz, G. J. Keeler, S. Strode, L. Jaeglé, and R. Talbot, J. Geophys. Res., 2008, 113, D10305, doi:10.1029/2007JD009579. Click here for PDF

Fate and Transport of Atmospheric Mercury from Asia , D. Jaffe, S. Strode , Environ. Chem. 2008, 5, 121, doi:10.1071/EN08010.
Environ. Chemistry

Influence of Fires on O3 Concentrations in the Western U.S. Jaffe D.A., Hafner W., Chand D., Westerling A., Spracklen D., Envir.Sci.Tech. 42 (16) pp 5885 - 5891; doi:10.1021/es800084k, 2008. Click here for PDF

Inter-annual Variations in PM2.5 due to Wildfires in the Western United States. Jaffe D.A., Hafner W., Chand D., Westerling A., Spracklen D. Envir.Sci.Tech. 42 (8), 2812–2818, 2008. doi: 10.1021/es702755v, 2008. Click here for PDF

Please refer to Publications to review articles from previous years.

Dr. Daniel Jaffe has been invited to participate with The National Academies on Science, Engineering and Medicine serving with a Provisional Committee Appointment, the committee will focus on The Significance of International Transport of Air Pollutants .
http://www8.nationalacademies.org/cp/committeeview.aspx?key=48937

Our article on the observations, analysis, and modeling of speciated mercury at Mt. Bachelor in the summer of 2005 has been published in JGR-Atmospheres. The article presents one of the first reports of high concentrations of reactive mercury in the free-troposphere. The reactive mercury was not correlated to recent anthropogenic emissions, but appears to be a shift in the ambient speciation. A comparison with the GEOS-Chem mercury simulation developed at Harvard University and the University of Washington showed that current oxidation mechanisms were not able to produce the high concentrations which were observed. This implies that oxidation rates are faster than currently estimated, or there are additional oxidation mechanisms which have not yet been identified.
Reference: P. C. Swartzendruber, D. A. Jaffe, E. M. Prestbo, P. Weiss-Penzias, N. E. Selin, R. Park, D. J. Jacob, S. Strode, L. Jaegle, Observations of Reactive Gaseous Mercury in the Free-Troposphere at the Mt. Bachelor Observatory, JGR-Atmospheres, 111, D24301, doi:10.1029/2006JD007415. Click here for a link to this paper http://research.uwb.edu/jaffegroup/publications/2006SwartzP_MBO_RGM.pdf.

Change in gaseous elemental mercury during reactive mercury enhancements, showing a nearly quantitative shift in speciation.

As part of the Western Airborne Contaminants Assessment Project (WACAP; http://www2.nature.nps.gov/air/Studies/air_toxics/wacap.cfm), we calculated daily backwards air-mass trajectories for 5 western U.S. National Park sites for the period 1998-2004. Using a trajectory clustering algorithm, paths of similar trajectories were averaged into 6 main transport patterns (represented by cluster centers) based on altitude, direction, and length of the trajectory. Among the questions asked for this analysis: Do the trajectory clusters at the WACAP sites represent known synoptic meteorologies? How well do clusters represent the expected patterns of pollution transport? (Please click "Read More" below.)

Trajectory Clusters for Mt. Rainier (Will Hafner)