Environmental Quality Branch

CODES, CRITERIA AND MORE

Air Monitoring Guidelines:
Volume 1 Particulate Non-continuous

Last Updated: March 1996

1.0 Introduction

The Air Monitoring Guidelines are prepared by the British Columbia Ministry of Environment to ensure that all atmospheric data collected, or for regulatory use, by the ministry are scientifically acceptable and consistent throughout the province.

The guidelines specify and standardize technical siting and operational monitoring procedures that are to be adopted by ministry staff, their contractors, and permit holders, if atmospheric monitoring data are to be processed by and/or accepted for use by the ministry.

Volume I of the Guidelines, Non-Continuous Particulate Monitoring, Part 1, documents the technical procedures required for the most common methods of non-continuous particulate sampling; High-Volume Total Suspended Particulate (TSP), High-Volume Inhalable Particulate 10 microns and smaller (PM10) , and Low-Flow Rate PM10.

The monitoring methods and procedures specified in this Guideline to a large degree mirror those derived and implemented in the United States by the U.S. Environmental Protection Agency (USEPA). USEPA methods and procedures have been modified for application in British Columbia as appropriate. Consequently, Ministry of Environment guidelines take precedence over USEPA requirements for monitoring applications in British Columbia. In general, USEPA methods and procedures are adopted for use in British Columbia where provincial methods and procedures have not been specified.

The Atmospheric Monitoring Guidelines are subject to constant revision and updating to stay current with new and developing technologies and to remain sensitive to modern monitoring requirements. The guidelines are maintained and kept current by the Ministry of Environment and made readily available for reference by ministry staff, permittees, and the public.

2.0 Scope

This document (Non-Continuous Particulate Monitoring: Part 1) provides the technical methods and procedures required for the static high-volume sampling of TSP and PM10 , and for static low-flow rate sampling of PM10.

This Guideline encompasses the recommended technical methods and procedures for monitor siting, instrument selection, and sampler installation and operation. Other ministry guidelines specify the planning and design of monitoring networks, air monitoring laboratory methods, and atmospheric data management requirements and are cited in this document where appropriate.

3.0 Equipment

3.1 Reference Method vs Equivalent Method

The USEPA designates particulate samplers as performing either reference or equivalent methods. Reference methods refer to sample collection using manual samplers which have been proven to meet specific performance criteria through rigorous laboratory and field testing. Equivalent status is assigned to those monitors which are proven to be acceptably comparable to a reference method (Federal Register, 1987).

Reference particulate sampling methods involve the drawing of an atmospheric sample through standard filter media. Reference methods require equilibration and weighing of the exposed filter in a laboratory. Equivalent methods, however, allow in situ determination of particle mass by beta-ray attenuation or by an inertial microbalance. Examples of manual samplers include high-volume and dichotomous samplers. The Tapered Element Oscillating Microbalance (TEOM) and beta gauge are examples of indirect (equivalent) methods which are able to provide near continuous measurements of ambient particulate concentrations.

USEPA reference and equivalent methods adopted for use in British Columbia are summarized in Table 1.

Table 1: Ministry of Environment Accepted Ambient Particulate Monitoring Methods

(1) Size-selection-inlet (PM10) high-volume sampler

3.2 Reference Method

3.2.1 Total Suspended Particulate
Total Suspended Particulate (TSP) monitoring captures atmospheric particulate smaller than 40 µm in diameter.

The high-volume (hi-vol) sampler is the recommended standard sampler for TSP monitoring in British Columbia. It has a peaked roof and draws air through a 20.3 cm by 25.4 cm filter at a rate of 1,132 L/min or 40 cfm.

TSP concentrations are determined by the net weight gain of the filter subsequent to exposure to the appropriate sample of air. The particulate sample may be further analysed in a laboratory to determine the chemical and metal constituents of the particulate sample collected.

3.2.2 Inhalable Particulate (PM10) High-Volume
British Columbia has adopted the USEPA size-selective inlet (SSI), retrofitted to the standard hi-vol sampler, as the reference method for sampling inhalable particulate (PM10).

