Addendum to the

“Technical Support Document

For the April 3, 2009

Pagosa Springs Exceptional Event”

Prepared by the Technical Services Program

Air Pollution Control Division

Colorado Department of Public Health and 

Environment

September 30, 2013
1.0 Introduction

This addendum serves to incorporate additional requested information regarding Section 5 “Local Dust 

Control Measures” of the “Technical Support Document for the April 3, 2009 Pagosa Springs Exceptional 

Event” submitted to the EPA on June 30, 2012. This addendum addresses additional support regarding 

local sources and controls outlined in the letter sent by EPA Region 8 on April 2, 2013. This letter states

that the Exceptional Event documentation submitted by APCD did not “sufficiently investigate whether 

local sources of windblown dust may have contributed to the exceedances.” Since receiving the EPA 

letter, the Colorado Air Pollution Control Division (Division) conducted a thorough investigation, 

including EPA’s suggestions, of local sources of windblown dust and relevant reasonable controls in 

place at the time of the April 3, 2009 Exceptional Event. These sources include the nine acre park along 

South 5th Street, the lots on the southeast corners of U.S. Highway 160 and Main Street/Lewis Street, and 

the expansion of the Springs Resort and Spa. This addendum documents the results of this investigation. 

In addition, this addendum also provides additional information for Section 1 “Introduction” of the 

“Technical Support Document for the April 3, 2009 Pagosa Springs Exceptional Event” submitted to the

EPA on June 30, 2012. Specifically, this addendum provides information regarding prompt public 

notification of the event, as required in 40 CFR 50.14 (c)(1)(i).

This addendum, the original report, and the analysis and data contained within it, clearly shows that this 

exceptional event passed the required tests under 40 CFR 50.14 (3)(iv).

2.0 Public Notification

The Federal EER requirements include public notification when an event occurs or is reasonably 

anticipated to occur which may result in the exceedance of an applicable air quality standard, per 40 CFR 

50.14(c)(1)(i).

In 2009, the Division was not providing detailed advisories for the entire state on a website. At that time, 

the focus of the Division website was AQI reporting and advisories for areas with populations over 

350,000, as required in 40 CFR 58.50, as well as advisories for areas under a Natural Events Action Plan. 

For other areas, phone calls or emails were provided to local officials as forecasting predicted that natural 

events had a likelihood of occurring. For the high wind/dust event on April 3, 2009, it is unknown if an 

advisory phone call or email was provided to local officials in Archuleta County or Pagosa Springs as, per 

State of Colorado archive requirements, phone and email records are not kept for extended periods.

It should be noted that the high values from this exceptional event were not from real-time samplers, but 

were from filter-based samplers where the values are not known for a few weeks after sampling.
3.0 Not Reasonably Controllable or Preventable: Local 

Particulate Matter Control Measures

While it is likely that some dust was generated within the local communities as gusts from the regional 

dust storm passed through the area, the amount of dust generated locally was easily overwhelmed by, and 

largely unnoticeable as compared to the dust transported in from the source regions of the dust storm. 

The following sections will describe in detail the regulations and programs in place designed to control 

PM10 in the affected community. These sections will demonstrate that the event was not reasonably 

controllable, as laid out in Section 50.1(j) of Title 40 CFR 50, within the context of reasonable local 

particulate matter control measures. 

The Colorado Air Pollution Control Division (Division) conducted thorough analyses and outreach with 

local governments to confirm that no unusual anthropogenic PM10-producing activities occurred in 

Pagosa Springs and that despite reasonable control measures in place, high wind conditions overwhelmed 

all reasonably available controls. The following subsections describe in detail Best Available Control 

Measures (BACM), other reasonable control measures, applicable federal, state, and local regulations, 

appropriate land use management, and an in-depth analysis of potential areas of local soil disturbance for 

the affected community during the March 30, 2012 event, as well as subsequent outreach designed to 

administer these activities. This information shall confirm that no unusual anthropogenic actions 

occurred in Pagosa Springs during this time.

Regulatory Measures- State

The Division’s regulations on PM10 emissions are summarized in Table 1.

