1. AIR SAMPLING
HEADLINES IN HYGIENE
JANUARY 2016

2. NEWSWORTHY TOPICS IN AIR SAMPLING FOR 2016
1. Vapor Intrusion
2. Formaldehyde
3. Methanol

3. VAPOR INTRUSION (VI): WHAT IS IT? HOW DOES IT HAPPEN?
Vapor intrusion is the
migration of volatile
chemicals from the
subsurface into overlying
buildings.
HOW DOES IT HAPPEN?
Volatile chemicals in buried
wastes and/or contaminated
groundwater emit
vapors that migrate
through subsurface soils and
into indoor air spaces of
overlying buildings via cracks,
conduits, and other openings.

4. ILLUSTRATION OF VAPOR INTRUSION

5. VAPOR INTRUSION WHAT’S NEW?
The original U.S. EPA DRAFT Guidance for Evaluating the Vapor Intrusion to Indoor Air Pathway from Groundwater and Soils was issued in 2002 (and never finalized).
Under pressure, EPA released an updated FINAL guidance document in June Preview the document on the EPA vapor intrusion website at

6. COMMON VAPOR INTRUSION SOURCES
Any site with volatile chemicals!
Manufacturing sites (especially those with chlorinated solvents)
Dry cleaners using perchloroethylene
Leaking sewers or septic tanks where chemical wastes have been dumped
Any site with a fuel spill
Landfills

7. NOTE ON PETROLEUM HYDROCARBONS
The 2015 VI Technical Guidance Document is NOT designed for hydrocarbons that are the result of releases from underground storage tanks.
For this application, EPA has a companion document which is a technical guide for petroleum vapor intrusion at leaking underground storage tanks.

8. MORE ON PETROLEUM HYDROCARBONS
The approaches in the VI Technical Guide are recommended by U.S. EPA for subsurface releases from the following:
Refineries
Bulk storage facilities
Oil exploration and production sites and pipelines
Chemical manufacturing sites
Fueling and storage operations at federal facilities
Dry cleaners

9. PREDOMINANT CONTAMINANTS
According to the EPA Indoor Air Vapor Intrusion
Database, the predominant TOXIC vapors found in
indoor air at vapor intrusion sites are chlorinated
hydrocarbons and petroleum hydrocarbons.
Methane and other vapor-forming chemicals can
also pose EXPLOSION hazards.

10. NOTEWORTHY VI CASE IN THE U.S.
Mercury at New Jersey Day Care Center
“The discovery of toxic mercury vapors in a day care
center built on the site of a former thermometer factory
is just the latest in a series of toxic scandals to rock
New Jersey. More than 30 children were exposed to
toxic mercury vapors at the Kiddie Kollege day care
center in Franklinville, New Jersey”.
( August 2006)

11. VI: A UNIQUE KIND OF INDOOR AIR CONCERN
Source of contaminants is underground
Evaluating the risk of VI from chemicals underground is complicated by the presence of those same chemicals from other indoor air emission sources or occupant activities.

12. VI MEASUREMENTS: NOT JUST INDOOR AIR
Involve multiple locations and matrices:
Groundwater
Soil gas
Indoor air
Outdoor air
Requires a multi-disciplinary team:
Risk Assessment
Soil/Groundwater/Air

13. HOW DO YOU ASSESS THE RISK?
U.S. EPA has developed a Vapor Intrusion Screening Level (VISL) Calculator.
This tool provides a list of chemicals in a spreadsheet format along with an indication of whether they are considered toxic and volatile enough to be a VI risk.
Provides recommended screening-level concentrations for various matrices including groundwater, soil gas, and indoor air.

14. WEBINAR FOCUS: INDOOR AIR SAMPLING AT VI SITES
PURPOSES:
To diagnose whether VI is occurring
To assess the presence and level of risk from vapor-forming chemicals
To evaluate the performance of mitigation systems and the health protectiveness of subsurface remediation systems.

15. INDOOR AIR SAMPLING: CONSIDERATIONS
EPA recommends that potential INDOOR sources be removed from the structure at least 24 to 72 hours prior to the start of sampling.
This will ensure that chemical concentrations measured are attributable to the vapor intrusion pathway.

16. INDOOR AIR SAMPLING: ENVIRONMENTAL CONSIDERATIONS
Contaminant levels
indoors can be
affected by
environmental
conditions:
Wind speed and direction
Barometric pressure
Rainwater and
flooding can push
vapors out of the soil
and into the overlying
structure.
EPA recommends several
rounds of sampling to address
temporal variability.

17. INDOOR AIR SAMPLING TRADITIONAL SAMPLERS
Evacuated stainless steel canisters have been the standard for collecting time-integrated samples at VI sites.
Prior to sample collection, the laboratory cleans and certifies the canister, evacuates the canister to the designated pressure level, and provides sample identification.
Typically, samples are collected over a 24-hr period in residences.