Size selective inlets provide a means to sample specific size fractions. Inlet design is such that particles exceeding a specified aerodynamic diameter (or cutpoint) are removed from the inlet airstream with progressively less efficiency. PM10 samplers are designed to have a 50% cutpoint (D50) of 10 µm. This means that the sampler collects 50% and rejects 50% of 10 µm particles.

The SSI head is rounded to allow for unbiased sampling from any direction, in direct contrast to the gabled roof design of the original hi-vol sampler (Hicks and Corr, 1983). Air is drawn through a series of baffles, 1,132 L/min (40 cfm), to eliminate particles greater than 10 mm in diameter from the sample.

Samples are collected on Teflon-coated glass fibre filters to reduce artifact sulphate and nitrate formation (Dann, 1994). The mass and analytical techniques used for TSP filter analysis can be used for SSI filter samples.

Monitors made by different manufacturers may differ in the type of fractionating device used. Some incorporate a greased impaction surface below a series of impactor jets, while others employ a greased cyclone.

3.2.3 Inhalable Particulate (PM10) - Low-Flow Rate
The Partisol™ Model 1200 has been designated a low-flow rate sampling reference method.

The Partisol™ sampler is a manual, low-flow rate sampler developed by Rupprecht & Patashnick. It was approved as a reference method by the EPA in 1994 (U.S. Federal Register, 1994). It consists of a hub station and up to two satellite stations. The hub unit contains a microprocessor with internal data storage, an active flow control system and a pump. Satellite units are fitted with a sample inlet and a 47 mm filter exchange mechanism which may employ quartz fibre, Teflon-coated glass fibre or Teflon filters. Only one satellite unit can operate at a time.

Menu-driven software can be used to determine conditions, such as wind speed, wind direction or mass loading, under which the hub or satellite units are active. Flow is controlled between 3-20 L/min.

The Partisol™ satellite units can be fitted with TSP, PM10 , PM2.5 or PM1.0 inlet heads to provide more selective sampling of particulate.

3.3 Sample Heads

Inertial impactors provide a means of segregating particles on the basis of size. In particular, they classify particles by their aerodynamic diameter, which is a useful parameter in respiratory health effects studies. Impactors are based on the following principle of operation: An airstream is drawn through a series of nozzles or jets and directed towards a flat impaction plate. The high inertia of larger particles will carry them into the impaction plate, which may be coated with an adhesive or grease to aid collection. Smaller particles will continue on with the airstream.

Virtual impactors differ from cascade impactors in that the impaction plate is replaced by an opening which directs larger particles to one sampling substrate, and the smaller particles to another. This principle is used in dichotomous samplers. Relative to cascade impactors, the effects of particle bounce-off and re-entrainment are reduced. However, this method requires that a portion of the total flow (typically 10%) be drawn through the virtual impaction surface. Hence, correction factors must be applied to the coarse channel flow to account for contamination by the fine fraction.

Cyclone samplers use an impeller to impose a circular motion to air entering a cylindrical tube. Centripetal force moves the particles toward the walls of the tube. Particles reaching the walls, which may be covered in an oil or grease coating, either adhere to it or drop into a hopper at the bottom of the tube. The inner tube and hopper are cleaned to minimize re-entrainment.

Sample head cut points differ slightly for different manufacturers. Consequently, it is recommended that a single brand and type of sample head be used in particulate monitoring programs that require multiple samplers.

3.4 Sampler/Equipment Specifications

Particulate samplers used by the Ministry of Environment or used as a requirement of the ministry, must qualify as either a USEPA Code of Federal Regulations (CFR) reference or equivalent method and must be accepted by the ministry for use in British Columbia.

High-Volume Sampler
Reference Method for the Determination of Total Suspended Particulate Matter in the Atmosphere (High-Volume Method) 40 CFR part 50 appendix B, section 2.2.11

High-Volume PM10 Sampler
Reference Method for the Determination of Particulate Matter as PM10 in the Atmosphere (High-Volume PM10 Sampler Method) 40 CFR part 50 appendix J, section 2.11.10

Low-Flow Rate PM10 Partisol™ Sampler
Reference Method for the Determination of Ambient Concentrations of Particulate Matter measured as PM10. (Rupprecht & Patashnick Partisol™ Model 2000 Air Sampler) 40 CFR part 50 appendix J, section 2.11.10, Partisol™ Operating Manual

4.0 Siting

1. Approval: Written approval must be obtained from the property owner before the monitoring site is established.

2. Access: There must be unrestricted access to the sampler and site during the monitoring period and the site and equipment must be safely accessible in all weather conditions for the duration of monitoring operations.

