# Nevada Air Quality Trend Report

2000

- 2010

Nevada Division of Environmental ProtectionNevada Air Quality Trend Report, 2000

- 2010

i 

## Contents

Disclaimers

................................ ................................ ................................ ................................ ................................ ................... ii

List of Tables

................................ ................................ ................................ ................................ ................................ ............... iii

List of Figures

................................ ................................ ................................ ................................ ................................ .............. iii

Acronyms and Abbreviations

................................ ................................ ................................ ................................ ...................... iv

Acknowledgements

................................ ................................ ................................ ................................ ................................ ..... v

Executive Summary

................................ ................................ ................................ ................................ ................................ .... vi

1 Introduction

................................ ................................ ................................ ................................ ................................ ........ 1

1.1 Background

................................ ................................ ................................ ................................ ................................ 1

1.2 Nevada’s Air Monitoring Network

................................ ................................ ................................ ............................. 2

1.3 Attainment Status of Areas

................................ ................................ ................................ ................................ ........ 5

1.4 Methodology for statistics analysis

................................ ................................ ................................ ............................ 5

2 Criteria Pollutants

................................ ................................ ................................ ................................ ............................... 6

2.1 Nati onal Ambient Air Quality Standards

................................ ................................ ................................ .................... 6

2.2 Carbon Monoxide

................................ ................................ ................................ ................................ ....................... 7

2.2.1 National Carbon Monoxide Trend

................................ ................................ ................................ ..................... 7

2.2.2 Carbon Monoxide Trends in NAPCP ’s Monitoring Network

................................ ................................ .............. 8

2.3 Lead

................................ ................................ ................................ ................................ ................................ .......... 10

2.3.1 National Lead Trend

................................ ................................ ................................ ................................ ........ 10

2. 4 Nitrogen Dioxide

................................ ................................ ................................ ................................ ...................... 12

2.4.1 National Nitrogen Dioxide Trend

................................ ................................ ................................ ..................... 12

2.5 Ground

- Level Ozone

................................ ................................ ................................ ................................ ................ 14

2.5.1 National Ground

- Level Ozone Trend

................................ ................................ ................................ ............... 15

2.5.2 Ozone Trends in NAPCP ’s Monitoring Network

................................ ................................ .............................. 15

2.6 Particulate Matter

................................ ................................ ................................ ................................ .................... 18

2.6.1 National PM 2.5 Trend

................................ ................................ ................................ ................................ ....... 19

2.6.2 PM 2.5 Trends in NAPCP ’s Monitoring Network

................................ ................................ ................................ 20

2.6.3 National PM 10 Trend

................................ ................................ ................................ ................................ ........ 23

2.6.4 PM 10 Trends in NAPCP ’s Monitoring Network

................................ ................................ ................................ 23

2.7 Sulfur Dioxide

................................ ................................ ................................ ................................ ........................... 28

2.7.1 National Sulfur Dioxide Trend

................................ ................................ ................................ ......................... 29

3 Appendixes

................................ ................................ ................................ ................................ ................................ ....... 30

3.1 Monitoring Station Description

................................ ................................ ................................ ................................ 30

3.2 Monitoring Data Availability

................................ ................................ ................................ ................................ .... 48

3.3 Monitoring Data

................................ ................................ ................................ ................................ ....................... 49Nevada Air Quality Trend Report, 2000

- 2010

ii 

## Disclaimers

The information contained in the Nevada Air Quality Trend Report, 2000

- 2010 is for public use; every effort has been made to ensure its accuracy. The information presented is as timely and accurate as practicable; no expressed or implied guarantees are made. Information contained herein may be freely distributed and used for noncommercial, scientific, and educational purposes.

Inquiries made in reference to this report sho uld be directed to: Nevada Air Pollution Control Program 901 South Stewart Street, Suite 4001 Carson City, Nevada 89701

- 5249 Telephone: (775) 687

- 4670Nevada Air Quality Trend Report, 2000

- 2010

iii 

## List of Tables

Table 1: Current National Ambient Air Quality Standards.