18. INDOOR AIR SAMPLING OPTIONS: NEW EPA RECOMMENDATION
EPA suggests that passive diffusive samplers may be a better option for measuring airborne chemicals at VI sites.
Passive samplers can yield results equivalent to canisters.
Less intrusive to building owners and occupants
More convenient to ship and transport
More economical
Longer sample times

19. SAMPLE TIME CONSIDERATIONS
EPA suggests that time-integrated samples at VI sites be collected over sample periods from 8 hours to several weeks.
SKC research indicates that passive samplers with charcoal can be used reliably to collect VOCs up to one month.

20. SAMPLE LOCATION CONSIDERATIONS
For typical residential and commercial buildings less than 1500 ft2, EPA recommends sample collection:
In the area directly above the foundation floor i.e. basement or crawl space
In the first floor living area or occupied space
At the breathing zone level

21. CONCURRENT SAMPLING: OUTDOORS
Once the building owner grants access for indoor air sampling, EPA recommends concurrently collecting 1-2 outdoor (ambient) air samples over similar durations using the same sampling methods.
Comparing indoor/outdoor results can foster insights and support findings about chemical contributions from VI and from background sources.

22. SKC PASSIVE SAMPLERS FOR VI STUDIES
The SKC Ultra® was developed for low level VOC sampling for environmental applications.
Available with a choice of sorbents for:
Thermal desorption OR
Solvent Extraction
SKC ULTRA ®

23. ULTRA SAMPLERS FOR THERMAL DESORPTION
Using designated sorbents, samplers designed for THERMAL DESORPTION can measure (sub)ppb concentrations in air with typical sample times of up to 24 hours.
Sample times may be extended up to 7 days depending on the compound and sorbent. Consult the SKC Passive Sampling Guide.
Analytically, the limit of detection is approximately 3 nanograms/sample.

24. LOGISTICS FOR THERMAL DESORPTION ULTRA SAMPLERS
When measuring (sub)ppb levels in air, it is imperative that the sorbent be ultra clean.
In general, after sorbents are thermally conditioned and loaded into the badge housing, SKC recommends that they be used within 30 days to ensure they remain clean.
So it is critical for users to collaborate with the laboratory on sample logistics.

25. TO AID IN SAMPLER LOGISTICS
SKC offers the OPTION of purchasing badge housings empty (SKC ) along with small vials of designated sorbents which contain the required amounts.
The laboratory can thermally condition the sorbent, load into the badge, and ship to you upon request to meet your project requirements.

26. SORBENTS FOR THERMAL DESORPTION
SKC Options Include:
Anasorb® GCB1
Chromosorb ® 106
Carbopack X
Tenax
Note that although
Tenax is commonly
used for thermal
desorption, it is a
weak sorbent prone to
reverse diffusion when
sampling 24 hours or
more.

27. LAB ANALYSIS USING THERMAL DESORPTION
Note that sorbent transfer in the laboratory is done by pouring the sorbent from the back of the sampler housing into a standard (empty) thermal desorption tube for GC analysis.

28. FOR EXTENDED SAMPLE TIMES UP TO 30 DAYS
Activated charcoal will retain collected compounds with no reverse diffusion.
Uses standard solvent extraction for GC analysis.
Ultra sampler options:
Pre-filled by SKC with charcoal OR
User-filled with vial of charcoal
Built-in blank layer OR
Single layer without blank

29. NOTE: LOW AIR VELOCITY AFFECTS PASSIVE SAMPLERS
Indoor air sampling situations may have near zero air velocity particularly in unoccupied buildings.
In this case, standard uptake rates for passive samplers will not be valid. SKC research studies indicate sampling rates drop up to 60% with limited air movement.
SKC has indoor/low face velocity (<5 cm/sec) uptake rates available for these conditions on the SKC website.

30. VI INDOOR AIR STUDIES COMPARISON OF METHODS
Benzene data showed correlation coefficients of and for Anasorb GCB1 and Tenax TA, respectively. In nearly all cases, Anasorb GCB1 gave higher results than those with Tenax TA since Anasorb GCB1 has better adsorptive properties.

31. FORMALDEHYDE BLOWOUT IN THE HEADLINES
U.S. OSHA has issued a Hazard Alert for hair smoothing products which can release formaldehyde during normal conditions of use by hairdressers.
Air samples taken by U.S. NIOSH in a hair salon study exceeded ACGIH ceiling limit of 0.3 ppm.

32. FORMALDEHYDE REPORT FLOORED US
TOXIC
In March 2015, a TV program, 60 Minutes, reported that laminate flooring from China is potentially TOXIC.
They alleged that formaldehyde is being released into the air at ALARMING levels.

