NADP: Keeping You Connected, Issue 10

 NADP: Keeping You Connected July 2017 | Issue 10 

NADP: Keeping You Connected is a quarterly e-newsletter designed to keep you informed about atmospheric chemistry trends and other updates from the National Atmospheric Deposition Program. To offer feedback or submit a suggestion, please email If you were forwarded this notification and would like to receive future newsletters, click here to subscribe.

In this issue:

This issue is focused on student activities and research involving the NADP networks. We would like to encourage interested students to participate with NADP through site operations and data usage, and increase workforce development for air quality and environmental science careers. If there are ideas for future student-themed articles to increase the student-engagement effort, please send an email to

Inside a Student-Led NADP Site

Dr. Janet Paladino directs the on-site programs for PA37. As the site supervisor, she integrate students into the NADP process. In this article, she shares her experience in doing this and provides details on how and why she engages students in sampling.

PA37 – MDN Site

Dr. Janet Paladino – Associate Professor of Biology, Waynesburg University

Figure 1. Matthew Colaluca, a mercury monitor intern and senior environmental science major at Waynesburg University who works with Dr. Janet Paladino. (Click to enlarge)

Our site is located on the campus of Waynesburg University, located in southwestern Pennsylvania south of Pittsburgh. The program has provided an internship opportunity to over 20 students since we started running the site in 2009.

Each semester, environmental science students are eligible to take a one-credit internship where they can serve as the site’s mercury monitor technician. They are responsible for taking mercury samples and collecting data from the mercury monitor. Students are involved in all aspects of the weekly sampling and maintenance of the site. If there is a problem, I try to let them troubleshoot the issue first with the aid of Mercury Deposition Network (MDN) technical support before I get involved in attempting to help them fix the problem. Following their internship, students are required to give a presentation for the Environmental Science Department to discuss their experience. A component of this discussion is to evaluate the data generated for the site to determine potential levels of mercury exposure from rainwater to human and ecological receptors.

Watch this video to hear more from Matt Colaluca, Dr. Palatino’s intern:

I believe that this program provides students with an excellent opportunity to learn the rigor of quantitative sample and data collection. Many of these students graduate and take jobs as technicians in environmental consulting, which requires them to do similar types of tasks using EPA protocols. Students who have completed this internship have reported that this opportunity was instrumental in obtaining employment as field technicians.

Having the mercury monitor on campus also provides an opportunity to educate the public about the hazards of mercury in the environment. Students in the Introduction to Environmental Science class visit the monitor during our discussion of toxicology and environmental health, where they observe the methodology used to take rainwater samples and to discuss the human health and environmental effects of mercury.

How are Students Using NADP Data?

This article highlights how two students are using NADP data in their graduate research studies. Jackie Gerson is a PhD student at Duke University but used NADP data for her Master’s research at Syracuse University to investigate mercury concentrations in the Adirondacks. Becky Forgrave is a first year PhD student at the University of Pittsburgh studying spatial and temporal variation in reactive nitrogen deposition in urban environments.

Jackie Gerson – PhD student, Duke University

Figure 2: Photo of Jackie Gerson (Click to enlarge)

Ms. Gerson is a currently first year PhD student in ecology at Duke University studying the fate and transformation of trace elements (mercury and selenium) from mountaintop coal mining and artisanal gold mining. This research will expand upon her Master’s project while at Syracuse University where she used data from NADP mercury networks to investigate mercury concentrations in the Adirondacks, New York [Gerson and Driscoll, 2016]. For her Master’s thesis, she examined mercury deposition using the NADP MDN and Atmospheric Mercury Network (AMNet) datasets in an effort to determine watershed response in a remote Adirondack forest to decreases in regional mercury emissions.

