TY - GEN
T1 - Fine particulate matter nitrate measurements by flash volatilization
T2 - Symposium on Air Quality Measurement Methods and Technology, 2005
AU - Reid, Catherine S.
AU - Turner, Jay R.
AU - Hering, Susanne V.
PY - 2005
Y1 - 2005
N2 - A flash volatilization method for quantifying ambient fine particulate nitrate developed by Aerosol Dynamics, Inc. (ADI) and commercialized by Rupprecht and Patashnick (R&P) as the Series 8400N Ambient Particulate Nitrate Monitor has been operated at the St. Louis - Midwest Supersite for a period of more than one year. This paper summarizes key findings from this field deployment including: 8400N nitrate recoveries relative to both filter measurements and Particleinto-Liquid-Sampler (PILS) measurements at the core monitoring location in East St. Louis, IL; and 8400N nitrate recoveries compared to filter measurements for a four-month study conducted in Reserve, KS. With respect to filter nitrate, 8400N recoveries were excellent below ∼2 μg/m3 nitrate but decreased and exhibited more variability with increasing nitrate concentration. A detailed analysis of hourly data for the 8400N nitrate, PILS nitrate, and Sunset carbon reveals a matrix effect between 8400N nitrate recovery and aerosol composition. At low carbon concentration there appears to be a deficiency of electron donors (for which carbon is the most likely source) necessary for the complete reduction of nitrate to NO/NO2; under these conditions, 8400N nitrate recovery with respect to PILS nitrate is low and variable. As the aerosol total carbon concentration increases, the 8400N nitrate recoveries increase and become less variable. The hypothesis that an electron donor deficiency can suppress nitrate reduction in the 8400N was tested in the field in spring 2005 using collocated 8400N units with the nitrogen purge gas for one unit doped with 10 ppmv carbon monoxide. The unit with the CO-doped purged gas exhibited an immediate and sustained 20% increase in reported nitrate concentration. This purge gas doping experiment confirms that in some environments - including St. Louis - an electron donor deficiency prevents the complete conversion of nitrate to NO/NO2 in the 8400N and therefore at least in part explains the low 8400N nitrate recoveries. More work is necessary to determine the optimal methodology for introducing electron donors into flash zone towards improving overall instrument performance.
AB - A flash volatilization method for quantifying ambient fine particulate nitrate developed by Aerosol Dynamics, Inc. (ADI) and commercialized by Rupprecht and Patashnick (R&P) as the Series 8400N Ambient Particulate Nitrate Monitor has been operated at the St. Louis - Midwest Supersite for a period of more than one year. This paper summarizes key findings from this field deployment including: 8400N nitrate recoveries relative to both filter measurements and Particleinto-Liquid-Sampler (PILS) measurements at the core monitoring location in East St. Louis, IL; and 8400N nitrate recoveries compared to filter measurements for a four-month study conducted in Reserve, KS. With respect to filter nitrate, 8400N recoveries were excellent below ∼2 μg/m3 nitrate but decreased and exhibited more variability with increasing nitrate concentration. A detailed analysis of hourly data for the 8400N nitrate, PILS nitrate, and Sunset carbon reveals a matrix effect between 8400N nitrate recovery and aerosol composition. At low carbon concentration there appears to be a deficiency of electron donors (for which carbon is the most likely source) necessary for the complete reduction of nitrate to NO/NO2; under these conditions, 8400N nitrate recovery with respect to PILS nitrate is low and variable. As the aerosol total carbon concentration increases, the 8400N nitrate recoveries increase and become less variable. The hypothesis that an electron donor deficiency can suppress nitrate reduction in the 8400N was tested in the field in spring 2005 using collocated 8400N units with the nitrogen purge gas for one unit doped with 10 ppmv carbon monoxide. The unit with the CO-doped purged gas exhibited an immediate and sustained 20% increase in reported nitrate concentration. This purge gas doping experiment confirms that in some environments - including St. Louis - an electron donor deficiency prevents the complete conversion of nitrate to NO/NO2 in the 8400N and therefore at least in part explains the low 8400N nitrate recoveries. More work is necessary to determine the optimal methodology for introducing electron donors into flash zone towards improving overall instrument performance.
KW - Ambient measurements
KW - Nitrate
KW - PM
KW - Semi-continuous instruments
UR - https://www.scopus.com/pages/publications/33847345512
M3 - Conference contribution
AN - SCOPUS:33847345512
SN - 0923204741
SN - 9780923204747
T3 - Symposium on Air Quality Measurement Methods and Technology, 2005
BT - Symposium on Air Quality Measurement Methods and Technology, 2005
Y2 - 19 April 2005 through 21 April 2005
ER -