Ambient sampling Facilities
Ambient Particle Sampling
Semi-continuous Field Systems
Semicontinuous PM2.5 mass can be measured using 2 Rupprecht and Patashnick Model 8500 Fluid Dynamics Measurement System (FDMS). The FDMS accounts for both the semi-volatile and non-volatile components of particulate matter, reporting the combination as a mass concentration result. The FDMS unit constantly samples ambient air and uses a switching valve to change the path of the main flow every six minutes.
We also have another TEOM 1400a/b with a Sample Equilibration System (SES). The SES is a nafion drier system that reduces the relative humidity in the inlet stream to remove particle bound water.
Carbonaceous materials in PM2.5 can be measured by using two analyzers, a semi-continuous Sunset Lab OC/EC field instrument (Sunset Laboratory, Forest Grove, OR) for OC, thermal EC (EC), and Sunset Lab optical EC (BCs) and a dual field Sunset OC/EC system that permits the measurement of the semivolatile component of the organic carbon as well as OC and EC. The OC/EC field instrument is based on NIOSH Method 5040.
Several two-wavelength Aethalometer, AE-20 (Magee Scientific, Berkeley, CA) are available to measure BC and UV BC. The BC is measured at λ = 880 nm and UV-absorbing aromatic organic material (UV-BC) is measured at 370 nm. The UV measurements by the two-wavelength Aethalometer identifies the presence of certain organic compounds such as polycyclic aromatic hydrocarbons ( PAH ) that strongly absorb UV wavelengths. The enhancement in the UV absorbing signal indicates the presence of additional quantities of non-black, UV-absorbing aromatic organic material such as wood smoke.
Ten-minute averaged continuous sulfate concentrations will be measured using Thermo Model 5020 continuous sulfate analyzers.
Light scattering can be measured using integrating nephelometers (Radiance Research, M903) with and without a Nafion dryer. The nephelometers are light weight, low power instruments designed for portable operation as well as general environmental monitoring. They measure the light scattering extinction using an optical filter at a wavelength of 530 nm.
Particle Size Distributions
We have several TSI scanning mobility particle sizers (SMPS) and two MSP wide-range particle spectrometers (WPS) for particle size determinations of particles below 500 nm and a Fast Mobility Particle Sizer. The WPS includes a laser particle counter that extends the range of the instrument to 20 µm. We also have several optical particle counters for size distributions measurements in the range of 300 nm to 20 μm. We have two TSI Aerosol Particle Spectrometers (model 3021) to also measure size distributions in the 0.25 to 20 μm range.
Aerosol Time-of-Flight Mass Spectrometry
A TSI Model Model 3800 Aerosol Time-of-Flight Mass Spectrometer (ATOFMS) spectrometer will be deployed. The ATOFMS measures single particle size and chemical composition in the range from 0.2 to 3 micrometers (up to 10 micrometers with optional disperser). It uses an aerodynamic sizing technique to size individual particles in real time. Then, it desorbs and ionizes the particle for chemical analysis in a bipolar, time-of-flight mass spectrometer. The instrument is capable of saving positive and negative mass spectra at a rate of up to 10 particles per second.
Ambient Gas Monitors
We have a collection of Thermo i-series ambient gas monitors including CO, NO/NO2/NOx, NOy/ SO2, and O3.
Mobile Air Pollution Laboratory (MAPL)
The MAPL (Figure 1) is constructed within a Recreational Cargo Van. One wall was cleared for bench space and shelving to outfit with instrumentation, as given in Table 1. A manifold inlet was installed to provide ambient air to all benched instruments, where the instruments with the higher flow rates were furthest downstream to provide sufficient flow to minimize diffusion losses of ultrafine particles that were sampled by the respective instruments upstream. Also, only one 90-degree turn exists to prevent losses of the larger particles. All instruments in the mobile lab are designed to primarily measure particles in the PM2.5 fraction, with the exception of the Grimm, an optical particle counter that measures particle number size distributions between 0.3 and 20 µm. Thus, the inlet manifold was designed to minimize both diffusion and inertial deposition losses.
The MAPL is powered with 8 heavy duty car batteries which are stored in a ventilated rack system, laterally housed behind the driver’s and front passenger seats. The batteries are connected to a programmable inverter which allows tracking of the power consumption and available current supply, providing a power capacity of about 30-35 amps, which lasted between 10 and 15 hours, depending on the overall load.
The collection of portable, continuous monitors (gases, particles) described above are available for deployment in the MAPL so the instrumentation can be customized for the particular monitoring program.
Ambient Integrated Particle Samplers
We have multiple Tisch 1000 high volume PM2.5 and Anderson RAAS samplers, as well as a Thermo ChemVol that can collect size segregated samples (2.5 to 10 µm; 1.0 to 2.5 µm; 0.2 to 1.0 µm; and < 0.1 µm) on PUF collection media for the larger sizes and a filter for the ultrafines at 900 Lpm. Two 8-stage Micro-orifice uniform deposit and 1 ten-stage Micro-orifice uniform deposit impactors (MOUDIs) are available. In conjunction with the 10-stage MOUDI, there is a three stage nano-MOUDI, that permits separation of particles below 100 nm into three size fractions.
Measurements can be made of both individual exposure and microenvironmental concentrations using 10 LPM personal exposure monitors (PEMs) with 2.5 μm or 10 μm cut-points. There are 23 such PM2.5 and 10 PM10 units available. These impactors can provide aerosol samples on a variety of 37 mm collection media.