Figure 3: Decadal trends in Hg flux in Arbutus Lake-watershed: (a) watershed litter and wet deposition Hg flux; (b) THg flux at the inlet and outlet of Arbutus Lake; and (c) MeHg flux at the inlet and outlet of Arbutus Lake. Stars represent a statistically significant trend. Error bars represent one standard deviation. (Click to enlarge)

To understand if reductions in U.S. mercury emissions led to decreases in mercury concentrations within aquatic systems, Ms. Gerson and Dr. Driscoll used weekly mercury wet deposition data collected through MDN and estimates of dry mercury from the pilot litterfall network at Huntington Forest (NY20). In addition, hourly atmospheric concentrations of elemental mercury, reactive gaseous mercury, and particulate mercury were also collected through the AMNet site at NY20. Using these data, they found that although wet mercury deposition has not changed over the past decade, total mercury deposition, which includes dry deposition, has decreased. This decrease is likely the result of decreases in mercury found in leaf litter. A reduction in mercury found in leaves is likely driven by decreased dry deposition from gaseous elemental mercury concentrations in the atmosphere (Figure 3). These decreases have led to decreased concentrations and fluxes of total mercury and methylmercury in the forested lake. Thus, it appears that decreased US mercury emissions have led to decreased lake water mercury, suggesting that ecosystems are capable of recovering from high mercury deposition once atmospheric concentrations are reduced.

Gerson, J. R., and C. T. Driscoll (2016). Is mercury in a remote forested watershed of the Adirondack Mountains responding to recent decreases in emissions?. Environ. Sci. Technol., 50(20), 10943–10950, doi:10.1021/acs.est.6b02127.

Becky Forgrave – PhD Student, University of Pittsburgh

Figure 4: Becky and her ion exchange resin column sample deployment in the Laurel Highlands. (Click to enlarge)

Ms. Forgrave is a first year PhD student at the University of Pittsburgh studying spatial and temporal variation in reactive nitrogen deposition in urban environments. The goals of this study are to use ion exchange resin (IER) columns to collect a finer spatial scale of atmospheric nitrogen deposition data than can be provided by a single collector representing a large area, as is typical of the existing networks. This study will compare deposition data collected at several sites across the City of Pittsburgh in an effort to test for deposition variability across an urban landscape. The urban flux data will then be compared to those collected at the nearest rural NADP site in the Laurel Highlands.

Atmospheric deposition in urban areas is a poorly understood component of watershed nitrogen budgets, yet it can be a significant source of anthropogenic nitrogen accumulated in watersheds, especially in urban areas close to the source of the pollution. Most NADP and CASTNET sites, however, are in rural areas, far from urban sources of nitrogen oxides. IER columns are small polyethylene polymer beads treated with counter ions that create charged exchange sites that selectively target anions or cations. These resins are used to collect nitrogen in precipitation and dry deposition, allowing for quantification of deposition fluxes integrated over many weeks without requiring the more time-consuming collection of precipitation directly.

This project is ongoing, with the goal of collecting a full year of data. Preliminary data show that IER columns collect equivalent deposition fluxes as does the NADP site, yet are much more cost effective to set-up and maintain allowing for sampling more locations and capturing spatial variation of localized deposition. Urban deposition fluxes are highly variable both among sites, as well as seasonally, yet on average are not significantly different from those measured in rural areas (Figure 5).

Figure 5: Total nitrogen deposition flux in the Laurel Highlands as measured by ion exchange resins from this study compared to the NADP (wet-deposition) and CASTNET (dry deposition) at the same site. Concurrent data is not yet available so the 2017 data from this study is compared to the average from 2012-2016. Error bars represent one standard deviation.

Face of NADP: Andy Johnson

The Face of NADP article – a new permanent feature in the newsletter – will highlight an interview with one NADP member, talking about how they got to where they are today. In this newsletter issue, NADP interviewed Andy Johnson from the Maine Department of Environmental Protection (DEP). Andy is the Director of the Division of Air Quality Assessment in the Bureau of Air Quality, and has been with Maine DEP since 1979.

Figure 6: Andy Johnson working at an ozone monitoring site in the early 1980s (Click to enlarge)

NADP: Where did you go to college and what was your major?

Andy Johnson (AJ): I attended the University of Maine for my freshman and sophomore years of college, and then transferred to Michigan State University for my junior and senior years, where I graduated with a B.S. in Music Education.

NADP: Where did you start your career after graduating college?

AJ: I began my career in air quality monitoring in Maine DEP’s Southern Maine Regional Office in Portland as an Environmental Aide, an entry-level position at the very bottom of the environmental scientist career ladder (a position classification that no longer exists in Maine state government).

Figure 7: Andy Johnson (left) and Don Darling (right) – from the Eastern Main Regional Office of DEP – at ME09 in Greenville, Maine. (Click to enlarge)

NADP: Could you explain a little bit about how you got to where you are today with Maine DEP – and how you transitioned from music education to air quality work?