33. FORMALDEHYDE SAMPLING OPTIONS IN 2016
FOCUS ON:
Active Samplers
Passive Samplers
Direct-Reading Devices
Samplers for Formaldehyde on Dust

34. OLD, CLASSIC METHOD IMPINGERS
Method of reference: NIOSH 3500
Commonly referred to as: Chromotropic Acid or Sodium Bisulfite Method
Analysis: Visible absorption spectrometry (VIS)
“Most sensitive formaldehyde method in the NIOSH Manual”
Range: Down to 0.1 ppm with 15-L sample
Better suited for area sampling

35. SORBENT TUBE METHOD #1 DUAL PURPOSE
Methods of reference: NIOSH 2541 and OSHA 52
Chemistry: XAD-2 sorbent coated with 2-HMP
Dual Purpose: Allows the simultaneous collection of formaldehyde and acrolein often found together in industrial environments.
Advantage: Eliminates use of impingers for formaldehyde
Advantage: Overcomes storage stability issues with previous sorbent tube method for acrolein
Working Range: to 16 ppm with a 10-L sample

36. SORBENT TUBE METHOD #2 MULTIPLE ALDEHYDES AND KETONES
Methods of reference: NIOSH 2016; U.S. EPA TO-11A; ASTM D5197
Chemistry: Silica gel coated with 2,4-DNPH
Target Compounds in addition to formaldehyde: Glutaraldehyde (NIOSH 2532); Acetaldehyde, Acetone, Butyraldehyde, etc. (ASTM D5197)
EPA Working Range: Low ppb level sampling from
1-24 hrs
NIOSH Working Range: to 2 ppm for 15-L sample

37. COMPARE THE SORBENT TUBE METHODS
1. XAD-2 with 2-HMP
Working Range down to 0.24 ppm
Simultaneous collection of acrolein
No methods for other aldehydes/ketones
Sorbent tubes do not require special storage and collected samples are stabile up to 3 weeks at 25oC
2. Silica gel with DNPH
Working Range down to ppm
Not suitable for acrolein
Published methods for other aldehydes/ketones
Sorbent tubes are very sensitive to temperature.
Store at 4oC and ship on ice/cold pack.

38. PASSIVE SAMPLER METHOD USES 2,4-DNPH CHEMISTRY
Methods of Reference: U.S. OSHA 1007; ISO 16000: U.S. EPA IP-6A
Principle of Operation:
Slide the green cover to
start/stop sampling
Working Range of UMEX 100: ppm to 3 ppm
Suitable for collection of other aldehydes
Sensitive to temperature like DNPH silica gel tubes
SKC UMEX 100

39. DIRECT-READING DEVICES PASSIVE COLOR TUBES
Provide an easy, economical way to do TWA sampling
Scale indicates levels in ppm-hours
Divide by the hours sampled to determine ppm in air
Gastec
Dosi-Tube

40. DIRECT-READING DEVICES PASSIVE COLOR TUBES
Gas detectors that use ELECTROCHEMICAL SENSORS for the measurement of formaldehyde have not been widely used as they have significant interferences from alcohols and are not reliable for low level sampling.
In recent years, a portable direct-reading instrument for formaldehyde has been developed using PHOTOELECTRIC PHOTOMETRY technology.

41. FORMALDEHYDE MONITOR PRINCIPLE OF OPERATION
Formaldehyde causes a
chemical reaction to occur
on treated porous glass
sensor elements. The
resultant color change is
read on the monitor.

42. FORMALDEHYDE MONITOR NOW AVAILABLE FROM SKC
Passive system (no pump)
Base unit with sensors can function as a continuous area monitor or sensors can be hung separately as stand-alone passive samplers
Detection range is 20-1,000 ppb for minimum sample times of 30 min

43. FORMALDEHYDE IN DUST TARGET INDUSTRIES
Formaldehyde-based resins are used as adhesives for particle boards/fiber boards.
Formaldehyde-based resins are also added to fabrics for wrinkle resistance.
Workers in furniture, wood board, or garment industries can be exposed to wood or textile dusts which slowly release formaldehyde.

44. FORMALDEHYDE IN DUST NIOSH METHOD 5700
Dust is collected onto PVC filters using the IOM sampler at 2 L/min
For analysis, filters are placed into distilled water and heated to liberate the formaldehyde from the dust for HPLC analysis.

45. INDUSTRIAL APPLICATIONS FOR METHANOL
Used in production of chemicals including formaldehyde, MTBE, and gasoline
Used as a solvent in anti-freeze, synthetic resins, and dyes.
Used as a fuel blend for race cars
Additive to fracking fluids as corrosion and scale inhibitors and friction reducers

46. ACTIVE SAMPLING METHODS FOR METHANOL
NIOSH METHOD 2000
Silica gel sorbent
Sample times of 100 min at 50 ml/min
Extensive migration between sorbent layers with storage
OSHA METHOD 91
Anasorb 747 sorbent
Sample times of 100 min at 50 ml/min
Two tubes in series to overcome migration issue

47. NEW DEVELOPMENTS: METHANOL SAMPLING
A new SKC passive sampler has been validated for use for 15 min to 8 hours at concentrations of 20 to 400 ppm methanol.
The SKC passive sampler contains Anasorb 747 sorbent with a rate reducing cap to eliminate reverse diffusion effects.
Samplers can be stored at ambient temperatures for one week or in a freezer at 4oC for 3 weeks followed by GC-FID analysis.

48. AIR SAMPLING HEADLINES AN OPPORTUNITY TO LEARN
EXTRA QUESTIONS?