IMPROVE

STANDARD OPERATING PROCEDURES

SOP 126

Site Selection

Date Last Modified Modified by:

09/12/96 EAR
SOP 126: Site Selection 2

SOP 126 Site Selection for the IMPROVE Aerosol Sampling Network.

TABLE OF CONTENTS

1.0 PURPOSE AND APPLICABILITY.......................................................................... 3

2.0 RESPONSIBILITIES................................................................................................ 4

2.1 Project Manager ................................................................................................. 4

2.2 Field Specialist.................................................................................................... 4

2.3 Local (On-Site) Contact...................................................................................... 4

3.0 REQUIRED EQUIPMENT AND MATERIALS....................................................... 5

4.0 METHODS............................................................................................................... 5

4.1 Locating Potential Sites ....................................................................................... 5

4.2 Reviewing and Selecting Potential Sites ............................................................. 12

4.3 Finalizing Site Selection ..................................................................................... 12

TABLE OF FIGURES

Figure 1 IMPROVE Aerosol Sampler Information.......................................................... 7

Figure 2 Siting Requirements for Regional Aerosol Monitoring ...................................... 8

LIST OF FORMS

FORM 1 Photographic Log for Potential Aerosol Monitoring Sites ................................ 9

FORM 2 Required Information for Evaluation of Potential Aerosol Monitoring Sites. .. 10

Technical References

none
SOP 126: Site Selection 3

1.0 PURPOSE AND APPLICABILITY

This standard operating procedure (SOP) outlines site selection criteria for installation of

IMPROVE protocol aerosol samplers.

The IMPROVE aerosol sampler collects ambient aerosols on a variety of substrates for

analysis of elemental and ion and carbon species involved in visibility impairment. The data

collected provide information for calculating trends in visibility and tracking sources of visibility

impairment in Class 1 areas.

The IMPROVE aerosol sampler collects ambient PM2.5 aerosols at a flow rate of twenty

three liters per minute twice per week, on Wednesdays and Saturdays. The sampler is designed

simply and ruggedly to withstand ambient field conditions, and for ease of operation and

maintenance.

IMPROVE aerosol samplers are generally sited in conjunction with other IMPROVE protocol

monitoring equipment such as camera sites , nephelometers, and transmissometers. The aerosol

sampler siting protocols closely reflect those of ARS for automatic camera sites and

transmissometers.

To assure consistent quality data and to minimize data loss, aerosol sampling sites are selected

to meet most if not all of the following criteria.

• Located to monitor the same air mass being monitored by associated IMPROVE network

equipment

• Removed from local sources such as diesel, wood smoke, automobile, road dust,

construction, etc.

• Site meets EPA siting requirements for regional aerosol sampling, including inlet height,

no interference in air flow from trees of buildings in a 30° cone above the sampler,

minimum of 270° of free air flow around the sampler.

• Located at a site where aerosols are representative of regional, not local, visibility

conditions.

• Is secure from potential vandalism.

• Has available servicing personnel (operator).

• Is accessible all months of the year, or all months of interest.

This SOP serves as a guideline to facilitate the following:

• Location of potential sites.

• Evaluation of potential sites.

• Selection of the most appropriate site from the potential sites.

• Finalization of the selected site.
SOP 126: Site Selection 4

2.0 RESPONSIBILITIES

2.1 Project Manager

The project manager shall:

• Prepare project specific siting and operational objectives, guidelines, and considerations.

• Select the most appropriate site for the aerosol samplers based on the criteria described in

the SOP.

2.2 Field Specialist

The field specialist shall:

• Initiate the search for potential sites by sending pertinent siting criteria and associated

siting materials to a local contact.

• Maintain communications with to local contact during the field survey of potential sites.

Verify that all potential sites have been identified and thoroughly evaluated, and that all

materials are returned for review in a timely fashion. The actual field survey may be

performed by the local contact, the field specialist, or both.

• Review potential sites with the project manager.

• Obtain permission from private or public land owners for permanent access to the aerosol

sampling site.

• Obtain permission to perform any special site preparation that may be required.

• Work with the local contact or sponsoring agency to identify a site operator and local

primary contact to service the equipment.

• Maintain careful records in permanent files and in the site database on all site selection

information.

2.3 Local (On-Site) Contact

The local contact shall:

• Review the technical and monitoring requirements provided by the field specialist.

• Identify potential sites.