3. Site category: Site requirements can be categorized as; (1) surface sites and (2) building or structure mounted sites. Surface located samplers are those samplers that are stand alone or enclosed in environmental enclosures on the ground rather than on a dominant structure.

4. Exposure: There must be unrestricted airflow in an arc of at least 270° around the sampler and no obstructions in the source direction of prime interest. TSP samplers should be oriented to the prevailing wind direction.

Avoid topographic hollows where air circulation is restricted.

Interference from buildings and trees must be avoided. There must be no trees or structures closer than a distance of two times the height of the obstruction from the sampler or a distance of 20 meters, whichever is greater.

The sampler must be elevated above the expected maximum flood stage in areas subject to flooding.

5. Inlet height: The sample inlet must be kept within 2 to 7 meters from the surface, unless the project terms of reference specifically require measurements above these limits.

6. Line power: Line power must be supplied on a dedicated circuit or circuits equipped with a fuse breaker.

7. Security: Adequate safeguards must be taken to ensure security of monitoring equipment.

8. Safety: The site must be inspected for unsafe conditions. All operators should have safety awareness training or be provided written instruction on safety considerations for the site.

Ladders must comply with local safety codes.

9. Source Contamination: Particulate monitors must be located well away from obvious local sources of sample contamination such as areas of high vehicle activity, dusty roads, or close to local wood burning sources, unless monitoring is being conducted primarily to capture the impact of such sources on local air quality.

10. Roof-top obstructions: A roof-top mounted sampler must be a minimum of 2 meters away from a wall or parapet. Penthouses on top of roofs are considered to be an obstruction and the sampler must be installed at least two obstruction heights away from the obstruction.

If the sampler is installed on a building that is lower than surrounding structures, then the 'two times the height' rule for local obstructions is used.

11. Roof-top turbulence: Well exposed buildings and similar large structures exhibit an aerodynamic cavity zone over the roof area and a turbulence zone downwind of the cavity. A sampler inlet must be positioned above this recirculation cavity and away from the turbulent zone to avoid drawing in roof-top contaminants.

The height of the roof-top recirculation cavity is calculated by a two step process:

(1) Determine the effective dimension [R] of the largest side of the building, in meters, using the following formula or extracting it from Figure 1. The effective dimensions of the wall area exposed to winds, may be reduced by sheltering from nearby buildings.

R = (Ss)exp[2/3] x (Sl)exp[1/3]

where:

• R is the characteristic length.
• Ss is the small dimension of the largest wall.
• Sl is the large dimension of the largest wall.

  

Figure 1: Characteristic Length as a Function of the Effective Dimension of Wall Dimensions

(2) Estimate the roof-top cavity height [Hc] in metres using the simple formula:

(Hc = 0.22 R)

or extract [Hc] from Figure 2 using the value [R] previously calculated.

 

Figure 2: Roof-Top Cavity Height as a Function of Characteristic Length

5.0 Installation

1. Monitoring sites established for ministry purposes are to be formally initiated using:

• MOE Station Startup Form (SSF)
• Parameter Sampling Description Form (PSD)
• MOE Equipment Inventory Form (EIF) [where equipment is ministry owned].
  

These forms are available from the Regional Air Monitoring Technician at the appropriate Ministry of Environment Regional Office.

Upon completion of the forms and approval by the Regional Air Monitoring Technician, a station number is issued and preparations completed for the processing of data and/or for inclusion of processed data in the appropriate provincial atmospheric database.

Monitors then are identified for inclusion in the Ministry of Environment air audit program.

2. Stand alone samplers must be provided with, and bolted to, a solid, level and stable foundation that is designed to prevent the sampler from toppling. Concrete, a concrete pad or elevated platform are acceptable.

