Chemical Characterization

Our lab is equipped with the following instruments to analyze the chemical characteristics of the particulate matter.

TSI 3800 Aerosol Time-of-Flight Mass Spectrometer (ATOFMS)

The ATOFMS measures the size and chemical components within individual aerosol particles ranging in size between 30nm and 10μm in near real-time on a continuous basis. The ATOFMS has a temporal resolution high enough to make multiple measurements per second, allowing the characterization of the mixture of aerosol particles present in the air, as well as the tracking of rapid fluctuations in aerosol composition.

Manufacturer: TSI Inc.
Location(s): WB facility (Field Measurement); MAPLE

Sunset Thermal-Optical Semi Continuous OC/EC Analyzer

The OC/EC provides a semi-continuous analysis of aerosol organic carbon (OC) and elemental carbon (EC) concentration with a sampling time ranging from 6 to 12 minutes. The OC/EC preferentially volatilizes OC and EC collected on quartz-fiber filters, oxidizing each species to determine their respective concentrations.

Manufacturer: Sunset Laboratory Inc.
Location(s): WB facility (Field Measurement); MAPLE

DMT Photoacoustic Soot Spectrometer (PASS)

Photo Acoustic Soot Spectrometer (PASS) measures the optical absorption and scattering coefficient of particles using a photo acoustic technique. The absorption coefficient can be converted to black carbon mass based on the assumption of black carbon mass absorption coefficient. Multiple wavelength measurement allows the absorbing angstrom exponent to be determined, giving an indication of the type and quantity of brown carbon present in addition to the soot.

Manufacturer: Droplet Measurement Technologies
Location(s): WB facility (Field Measurement); MAPLE

Aethalometer (AE-33)

This dual-channel Aethalometer offers real-time aerosol absorption analysis with rapid time resolution to 1 second. This permits the measurement of optically-absorbing aerosols – ‘Black’ Carbon and ‘Brown’ Carbon components of particulate matter.

The aerosol-laden air stream is drawn through a spot on a filter tape at a measured flow rate.  Simultaneously, the tape is illuminated by light: and sensitive detectors measure the intensities of light transmitted through an un-exposed portion of the tape acting as a reference; versus the collecting spot.  As optically-absorbing material accumulates on the spot, the intensity of light transmitted through it, gradually decreases.  The decrease in light intensity from one measurement to the next is interpreted as an increase in the amount of collected material.  This increase amount is divided by the known air-flow volume to calculate the concentration.

In this model, two sample spots are collected from the same input air stream with different rates of accumulation, and analyzed simultaneously.  The two results are combined mathematically to eliminate the “Filter Loading Effect” nonlinearity, and provide an accurate measurement of the aerosol concentration.
Additionally, the analysis is made at 7 optical wavelengths spanning the spectrum from 370 nm to 950 nm. 

Manufacturer: Magee Scientific Company
Location: (on loan from Environment Canada)

Aerodyne Aerosol Chemical Speciation Monitor (ACSM)

Aerosol Chemical Speciation Monitor (ACSM) measures aerosol mass and chemical composition of non-refractory submicron aerosol particles (i.e. ammonium, nitrate, sulphate, organics, and chloride) in real-time (up to 15 min). The ACSM is designed and built on the same technology as Aerosol Mass Spectrometer (AMS) combining an aerodynamic particle focusing lens (~40-1000 nm) with high vacuum thermal particle vaporization and mass spectrometry.

Manufacturer: Aerodyne
Location(s): WB Facility

EcoChem Photoelectric Aerosol Sensor PAS 2000

The Photoelectric Aerosol Sensor (PAS) is used for real-time measurement of Carbon aerosols.
It uses an UV Excimer lamp which has a higher efficiency than any traditional UV lamp. The Excimer lamp can be rapidly switched on and off without a time delay. The offset produced by pre-charged particles can be eliminated by operating the lamp in a chopped mode. The Excimer lamp produces monochromatic radiation with a half bandwidth of 2%.

Manufacturer: EcoChem Analytics
Location(s): WB Facility (Field Measurement)

Xact metal monitor (Xact 625, Cooper Environ.)

Xact metal monitor (Xact 625, Cooper Environ.) measures hourly concentrations of trace metals in PM2.5 (particulate matter maller than 2.5 μm in aerodynamic diameter). In brief, particles are sampled through a section of Teflon filter tape at a flow rate of 16.7 lpm. The filter tape spot then advances in an analysis area, where the collected PM2.5 is analyzed by energy-dispersive X-ray fluorescence (ED-XRF) to determine metal mass. The sequence of sampling and analysis can continue automatically on an hourly basis. The metal monitor measures the following 24 metals: Ag, As, Ba, Br, Ca, Cd, Ca, Co, Cr, Cu, Fe, K, Mn, Ni, Pb, Rb, S, Se, Si, Sn, Sr, Ti, V, Zn.

Manufacturer: Pall Corp
Location(s): WB facility