• Maintain communication with the field specialist during the field survey of potential sites.

• Photograph and document potential sites. Provide a set of processed 3"x5" photos

showing each potential site, and the views from the sampling site toward the north, the

south, the east, and the west. The contact should keep one set of prints for on-site review.

• Document the selected site location(s) on a topographic map.

• Identify and contact local landowners, primary contacts, and operators regarding site

installation and routine maintenance requirements.
SOP 126: Site Selection 5

3.0 REQUIRED EQUIPMENT AND MATERIALS

The following materials are required to complete the site selection process:

• Maps

• A camera to take photographs of the proposed site and surrounding areas.

• A list of monitoring requirements and associated IMPROVE protocol monitoring

equipment.

• A list of local sources affecting the air in the area of interest.

• Information about the availability of AC power and telephone service for associated

monitoring equipment.

4.0 METHODS

This section describes the site selection process and includes three (3) major subsections:

4.1 Locating Potential Sites.

4.2 Reviewing and Selecting Potential Sites.

4.3 Finalizing Site Selection.

4.1 Locating Potential Sites

Site selection begins with the process of locating potential sites in the monitoring area

of interest. The following steps detail the process:

OBTAIN SITING

CRITERIA

Obtain specific siting criteria from the project manager. The siting

criteria may include regional or site specific program objectives,

meteorological conditions of the monitoring area, and/or other

considerations.

The site should not be located in areas subject to unusual aerosol

transport conditions. There should be no local pollution sources or

unusual meteorology. The aerosol at the site should be representative

of the regional air mass.

LOCATE

POTENTIAL

SITES

Locate potential sites from maps and through consultation with local

contacts familiar with the monitoring area of interest.
SOP 126: Site Selection 6

SEND SITING

PACKAGE TO

LOCAL

CONTACT

Send the aerosol sampler siting package to a local contact familiar with

the proposed monitoring area. The siting package includes the

following:

• Information on aerosol samplers and monitoring (Figure 1)

• Siting protocols for aerosol monitoring (Figure 2)

• A roll of 35mm film or a disposable 35mm camera.

• Photographic log (Form 1)

• Potential aerosol monitoring site information (Form 2 )
SOP 126: Site Selection 7

Figure 1 IMPROVE Aerosol Sampler Information

IMPROVE is a cooperative program of the National Park Service, Forest Service, Bureau of Land

Management, Fish and Wildlife Service, and Environmental Protection Agency, whose primary purpose is

to monitor visibility and particulate components in Federal Class I areas (includes most national parks and

wilderness areas and many national monuments). The 1977 Clean Air Act requires Federal Land

Managers to protect the visibility in Federal Class I areas from manmade pollution.

The IMPROVE protocols were designed to obtain a complete signature of the composition of airborne

particles in relation to visibility. Use of the four filter module IMPROVE sampler is "standard" protocol if

all of the analytical measurements in Table 1 are needed. However, if only one or two of analytical

measurements are needed, fewer modules are installed. Shown below are the standard types of

measurements individually done using the IMPROVE sampler.

Module Size Region Filter Analytical Measurement

A

includes clock

controller

fine particles Teflon mass, optical absorption,

elemental (H, Na-Pb)

B fine particles nylon with denuder nitrate, sulfate, chloride

C fine particles Quartz organic and elemental carbon

D PM-10 particles Teflon PM10 mass

The standard IMPROVE particulate sampler consists of four modules, three filter modules for collection

of PM2.5 particles and one for collection of PM10 particles. Twenty-four hour aerosol samples are

collected twice per week (Wednesday and Saturday, midnight to midnight). Each filter module has

solenoids and elapsed timers for exposing two filter cassettes between weekly sample changes by the site

operator.

A Module A is a fine filter module in addition to being the "controller" module. Every fine filter

module contains a cyclone (to separate out particles larger than PM2.5), elapsed timers, critical orifice

flow control, flow gauges, inlet stack plus inlet head, etc. enclosed in a fiberglass box. The Module A

controller also contains a digital 7 day cycle clock to control sample collection for all the filter

modules at the site. The electrical system powers the vacuum pumps for each sampling module. The

controller requires 120 Volt, 60 Hertz AC power, and at least 5 amperes of electrical power for each

sampling module at the site. The module A controller measures 11" x 19" x 20" and weighs 60

pounds.

