A04 SOW IMPROVE Ion Analysis 2021 _0001.docx

SCOPE OF WORK FOR IMPROVE ION ANALYSIS

CONTENTS

1 Introduction and Background

1.1 Introduction

The National Park Service (NPS) is responsible for the protection and enhancement of air quality related values in the areas it manages by ensuring compliance with directives, regulations, and applicable requirements of the NPS Organic Act of 1916 and the Clean Air Act. The Organic Act mandates the National Park Service to, "…conserve the scenery and the natural and historic objects and the wildlife therein and to provide for the enjoyment of the same in such manner and by such means as will leave them unimpaired for the enjoyment of future generations."

The Clean Air Act affords special air quality protections to certain national parks and wilderness areas, designating them as mandatory Class I federal areas, and assigns to the Federal Land Managers (FLMs) of those areas "the affirmative responsibility to protect the air quality related values (including visibility)" of Class I lands. It also established "as a national goal the prevention of any future, and the remedying of any existing, impairment of visibility in mandatory Class I federal areas which impairment results from manmade air pollution." The Clean Air Act established a detailed program that provides guidance to the NPS in meeting these mandates. On behalf of the NPS, the Air Resources Division (ARD) has an air quality program to help carry out these responsibilities.

The National Park Service administers 48 parks and wilderness areas that are designated Class I, the U.S. Fish and Wildlife Service (FWS) administers 21 Class I wilderness areas, the U.S. Forest Service (USFS) administers 88 Class I wilderness areas, and there is one international park that is Class I. Of these 158 mandatory Class I Federal areas, visibility is considered an important attribute in all but two USFS wilderness areas.

The Regional Haze Rule (RHR) established the regulatory framework by which the national visibility goal is to be met [United States Environmental Protection Agency, 1999] and requires monitoring representative of the 156 visibility-protected Class I areas. The Interagency Monitoring of Protected Visual Environments (IMPROVE) Program [Joseph et al., 1987; Malm et al., 1994] oversees the RHR monitoring efforts, providing particle sampling and analysis of the major aerosol components. The IMPROVE program establishes current visibility and aerosol conditions in mandatory Class I areas; identifies chemical species and emission sources responsible for existing man-made visibility impairment; documents long-term trends in visibility; and provides regional haze monitoring representing all visibility-protected federal Class I areas, where practical. Because the RHR requires tracking of trends over an extended time period, it is important that IMPROVE measurements produce comparable data over a period of many decades.

The IMPROVE Program is a cooperative measurement effort managed by a Steering Committee that consists of representatives from the U.S. Environmental Protection Agency (EPA), the NPS, the USFS, the FWS, the Bureau of Land Management (BLM), the National Oceanic and Atmospheric Administration (NOAA), four organizations representing state air quality organizations (the National Association of Clean Air Agencies, the Western States Air Resources Council, the Northeast States for Coordinated Air Use Management, and the Mid-Atlantic Regional Air Management Association), and three Associate Members: the State of Arizona Department of Environmental Quality, Environment Canada, and the South Korea Ministry of Environment.

The National Park Service manages the IMPROVE monitoring efforts on behalf of the Steering Committee. The purpose of this contracting effort is to assist the NPS in these efforts by conducting ion analysis of IMPROVE samples collected on nylon filters, as detailed in the following sections. The contractor shall provide the results of the analyses specified in this solicitation to the IMPROVE Operations Contractor. This solicitation is sponsored by the NPS, but covers the monitoring efforts for all mandatory Class I Federal areas, as well as other monitoring using the IMPROVE monitoring protocols (described further below). The successful offeror of this solicitation will work through the NPS on all contractual related matters; other agencies sponsoring IMPROVE and IMPROVE protocol sites will work through the NPS to access the resources available through this contract.

1.2 Background

IMPROVE was established as a national visibility monitoring program in 1985. The IMPROVE network initially was funded by the NPS and consisted of 30 monitoring sites primarily located in national parks, 20 of which began operation in 1987. IMPROVE network operations were fully implemented in March 1988. Beginning in 1998 the EPA provided supplemental support to expand the IMPROVE network in order to provide representative particle speciation monitoring for all 156 visibility-protected Class I areas, as required under the RHR. In a site selection process [Malm et al., 2000; http://vista.cira.colostate.edu/improve/] which included input from all interested state air quality agencies, the IMPROVE Steering Committee identified locations for 110 monitoring sites that were deemed representative of the regional haze conditions for 155 of the mandatory 156 Class I areas, the Bering Sea Wilderness being the exception.

