The purpose of this activity, which is part of the larger Pittsburgh Air Quality Study, is to create an extensive database of ambient PM measurements for source apportionment, examination of aerosol processes, and air quality model development and evaluation. The measurement campaign will last for 18 months (May 2001-October 2002) to include two summers and will consist of regular measurement periods and three 14-day intensive periods. The first intensive period is scheduled for July 2001; the second and third intensive periods are tentatively scheduled for January and September of 2002.

The work is being conducted under the direction of a project management team headed by Carnegie Mellon University and includes DOE, RJ Lee Group, University of Maryland College Park, University of California at Davis, University of Delaware, Clarkson University, Ohio University, Brigham Young University, and Rutgers University. The project team has determined the direction of the research, finalized the work plan, and carrying out the work.

PM Size Distributions
CMU will measure the ultrafine aerosol size distribution (3 nm to 50 nm) at the central supersite. These measurements will be made continuously using Ultrafine Scanning Mobility Particle Spectrometer (TSI model 3936N25) for 0.003-0.150 µm. They will measure of surface area concentrations at the central site using an epiphaniometer.

Size-resolved PM Mass and Composition
CMU will make size-resolved PM mass (PM_x) and composition measurements using Micro-Orifice Uniform Deposit Impactors (MOUDI). Mass size distribution measurements will be made periodically during the baseline-sampling period, tentatively on a 1 in 6 sampling schedule. Size-resolved samples collected during the intensives will be analyzed for chemical composition including ions, metals, and Organic Carbon/Elemental Carbon (OC/EC). These analyses will be performed in the CMU Air Quality Laboratories.

Advanced Characterization of PM2.5 Chemical Composition

• Sampling Artifacts: Brigham Young University (Eatough group) will examine sampling artifacts in conventional sampling systems using the PC-BOSS diffusion denuder sampler during the intensive periods. The PC-BOSS will provide data for OC and EC as well as semi-volatile organics lost from particles during sampling. In addition, analyses will be conducted for sulfate, nitrate, ammonium, and acidity.

• Organic Aerosol Characterization:Rutgers University (Turpin Group) (Rutgers) will perform advanced characterization of organic aerosol using Fourier Transform Infrared Spectroscopy (FTIR) and other techniques. High volume samples will be collected for analysis of organic mass, functional groups and carbon by polarity with the likelihood of further exploratory analyses on fractions. During the intensive periods size-resolved samples will be collected and at least qualitative functional group analysis by polarity.

Continuous and Semi-Continuous PM Composition

• In situ OC/EC
  Rutgers will design and construct an improved in-situ semi-continuous OC and EC analyzer. The new analyzer should reduce sampling times to 1 hour per measurement (a reduction of a factor of two over the existing instrument). The in-situ carbon analyzer collects PM 2.5 samples on a quartz fiber filter mounted inside a thermal-optical carbon analyzer. The analyzer will be deployed at the central site throughout the monitoring period.

• Semi-continuous elements
  The University of Maryland (Ondov group) will measure the concentration of 18 metals species (As, Cu, Mn, Ni, Cr, Cd, Se, Ag, Pb, Al, Fe, Zn, Ca, Bi, V, Ti, Be, and Ba) during two intensive periods at both the central supersite and one of the rural satellite sites. Their semi-continuous system consists of a high-frequency aerosol sampler (HFAS) (dynamic aerosol concentrator) and a true simultaneous multi-element Graphite Furnace Atomic Absorption (GFAA) spectrometer. The initial target sample collection period is 10 minutes, but will depend on ambient concentrations and preliminary findings.

Single Particle Characterization

• Single Particle Mass Spectroscopy
  The University of California at Davis (Wexler group) and the University of Delaware (Johnston group) will deploy a new, more portable, single particle instrument based on ion mobility spectrometry. The new instrument, APS-IMS, is a TSI Aerodynamic Particle Sizer with an attached Ion Mobility Spectrometer. Over the size range of the APS, APS-IMS is able to size, count, and chemically analyze individual particles. It complements RSMS-II (another single particle mass spectrometer supported by EPA funds), whose size range is roughly 10 nm to 2 microns, because it operates over roughly the 500 nm to 15 micron size range. In addition, APS-IMS is likely to be better at speciating organic compounds than RSMS-II, because the ablation step occurs in the presence of a one-atmosphere carrier gas, effectively cooling the ablated ions so they can remain intact before analysis. The APS-IMS will be deployed during the intensive periods, and other times as the budget permits.

• Laser-Induced Breakdown Spectroscopy (LIBS)
  The University of Maryland (Buckley group) will measure the elemental composition of single particles in the atmosphere by Laser-Induced Breakdown Spectroscopy (LIBS). Using atomic emission, the mass concentration of a number of elements (Be, Cd, Cr, Na, K, V, Ni, Si and Pb) and particle mass within the spark volume will be quantitatively measured. The LIBS system will be deployed during two of the intensive sampling periods and during one month of the baseline-sampling period.
• CSEM analysis
  During the intensive periods, CMU will collect samples on polycarbonate filters for analysis by the RJ Lee Group using computer controlled scanning electron microscopy (CCSEM).

Aerosol Optical Properties
CMU will measure the aerosol scattering coefficient using an integrating nephelometer. The visual range will also be measured during the measurement periods and additional observations will be collected from the airports in the area and archived. Pictures (in electronic form) of the area surrounding the supersite will be taken every hour during the intensive sampling period and every six hours during the rest of the study period for the calculation of the visual range and documentation of the prevailing conditions.