Instrument Information

Ozone • PM_2.5 • PM_2.5 Speciation • Carbon Monoxide • Nitrogen Dioxide • Sulfur Dioxide • Carbonyl • VOC • PAH • BTEX

Ozone (O3) Advanced Pollution Instruments (API) Model 400 Ultraviolet Absorption Ozone analyzer: The State of Vermont APCD operates two continuous ozone monitoring sites within the state. The instrument samples local ambient air quality 24 hours a day, 365 days a year. Averaging intervals of 1, 5, 60, 480 minutes are automatically logged with the data acquisition systems. The unit is setup and operated to monitor ambient ozone concentrations up to 500 parts per billion. The one hour ozone and running eight hour averages from the two monitoring sites are compiled and presented on a hourly basis on this web site. Reference/Equivalent Method Designation: The Model 400 is designated by EPA as a automated Equivalent Method (EQOA-0992-087) for the measurement of ambient concentrations of nitric oxide. The Model 400 must be and is set up and operated as per the reference designation. Principle Utilized: The instrumental operation utilizes the principle of "Ultraviolet Absorption" that is based on the fact that ozone molecules absorb ultraviolet energy at a known wave length of 254nm. The UV light available for detection is proportional to the amount of ozone in the sample chamber.

Fine Particulates (PM2.5) R&P Partisol-Plus Model 2025 Sequential Air Sampler: Vermont APCD operates four PM2.5 Federal Reference Method (FRM) monitoring sites within the state. The PM2.5 FRM samples local ambient air quality every third day for a period of 24 hours. Currently sharp-cut cylcones (VSCC) are used as the PM size separator. Air is sample at a rate of 1 m3 per hour and the particulate matter is collected on a Teflon filter that is weighed both before and after sampling. Archived 24-hour validated data are available on this website.

R&P TEOM Series 8500 with Filter Dynamic Measurement System (FDMS) : The State of Vermont APCD operates four FDMS TEOMs in Rutland, Burlington, Underhill and Bennington, VT. The instrument samples local ambient air quality 24 hours a day, 365 days a year. The FDMS TEOM operates at 30°C and continuously measures PM2.5 mass. The one-hour PM2.5 averages and running 24-hour averages are reported on a hourly basis on this web site.

Model 1405-F Single Flow TEOM: This unit measures PM 2.5 while accounting for volatiles & semi-volatiles. The unit utilzies TEOM (Tapered Element Oscillating Microbalance) and FDMS (Filter Dynamics Measurement System) technologies. TEOMs provide NIST (National Institute of Standards and Technology) traceable direct mass measurements. The instrument samples local ambient air quality 24 hours a day, 365 days a year. The TEOM operates at 30°C and continuously measures PM2.5 mass. The one-hour PM2.5 averages and running 24-hour averages are reported on a hourly basis on this web site.

Fine Particulate (PM2.5) Speciation MetOne SASS Sampler: The MetOne SASS unit, which measures PM2.5 mass and PM2.5 chemical speciation, is located in Burlington, VT at the Zampieri State Office Building and is part of the EPA Speciation Trends Network (STN). The MetOne SASS was deployed on 12/14/00 on a 1-in-6 day sampling schedule. Sampling frequency was increased to 1-in-3 day sampling on 3/2/01. Data is validated on a monthly basis when reports are received from the contract laboratory (Research Triangle Institute). Archived STN speciation data is available on this web site and will be updated as it reported to APCD.

IMPROVE Sampler: The IMPROVE (Interagency Monitoring of Protected Visual Environments) sampler, which measures PM2.5 mass, PM10 mass and PM2.5 chemical speciation, was deployed on 2/15/01 on a 1-in-3 day sampling schedule in Underhill, VT at the Proctor Maple Research Facility. Data is validated at the Crocker Nuclear Laboratory at UC-Davis and is then reported to the operating site usually within a 6-month period. Archived IMPROVE speciation data is available on this web site and will be updated as it reported to APCD.