The foundation must be at such a height so as to maintain the sample head at a minimum of 2 meters above the surface at all times. This applies to the snow surface in winter.

3. Sampler line power must be provided with service wires that comply with local and Provincial electrical codes.

Outdoor receptacles are to be protected with a dedicated ground-fault interrupter circuit.

Access to the circuit breaker must be provided at all times.

All exposed extension cables must use waterproof interlocking electrical connectors and the cable should be protected from mechanical damage, abrasion and ultraviolet deterioration by containing it in a protective (flexible) conduit.

4. Samplers must be located at least 2 meters, but not more than 4 meters, apart where more than one sampler is located at a given site. It is preferable to sample perpendicular to the prevailing wind flow.

5. Each sampler is to be fitted with an exhaust conduit that must be at least the same size as the exhaust port of the blower. The conduit is to extend at least 5 meters from the monitor inlet downwind of the prevailing wind direction.

6. All sides of the sampler must be easily accessible so that the operator may always service the instrument from the down wind side.

6.0 Field Operations

An operational log book is to be maintained by the operator, for each monitoring station and retained for easy access by Ministry of Environment personnel. The log book must contain a record of all activities the operator, contractor, or audit member has undertaken in the operation and maintenance of the site and equipment.

Manufacturers instructions are to be followed for the routine operation of particulate monitors.

All operators and administrators associated with the sampling program are required to be in compliance with local and Provincial Workers' Compensation Board (WCB) safety codes.

Operators must follow the operational safeguards documented in the manufacturers equipment manuals. Since samplers are quite often located on rooftops and other unusual locations that are accessed by ladders or ramps in all weather conditions, a safe method for the access and egress of the site must be specified, in writing, for the operator.

Newly installed monitors require a multipoint flow rate calibration before sample collection begins.

The standard sampling duration for non-continuous monitoring of TSP and PM10 is 24 hours. The minimum sampling schedule endorsed by the Ministry of Environment is one 24 hour sample every 6th day and is consistent with the federal National Air Pollution Surveillance (NAPS) monitoring schedule.

High-volume sampling schedules are to be harmonized with the NAPS schedule for federal and provincial consistency. Schedules can be obtained from the air technical staff in the nearest Ministry of Environment regional office.

More frequent extraction of 24-hour samples may be undertaken within the NAPS monitoring schedule as dictated by the objectives of the individual monitoring program.

6.1 High-Volume TSP and PM10 Sampler

1. Particulate filters are to be conditioned and analyzed only by a laboratory approved by the Ministry of Environment.

2. Particulate filters are to be inspected, preconditioned, and weighed in a manner consistent with approved Ministry of Environment air laboratory methods (Air Laboratory Methods Manual, 1996).

3. Filters are to be ordered in sufficient quantity to ensure no disruption of the sampling schedule.

4. Filters must be handled with clean freshly laundered cotton gloves to avoid sample contamination. 47 mm filters require handling using Teflon coated, serration free, forceps.

5. New filters must be loaded into a filter cassette, in a clean room environment, prior to deployment into the field.

6. Filters are to lie flat in the sampler, remain in one piece, and provide a good seal with the sampling system to eliminate leaks.

7. Filters must be placed in the cassette with the smooth side down (control numbered side). Filters in their cassette must be covered with the cover provided and then stored in a plastic bag until deployment in the field.

8. Filter replacement in the field must be performed so as to reduce opportunities for sample contamination. The operator is to stand downwind of the filter when handling it. Clean cotton gloves or powder free plastic disposable gloves are used when handling the cassette.

9. The exposed filter is to be returned as soon as possible to a clean room environment where it is removed from the cassette for shipment to the analytical lab.

The exposed area of the filter must not be touched to avoid dislodging particle matter from the filter and to avoid sample contamination.

10. The filter cassette must be cleaned thoroughly prior to loading with a new filter. Clean the cassette with a soft brush and a clean compressed air source. For severely soiled cassettes use a laboratory grade cleaner and rinse six times in deionized water, then dry thoroughly.