Table 1: State Regulations Regulating Particulate Matter Emissions

Rule/Ordinance Description

Colorado Department of Public Health and 

Environment

Regulation 1- Emission Control For Particulate 

Matter, Smoke, Carbon Monoxide, And Sulfur 

Oxides

Applicable sections include but are not limited to:

Everyone who manages a source or activity that is 

subject to controlling fugitive particulate emissions 

must employ such control measures and operating 

procedures through the use of all available practical 

methods which are technologically feasible and 

economically reasonable and which reduce, prevent 

and control emissions so as to facilitate the 

achievement of the maximum practical degree of air 

purity in every portion of the State. Section III.D.1.a)

Anyone clearing or leveling of land greater than five 

acres in attainment areas or one acre in non-attainment 

areas from which fugitive particulate emissions will be 

emitted are required to use all available and practical 

methods which are technologically feasible and 

economically reasonable in order to minimize fugitive 

particulate emissions.(Section III.D.2.b)

Control measures or operational procedures for 

fugitive particulate emissions to be employed may 

include planting vegetation cover, providing synthetic 
cover, watering, chemical stabilization, furrows, 

compacting, minimizing disturbed area in the winter, 

wind breaks and other methods or techniques 

approved by the Division. (Section III.D.2.b)

Any owner or operator responsible for the 

construction or maintenance of any existing or new 

unpaved roadway which has vehicle traffic exceeding 

200 vehicles per day in the attainment/maintenance 

area and surrounding areas must stabilize the roadway 

in order to minimize fugitive dust emissions (Section 

III.D.2.a.(i))

Colorado Department of Public Health and 

Environment

Regulation 3- Stationary Source Permitting and 

Air Pollutant Emission Notice Requirements 

Construction Permit required if a land development 

project exceeds 25 acres and spans longer than 6 

months in duration (Section II.D.1.j)

Colorado Department of Public Health and 

Environment

Regulation 6- Standards of Performance for 

New Stationary Sources

Implements federal standards of performance for new 

stationary sources including ones that have particulate 

matter emissions. (Section I)

Colorado Department of Public Health and 

Environment

Regulation 9- Open Burning, Prescribed Fire, 

and Permitting

Prohibits open burning throughout the state unless a 

permit has been obtained from the appropriate air 

pollution control authority. In granting or denying any 

such permit, the authority will base its action on the 

potential contribution to air pollution in the area, 

climatic conditions on the day or days of such burning, 

and the authority’s satisfaction that there is no 

practical alternate method for the disposal of the 

material to be burned. Among other permit conditions, 

the authority granting the permit may impose 

conditions on wind speed at the time of the burn to 

minimize smoke impacts on smoke-sensitive areas.

(Section III)

Federal Motor Vehicle Emission Control 

Program

The federal motor vehicle emission control program 

has reduced PM10 emissions through a continuing 

process of requiring diesel engine manufacturers to 

produce new vehicles that meet tighter and tighter 

emission standards. As older, higher emitting diesel 

vehicles are replaced with newer vehicles; the 

PM10 emissions in areas will be reduced.

3.1 Pagosa Springs

Regulatory Measures- City and County

The Division and Archuleta County are responsible for implementing regulatory measures to control 

emissions from agricultural sources, stationary sources, fugitive dust sources, and open burning within the 

city limits of Pagosa Springs and Archuleta County. Archuleta County regulations pertaining to PM10

emissions are summarized in Table 2.
Table 2: Rules and Ordinances Regulating Particulate Matter Emissions in Archuleta County

Rule/Ordinance Description

Pagosa Springs 

Land Use and Development Code 6.6.3(h)

Requires that all new developments have paved 

streets.

Pagosa Springs 

Land Use and Development Code 6.6.3(m)(i)

All new roads having a projected trip generation of 

200 or greater ADT (average daily traffic) shall be 

paved. 

The following control measures resulted in the area’s attainment of the PM10 NAAQS, and these 

measures should ensure continued maintenance of the PM10 NAAQS through the year 2021, which is the 

duration of the maintenance period:

Control of Emissions through Road Paving

The Town of Pagosa Springs paved 6.5 miles of unpaved roads during 1992, 1993, and 1994 in 

order to reduce PM10 emissions. This strategy was adopted locally in 1991 and included in State 

regulation in 1992 (Section I.B. of the State Implementation Plan-Specific Regulations for 

Nonattainment - Attainment/Maintenance Areas (Local Elements)). The rule was approved by 

EPA in 1994 and was removed from the Colorado regulation in 2000 as the paving requirements 

had been completed.

Street Sanding Controls

There is a requirement that any user that applies street sanding material on Highway 160 and 

Highway 84 in the Pagosa Springs attainment/maintenance area must use materials containing 

less than one percent fines. Users of street sand on these highways must also use 15 percent less 

sand than an established base sanding amount. These strategies were adopted in 1992 and 

approved by EPA in 1994, and they are defined in detail in Sections I.B. and C., respectively, of 

the State Implementation Plan-Specific Regulations for Nonattainment -Attainment/Maintenance 

Areas (Local Elements) Regulations (5 CCR 1001-20).

