Table 4.
Comparison of common thermal/optical protocols: IMPROVE_A, STN, and EUSAAR_2
| Carbon fraction | Atmosphered | IMPROVE_A_TORa | STN_TOTb | EUSAAR_2_TOTc | |||
|---|---|---|---|---|---|---|---|
| Temp. (°C) | Residence time (s)e | Temp. (°C) | Residence time (s) | Temp. (°C) | Residence time (s) | ||
| OC1 | Inert | 140 | 80–580 | 310 | 60 | 200 | 120 |
| OC2 | Inert | 280 | 80–580 | 480 | 60 | 300 | 150 |
| OC3 | Inert | 480 | 80–580 | 615 | 60 | 450 | 180 |
| OC4 | Inert | 580 | 80–580 | 900 | 90 | 650 | 180 |
| Oven coolingf | NA | NA | NA | 30 | NA | 30 | |
| EC1 | Oxidizing | 580 | 80–580 | 600 | 45 | 500 | 120 |
| EC2 | Oxidizing | 740 | 80–580 | 675 | 45 | 550 | 120 |
| EC3 | Oxidizing | 840 | 80–580 | 750 | 45 | 700 | 70 |
| EC4 | Oxidizing | NA | NA | 825 | 45 | 850 | 80 |
| EC5 | Oxidizing | NA | NA | 920 | 120 | NA | NA |
NA not applicable
aThe non-urban Interagency Monitoring of Protected Visual Environments (IMPROVE) network and urban Chemical Speciation Network (CSN), measures and reports both thermal/optical reflectance (TOR), and thermal/optical transmittance (TOT), following the IMPROVE_A_TOR protocol (Chow et al. 2007b, 2011)
bSpeciation Trends Network (STN), also called NIOSH-like protocol (Peterson and Richards 2002)
cEuropean Supersites for Atmospheric Aerosol Research, EUSAAR_2, protocol (Cavalli et al. 2010)
dInert atmosphere ultra-high purity (UHP) helium (He) for OC analysis. Oxidizing atmosphere 98 % He/2 % oxygen (O2) for all protocols
eRamping to the next temperature or atmosphere begins when the flame ionization detector (FID) response returns to either baseline or a constant value; these times represent minimum and maximum times to be spent in any segment, respectively
fAt the end of OC analysis, a cooling blower turns on for ∼30 s. EC analysis starts ∼10 s after the introduction of 98 % He/2 % O2