AJ: As a freshman in high school, I had decided that I wanted to teach music as my career choice, and pursued that goal with passion and vigor because I so genuinely enjoyed every aspect of it – performing, conducting, arranging, and sharing what I had learned with others by teaching to spread the joy and fulfillment that music gave to me. At the same time, I had always had a love of the outdoors and for the environment, and during my college years, became very interested in and engaged with the growing environmental movement, so much so that the elective courses I took at MSU essentially constituted me having a minor in natural resources.

After college, I applied for a variety of entry-level positions with the state, such as biologist, park ranger, forest ranger, environmental scientist, etc., which my minor in natural resources afforded me to meet the very minimum required qualifications for each position, never expecting anything would ever come from it. One day, I got a call from a person at Maine DEP asking me if I was interested in interviewing for an environmental aide position in its Portland office doing air quality monitoring. Long-story short, they offered me the job and I accepted.

If someone had told me then that I would still be working in the air quality monitoring and environmental field 38 years later, I would have said they were crazy! But here I am, doing exactly that and really enjoying what I do all these years later. The variety of issues and new challenges that always seem to emerge have kept the work from never becoming boring.

Today I still indulge my music passion but purely for my own personal gratification - not to earn a paycheck - and it has been equally rewarding by performing in a DEP band for various staff functions, singing in a local men’s chorus and getting together weekly with a composer friend to play and record his music.

NADP: What does your average day look like with Maine DEP?

AJ: My average day at Maine DEP has obviously changed over the years with promotions within the Bureau of Air Quality (BAQ). In the early days, it was this idyllic balance of field and office work, operating and maintaining the equipment at monitoring sites at some pretty scenic locations along the southern Maine coast, in downtown Portland and greater Portland’s surrounding communities, as well as in the western Maine foothills (location of ME02). Validating and reporting the data was a completely manual and paper-based process.

With each successive promotion, the positions’ responsibilities changed with ever decreasing hands-on and field related activities, while those related to administrative, fiscal, personnel, planning and overall management increased. My average day today reflects managing overall activities and interacting with staff in our Ambient Air Monitoring, Laboratory & Quality Assurance, and Atmospheric Science and Analyses sections.

NADP: How does your current day-to-day job tie into NADP?

AJ: My current day-to-day job ties into NADP in several ways. One of my key responsibilities is to ensure there is funding to support our ongoing long-term deposition monitoring at our four DEP-sponsored NTN and MDN sites (ME00, ME02, ME09 and ME96). I also work closely with the National Park Service staff at Acadia on their deposition monitoring efforts and provide half a year’s funding for operation of their MDN site (ME98), as well as providing a variety of non-funding support of NADP sites sponsored and operated by Maine tribes (ME04 and ME94).

NADP also recently interviewed Andy for an outreach video titled “A State’s Perspective of the National Atmospheric Deposition Program”. You can view the video here:

I help support our BAQ field staff as needed, sometimes on dealing with equipment or other technical issues, but more often by ensuring they have the necessary resources, tools and services available to perform their deposition related monitoring responsibilities (e.g. shipping accounts, non-NED parts and supplies, utilities, site infrastructure, MOUs with property owners, etc.).

Lastly, at every opportunity I can, I try to relate the results and observations from our annual assessments we perform of our NTN and MDN data, to tangible environmental outcomes and/or trends in a variety of environmental programs. For example, how various regulatory emission control efforts to reduce sulfur, nitrogen and mercury impact air and water quality goals and standards.

Calling All Students!

Tamara Blett, Air Resources Division – National Park Service (2017 Fall Meeting Organizer)

The 2017 NADP Science Symposium meeting, taking place in San Diego, California from October 30- November 3, will have a special emphasis on student involvement and you are invited to attend!

NADP 2017 meeting

Session topics will include:

  • Agriculture: ammonia emissions, trends, and deposition
  • Urban air quality: aeroallergens to acidic pollutants
  • Nitrogen: transport, deposition, and effects
  • Mercury deposition: wet, dry, and total
  • Critical loads: acidification and excess nitrogen
  • Air and water quality: linkages and synergies
  • Education, land management, and air quality policy: application of NADP data to today’s challenges

Currently registered undergraduate and graduate students presenting posters or talks in science symposium sessions will receive a registration fee waiver (that means registration for students is free!). Awards for best student talk and best student poster will also be presented.

