AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
The Age Old Question: Continuous or 24-hr Integrated Measurements
Oliver Rattigan, H. Dirk Felton, Kevin Civerolo, JAMES SCHWAB, New York State Dept. of Environmental Conservation
Abstract Number: 407 Working Group: Instrumentation and Methods
Abstract PM2.5 chemical species measurements are routinely performed using 24-hr integrated methods. The measurements provide a reliable database for determining long term trends which can be used to assess the impact of emission controls e.g. SOX and NOX on fine particle concentrations downwind of sources. Since the 24-hr samples are collected on a 1 in 3 or 1 in 6 day basis due to the high cost of filter analysis, the data is best suited for annual and seasonal trends. In addition single pollution episodes and sub-daily events can be missed. In recent years commercial instruments have been developed that can measure most of the major particle species, SO4, NO3 as well as organic and elemental carbon (and black carbon) on an hourly or sub-hourly basis. The higher temporal information is used in the interpretation of varying pollutant patterns with changing emissions and meteorological conditions. High frequency wind and species data can aid in the identification of individual sources or a localized widespread source. The temporally resolved data can also help identify high concentration periods that are likely to have the greatest impact on health. The limitation of the continuous based methods is that their response factor relative to 24-hr integrated methods can differ from unity and may vary with location or season making mass closure analysis difficult. In this poster we provide examples where 24-hr integrated data is useful and examples where continuous measurements are beneficial.