Control of Emissions from Stationary Sources

Although there are no stationary sources located in the Pagosa Springs attainment/maintenance 

area, the State‘s comprehensive permit rules will limit emissions from any new source that may, 

in the future, locate in the area. These rules are outlined in Table 1.

As indicated above, emissions from new or modified major stationary sources emissions of PM10

are controlled under AQCC Regulation No. 3's nonattainment-area (NAA) new source review 

(NSR) permitting requirements. The NSR provisions require all new and modified major 

stationary sources to apply emission control equipment that achieves the "lowest achievable 

emission rate" (LAER) and to obtain emission offsets from other stationary sources of PM10.

The EPA approval of the original PM10 Maintenance Plan, effective on 08/14/01, reinstates the 

prevention of significant deterioration (PSD) permitting requirements in the Pagosa Springs 

Attainment/Maintenance area. The federal PSD requirements are considered a relaxation from the 

NAA NSR requirements, as LAER is no longer required and is replaced by the less stringent 

"best available control technology" (BACT), along with the removal of the requirement to offset 

PM10 emissions. The future reapplication of NAA NSR provisions appears unlikely in the Pagosa 

Springs Attainment/Maintenance area based on current PM10 monitoring trends.
Voluntary and State-Only Measures

In addition to the mandatory control measures discussed above, there are other activities that 

result in the reduction of PM10 emissions that are not classified as “federally enforceable control 

measures.” Some notable examples include:

The Town of Pagosa Springs has historically cleaned Highway 160 in town throughout the winter 

and spring using regenerative air vacuum sweepers. The frequency of this voluntary 

sweeping/cleaning has been about once after each street sanding deployment. The Town of 

Pagosa Springs is committed to regularly vacuum sweep/clean Highway 160 within four days of 

the roadway becoming free and clear of snow and ice following each street sanding deployment, 

as weather, temperature, and street conditions permit, between the intersections of Highway 84 to 

the east and 14th street to the west. The town also street sweeps side streets regularly.

The Town of Pagosa Springs encourages private businesses to properly clean/sweep private 

parking lots on a regular basis. These strategies are considered to be voluntary local initiatives 

intended to reduce PM10 emissions. These strategies are not intended to be federally enforceable. 

Archuleta County annually treats about 95 miles of unpaved roadways that exceed 200 ADT with 

MgCl2 to control dust and stabilize the road according to the County Public Works Director. 

Windblown Dust from Disturbed Soils

Pagosa Springs has a semi-arid climate with approximately 17 inches of precipitation annually. 

The town is located about 35 miles north of the New Mexico border at 7,000 feet. This area is 

considered a high desert plateau, creating an unusually mild climate. In winter and spring, 

regional windstorms are common, especially in drier years. It is during these high velocity 

windstorms that Pagosa Springs experiences PM10 issues. Figure 1 illustrates potential areas of 

local soil disturbance that have been evaluated by the Division.
Figure 1: Relative positions of Pagosa Springs PM10 monitor and known or potential disturbed soil. 

(Image from EPA)

Site A in Figure 1 shows a 1 acre vacant lot (southeast corner of U.S. Highway 160 and Main 

Street/Lewis Street) that previously contained a small convenience store which was torn down by the new 

owner between March and April of 2006. Division conversations with neighboring local business owners 

indicate the owner seeded the vacant lot (site A) with grass soon after demolishing the building. 

According to several nearby businesses and a court house clerk, the lot has been under continuous 

vegetative cover since the seeding in 2006. The grass is well maintained and is enclosed by a small fence 

(shown in Figure 2) to deter people from walking on the grass. Moreover, the lot is not used for parking 

or storage. As of August 2013, the lot is for sale. 

D

C

A

B
Figure 2: Site A (August 2013)

Site B in Figure 1 (approximately 2 acres) shows part of The Springs Resort and Spa. The resort 

underwent an expansion where construction began in June 2008 and was completed in May 2009. The 

construction project was awarded “Gold Status” (second highest award) for complying with the 

Leadership in Energy & Environmental Design (LEED)

1

standards for New Construction Version 2.2

(Appendix B). The LEED New Construction Standards require the developer to create (during the design 

phase of the project) and implement an Erosion Control and Sedimentation Control Plan to prevent 

polluting the air with particulate matter during and after construction. Figure 3 shows the completed hotel 

addition as of August 2013. The Town of Pagosa Springs has provided Building Inspection Reports 

(Appendix A) demonstrating that on February 27, 2009, the exterior lath2 was inspected. The building 

inspection report from April 29, 2009 (Appendix A) shows that the hotel was approved for temporary 

occupancy for 60 days. The final building inspection was completed on June 18, 2009 (Appendix A). 