................................ ................................ ............................ 6

Table 2: Total number of exceedances of the PM 10 24

- Hour Standard, between 2000 and 2010.

............................. 26

Table 3: Carbon monoxide. Annual maxima ( p pm) and number of exceedances for each NAAQS for the Long Street and Harvey’s Resort Hotel in the 2000

- 2010 period.

................................ ................................ ................................ .. 51

Table 4: Ozone: 3

- year average of the annual 4 th

- highest daily maximum value

. . ................................ .................... 53

Table 5: PM 10 : 3

- year average for annual mean and annual 98th percentile of 24

- hour average.

............................. 55

Table 6: Total number of exceedances of the PM 10 24

- Hour Standard, between 2000 and 2010.

............................. 57



## List of Figures

Figure 1: Location of NAPCP Monitoring Sites, 200 0

- 2010, and NAPCP planning areas

................................ ............... 4

Figure 2: National average carbon m onoxide trend from 1980 to 2010

................................ ................................ ....... 8

Figure 3: Carbon Monoxide (1

- hour Average) for the Long St. and Harvey’s Resort Hotel monitoring stations..

........ 9

Figure 4: Carbon Monoxide (8

- hour Average) for the Long St. and Harvey’s Resort Hotel monitoring stations.

......... 9

Figure 5: National lead trend, 1980

- 2010..

................................ ................................ ................................ .................. 11

Figure 6: National ni trogen dioxide trend, 1980

- 2010

................................ ................................ ................................ 13

Figure 7: National ozone trend, 1980

- 2010.

................................ ................................ ................................ ................ 15

Fig ure 8: Ground level ozone trend

................................ ................................ ................................ ............................. 16

Figure 9: Ground

- level ozone trend.

................................ ................................ ................................ ............................ 17

Figure 10: Design values for grou nd

- level ozone

................................ ................................ ................................ ........ 17

Figure 11: National PM 2.5 Trend, 2000

- 2010 based on seasonally

- weighted average

................................ ................ 20

Figure 12: 24

- hour 98th percentile trend for PM 2.5. ................................ ................................ ................................ .... 21

Figure 13: 24

- hour 98th percentile trend for PM 2.5 , averaged over 3 consecutive years (i.e. the design values)

...... 21

Figure 14: Annual averages of PM 2.5 concentrations.

................................ ................................ ................................ .. 22

Figure 15: 3

- year average of annual mean PM 2.5 concentrations (i.e., the design values).

................................ ........ 22

Figure 16: National PM 10 Trend, 2000

- 2010

................................ ................................ ................................ ................ 23

Figure 17: Annual 1st

- highest value (1st H) for PM 10 , based on the 24

- hour average.

................................ ............... 25

Figure 18: Annual average for PM 10 from active (above) and discontinued (below) monitors

................................ ... 27

Figure 19: Annual national average for SO 2 from 1980 to 2010

. ................................ ................................ ................. 29Nevada Air Quality Trend Report, 2000

- 2010

iv 

## Acronyms and Abbreviations

Nevada’s 15 Rural Counties: Carson City, Churchill, Douglas, Elko, Esmeralda, Eureka, Humboldt, Lander, Lincoln,

Lyon, Mineral, Nye, Pershing, Storey, and White Pine

AMSL Above Mean Sea Level

BAQP Bureau of Air Quality Planning

BAM Beta Attenuation Monitor

BTU British Thermal Unit

CAA Clean Air Act

CFR Code of Federal Regulations

CO Carbon Monoxide

DCNR Department of Conservation and Natural Resources

GDP/GSP Gross Domestic Product/Gross State Product

H 2 S Hydrogen Sulfide

IMPROVE Interagency Monitoring of Protected Visual Environments

NAAQS National Ambient Air Quality Standard

NAC Nevada Administrative Code

NDEP Nevada Division of Environmental Protection

NAPCP Nevada Air Pollution Control Program

O 3 Ozone

Pb Lead

PM 2.5 Particulate Matter less than 2.5 microns in diameter

PM 10 Particulate Matter less than 10 microns in diameter

SLAMS State and Local Air Monitoring Station

SO 2 Sulfur Dioxide

SPMS Special Purpose Monitoring Station

SSMS Special Study Monitoring Station

USEPA United States Environmental Protection AgencyNevada Air Quality Trend Report, 2000