URG-3000N Sequential Particulate Speciation Sampler: consists of one module C, one controller, one stand, one stand rain shield and one 36” inlet tube. The controller contains a timer, keypad, and other electronic equipment. The stand contains the vacuum pump & mass flow controller to provide active volumetric flow control; corrections are made for temperature & barometric pressure variations. The sampler controller is used to control the sample collection & acquired data during the sampling. The ambient air enters through an inlet to then pass through a cyclone that removes particulates larger then 2.5 um.  The cyclone is located inside the module. The module C collects PM 2.5 particulates on a quartz filter. These filters are analyzed for organic & elemental carbon using thermal optical analysis method. (TOA)

Carbon Monoxide (CO) Thermo Environmental Instruments (TEI) Model 48C Gas Filter Correlation Analyzer: The State of Vermont APCD operates two continuous carbon monoxide monitoring sites within the state. The carbon monoxide instrument samples local ambient air quality 24 hours a day, 365 days a year. Carbon monoxide averaging intervals of 1, 5, 60, 480 minutes are automatically logged with the data acquisition systems. The unit is setup and operated to monitor ambient concentrations up to 50 parts per million. The one hour and running eight hour averages from the two monitoring sites are compiled and presented on a hourly basis on this web site. Reference/Equivalent Method Designation: The Model 48 C is designated by EPA as a Reference Method (RFCA-0981-054) for the measurement of ambient concentrations of carbon monoxide. The Model 48 C must be and is set up and operated as per the reference designation. Principle Utilized The instrumental operation utilizes the principle of "Gas Filter Correlation" that is based on the fact that carbon monoxide molecules absorb infrared radiation at a know spectral wavelength of 4.6 mm. The infrared absorption characteristic is a non-linear technique. The TEI Model 48C electronics package transforms the data output to a linear format. The signal is then processed to digital and analog outputs.

Nitrogen Dioxide (NO2) Thermo Environmental Instruments (TEI) Model 42C Chemiluminescence Oxides of Nitrogen Analyzer: The State of Vermont APCD operates two continuous oxides of nitrogen monitoring sites within the state. The instrument samples local ambient air quality 24 hours a day, 365 days a year. Averaging intervals of 1, 5, 60, 480 minutes are automatically logged with the data acquisition systems. The unit is setup and operated to monitor ambient NO and NO2 concentrations up to 500 parts per billion. The one hour (NO & NO2) and running twenty four hour averages(NO) from the two monitoring sites are compiled and presented on a hourly basis on this web site. Reference/Equivalent Method Designation: The Model 42C is designated by EPA as a automated Reference Method (RFNA-1289-074) for the measurement of ambient concentrations of nitric oxide. The Model 42C must be and is set up and operated as per the reference designation. Principle Utilized: The instrumental operation utilizes the principle of "Chemiluminescence" that is based on the rapid gas phase reaction of nitric oxide molecules and ozone molecules. Light emissions from the excited nitrogen dioxide molecule to it's lower ground state by a photomultiplier tube (PMT). The TEI Model 42C electronics package transforms the data output to a linear format.

Sulfur Dioxide (SO2) Thermo Environmental Instruments (TEI) Model 43C Pulsed Fluorescence Analyzer: The State of Vermont APCD operates two continuous sulfur dioxide monitoring sites within the state. The instrument samples local ambient air quality 24 hours a day, 365 days a year. Averaging intervals of 1, 5, 60, 480 minutes are automatically logged with the data acquisition systems. The unit is setup and operated to monitor ambient concentrations up to 500 parts per billion. The one hour and running three and twenty four hour averages from the two monitoring sites are compiled and presented on a hourly basis on this web site. Reference/Equivalent Method Designation The Model 43C is designated by EPA as a automated Equivalent Method (EQSA-0486-060) for the measurement of ambient concentrations of sulfur dioxide. The Model 43C must be and is set up and operated as per the equivalency designation. Principle Utilized: The instrumental operation utilizes the principle of "Pulsed Fluorescence" that is based on the fact that sulfur dioxide molecules absorb fluorescent energy, producing electronically excited SO2 molecule with a known spectral decay rate to the ground state. The fluorescence emitted by the reaction is detected by a photo multiplier tube and the signal is converter proportionally to a electronic output signal.