B. The other two fine filter modules (B, C) are identical to the controller "A" except for the lack of a

controller clock and independent electrical system. The fourth filter module, module "D" collects

PM10 aerosols rather than fine aerosols. Each non-controller module is controlled with a 24 volt

signal from the module A controller. The filter modules B, C, and D measure 11" x 19" x 20" and

weigh 35 pounds.

C. Four vacuum pumps provide air flow through the filters, each measures 12" x 7" x 9" and weigh 25

pounds. Each pump draws about 2.5 amperes of power at 120 volts. The pumps draw 95% of the

power used by the sampler. The pumps will operate best on the floor of the shelter. If the pumps are

left outside, a pump house will be required to shelter the pumps.

D. Five blue transport boxes (12" x 9" x 5"), each containing eight filter cassettes. These are mailed

between Davis and the site to provide a weekly rotation of filters for sample changes..
SOP 126: Site Selection 8

Figure 2 Siting Requirements for Regional Aerosol Monitoring

A. The site must be away from local sources of pollution

1. Vehicular Traffic (surface road, light traffic). For surface roads within 5 meters of the sampler

elevation and with fewer than 3000 vehicles per day, the sampler should be 25 meters from the

nearest lane and between 2 and 15 meters above the ground. However, the sampler may be

located as close as 5 meters from the nearest lane as long as the stack height does not exceed 15

meters but is greater than the height derived from

Height = -0.65 (distance from road) + 18.25

2. Vehicular Traffic (surface road, heavy traffic). For surface roads within 5 meters of sampler

elevation, with more than 3000 vehicles per day, the sampler should be located according to the

following criteria.

3000 - 10,000 cars per day sampler > 25 meters from road

10,000 - 20,000 cars per day sampler > 50 meters from road

20,000 - 40,000 cars per day sampler > 75 meters from road

more than 40,000 cars per day sampler > 100 meters from road

3. Vehicular Traffic (elevated road). For roads elevated more than 5 meters above the sampler, the

sampler should be 25 meters or more from the nearest traffic lane.

4. Combustion Sources. Avoid areas influenced by excessive diesel generator smoke, gasoline or

diesel engine emissions, wood smoke, and incinerators.

5. Dust Sources. The minimum distance from a potential source of dust (e.g. a landfill, agricultural

operations, heavily used dirt roads, etc.) should be approximately one quarter mile.

B. The site must not have obstructions, such as trees or buildings, that would hinder sampling of

regional representative aerosols.

1. The distance between obstacles (trees and buildings) and the sampler must be greater than twice

the height the obstacle protrudes above the level of the sampler inlets. This is an angle less than

twenty-seven degrees from horizontal (from the top of the stack to the top of the obstruction).

2. There must be 270° of unrestricted airflow around the sampler and the predominant wind

direction for the season of greatest pollutant concentration potential must be in this arc.

3. There must be a minimum distance of 2 meters between the sampler and any solid barrier such as

a wall, roof or the ground.

4. The distance between the sampler and the drip line of trees that are obstacles should be at least

20 meters.

5. The inlet must be located more than 1 meter vertically and horizontally away from any

supporting structure.

C. To be considered a regionally representative site, the site must not be located in a small valley, or on

barren ground that is not typical of the region.

D. The site must have 2.5A of current at 120V available for each module.

E. The site must be accessible for filter changes in all weather conditions.

F. The site should be located near existing particulate monitoring stations to provide continuity in the

data set whenever possible.

G. The sampler inlets must be located between 2 and 15 meters above the ground, except where SO2

sampling is being done in which case the inlet should be between 3 and 15 meters above the ground.
SOP 126: Site Selection 9

FORM 1 Photographic Log for Potential Aerosol Monitoring Sites

POTENTIAL SITE #1 NAME:

Photo # Date Time Description/Comments

Photo from N. including site

Photo from E. including site

Photo from S. including site

Photo from W. including site

Photo of power source relative to site

Close-up of building or location from N.

Close-up of building or location from E.

Inside of building facing N.

Inside of building facing E.

Inside of building facing S.

Inside of building facing W

Photo of nearby air sampling/meteorological equip.

Photo of nearby air sampling/meteorological equip.

POTENTIAL SITE #2 NAME:

Photo # Date Time Description/Comments

Photo from N. including site

Photo from E. including site

Photo from S. including site

Photo from W. including site

Photo of power source relative to site

Close-up of building or location from N.

