Measurement of Acrylonitrile in Ambient Air AMTAC April 12, 2011 John Bricarello California Air Resources Board

2 Requirements  Need to find alternate to 910 sampler  Cannot pass air through an instrument prior to capturing the acrylonitrile  Must be more sensitive than current method (MLD066 RL = 0.3 ppb)  Must be able to deploy a sampler without too much disruption to field personnel

3 Where we left off May 2009  Select appropriate sorbent material  Finalize instrumental method  Select sampler for sorbent tubes  Establish sampling protocol with low flow pump  Test designed methodology and generate results  Move final methodology to field

4 Solid Sorbent Carboxen 1000  Advantages  Good reproducibility for standards  Low trap desorption temperature, few artifacts  Can be used more than 200 times  Handles low sampling flows over 24 hour period  Detection ‘on tube’ <0.05ng  Disadvantages  Advertised as hydrophobic, it still retains a significant amount of water  Designed for C2 – C5 molecules it retains up to C10 organics both polar and non-polar

5 Instrumentation

6 Sampling and Problems  Startup  Battery operated personal pump equipped with four tube holder  One sample tube, three spiked tubes  Battery operated – did not last 24 hours  Fair recovery with inside air, very poor recovery in outside air  Water in air interfered with retention of acrylonitrile  Theorized that pressure drop across sorbent tube led to water condensation

7 Sampler Version 1 Quad Manifold Tube Heater Variac Heater Controller Pump Tubes Clips Heater

8 Sampler Version 2 Figure 1Figure 2 Figure 3 Figure 4 Figure 5

9 MLD’s Roof Top Monitoring Platform Results Average Median Maximum Minimum Result, ppt Recovery, % Correl. Coeff Average of all >300ppt (60 in Million cancer risk) canister results = 590ppt

10 Typical Acrylonitrile MS Output Typical TIC of Sample containing methanol Extracted Ion Chromatogram of Standards, Sample & Spikes

11 Acrolein  Testing  Added acrolein to acrylonitrile standards  Issues  Stability of acrolein in canisters compared to acrylonitrile  Alternate methodology  The follow slide shows acrylonitrile - acrolein comparison

12 Acrolein Results MLD Roof ACN Acrolein ppt Avg Med Max Min Rec. avg 78% 57% All Monitoring Sites Avg n= n: > 300ppt results 4560 total measurements

13 Observations and Other Anecdotal Information  Passivated Carboxen 1000  Fiberglass epoxy enclosure caused interferences  PVC led to elevated acrylonitrile levels  Sampler influences result  Higher results on calm days than windy days  Tubes need to be heated all the time

14 What is Coming  Develop Sampler version 3  Deploy sampler to selected sites  Finalize analytical SOP for acrylonitrile and possibly acrolein  Compare site data  Determine shipping, sampling and receiving logistics  Deploy to all network sites if feasible

15 Contact John Bricarello, APS California Air Resources Board Monitoring and Laboratory Division (916)