In addition to the 110 IMPROVE network sites that are used to represent Class I areas, a number of IMPROVE protocol sites are currently in operation that provide expanded spatial coverage in regions outside of Class I areas. Protocol sites are separately sponsored by state, regional, tribal, and national organizations and use the same instrumentation, monitoring, and analysis protocols as IMPROVE. The use of identical samplers and analysis protocols by the same contractors ensures that data generated by IMPROVE and IMPROVE protocol sites can be treated as directly comparable. Sites are listed in Attachment 2 and their locations are shown in Figure 1. Most sites are located in rural areas. However, for the purpose of comparing differences in aerosol composition between rural and urban areas, there are currently three urban sites in Fresno, CA, Seattle, WA, and Phoenix, AZ. Likewise, to better facilitate intercomparison and integration of IMPROVE data with EPA’s Chemical Speciation Network (CSN), six sites are collocated with CSN sites, one of which is Carbon only (see Attachment 2). Data from all IMPROVE sites are available on the Federal Land Manager Environmental Database (FED; http://views.cira.colostate.edu/fed/).

Figure 1. Map of 157 IMPROVE and IMPROVE Protocol Sites as of September 2020 To collect samples for the speciated particle measurements, IMPROVE employs a 4-channel (labeled A, B, C, and D) particle sampling system. A description of the current IMPROVE sampler and standard operating procedures can be found on the IMPROVE website (http://vista.cira.colostate.edu/improve/). The PM2.5 (particles <2.5 m in diameter) samplers operate with a nominal flow rate of 22.8 liters/minute (LPM), while the PM10 sampler (particles <10 m in diameter) runs at 16.9 LPM. Both collect samples for a 24-hour time interval, midnight to midnight local time, every third day. Channel A (PM2.5), operated with Teflon filters, is used for determining fine mass, elemental composition and optical absorption. Channel B (PM2.5) is operated with a nitric acid denuder and a nylon filter. The nylon filter is analyzed for the anions nitrite, nitrate, sulfate and chloride. Channel C (PM2.5), operated using pre-fired quartz filters, is used to determine elemental and organic carbon using the thermal/optical reflectance technique. Channel D is operated with a Teflon filter and PM10 inlet. The PM10 filters are analyzed for total mass. Laboratory blanks are also utilized for each of the channels, and field blanks are employed to better assess detection limits and potential contaminants in the samples. For further details on all measurements and analysis, see the IMPROVE website, and the pages describing standard operating procedures (SOPs) contained therein http://vista.cira.colostate.edu/improve/Publications/IMPROVE_SOPs.htm).

2 Objective/Purpose The purpose of this contract is for the analysis and reporting of ion masses from IMPROVE nylon filters (module B). The successful bidder will perform analyses on module B filters as detailed in the following sections and will report results on the schedule described. The successful bidder must also conduct an internal quality assurance program and participate in laboratory audits. The successful bidder is expected to use established protocols for analyzing module B IMPROVE filters. The current SOP for IMPROVE filter extraction and ion analysis can be found at: http://vista.cira.colostate.edu/Improve/ion-chromatography-analysis-of-module-b/. As new methods and quality assurance measures evolve, the contractor shall incorporate these updated methods into the IMPROVE routine operations through the modification of SOPs, as approved by the IMPROVE Steering Committee and directed by the Contracting Officer Representative (COR). At the direction of the COR, the contractor also will ensure that all pertinent information developed by the contractor for routine operations are available to other organizations, as needed.

As part of this effort, the successful bidder will work closely with the IMPROVE Operations Contractor, currently the University of California, Davis. The IMPROVE Operations Contractor is responsible for the purchase of module B nylon filters, shipment of exposed and blank nylon filters to the successful bidder of this contract for analysis, and incorporation of the ion data into the larger IMPROVE dataset.

3 Scope of Work

3.1 Standard Analysis

This contract is broken up into a base year and four option years. For each year, proposals should be prepared based on the current network (~18,000 filters per year), with costs given on a per filter basis. The exact number of filters to be analyzed annually is subject to change, based on changes to the network configuration. As described in more detail in the following sections, all B module nylon filters shall be analyzed for nitrite (NO2-), nitrate (NO3-), sulfate (SO42-) and chloride (Cl-), and concentrations shall be reported to the IMPROVE Operations Contractor for incorporation into the larger IMPROVE dataset.

