ACRYLONITRILE

Measurements in Ambient Air, Concerns and Sampling Issues

ACRYLONITRILE CHEMICAL FORMULA

1. May polymerize spontaneously and violently in the presence of sunlight

2. Has a half-life of about 50 hrs in air3. Reacts readily with oxygen and

hydroxyl radicals to form formaldehyde, formic acid, and formyl cyanide

4. No natural sources

OUTLINE

• Monitoring and Data Review

• Relative Risk and Possible Sources

• Results of ARB and SCAQMD Parallel Monitoring

• Issues and Steps Taken in an Attempt to Reconcile Sampler Differences

• Conclusions and Next Steps

MONITORING

• Started in July, 2003, MLD SOP066

• Samples in canisters collected over 24 hrs 1-in-12 days in regular TAC network using regular samplers in place (not cleaned)

• Analyzed by preconcentration GC/MS

• NIST calibration standard used

• Lab results confirmed independently by Dr. Rasmussen

DATA ANALYSIS

• Maximum concentrations found in the summer

• Maximum concentrations found during the periods of highest temperature

• No correlation with auto exhaust pollutants

• Concentrations in 12 other states found to be greater than in California

• Up to 47 ppb found in homes in 1998

NATTS Data Review by STI

• Called CA ACN data “questionable”

• Only looked at annual averages

• Used benzene data as the only analysis tool, but admitted that benzene might not be appropriate in this case

• Didn’t know we had a NIST standard

• Admitted that data from Arizona NATTS site look high, as well

RISK FROM ACRYLONITRILE

• 2004 statewide annual average was 0.48 ppb, a risk of 300 in a million

• 2004 South Coast annual average was 0.52 ppb, a risk of 320 in a million

• Risk from diesel pm is estimated at 300 – 650 in a million

• Risk from benzene and butadiene together is 83 in a million

2004 South Coast Average Risk

0

100

200

300

400

500

600

700

Diesel Acrylo Butadiene Benzene Perc

per

mil

lio

n r

isk

Series1

SOURCES?

• Emission inventory contains little information on emissions

• No acrylonitrile manufacturing use in California

• Acrylonitrile used in a wide variety of polymers, paints, adhesives, and fibers

• Landfills?

• Polymer extruding operations?

GRAB SAMPLING

• Grab samples taken in three Sacramento homes: <0.3, 0.6, <0.3 ppb

• Grab sample taken in cab of truck on car lot: 6 ppb

• Grab sample taken in private garage: 11 ppb

FLUX CHAMBER EMISSIONS

• ABS Polymer 4.4 ug/gm• ABS Pipe 11 ug/gm• ABS Plate 5 ug/gm• Acrylic glue 47 ug/gm• Latex Paint 0.4 ug/gm• Enamel Paint 1.2 ug/gm• N Gloves 1.5 ug/gm• Carpet 0.3 ug/gm• Sheet Vinyl 0.3 ug/gm• Ceramic Glue 0.2 ug/gm

• Fingernail Polish 12 ug/gm

OTHER PUBLISHED WORK

• Sampling and Analysis of Volatile Organic Compounds Evolved During Thermal Processing of ABS Composite Resins

• Contos, et al.• JAWMA, 45, 686-694

• Acrylonitrile, ug/gm• Auto Parts: 5.74• Pipe: 9.75• Refrigeration: 10.4

PARALLEL MONITORING

• ARB and SCAQMD at LA N Main in Fall of 2006

• Samples collected by ARB contained detectable concentrations of acrylonitrile

• Samples collected by SCAAQMD contained no detectable acrylonitrile

• Possibilities: ARB sampler creating acrylonitrile or SC sampler destroying it

ARB SAMPLER CHECKS

• Bakersfield collocated sampler removed to lab and challenged with humidified zero air, no acrylonitrile detected

• Used sampler challenged with zero air, no acrylonitrile detected

• ARB sampler in place at Fremont challenged with zero air by BAAQMD, no acrylonitrile detected

THROUGH-THE PROBE (TTP) PERFORMANCE AUDIT

LA N Main

How is a TTP done?

• Audit gases are mixed in the van using a gas calibrator to dilute the high pressure gases of high concentrations with zero air

• Diluted gas mixture is introduced into van’s probe line, where it is drawn in from the probe inlet of ambient air monitoring stations

• Bypass ensures no dilution to audit gases• Sample introduced over 24 hr period

TTP History

• In use since 1988

• Used for both criteria pollutants and Toxics

• Peer reviewed with 4 papers and presentations

• For VOC determinations, +/-20% agreement considered acceptable. This includes dilution and analytical precision