11. The filter cassette gasket must be inspected carefully with each handling and replaced if there are signs of damage or over-compression.

12. The sampler must be cleaned regularly and as conditions dictate. Size selective inlets (SSI) must be re-oiled according to the manufacturers specifications, if required, to prevent particle contamination and particle bounce from occurring.

6.2 Partisol™ Low-Flow Rate Sampler

The manual provided with the Partisol™ sampler is very comprehensive. All aspects of routine field operations are described in detail. Partisol™ filters are pre-loaded in a filter cassette and shipped in a petri dish so loading/unloading of the filter into the cassette by field staff is not required.

7.0 Filter Media

A particle sampling filter consists of a tightly woven fibrous mat or plastic membrane that has been penetrated by microscopic pores. Filters should remove more than 99% of suspended particles drawn through them.

Filter media used in monitoring activities must have physical and chemical properties appropriate for the sample methodology and the laboratory analysis method used. Table 2 identifies air sampling filter types, acceptable to the Ministry of Environment.

Table 2: Filter Media Acceptable to MOE

TSP	PallflexTX40H120WWWEMFAB;20.3 cm x 25.4 cm
PM10 Ambient Particulate	PallflexTX40H120WWWEMFAB;20.3 cm x 25.4 cm
Partisol Ambient Particulate	PallflexTX40H120-WW 47 mm

7.1 Mechanical Stability

Filters are to lie flat in the sampler, remain in one piece, and provide a good seal with the sampling system to eliminate leaks

A filter must allow precise and accurate sectioning in any subsequent laboratory analysis.

Brittle filter material may flake and negatively bias mass measurements. The pure quartz-fiber filters are very brittle, and portions of their edges often become attached to the filter holder, thereby biasing the mass measurement. Ringed Teflon membranes are stretched between a ring, and these curl when they are cut in half or when a punch is removed.

7.2 Chemical Stability

Filters must not chemically react with the deposit, even when submitted to strong extraction solvents. They must not absorb contaminating gases. When gas absorption is desired, as it may be when the precursors of secondary particles are measured, the filter material should absorb those gases at near 100% efficiency. Some filter material are known to absorb artifacts such as sulfate, nitrate, organic vapor and also water vapor that can greatly bias mass measurements.

7.3 Temperature Stability

Filters should retain their porosity and structure in the presence of temperatures typical of the sampled airstream and the analytical methods.

7.4 Blank Concentrations

Filters should not contain significant and highly variable concentrations of the chemicals which are being sought by analysis. Each batch of the unexposed filters should be examined for blank concentration levels prior to field sampling.

7.5 Flow Resistance and Loading Capacity

Filters should allow sufficient amounts of air to be drawn through them to satisfy the flow rate requirements of the inlet and to obtain an adequate deposit. Particle concentrations up to 500 µg/m3 should be attainable over a 24 hour period.

7.6 Acceptance Testing

All filters require an "acceptance testing" program when they are to be used for, chemical characterization of the deposits. At least one filter from each lot, typically one per hundred, should be blank tested and analyzed for filter interference's. Each filter must be individually light tested over a light table for discoloration, pin-holes, creases or other defects. In addition to laboratory blanks, 5 to 10% of all filters should be designated as field blanks to follow all handling procedures except for actual sampling.

Some filters also require pretreatment before sampling. For example, quartz-fiber filters can be baked at high temperatures (> 500°C) prior to acceptance testing to remove adsorbed organic vapors. Nylon-membrane filters, used to collect nitric acid and total particulate nitrate, absorb nitric acid over time and need to be tested and/or cleaned prior to use. Cellulose-fiber and quartz-fiber filters can be soaked in solutions of gas-absorbing chemicals prior to sampling to collect gaseous nitric acid (HNO3), ammonia (NH3), sulfur dioxide (SO2), and nitrogen dioxide (NO2). Triethanolamine (TEA) has been use as an absorber for nitrogen dioxide (NO). The TEA is usually mixed with glycol or glycerin to improve its absorbing capacity. Peroxyacetytl nitrate (PAN), organic nitrates, and sulfur dioxide are also collected by TEA, and the nitrogen-containing compounds will appear as nitrite during analysis. TEA oxidizes in air and light, so impregnated filters must be stored in the dark in sealed containers.