3.2 Deliverables

Ion mass concentration data for nitrite, nitrate, sulfate and chloride on each filter, to be delivered to the IMPROVE Operations Contractor (3.3.4 and 3.4.1).

Relevant data from the Additional Laboratory Tasks (section 4), as these tasks are implemented, to be delivered to the COR.

Quality assurance report: a summary report on quality assurance plan and quality control data shall be provided to the COR once per year (3.3.5 and 3.4.2).

Up to date records on system calibrations and changes to procedures shall be maintained and submitted to the COR upon request.

Standard Operating Procedures (SOPs) for Ion Analysis and for analysis related to Additional Laboratory Tasks shall be maintained and updated on the IMPROVE website as changes occur. The contractor must obtain written approval from the COR before any changes to ion analysis procedures are implemented.

Technical and scientific progress reports presented annually at IMPROVE Steering Committee Meetings (4.4).

3.3 Ion Analysis

3.3.1 Filter Supply and Distribution

The IMPROVE Operations Contractor is responsible for purchasing the nylon filters and shipping the exposed filters to the successful bidder of this contract. The successful bidder of this contract will work with the IMPROVE Operations Contractor for acceptance testing of the nylon filters during the purchasing process. Batches of exposed nylon filters will be sent to the Ion Analysis Contractor on at least a monthly basis; shipments will include laboratory blanks, field blanks, and quality assurance filters (replicate samples) to be analyzed in addition to the field samples.

3.3.2 Filter Receipt and Sample Storage

The Ion Analysis Contractor will receive approximately 18,000 B module nylon filters each year. The contractor shall identify each sample using the code provided by the IMPROVE Operations Contractor. Each batch of exposed filters delivered to the contractor shall be analyzed within sixty (60) calendar days from the receipt of each batch. Analyzed samples shall be stored by the Ion Analysis Contractor in a manner that prevents contamination for possible reanalysis for at least six months. After this time, the stored samples may be destroyed, provided that the final dataset has been submitted.

3.3.3 Sample Extraction

The contractor will extract ions from all filters using an SOP for extraction that is shown to be quantitatively reproducible. The existing SOP for ion extraction can be found at: http://vista.cira.colostate.edu/Improve/ion-chromatography-analysis-of-module-b/. Using current methods, the mean extraction efficiency is greater than 95% for, nitrate (NO3-), sulfate (SO42-) and chloride (Cl-); nitrite (NO2-) has a mean extraction efficiency of greater than 92%. The offeror may propose an alternate extraction procedure; if using an alternate method, the proposed SOP should be submitted as part of the response to this solicitation. Proposed methods should have extraction efficiencies that are equivalent to or better than the current method.

3.3.4 Sample Analysis

The contractor shall analyze the extracted samples for nitrite (NO2-), nitrate (NO3-), sulfate (SO42-) and chloride (Cl-) using standard methods. IMPROVE currently uses ion chromatography (IC) for ion analysis. The SOP for ion analysis can be found at: http://vista.cira.colostate.edu/Improve/ion-chromatography-analysis-of-module-b/. Using the current SOP, the minimum detection limits (MDL) are as follows: nitrite = 0.010 ppm; nitrate = 0.008 ppm; sulfate = 0.011 ppm; chloride = 0.005 ppm. The offeror may propose an alternate analysis procedure; if using an alternate method, the proposed SOP should be submitted as part of the response to this solicitation. Proposals should utilize methods which produce comparable or better MDLs. The offeror also must be able to measure across the range of anticipated concentrations. The upper limit for ionic mass on a filter is expected to be 2,000 g for each ion; this equates to ambient concentrations of ~60 g m-3 sampled for 24 hours from the fine (PM2.5) particle inlet.

Ion analyses shall include field samples, laboratory blanks, field blanks, and quality assurance filters. In addition to filter analysis, the contractor shall:

Characterize the sensitivity, accuracy, and precision of the analytical techniques;

Perform replicate analyses on the network filters at a rate sufficient to establish measurement precision;

Routinely analyze laboratory and field blanks; and Document any changes to the analytical techniques, equipment, or processing procedures needed to properly interpret and understand the quality of the data delivered.

Proposals should specify the frequency and type of quality control and replicate analyses to be performed.

The contractor shall obtain approval from the COR before any changes to the Standard Operating Procedures are implemented.