From the dates of the Town’s Building inspections it is clear that by April 2009, the entire construction 

site was paved and the building was completely constructed; the interior was just being finished. 

 

1

LEED: http://www.usgbc.org/leed

2 Lath: weatherproofing material that covers the exterior of the building before stucco is applied
Figure 3: Site B- The Springs Resort and Spa (August 2013)

Site C in Figure 1 is a 35-acre area of vacant land that is proposed for future expansion of the Springs 

Hotel and Spa. According to the Pagosa Springs Parks Department, the area is private property and is 

entirely naturally vegetated because of a continuous supply of ground water from the nearby stream. The 

Parks Department also indicates that off-road recreational vehicles are prohibited on the property and 

signs are posted. The Parks Department is very aware of dust prevention practices and does not believe 

that the area is a significant source of dust during high winds. Figure 4 demonstrates that site C is fully 

vegetated as of August 2013. With regard to AQCC Regulation 1 requirements (Section III.D.2.b), the 

Division considers the natural vegetation with regular ground water availability due to the low-lying 

terrain to be the appropriate available and practical method that is technologically feasible and 

economically reasonable in order to minimize fugitive particulate emissions for this lot at this time. Local 

sources, including the Pagosa Daily Post3, cite the proposed future 35-acre hotel expansion (Site C) to be 

projected to occur in several phases over a 10-15 year time period. 

The Division has conducted appropriate outreach and compliance assistance so the hotel and County are

aware of potentially applicable AQCC Regulations, including Regulation 1 (Section III.D.2.b) and 

Regulation 3 (Construction Permit required if the project exceeds 25 acres and spans longer than 6 

months in duration) requirements for future construction projects. The Division has specific Air Pollutant 

Emissions Notices (APENs) for land development and associated guidance documents posted on its 

website for these types of sources. Additionally, the Division has staff that conducts Small Business 

Assistance outreach as warranted. Compliance and enforcement inspectors from the Division are 

assigned regions throughout the state. As part of their workplans, they are required to be reasonably 

 

3

http://www.pagosadailypost.com/news/8417/Springs_Resort_Sketch_Gets_Planning_Commission_Okay/
(within one-two business days) responsive to community and local government concerns and complaints 

regarding air quality issues, including fugitive dust.

Figure 4: Site C (August 2013)

Site D in Figure 1 is Yamaguchi Park, a 16-acre park consisting of well-maintained turf, irrigated grass, 

and some stabilized clay associated with a baseball field. The entire park is irrigated on a regular basis to 

both maintain the vegetation and to mitigate dust. In the fall of 2008, Pagosa Springs hydro-seeded the 

park which was watered on a regular basis to help the vegetation grow. In Figure 5 and Figure 6, it is 

apparent that the park has well maintained vegetation and a small amount of stabilized clay (on the 

baseball field). With regard to AQCC Regulation 1 requirements (Section III.D.2.b), the Division 

considers hydro-seeding to be the appropriate available and practical method that is technologically 

feasible and economically reasonable in order to minimize fugitive particulate emissions for this 

magnitude of construction project.
Figure 5: Yamaguchi Park- Google Image from 10-2011

Figure 6: Site D Yamaguchi Park (August 2013)

The Division conducted thorough assessments to determine if the potential soil disturbances shown in 

Figure 1 were present during the 2009 exceedances. During the course of these assessments, the Division 
discovered that these sites were reasonably controlled during the April 3, 2009 high wind event. 

Therefore, these sites were not significant contributors to fugitive dust in the Pagosa Springs area during 

the April 3, 2009 high wind event.
Appendix A-Building Inspection Reports for Expansion of The 

Springs Resort and Spa from the Town of Pagosa Springs 
Building Inspection Report from the Town of Pagosa Springs for the Expansion of The Springs 

Resort and Spa- 2/27/2009
Building Inspection Report from the Town of Pagosa Springs for the Expansion of The Springs 

Resort and Spa- 4/29/2009
Building Inspection Report from the Town of Pagosa Springs for the Expansion of The Springs 

Resort and Spa- 6/18/2009
Appendix B-LEED for New Construction and Major Renovations 

Version 2.2