TO15 - VOC Air Monitoring

ALS provides UKAS-accredited VOC air monitoring and analysis using USEPA Method TO-15 with Silonite®-coated canisters, supporting consultants, contractors, and site operators across the UK.

What is TO-15?

USEPA Method TO-15 measures volatile organic compounds (VOCs) in air using Silonite®-coated stainless steel canisters, analysed by gas chromatography–mass spectrometry (GC-MS). This provides sensitive, quantitative reporting across a wide VOC compound list, including tentatively identified compounds (TICs).

TO-15 is widely used for ambient air, indoor air, soil gas, and sub-slab investigations where accurate, low-level detection of VOCs is required.

Why Monitor VOCs?

• Assess air quality at industrial or remediation sites
• Investigate odour or nuisance complaints
• Support indoor air quality (IAQ) and vapour intrusion assessments
• Meet regulatory compliance and due diligence requirements
• Carry out boundary and emissions monitoring across the UK

Advantages of Silonite® Canisters

• No pumps required, allowing simple deployment
• Capture of a true whole-air sample
• Repeat analyses possible from the same sample
• Improved stability for reactive compounds
• 28-day holding time
• Suitable for ambient air, soil gas, sub-slab, and indoor air sampling

How Sampling Works

Plan – Sampling duration, flow control, and target analytes are defined with ALS guidance.

Sample – Certified Silonite® canisters are supplied with flow controllers for grab or time-integrated sampling, typically between 1 and 24 hours.

Analyse – Samples are analysed by GC-MS in accordance with TO-15 methodology, supported by UKAS-accredited quality assurance and quality control.

Report – Full VOC compound tables are provided, including TICs, detection limits, and quality flags.

What You Receive

• UKAS ISO/IEC 17025 accredited TO-15 report
• Results reported in µg/m³ or ppbv
• Full chain-of-custody traceability
• CSV or EDD digital data exports available
• Secure WebTrieve portal access for results

Target Compounds and Additional Analysis

The standard TO-15 compound list includes BTEX, trichloroethylene (TCE), tetrachloroethylene (PCE), vinyl chloride, chloroform, carbon tetrachloride, 1,3-butadiene, styrene, and more than 60 VOCs.

Optional additional services include:

• TPH aliphatic and aromatic splits (C4–C12)
• Bulk gas analysis including H₂, O₂, N₂, CO, CH₄, and CO₂
• Helium tracer testing for integrity verification

Accreditation and Quality

TO-15 analysis is performed under UKAS ISO/IEC 17025 accreditation. Quality controls include blanks, duplicates, and calibration checks to ensure reliable and defensible data.

All Silonite® canisters are verified to background concentrations below 0.2 ppbv prior to issue.

Equipment Supplied

• 1 litre and 6 litre Silonite® canisters
• Flow controllers for 1–24 hour sampling durations
• Carry cases and clear user instructions

UK Sampling Support

ALS technicians are available to deploy, flow-check, and collect TO-15 samples across the UK, providing additional assurance for complex or high-profile projects.

Applications

• Landfill and waste management facilities
• Brownfield and remediation projects
• Industrial boundary and perimeter monitoring
• Indoor air quality and workplace exposure assessments
• Vapour intrusion and sub-slab investigations

Get Started

To begin a TO-15 project, provide the site location, number of canisters required, and the monitoring objective. ALS will confirm the sampling setup, duration, and quotation.

Canisters can be shipped directly, or technician deployment can be arranged.

Contact us