Ministry of the Environment, Conservation and Parks
Mobile Monitoring and Passive Sampling of Volatile Organic Compounds Robert Healy
Background
• Emergency response - chemical spills and fires
• Industrial non-compliance field studies
• Focused community-scale air quality studies
• Development of new methodologies for measuring air pollutants
The Terrestrial Assessment and Field Services Unit (TAFSU)
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Functions - Air:
• Part of the Environmental Monitoring and Reporting Branch
• Staff are a mix of environmental officers, scientists and technicians
Mobile Platforms
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• TAFSU deploys mobile monitoring platforms with complementary measurement capabilities for emergency response and assessing non-compliance by the regulated community
• The vehicles feature on-board generators, meteorological towers, data logging servers and air quality monitoring instrumentation
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Mobile Platforms: Instrumentation
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TSQ truck
• Atmospheric pressure chemical ionization mass spectrometer (APCI-MS) for VOCs
• Particulate matter, sulphur dioxide, total reduced sulphur instrumentation
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Mobile Platforms: Instrumentation
PTR truck
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• Proton transfer reaction mass spectrometer (PTR-MS) for VOCs
• Particulate matter, black carbon, nitrogen oxides instrumentation
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Mobile Platforms: Mass Spectrometers
Complementary measurements of VOCs
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• PTR-MS well suited to real-time measurements of benzene, aromatic VOCs, chlorinated VOCs
• Switchable reagent ion source for measuring additional species including 1,3-butadiene
• APCI-MS targets polar VOCs including aldehydes, ketones, alcohols and amines
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Emergency Response Activities
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• TAFSU responds to environmental emergencies involving emissions to air, including fires that may impact public health
• Measurements of air pollutants are compared with emergency screening values and the real-time results are provided to fire department staff at the scene
• The unit has responded to four emergencies in 2019 so far
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Wind direction
Mobile Monitoring: Source Identification
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Wind direction
Mobile Monitoring: Source Identification
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Mobile Monitoring: Source Identification
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Assessing non-compliance with O. Reg. 419/05
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• Measurements of VOCs and other air toxics are compared with Ontario Regulation 419/05 standards and guidelines to assess whether concentrations downwind of a facility are within acceptable limits
• Measurement data need to be continuous and measured over a defined averaging period, for example 10 minutes, 1 hour or 24 hours depending on the standard
• Standards for VOCs are predominantly now based on 24 hour averaging periods, therefore mobile monitoring is less suitable for assessing non-compliance by industry
• A new method was required to enable continuous 24 hour measurement in the vicinity of industrial facilities in Ontario
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Passive Monitoring of VOCs
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• Passive monitoring using sorbent packed tubes was recently introduced for monitoring benzene at refinery fencelines in the US using EPA Method 325
• Assessments of the performance of the passive tube method are relatively few and focused on US refinery sites, e.g. Texas
• Not representative of Ontario sampling conditions
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Assessment of the Passive Tube Method
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• The thermal desorption tubes contain Carbopack X sorbent
• Method is calibrated by doping tubes using a gas dilution system
• Tubes are analyzed by thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS)
• For field sampling one end of the tube is fitted with a diffusion cap
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Assessment of the Passive Tube Method
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• Two separate six-week measurement campaigns (summer and winter) were undertaken at MECP’s roadside research station adjacent to Highway 401
• This section of highway is the busiest in North America, with >400,000 vehicles per day
• This traffic represents a continuous source of VOCs, including benzene, toluene, ethylbenzene and xylenes (BTEX)
Air and Odor Management Conference, Toronto, September 20 2019
Assessment of the Passive Tube Method
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• Tubes were deployed for 24 hour and 14 day periods
• 24 hour canisters were also deployed and analyzed by ECCC
• Online GC systems were used to confirm BTEX concentrations
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14-day Results
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24-hour Results
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Applications of Passive Sampling
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Wind direction
Mobile monitoring data
Applications of Passive Sampling
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Wind directionWind direction
Mobile monitoring data Passive tube data
Applications of Passive Sampling
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Conclusions
• Mobile real-time air quality monitoring is essential for emergency response activities
• Mobile monitoring is also effective for identifying point sources of VOCs
• Passive sampling is relatively inexpensive, does not require power, and can be used to assess non-compliance with 24 hour standards
• Passive sampling is also well suited to long term community scale monitoring of VOCs for assessing chronic exposure
• The combination of mobile and passive monitoring of VOCs has proven to be a useful weight of evidence based approach to assessing non-compliance by the regulated community in Ontario
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Thanks to:
MECPJon WangNick KarellasGeorge RioualJulie BennettQingFeng ChenColman WongYemi SofowoteYushan SuLinda di FedericoTony Munoz Aaron ToddChris Charron
ECCCMay SiuSam BryantLuc WhiteDennis HerodJean-Pierre Charland
Appendix
24-hour Results: Temperature Dependence
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24-hour Results: Temperature Dependence
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Benzene Toluene Ethylbenzene p-Xylene
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24-hour Results: Temperature Dependence
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Benzene Toluene Ethylbenzene p-Xylene
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Mobile Monitoring and Passive Sampling of Volatile Organic Compounds BackgroundMobile PlatformsMobile Platforms: InstrumentationMobile Platforms: InstrumentationMobile Platforms: Mass SpectrometersEmergency Response ActivitiesMobile Monitoring: Source IdentificationMobile Monitoring: Source IdentificationMobile Monitoring: Source IdentificationAssessing non-compliance with O. Reg. 419/05Passive Monitoring of VOCsAssessment of the Passive Tube MethodAssessment of the Passive Tube MethodAssessment of the Passive Tube Method14-day Results24-hour ResultsApplications of Passive SamplingApplications of Passive SamplingApplications of Passive SamplingConclusionsSlide Number 22Thanks to:Appendix24-hour Results: Temperature Dependence24-hour Results: Temperature Dependence24-hour Results: Temperature Dependence