Close-up of building or location from E.

Inside of building facing N.

Inside of building facing E.

Inside of building facing S.

Inside of building facing W

Photo of nearby air sampling/meteorological equip.

Photo of nearby air sampling/meteorological equip.
SOP 126: Site Selection 10

FORM 2 Required Information for Evaluation of Potential Aerosol Monitoring Sites.

POTENTIAL SITE SKETCHES

(copy as needed for each potential site)

SITE NAME: 

Site Access Constraints (4-wheel drive road, gates/locks, time of day/week/month/year): 

 

 

Elevation: 

Nearest City or Town: Distance: Direction 

Potential for Vandalism: 

Site Area Uses Within 200 Yards: 

Average and Maximum Snow Depth at Proposed Site: 

Is there any nearby air monitoring instrumentation (aerosol, meteorological, nephelometer, gaseous)?___

If yes, describe type, location, distance and direction from the proposed site. 

 

 

Is 120 volt AC power available (Distance?): 

Is a telephone available nearby? (Distance?): 

Nearest Telephone Pole #, Box #, or Telephone #: 

Particulate Sources Type / Distance / Direction

Site (within 200 yards.)

Fugitive Dust: 

Combustion: 

Other: 

On the back of this page:

1. Please draw a quick sketch of the proposed site. Indicate North, and include the dimensions of

nearby buildings and the distances to prominent objects seen in the photos.

2. Also, sketch the route taken to get from a main road to the site.

3. If possible, please send a topographic map or photocopy of a map or the site area and return it

with this form.
SOP 126: Site Selection 11

Form 2 (Continued)

FIELD SURVEY

AND SITE

SELECTION

DOCUMENTATION

The local contact should review the technical and monitoring

requirements and identify potential sites. Actual field surveys may be

performed by the local contact, an Air Quality Group field specialist,

or both.

The results of the field survey should include:

• A series of 35mm camera photos, recorded in the photographic

log along with identifying features of each shot, and including the

following shots:

 - One photo of the proposed site

 - Four photos, all taken from the proposed site, but one facing

north, one south, one east and one west.

 - Photos of any potential local aerosol sources or sinks.

 - Photos of any other features the contact deems necessary.

• Topographic maps with the proposed sites, and major local

sources, clearly identified.

• A record of pertinent information regarding accessibility, security,

site preferences, special requirements for site usage, etc.

Return the siting package with the above listed contents to the Air

Quality Group for review and site selection.

CHECK

RETURNED

SITING

PACKAGE

Check the returned aerosol monitoring documentation and

photographic log for completeness. Process undeveloped film.

Obtain any missing information from the local contact. Evaluate the

photos from each potential site for compliance with EPA siting

guidelines. If additional photographs are required, send more film or

another disposable camera to the local contact with instructions

detailing the shots required.
SOP 126: Site Selection 12

4.2 Reviewing and Selecting Potential Sites

The siting package for potential sites must be reviewed to

determine if any of the monitoring sites are acceptable. The

following criteria should be used to evaluate the suitability of a

potential site.

EVALUATE SITE

SUITABILITY

• Overall monitoring criteria defined by the project manager.

• Relation to existing visibility monitoring equipment.

• Year-round site operator accessibility

• Availability of a reliable site operator.

• Security from potential vandalism.

• Location of obstructions or interfering factors

• Locations of potential sources or sinks for aerosols.

• Type and location of any co-located instrumentation.

• Local land manager or land owner cooperation.

SELECT BEST

SITE

In consultation with the local contact, select the best site based on

the results of the evaluation and pertinent on-site comments.

Compromises may be required.

• Provide selected site description, map, and photographs to the

project manager for final approval

• As required, provide the above materials to the local contact and

any other personnel involved in the final review process.

4.3 Finalizing Site Selection

After evaluating potential sites and selecting the most appropriate site, the following

actions are required to finalize the site selection.

• Obtain approval of the selected site from the project manager.

• Obtain approval from the IMPROVE contact requesting the project.

• Provide a detailed description of the selected site, proposed instrumentation, and

installation schedule to the property manager.

• Obtain permission to use the site and arrange for any special site preparation from

the property manager, land manager (public lands), or land owner (private land).

• Initiate installation protocols as described in SOP 151, Installation and Site

Documentation for IMPROVE Aerosol Monitoring Equipment.