TTP AUDIT CONFIGURATION

2002 TTP RESULTS

Cmpound Ave. Difference %

St. Dev % Max Diff %

Benzene -4.9 5.9 -15.4

Toluene -6.8 5.9 -14.4

m/p Xylene

13.8 16.2 26.1

o Xylene -5.6 4.6 -15.7

TTP SAMPLING PROTOCOL

• Week 1, ARB Sampler

• Days 1, 3, 5: humidified zero air challenge

• Days 2, 4: diluted standard air challenge

• Week 2, SCAAQMD sampler

• Days 1, 3: humidified zero air challenge

• Days 2, 4: diluted standard air challenge

ANALYSIS PROTOCOL

• ARB sampler samples sent to ARB lab for analysis

• ARB samples sent to SCAQMD lab for analysis

• ARB samples returned to ARB lab for re-analysis

• SCAQMD samples analyzed by SCAQMD lab, sent to ARB for analysis, and returned

ARB LAB RESULTS

Sample Date Collected

Result 1, ppb

Result 2, ppb

Percent Difference

“True Value”, ppb

ARB, Can #3059

3/20/07 1.59 (3/29)

1.45 (4/24)

-9.1 1.75

ARB, Can #24856

3/22/07 2.0 (3/29) 1.94 (4/24)

+14.0 1.75

SC Can #E3387

3/27/07 1.13 (4/9) -35.4 1.75

SC Can #E3759

3/29/07 1.23 (4/9) -29.7 1.75

SCAQMD LAB RESULTS

Sample Date Collected

Result 1, ppb

Date Analyzed

Percent Difference

“True Value”, ppb

ARB, Can #3059

3/20/07 1.2 4/4/07 -31.4 1.75

ARB, Can #24856

3/22/07 1.4 4/4/07 -20.0 1.75

SC Can #E3387

3/27/07 1.1 4/4/07 -37.1 1.75

SC Can #E3759

3/29/07 1.4 4/4/07 -20.0 1.75

RESULTS COMPARISON

Sample ARB Results, ppb

SCAQMD Results, ppb

Results Ratio

Date Analyzed, ARB

Date Analyzed, SCAQMD

ARB, Can #3059

1.5 1.2 0.8 3/29 4/4

ARB, Can #24856

2.0 1.4 0.7 3/29 4/4

SC Can #E3387

1.1 1.1 1.0 4/9, rc’d 4/5

4/4

SC Can #E3759

1.2 1.4 1.2 4/9, rc’d 4/5

4/4

• Results for all humidified zero air challenges were <0.3 ppb (ARB), <0.2 ppb (SCAQMD)

CHICO SAMPLING

• SCAQMD sampler and sampling line installed in parallel with existing Chico ARB sampler 8/20/07

• Samples collected in parallel and analyzed by ARB lab

• Although differences in acrylonitrile recoveries, all other pollutants agreed well in ambient sampling

CHICO LAB RESULTS

Date Collected

ARB Sampler ppb

SC Sampler ppb

ARB Percent Difference

SC Percent Difference

“True Value”, ppb

8/22 0.66 0.25 N/A N/A Ambient

8/30 – temp.: 107 F

1.26 0.1 N/A N/A Ambient

9/11 1.06 0.58 +6.0 -42 1.0 (TTP)

9/12 1.45 0.48 +45 -52 1.0 (TTP)

SAMPLER TESTING IN SACRAMENTO

• Both the ARB and SCAQMD samplers were removed from the Chico site and sent to the Sacramento facility for inspection and testing without sampling lines.

• It was agreed, due to the coming of winter, that further ambient testing was not likely to produce useful data.

SAMPLER INSPECTIONS

• The interior and pumps for both samplers were inspected by instrument techs without repair or cleaning

• The techs concluded that the samplers were identical, except that the pump head on the ARB sampler was dirty, whereas the pump head for the SCAQMD was clean. The ARB sampler had been in the field for over 15 years.

ARB Pump

• The deposition pattern of the brown residue on the piston head indicates that liquid may have been in pump

• Black powdery residue on the Teflon diaphragm

SCAQMD Pump

• Piston head and Teflon diaphragm are both clean

SACRAMENTO LAB RESULTS

Date Collected

ARB Sampler ppb

SC Sampler ppb

ARB Percent Difference

SC Percent Difference

“True Value”, ppb

10/26 0.48 0.33 -4 -34 0.5

10/29 1.03 0.85 +3 -15 1.0

11/2 2.38 2.15 +19 +7.5 2.0

CONCLUSIONS

• New and/or cleaned samplers collect acrylonitrile at active sites in the equipment causing loss of sample

• The mechanism of this loss is still unknown

• All new samplers must be challenged with acrylonitrile until the active sites are passivated

FOLLOWUP WORK

• New samplers are to be challenged with acrylonitrile to determine the extent of passivation required

• The acrylonitrile working group should be re-activated and efforts to determine sources of acrylonitrile be continued

• Other groups nationally (NATTS) should be advised