NADP fall science meetings are a great place to network with staff from Federal and State agencies, tribes, consulting firms, NGOs, and others doing work involving deposition and effects of air pollutants. There will also be opportunities to discuss internship and career options with professionals.

Abstract submission deadline is July 28, 2017 – find more information here.

Long-Term Trends in Acid Precipitation through Animated Maps

A goal of NADP’s National Trends Network (NTN) is to document temporal and spatial changes in precipitation chemistry. Animated (time series) maps, available from the NADP website, are one method for documenting these changes.

Time-series maps are available for:

  • Concentration of ammonium, nitrate and sulfate;
  • Deposition of ammonium, nitrate, inorganic nitrogen (ammonium plus nitrate) and sulfate;
  • pH (represented as hydrogen ion); and
  • Total precipitation

To smooth the transition between successive maps in the series, each map represents the mean for a three-year period and is identified by the middle year. That is, a map in the series with the label “1985” represents the 1984-1986 period, and is followed by a map labeled “1986” representing the 1985-1987 period.

Figure 8: Animated time-series for hydrogen ion concentration (i.e., pH) for 1985-2012. Click to run animation

pH is a measure of the acidity or alkalinity of a water-based solution (i.e., the concentration of hydrogen ion in a solution). A pH value of seven is considered neutral, while values below seven are acidic (e.g., lemon juice has a pH of 2) and values above seven are alkaline (e.g., soapy water has a pH of 12).

The animated pH maps illustrate that the pH of precipitation has been increasing (becoming less acidic) since 1985 (Figure 8). Though precipitation is less acidic, particularly in the eastern United States, continued monitoring is essential for documenting long-term trends.

To access the animated maps for pH and other variables, download the PowerPoint from the Animated Maps page, and the animation will automatically run once the slideshow is started.

NADP’s Efforts for Aeroallergen Monitoring

Andrew Johnson, Maine Department of Environmental Protection and Norman Anderson, Anderson Environmental Health – AMSC Co-Chairs

At the 2016 fall NADP meeting in Santa Fe, New Mexico, the Executive Committee approved the creation of a new science committee, for one year initially, in response to a motion brought by a couple of longtime deposition program participants. The new “Aeroallergen Monitoring Science Committee” (AMSC) was established to help take the next steps necessary to explore the creation of a national “aeroallergen” (e.g. pollens and mold spores) monitoring network.

Figure 9: Pollen Grains (Click to enlarge)

This is in response to the groundwork that the Council of State & Territorial Epidemiologists (CSTE) Asthma & Allergy work group, in collaboration with the national Center for Disease Control, had done to make a clear and compelling case of the need for and benefit of such a network. While presently there is a National Allergy Bureau (NAB) network of about 80 aeroallergen monitoring sites, as well as scores of other individually operated and supported sites scattered about the country, their efforts are not highly coordinated. The AMSC is exploring what a better coordinated and truly national monitoring network would look like and how it would operate, so that the health, environmental and scientific benefits of its shared data can benefit a multitude of interested stakeholders. The AMSC’s mission and specific charges, as approved last fall, are available on the website.

Figure 10: A Rotorod sampler, which is a scientific instrument that is used for collecting pollen grains and fungus spores from the atmosphere
Figure 10:A Rotorod sampler, which is a scientific instrument that is used for collecting pollen grains and fungus spores from the atmosphere.

Since January 2017, the committee has held three conference calls and one in-person gathering at the NADP spring meeting in Louisville, KY. The committee is further engaging its members in the upcoming months to participate in one or more of the following four “focus task areas”: Sample Collection, Analysis & Network Design; Data Handling & Dissemination; Quality & Standards; and Forecasting & Analysis. One of the AMSC’s near-term goals is to seek a full 4-year approval as a science committee at the 2017 fall meeting in San Diego, CA, so it may further continue working to achieve its mission and charges. It is also beginning to engage with the NADP subcommittee on urban air monitoring (SCUAM) to identify potential areas of common and overlapping interests and objectives. An important ongoing element in all of AMSC’s future efforts will be to further strengthen our public health partnership with CSTE to the mutual benefit of both organizations. Individuals interested in joining the AMSC to contribute their knowledge, expertise and/or experience in the field of aeroallergen monitoring can subscribe to the email list serve to receive announcements on committee happenings.