8.0 Calibration

Calibration of High Volume samplers are to be performed in accordance with USEPA Code of Federal Regulations (CFR) calibration procedures:

• Reference Method for the Determination of Suspended Particulate Matter in the Atmosphere (High -Volume Method) 40CFR part 50, Section 2.2.2
• Reference Method for the Determination of Particulate Matter as PM10 in the Atmosphere (High -Volume PM10 Sampler Method) 40CFR part 50, Section 2.11.2

Calibration of the Partisol™ low-flow rate sampler is to be done in accordance with Rupprecht & Patashnick Co. calibration procedures:

• Partisol™ Model 2000 Air Sampler, Operating Manual, Section 10

8.1 Calibration Frequency

Single-Point (Quality Control Procedure)
A field-calibration check of the operational flow rate is recommended at least once per month.

Multi-Point (Quality Control Procedure)
1. When sampler first installed
2. Every six months
3. After major repair work

High-Volume Sampler
4. Any time a one-point calibration check deviates by more than ± 7% from the calibration curve.

Partisol™ Low-Flow Rate Sampler
5. When a one-point calibration check of the flow in the "calc" column of the Calibration Screen, deviates by more than ± 7% from the external flow metre reading.

9.0 Maintenance

Operators are to follow the operational maintenance and preventive maintenance schedules provided in the manufacturer's Operators Manual .

The operator must be aware of the sampler condition at all times and must provide routine and thorough inspection of the monitors and support systems. Proper maintenance requires that the operator be knowledgeable of the monitoring equipment and understand the theory of operation.

A maintenance and preventive maintenance schedule should be established for a monitoring installation concurrent with the installation of the monitoring equipment. A copy of this schedule is to be attached to the site log book.

10.0 Audit

High Volume Samplers will be audited once yearly by the Environmental Quality Branch, Air Audit Program, in accordance with USEPA Code of Federal Regulations (CFR) audit procedures:

• Reference Method for the Determination of Suspended Particulate Matter in the Atmosphere (High-Volume Method) 40CFR part 50, Section 2.2.7
• Reference Method for the Determination of Particulate Matter as PM10 in the Atmosphere (High-Volume PM10 Sampler Method) 40CFR part 50, Section 2.11.7

Partisol low-flow rate samplers will be audited once yearly by the Environmental Quality Branch, Air Audit Program, in accordance with Rupprecht & Patashnick Co. audit procedures:

• Partisol Model 2000 Air Sampler, Operating Manual, Section 9

10.1 Laboratory Procedure

Particulate laboratory filter analysis techniques required by the ministry for use in British Columbia are documented in Air Laboratory Methods Manual, 1996. This procedure encompasses those instructions established by the USEPA Code of Federal Regulations (40CFR 50, Appendix J) .

11.0 Data Reporting

Data are to be provided to the Ministry of Environment on a schedule and in a form required by the ministry. The ministry data submission guidelines are specified in the B.C. Water, Land and Air Protection (now the B.C. Ministry of Environment) document Atmospheric Data Management Guidelines, 1996.

12.0 Training

Operators must be adequately trained in the operation of ambient particulate monitoring samplers. They require a thorough understanding in the principals of ambient particulate monitoring techniques, and of the need to follow proper quality assurance\quality control (QA\QC) procedures. They must be sensitive to the wide range of problems that may arise in the operation of electronic instruments.

Operators should have received formal instruction in the area of physical sciences and demonstrate an aptitude in the operation of electronic instruments. An effective way to train capable new operators is through on-the-job training and mentoring by experienced technical staff.

Short courses from USEPA, seminars and workshops given by equipment manufacturers and government organization are good methods to bring the operating staff up to date on the latest developments of air monitoring technology and QA\QC procedures.

For More Information:

Environmental Quality Branch
Ministry of Environment
Government of British Columbia

PO Box 9341
Stn Prov Govt
Victoria, British Columbia
Canada V8W 9M1
http://www.env.gov.bc.ca/air/