Assessment and Comparison of Hourly Speciated Atmospheric Nitrogen Measurements with Integrated Methods at CASTNET Site in Beltsville, MD
Poster Presentation
Prepared by G. Beachley, M. Puchalski
US Environmental Protection Agency, 1200 Pennsylvania Ave NW, MC-6204 M, Washington, DC, 20460, United States
Contact Information: [email protected]; 202-343-9621
ABSTRACT
The US EPA has recently been supplementing long-standing Clean Air Status and Trends Network (CASTNET) filter pack measurements of weekly integrated atmospheric nitric acid (HNO3), nitrate (NO3-), and ammonium (NH4+) concentrations with hourly resolved and speciated measurements of atmospheric nitrogen to provide a detailed look at short-term concentration variations and to enable a more complete assessment of contributors to the nitrogen budget. In addition, CASTNET sites have been expanded to collocate with the National Atmospheric Deposition Program (NADP) Ammonia Monitoring Network (AMON) which provides a 2-week passive measurement of Ammonia (NH3).
Hourly atmospheric ambient concentrations of nitrogen gases (HNO3, NH3) and aerosols (NO3-, NH4+) have been measured using the Monitor for AeRosols and GAses (MARGA) systems at the Beltsville, MD (BEL116) site during extended sampling periods over the past two years.
An experimental hourly trace level total reactive nitrogen sampling system, Nitrotrain, has been developed to analyze the components of the reactive nitrogen sample. The Nitrotrain consists of a solenoid sampling system to divert flows, a single commercially available chemiluminescence analyzer, and four converter boxes: a total nitrogen (TNx) stainless steel converter, two traditional molybdenum converters (one at 10m for NOy and a second at the analyzer for NOx), and an LED-based photolytic NOx converter. Calculated and measured parameters include NO, NOx, NHx, NO2 from the Molybdenum converter, and NO2 (true) from the photolytic converter.
Nitrogen measurements taken at the Beltsville site since November of 2014 will be compared and analyzed to assess instrument performance of the Nitrotrain and the MARGA against the integrated sampling methods. Any sampling artifacts and short-term atmospheric processes that contribute to the total nitrogen budget will be identified.
Poster Presentation
Prepared by G. Beachley, M. Puchalski
US Environmental Protection Agency, 1200 Pennsylvania Ave NW, MC-6204 M, Washington, DC, 20460, United States
Contact Information: [email protected]; 202-343-9621
ABSTRACT
The US EPA has recently been supplementing long-standing Clean Air Status and Trends Network (CASTNET) filter pack measurements of weekly integrated atmospheric nitric acid (HNO3), nitrate (NO3-), and ammonium (NH4+) concentrations with hourly resolved and speciated measurements of atmospheric nitrogen to provide a detailed look at short-term concentration variations and to enable a more complete assessment of contributors to the nitrogen budget. In addition, CASTNET sites have been expanded to collocate with the National Atmospheric Deposition Program (NADP) Ammonia Monitoring Network (AMON) which provides a 2-week passive measurement of Ammonia (NH3).
Hourly atmospheric ambient concentrations of nitrogen gases (HNO3, NH3) and aerosols (NO3-, NH4+) have been measured using the Monitor for AeRosols and GAses (MARGA) systems at the Beltsville, MD (BEL116) site during extended sampling periods over the past two years.
An experimental hourly trace level total reactive nitrogen sampling system, Nitrotrain, has been developed to analyze the components of the reactive nitrogen sample. The Nitrotrain consists of a solenoid sampling system to divert flows, a single commercially available chemiluminescence analyzer, and four converter boxes: a total nitrogen (TNx) stainless steel converter, two traditional molybdenum converters (one at 10m for NOy and a second at the analyzer for NOx), and an LED-based photolytic NOx converter. Calculated and measured parameters include NO, NOx, NHx, NO2 from the Molybdenum converter, and NO2 (true) from the photolytic converter.
Nitrogen measurements taken at the Beltsville site since November of 2014 will be compared and analyzed to assess instrument performance of the Nitrotrain and the MARGA against the integrated sampling methods. Any sampling artifacts and short-term atmospheric processes that contribute to the total nitrogen budget will be identified.
