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

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

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

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

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

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

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

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