3.3.5 Quality Assurance

The contractor shall follow, and develop where appropriate, strict quality assurance protocols. The contractor may be required to contribute to the IMPROVE Quality Assurance Project Plan (QAPP), as it is updated, specifically as it relates to ion analysis. The current QAPP for the IMPROVE Program is available at: http://vista.cira.colostate.edu/improve/wp-content/uploads/2020/02/IMPROVE-QAPP-Signed_3_2016_updated.pdf.

As part of quality assurance efforts, the contractor shall:

Conduct acceptance testing of new filters for filtration characteristics and analytic suitability (especially trace contamination);

Ensure that written procedures and protocols are followed;

Certify that the reported data have been collected using the established criteria for accuracy and precision;

Validate the ion analysis results via formal third party protocols;

Perform reanalysis of previous samples as needed;

Maintain records on system calibration and comparison to standards, and document all routine procedures and changes to the procedures;

Participate in Laboratory Audits, as specified in the IMPROVE QAPP; and Assist the IMPROVE Operations Contactor in determining analytical uncertainties and artifacts.

3.4 Data Reporting

3.4.1 Data Reduction and Reporting

The contractor shall be responsible for data reduction. Data reduction is limited to determining ion mass for nitrite (NO2-), nitrate (NO3-), sulfate (SO42-) and chloride (Cl-) on each filter, plus determining accuracy and precision of the analysis procedures. The contractor shall submit the results of the analyses for the samples in each batch within sixty (60) calendar days of the receipt of the filters. Reduced data shall be submitted to the IMPROVE Operations Contractor. The results shall include the sample identification code and the ion masses in micrograms. The contractor shall include relevant quality assurance data, including comparisons to standards and results of re-analyses, as appropriate.

3.4.2 Quality Assurance Report

The contractor shall provide quality assurance reports covering all aspects of laboratory operations and submit to the COR once per year. Previous reports are available at: http://vista.cira.colostate.edu/Improve/quality-assurance/. Upon request, the contractor shall provide the detailed quality control test data. Examples of quality control tests might include calibrations against standards, replicate analyses, blank analyses, cross-comparisons of analyzers, and analyses of independent audit samples.

3.4.3 Network Documentation

The contractor shall maintain up-to-date documentation of:

· Standard Operating Procedures (SOPs) for ion analysis;

· Records on system calibrations and changes to procedures; and

· Quality Assurance Reports.

All documentation must be made available upon request from the COR. The contractor shall obtain written approval from the COR before any changes to ion analysis procedures are implemented.

3.4.4 Steering Committee Meetings

The contractor shall attend and provide technical and scientific progress reports at IMPROVE Steering Committee Meetings, held annually.

4 Additional Laboratory Tasks Changes to the contract may occur during its five-year term to keep pace with emerging air quality issues. Such changes may require additional analyses. Such analysis is considered separate from the routine monitoring network and should be addressed separately in the proposal both in terms of cost and technical approach. The following tasks may be needed at any time during the contract period of performance and may include any combination of the tasks below. The Offeror should provide cost estimates for each of these Additional Laboratory Tasks.

4.1 Additional Analyses

The contractor may be asked to carry out analysis for species other than NO2-, NO3-, SO42- and Cl-. In the following sections, some likely species to be analyzed as part of this contract are outlined. However, Additional Analyses may also include species not specifically noted here.

4.1.1 Measurements of cations

The contractor may be asked to analyze the exposed filters from module B for cations, including ammonium (NH4+), sodium (Na+), potassium (K+), calcium (Ca2+) and magnesium (Mg2+). This analysis would use ion chromatography and would be conducted in addition to the standard anion analysis. The contractor would also be expected to report results and provide the required quality control associated with this effort. The current SOP for cation analysis is available: http://vista.cira.colostate.edu/Improve/ion-chromatography-analysis-of-module-b/.

Upon receipt of exposed filters from the IMPROVE Operations Contractor, the contractor shall extract and analyze each filter for cations using IC following a standard method. Each batch of exposed filters delivered to the contractor shall be analyzed within sixty (60) calendar days from the receipt of each batch. The IMPROVE Operations Contractor shall be responsible for including laboratory blanks, field blanks, and quality assurance filters to be analyzed by the Ion Analysis Contractor, in addition to the field samples. The contractor shall store all samples for possible re-analysis as requested by the COR for a period of at least six (6) months. The contractor shall provide the IMPROVE Operations Contractor with certified results of the laboratory analyses of exposed filters (and blanks) expressed as micrograms of ion per filter. All reported results will bear the sample identification codes assigned by the IMPROVE Operations Contractor.