Carbonyl ATEC Model 300 Cartridge Sampler: Carbonyl compound sampling and analysis is performed following EPA method TO11A from EPA's Compendium of Methods for the Determination of Toxic Organic Compounds in Ambient Air EPA/625/R-96/010b. Carbonyl samples are collected using Waters Sep-Pak DNPH-silica cartridges (2,4-Dinitrophenylhydrazine) and an ATEC Model 300 Cartridge sampler. Carbonyl samples are collected over 24-hour periods (midnight to midnight) following EPA's published 12th Day Schedule. DNPH cartridges are transported at 4°C to the laboratory for analysis. The Vermont DEC lab performs the Carbonyl cartridge sample extraction and subsequent analysis for 14 compounds using a Waters High Performance Liquid Chromatograph (HPLC) with a multi-wavelength UV detector.

VOC ATEC Model 301 Canister Sampler: VOC sampling and analysis is performed following EPA method TO15 from EPA's Compendium of Methods for the Determination of Toxic Organic Compounds in Ambient Air EPA/625/R-96/010b. VOC samples are collected in specially treated 6-liter Silcosteel stainless steel canisters (which have been pre-cleaned and certified prior to each use) using ATEC Model 301 Canister Sampler. VOC samples are collected over 24-hour periods (midnight to midnight) following EPA's published 12th Day Schedule. Canister samples are transported to the laboratory for analysis. The Vermont DEC (and/or contract lab) performs the VOC canister sample analysis for 59 compounds using an ENTECH model 7100 Cryogenic Concentrator Microscale Purge and Trap Unit (to acquire and condition the sample) and a Hewlett-Packard (HP) 6890 gas chromatograph/5973 mass spectrometer (GC/MS) with the mass selective detector.

PAH PAH (semi-volatile) TISCH PUF+: Poly-aromatic hydrocarbon (PAH) sampling and analysis is performed following EPA method TO-13A from EPA's Compendium of Methods for the Determination of Toxic Organic Compounds in Ambient Air EPA/625/R-96/010b and the ASTM D6209-98. The TISCH PUF+ sampler is used to collect ambient air samples for determining vapor and particulate concentrations of PAHs (semi-volatile organic compounds such as naphthalene and benzo [a] pyrene). This sampler is comprised of a small outdoor aluminum shelter which houses a vacuum/blower motor and a programmable microprocessor timer/controller which automatically starts and stops sample collection, controls air flow through the sampling module and collects and stores sample-related information. Approximately 200m 3 of air is sampled through a special module containing a polyurethane foam (PUF) plug insert combined with a special adsorbent (XAD-2: styrene-divinylbenzene resin) and a 104 mm quartz-fiber filter. Samples are collected for 24-hours (midnight to midnight) following EPA's 6 th day sampling schedule. Samples are kept cool during transport/shipment to the laboratory for analysis. The EPA contract lab performs the PAH/semi-volatile analysis for 22 compounds using a Soxhlet extraction and gas chromatography/mass spectrometry (GS/MS).

BTEX Syntech Spectras GC955 series 600 Gas Chromatograph: The State of Vermont APCD operates a semi-continuous BTEX (benzene, toluene, ethylbenzene, xylene) monitoring sit in Burlington . The BTEX instrument samples local ambient air quality 24 hours a day, 365 days a year. BTEX 15 minute averaging intervals are automatically written to a log file on the instrument. The unit is setup and operated to monitor ambient concentrations up to 5 parts per billion. Principle Utilized The instrumental operation utilizes the principle of "Gas Chromatography” with a “Photoionization Detector” (GC/PID). During each 15-minute cycle, the sampling cylinder/piston draws a total of 150 cc of ambient air sample through a preconcentrator at set intervals. Simultaneously, the previous 15 minute sample undergoes a 15 minute analysis cycle. The sample is thermally desorbed from the preconcentrator into a stripper column and then into the analysis column. Once BTEX compounds move through the stripper column (after injection mode) the 10-port valve switches and back flushes the remaining VOCs from the stripper column. The BTEX compounds are separated in the column and exit to the PID for measurement at specific retention times. The PID ionizes the molecules using ultraviolet radiation. The charged gas ions flow to charged electrodes in the sensor and produce a current which is measured and displayed as a concentration on the meter. The greater the concentration of the component, the more ions are produced, and the greater the current.