Volatile Organics Compound Monitoring Service Brochure

8Volatile Organic Compounds MonitoringThe availability of reliable, accurate and precise monitor-ing methods for VOCs is a primary need for Governmentagencies and Industry addressing daily monitoringrequirements related to odour complaints, fugitive emissionsand trend monitoring.Volatile Organic Compounds (VOCs) are organic chemi-cals that easily vaporize at room temperature. They are calledorganic because they contain the element carbon in theirmolecular structures. VOCs include a wide range of individualsubstances, such as hydrocarbons (for example benzene andtoluene), halocarbons and oxygenates. Hydrocarbon VOCsare usually grouped into methane and other non-methaneVOCs. Methane is an important component of VOCs, its envi-ronmental impact is principally related to its contribution toglobal warming and to the production of ground level orlower atmospheric ozone. Oxygenates arise in vehicleexhausts and via atmospheric chemical reactions.Evaporation of solvents, used for example in paints, cause arelease of hydrocarbons, oxygenates and halocarbons to theatmosphere.Two sampling methods most commonly used to collectambient VOC samples are solid adsorbents and stainless steelcanisters. Samples can becollected over varioustime periods to complywith Provincial andFederal regulation.Solid AdsorbentsSampling(Figure 1)Ambient air is drawnthrough a cartridge con-taining adsorbent materi-al. Volatile organic com-pounds are captured onthe adsorbent whilemajor organic atmos-pheric constituents passthrough. After sampling,the cartridge is returnedto a laboratory for analy-sis.Air volume is critical tothe accuracy of theresults. Mass flow con-trollers are highly recom-mended in determining accurate sample volumes. (Figure 2)Analog output from the mass flow controller can be connect-ed to a data logger to continuously record flowrate and totalair volume.Stainless Steel Canister Sampling(Figure 3)Canister-based monitoring method for VOCs has provento be viable and widely used since the 1980s. Ambient air iscollected in a stainless steel canister. A sample is drawnthrough a sampling train comprised of components that reg-ulate the rate and duration of sample into a canister.Advantages of canister sampling is as follows;• convenient integration of ambient samples over specifictime period• ease of storing and shipping• storage stability for many VOCs over periods of up to30 days• repeat analysis (unlike adsorbent material, additionalsamples can be removed from the canister for subse-quent analysis)• multiple sample analysis utilizing several analyticaltechniquesRotek Environmental Inc. has designed and developedinstrumentation to support both adsorbent cartridge and can-ister sampling methods.Figure 2 - Mass Flow Controlled VOC SamplerFigure 1 - VOC Tubes9Sampling equipment can be automatically triggered onwith external parameters such as wind direction or otherambient air monitoring equipment.Rotek can coordinate sampling and QA/QCrequirements such as;• installation and removal of samples• flowrate calibration• travel, duplicate and field blank require-ments• sample submission, chain of custody docu-mentation• data reporting and validation• liaison between client and laboratoriesPolycyclic Aromatic Hydrocarbons(PAHs) and Dioxins/FuransMonitoring(Figure 5)Compounds such as PAH, Dioxins / Furansand PCBs could be considered semi-volatile andneed to be collected in both vapour and particu-late form. Gases will adhere to the particulates.Sampling equipment is designed to collect bothVOC compounds along with the particulates. Thevapour portion of the sample will be drawnthrough the filter and is collected on several collection medi-ums such as; Polyurethane foam or XAD resin.The following US EPA approved sampling andanalysis methods are recommended for the samplingof organic compounds;• METHOD TO-2 ( Method for the Determination ofVolatile Organic Compounds (VOCs) in Ambient Air byCarbon Molecular sieve Adsorption and GasChromatography/Mass Spectrometry (GC/MS)• METHOD TO-4A ( Determination of Pesticides andPolychlorinated Biphenyls in Ambient Air using highVolume Polyurethane Foam(PUF). Sampling followed byGas Chromatographic/ Multi-Detector Detection(GC/MD)• METHOD TO-9A (Determination of Polychlorinated,Polybrominated and Brominated/Chlorinated Dibenzo-p-Dioxins and Dibenzofurans in ambient air.• METHOD TO-13A (Determination of Polycyclic AromaticHydrocarbons (PAHs) in Ambient Air Using GasChromatographic / Mass spectrometry (GC/MS)Figure 3 - Canister SamplingFigure 4 - CanisterControl ModuleFigure 5 - PUF Sampler• METHOD TO-14ADetermination of VolatileOrganic Compounds (VOCs)In ambient Air Using spe-cially-Prepared Canisterswith Subsequent Analysis byGas Chromatography• METHOD TO-15Determination of VolatileOrganic Compounds (VOCs)In Air Collected in Specially-Prepared Canisters andAnalyzed by GasChromatography MassSpectrometry (GC/MS).