4.1.2 Measurements of NHx

The contractor may be asked to carry out analysis on reduced nitrogen (NHx). For this work, an additional module may be installed at select sites and operated with a phosphorous acid impregnated cellulose filter used to determine NHx concentrations. The contractor may be asked to prepare the impregnated filters used for sampling, analyze the NHx mass on exposed filters using IC, report the results, and provide the required quality assurance associated with this effort.

4.1.2.1 Filter Preparation

The contractor shall prepare filter media for the collection of NHx (NH3 and NH4+) samples on filters (SKC Filter, Cellulose Fiber [ashless], 37 millimeters, or equivalent). Filters will be impregnated with 3% phosphorous acid (H3PO3) solution (15 mg H3PO3, 50 ml, deionized water, 450 ml methanol). The acid impregnated filters will be loaded into clean IMPROVE filter cassettes in an ammonia free environment. Loaded cassettes will be shipped to the IMPROVE Operations Contractor double-bagged, with ammonia adsorbent. Sample cassettes will be sealed on both ends. The IMPROVE Operations Contractor will ship the filters to the field sites for use and subsequently send the cassettes with exposed filters to the Ion Analysis Contractor for analysis.

4.1.2.2 Analysis of NHx Samples

Sampled IMPROVE filter cassettes will be shipped to the Ion Analysis Contractor in a double-bag to minimize ammonia contamination. Upon receipt of the cassettes, the contractor shall remove the filter from the cassettes and extract the samples from the filters in an ammonia free environment using a method that is shown to be at least 95% efficient. The extract is to be analyzed for NH4+ using IC following a standard method specified by a SOP that is shown to be quantitatively reproducible. A description of the method can be found in Chen et al., 2014. Analyses are to be performed within fifteen (15) calendar days of receipt of the filters from the IMPROVE Operations Contractor. The filters may contain field blanks to be analyzed by the contractor in addition to the exposed filters. The contractor shall store all samples for possible re-analysis as requested by the COR for a period of at least six (6) months. The contractor shall provide the IMPROVE Operations Contractor with certified results of the laboratory analyses of exposed filters (and blanks) expressed as micrograms NH4+ per filter. All reported results will bear the sample identification codes assigned by the IMPROVE Operations Contractor.

4.1.2.2 Analysis of methylamines

In addition to NHx, the contractor may be asked to analyze the exposed NHx filters for methylamines using the method described in Chen et al., 2014. The Offeror should provide a cost estimate for quantification of this additional species separately.

4.1.3 Measurements of SO2

The contractor may be asked to carry out analysis on sulfur dioxide (SO2). The D module of the IMPROVE sampler can be operated with an optional potassium carbonate (K2CO3) impregnated filter to determine gaseous SO2 concentrations. For this optional task, the contractor may be asked to prepare the impregnated filters used for sampling, analyze the sulfate mass on exposed filters using IC, report the results, and provide the required quality assurance associated with this effort.

4.1.3.1 Filter Preparation

The contractor shall prepare filter media for the collection of SO2 samples on filters (Pallflex quartz fiber filter No. 3700 AT-UP, 37 mm, or equivalent). Filters will be impregnated with K2CO3/2% glycerol solution. The contractor shall deliver prepared filters to the IMPROVE Operations Contactor as requested. The IMPROVE Operations Contactor will ship the filters to the field sites for use and subsequently send the exposed filters to the contractor for analysis.

4.1.3.2 Analysis of SO2 Samples

Upon receipt of exposed filters from the IMPROVE Operations Contractor, the Ion Contractor shall extract the filters following a method specified by an SOP that is shown to be at least 95% efficient and analyze each filter for sulfate using IC. Each batch of exposed filters delivered to the contractor shall be analyzed within sixty (60) calendar days of receipt. The filters may contain field blanks to be analyzed by the contractor in addition to the exposed filters. The contractor shall store all samples for possible re-analysis as requested by the COR for a period of at least six (6) months. The contractor shall provide the IMPROVE Operations Contractor with certified results of the laboratory analyses of exposed filters (and blanks) expressed as micrograms sulfate per filter. All reported results will bear the sample identification codes assigned by the IMPROVE Operations Contractor.

4.1.4 Measurements of Organic Acids and Smoke Markers

The contractor may be asked to carry out analysis on the filters to quantify organic acids and smoke markers (e.g. levoglucosan). For this optional task, the contractor may be asked to develop an SOP, analyze the exposed filters for ambient organic acids and smoke markers, report the results, and provide the required quality assurance associated with this effort.

