DRI MODEL 2015
DRI MODEL 2015
The DRI Model 2015 Multi-Wavelength Thermal/Optical Carbon Analyzer is the most advanced instrument globally for the thermal analysis of the carbonaceous content of aerosol samples collected on filters.
In multiple temperature fractions, it quantifies organic carbon (OC) and elemental carbon (EC, closely related to Black Carbon [BC]). It monitors both the optical transmittance and optical reflectance of the sample simultaneously at 7 wavelengths. These optical signals correct the thermal analysis for the effects of pyrolysis and allow for apportionment in terms of ‘Brown’ carbon, an indicator of biomass combustion. The DRI-2015 represents a very major advance over the widely-used earlier model DRI-2001.
The DRI-2015 was designed by Professors J.C. Chow and J.G. Watson at the Desert Research Institute of the University of Nevada, Reno, USA. Manufacturing and commercialization of this highly sophisticated instrument were licensed to Magee Scientific Corporation of California and its partner company Aerosol. The DRI-2015 provides the most advanced and complete analysis of carbonaceous aerosol particles collected from the atmosphere or directly from sources.
The DRI Model 2015 Multi-Wavelength Thermal/Optical Carbon Analyzer is a major advance over the earlier model DRI-2001, which has been widely used to quantify the organic carbon (OC) and elemental carbon (EC) fractions in aerosol samples collected on quartz fiber filters.
The DRI-2015 has been extensively inter-compared against the DRI-2001 and other analyzers to demonstrate complete consistency with previous measurements.
The DRI-2015 uses 7 lasers operating at wavelengths of 405, 445, 532, 635, 780, 808, and 980 nm to measure the intensity of light both reflected from the sample (R); and transmitted through the sample (T). This allows for analysis using both the ‘TOR’ and ‘TOT’ protocols simultaneously. The multi-wavelength analysis provides a determination of the “Brown Carbon” (BrC) component of the sample and provides detailed data for source apportionment studies.
The DRI-2015 software provides full instrument control, data acquisition, and display. It includes temperature programs for commonly-used protocols such as IMPROVE_A, EUSAAR, and NIOSH, and it can be programmed to emulate any other protocol. The simultaneous measurement of both R and T at all wavelengths throughout each analysis allows the system to reproduce any other thermal/optical method for characterizing additional properties of the carbonaceous aerosol.
- Air quality and climate change research
- Particulate Matter (PM) speciation trends networks
- PM source apportionment
- Carbonaceous material analysis
FEATURES AND IMPROVEMENTS
- Compatible with the IMPROVE_A carbon analysis protocol, used in the U.S. urban Chemical Speciation Network (CSN), the non-urban Interagency Monitoring of Protected Visual Environments (IMPROVE) Network, and long-term networks in other countries.
- High-intensity light sources and perpendicular orientation of R and T measurements to maximize optical sensitivity.
- Nondispersive infrared (NDIR) CO2 detection eliminates the need for hydrogen gas and methanation as required for a flame ionization detector (FID).
- Reduced helium gas consumption.
- Mass flow controllers interfaced with the computer system provide precise control of all reagent gases.
- LabVIEW-based software provides enhanced user interface and instrument control.
- Completely re-designed engineering provides improved access for maintenance and service.
Thermal/optical carbon analysis is based on the progressive decomposition of OC and EC fractions at increasing temperatures and inert or oxidizing atmospheres. A small punch from a sample collected on a quartz-fiber filter is heated in programmed temperature steps. Organic compounds are released in a non-oxidizing helium atmosphere at temperatures up to 580 °C. In comparison, ‘elemental’ carbon is combusted in an oxidizing atmosphere consisting of helium with oxygen at temperatures up to 840 °C. The carbon released from the sample is converted to carbon dioxide (CO2) by a heated manganese dioxide catalyst oven, and an NDIR detector quantifies the CO2. Seven modulated diode lasers operating at wavelengths from 405 to 980 nm measure the reflectance from and transmittance through the sample on the filter.