1. Low-Power Annular Denuder System for Measurement of HNO3, NH3 and PM2
Low-Power Annular Denuder System for Measurement of HNO3, NH3 and PM2.5 components at Forest Health Sites Eric S. Edgerton Atmospheric Research & Analysis, Inc.
WBEA Science Integration Workshop:
State of Knowledge/Understanding and the Path Forward:
Confirming and Enhancing the Source-Receptor Response Relationships in the AOSR
Delta Calgary Airport Hotel, Calgary, Alberta
January 27-28, 2016
Edgerton

2. Motivation
High quality measurements of atmospheric reactive nitrogen species are needed to
Evaluate sources
Estimate loadings to aquatic and terrestrial bodies
Determine potential acidification and eutrophication
HNO3 and NH3 are among the most important reactive nitrogen species, especially in terms of wet and dry deposition rates
Edgerton

3. JP104 has collocated samplers for precision
Study Sites
Measurement height ~5m above canopy
JP104 has collocated samplers for precision
and design testing
Picture courtesy of Mike Solohub
Edgerton

4. HNO3 Concentrations LD * All samples > LD, highly seasonal pattern.
* Indicates 2-month sample
Edgerton

5. Most samples >LD, seasonal pattern punctuated by wildfire emissions
NH3 Concentrations
2.43
4.22 * LD
Most samples >LD, seasonal pattern punctuated by wildfire emissions
(Aug 2014, Jun-Jul 2015)
* Indicates 2-month sample
Edgerton

6. Cold and Warm Season HNO3
Warm = May through September
8 months
10 months
Warm =2XCold, except JP201
Edgerton

7. Cold and Warm Season NH3 Warm Season = May through September 8 months
Warm = 4-10XCold
Edgerton

8. Conclusions and Information Gaps
Denuder-based measurements are able to detect seasonal variability and spatial gradients for HNO3 and NH3
For HNO3
Average concentrations are low
Warm season concentrations 2x Cold season
Suggestions of moderate N-S and E-W gradients
For NH3
Average concentrations are similar to other forested ecosystems
Warm season concentrations dramatically higher than Cold season
Spatial gradients driven to a large extent by wildfire emissions
Evaluation for PM ions and trace elements (ongoing)
Potential testing for PAHs
Additional spatial coverage needed
South of JP104
Between JP104 and JP201 or JP213
Edgerton