4.1.5 Measurements of Soluble Elemental Constituents

The contractor may be asked to carry out analysis on the filter extracts to quantify soluble elemental constituents using ICP-MS or other suitable analysis method. For this task, the contractor may be asked to develop an SOP, analyze the filter extracts for soluble elemental composition, report the results, and provide the required quality assurance associated with this effort

4.2 Enhanced Quality Assurance and Method Development

Enhanced quality assurance methods are intended to assess measurement artifacts and improve interpretation and understanding of the data. The contractor may be asked to conduct studies to enhance and improve the ion analysis methodology, as well as methodologies associated with the Additional Laboratory Tasks. These tasks may include, but are not limited to, reanalysis of archived samples, method development to improve detection of existing or new compounds, characterization of potential measurement artifacts, and method development to reduce measurement uncertainties. All enhanced quality assurance and method development efforts initiated by the COR are included as part of this task. For pricing of this task, the Offeror should include fully loaded labor rates of relevant personnel. A list of personnel is included in Attachment 1: Pricing Worksheet.

5 Incorporation of the Technical Proposal and Proposal Length

(a) The Contractor’s technical proposal will be incorporated herein by reference. In the event of conflict between the provisions of the technical proposal and any other clause of this contract (including, the statement of work), the conflict will be resolved in accordance with 52.212-4(s), Order of Precedence. For this contract, the Contractor’s technical proposal will be deemed to be the last in order of precedence. The detailed technical content of the Contractor’s proposal is an important factor in the selection of the Contractor for award of this contract. It is agreed, therefore, that in performance of this contract, the Contractor shall not change or otherwise deviate from the content of the technical proposal without prior written approval of the Contracting Officer. If it is necessary for the Contractor to change the performance, design, configuration, or other items specified in the technical proposal, in order to comply with the requirements of the Statement of Work, contract clauses, or special contract requirements, the contract shall be modified at the discretion of the Government to reflect the changes at no increase in contract cost/price or extension of the delivery schedule or shall be negotiated if warranted.

(b) The Government, upon award of this contract, shall have full rights of ownership in the technical proposal and the data contained therein.

(c) The technical proposal package should not exceed 100 pages in length.

6 Contingency of Operations The offeror shall provide in its technical proposal a contingency of operations plan in the event of a catastrophe or catastrophic failures of computer systems, hard drives, etc. This shall include plans to replace key personnel, recovery of data, alternate locations, and methods of contingency data validation and processing.

7 Government Owned Property There is no government-furnished property related to this contract.

8 Transition Phase An incumbent contractor is currently providing the services described in this Statement of Work under an IDIQ contract. Upon contract completion or termination, the incumbent contractor shall work to ensure a smooth and coordinated transition to the successful offeror by making staff and resources available to ensure timely transfer of existing inventories to the new contractor. The incumbent contractor shall also make available to the new contractor any data collected through the previous contract which may assist the successful offeror during the transition phase.

9 References Chen, X., D. Day, B. Schichtel, W. Malm, A.K. Matzoll, J. Mojica, C.E. McDade, E.D. Hardison, D.L. Hardison, S. Walters, M. Van De Water, and J.L. Collett Jr., Seasonal ambient ammonia and ammonium concentrations in a pilot IMPROVE NHx monitoring network in the western United States, Atmos. Environ., 91, 118-126, 2014.

Joseph, D. B. J. Metza, W. C. Malm, and M. L. Pitchford, A federal program to monitor visibility in class I areas, in Visibility Protection: Research and Policy Aspects; P.J. Bhardwaja, Ed., Air Pollution Control Assoc., Pittsburgh, PA, 1987.

Malm, W. C., J. F. Sisler, D. Huffman, R. A. Eldred, and T. A. Cahill, Spatial & seasonal trends in particle concentration & optical extinction in the U.S., J. Geophys. Res., 99, 1347-1370, 1994.

Malm, W. C., J. F. Sisler, M.L. Pitchford, M. Scruggs, R. Ames, S. Copeland, K.A. Gebhart, and D.E. Day, IMPROVE (Interagency Monitoring of Protected Visual Environments): Spatial and seasonal patterns and temporal variability of haze and its constituents in the United States: Report III, CIRA Report ISSN: 0737-5352-47, Colorado State University, Fort Collins, CO, 2000.

United States Environmental Protection Agency, Regional Haze Regulations: [40 CFR Part 51.308-309].

10 Exhibits and Requirements

10.1 List of Exhibits

Attachment 1: Pricing Worksheet image1.jpeg