Recent Publications

New Book Release

book cover

The NADP highlights a new book released titled Air Pollution and Its Impacts on U.S. National Parks. The author, Timothy J. Sullivan, is a member of the NADP and its Critical Loads Science Committee.

A variety of air pollutants are emitted into the atmosphere from human-caused and natural emissions sources throughout the United States and elsewhere. These contaminants impact sensitive natural resources in wilderness, including the national parks. The system of national parks in the United States is among our greatest assets. This book provides a compilation and synthesis of current scientific understanding regarding the causes and effects of these pollutants within national park lands. It describes pollutant emissions, deposition, exposures, and identifies the critical (tipping point) loads of pollutant deposition at which adverse impacts are manifested.

For more information about the author, please visit:

The book is available from Cornell University Press. NADP affiliates receive a 20% discount by using the promo code: EEN17.

Journal Listings

A listing of recent journal publications that have used NADP data (the networks used are listed in bold next to the DOI). An publicly-available online database that lists citations using NADP data, including a full list from 2016, is available on the NADP Web site.

Felix, J. D., Elliott, E. M., & Gay, D. A., 2017. Spatial and temporal patterns of nitrogen isotopic composition of ammonia at US ammonia monitoring network sites. Atmospheric Environment, 150, 434-442.
doi:10.1016/j.atmosenv.2016.11.039  AMoN

Iavorivska, L., Boyer, E. W., & Grimm, J. W., 2017. Wet atmospheric deposition of organic carbon: An underreported source of carbon to watersheds in the northeastern United States. Journal of Geophysical Research: Atmospheres, 122(5), 3104-3115.
doi:10.1002/2016JD026027 NTN

Kaulfus, Aaron S., Udaysankar Nair, Christopher D. Holmes, and William M. Landing, 2017. Mercury Wet Scavenging and Deposition Differences by Precipitation Type. Environmental Science & Technology, 51 (5), 2628-2634.
doi:10.1021/acs.est.6b04187  MDN

Paulot, F., Fan, S., & Horowitz, L. W., 2017. Contrasting seasonal responses of sulfate aerosols to declining SO2 emissions in the Eastern US: implications for the efficacy of SO2 emission controls. Geophysical Research Letters, 44, 455–464.
doi: 10.1002/2016GL070695 NTN, AIRMoN

Richardson, J. B., 2017. Manganese and Mn/Ca ratios in soil and vegetation in forests across the northeastern US: Insights on spatial Mn enrichment. Science of The Total Environment, 581–582, 612–620.
doi:10.1016/j.scitotenv.2016.12.170 NTN

Schilling, K. E., Kult, K., Wilke, K., Streeter, M., & Vogelgesang, J., 2017. Nitrate reduction in a reconstructed floodplain oxbow fed by tile drainage. Ecological Engineering, 102, 98-107.
doi:10.1016/j.ecoleng.2017.02.006 NTN

Wason, J. W., Dovciak, M., Beier, C. M., & Battles, J. J., 2017. Tree growth is more sensitive than species distributions to recent changes in climate and acidic deposition in the northeastern United States. Journal of Applied Ecology.
doi:10.1111/1365-2664.12899 NTN

Wetherbee, G. A., 2017. Precipitation collector bias and its effects on temporal trends and spatial variability in National Atmospheric Deposition Program/National Trends Network data. Environmental Pollution, 223, 90-101.
doi:10.1016/j.envpol.2016.12.036 NTN, MDN

Williams, Jason J., Serena H. Chung, Anne M. Johansen, Brian K. Lamb, Joseph K. Vaughan, and Marc Beutel, 2017. Evaluation of atmospheric nitrogen deposition model performance in the context of US critical load assessments. Atmospheric Environment, 150, 244-255.
doi:10.1016/j.atmosenv.2016.11.051 NTN

Wolff, B. A., Johnson, B. M., & Lepak, J. M., 2017. Changes in Sport Fish Mercury Concentrations from Food Web Shifts Suggest Partial Decoupling from Atmospheric Deposition in Two Colorado Reservoirs. Archives of Environmental Contamination and Toxicology, 72 (2), 167–177.
doi:10.1007/s00244-016-0353-x MDN