- 2010

v 

## Acknowledgements

This Trend Report presents ambient air quality data collected by the State of Nevada and the California Air Resources Board. The Nevada Department of Conservation and Natural Resources (DCNR) , Division
of Environmental Protection (NDEP)

, Nevada Air Pollution Control Program ( NAPCP ) gratefully acknowledges the ambient monitoring data contributions of the California Air Resources Board, Monitoring and Laboratory Division. The cover photo is of the Big Smoky Valley in central Nevada; provided courtesy of Michelle Stamates of NDEP.Nevada Air Quality Trend Report, 2000

- 2010

vi 

## Executive Summary

The primary purpose of NAPCP ’s ambient monitoring network i s to determine current and projected
concentrations of ambient air pollutants within the state, ensure current resource management strategies are working properly, and to develop new measures by which the ambient air quality
standards will continue to be attained

.

NAPCP ’s current active monitoring network consists of monitors located in the following towns:

 Carso n City

– PM 10 , PM 2.5 , CO, and O 3

 Gardnerville

– PM 10 , PM 2.5 , and O 3

 Stateline

– CO

 Fernley

– PM 10 , PM 2.5 , and O 3

 Fallon

– PM 10 , and O 3

 Elko

– PM 10

 Pahrump

– multiple sites with PM 10

This report spans the monitoring period from 2000 to 2010. During this period

, NAPCP monitored the following criteria pollutants and observed the following trends:

 Carbon Monoxide (CO): A mbient concentrations of CO have decreased and remained well
below the current National Am bient Air Quality Standards (NAAQS) ;

 Ground

- Level Ozone (O 3 ): Ambient concentrations of O 3 have remained steady and below the current 2008 NAAQS;

 Particulate Matter ≤ 2.5 micrometers in diameter (PM 2.5 ): Ambient concentrations of PM 2.5 have trended upward in Gardnerville and are close to the NAAQS in Carson City and
Gardnerville

. NAPCP is in the process of analyzing samples to determine the cause(s) of the
elevated levels. Ambient concentrations of PM 2.5 have decreased in Fernley.

 Particulate Matter ≤ 10 micrometers in diameter (PM 10 ): PM 10 monitoring conducted in Elko
has shown no significant change in ambient concentrations. Monitoring conducted in Pahrump
shows that annual concentrations of PM 10 have decreased in most of the mon itored locations
and remain well below the annual standard. The 24

- hour PM 10 concentrations in Pahrump remain steady at or near the standard. However, the number of actual exceedances of the 24

- hour standard have been reduced, most of which occurred dur ing uncontrollable high wind

events. As a result, the design values for PM 10 show no exceedances of the NAAQS in the past 5

years.

It should be noted that USEPA is actively reviewing and revising several of the NAAQS . Generally, these
reviews are result ing in revised standards that are more stringent. More stringent standards may affect the future attainment status within Nevada’s 15 Rural Counties. As a result, NAPCP will be required to expand the State’s monitoring network.Nevada Air Quality Trend Report, 2000

- 2010

1 

## 1 I ntroduction

1.1 B ackground

Clean air is a managed natural resource. Nevada Revised Statute (NRS) 445B.100 establishes public policy regarding air quality in Nevada. This statute states:

“ It is the public policy of the State of Nevada . . . to achieve and maintain levels of air quality which will protect human health and safety, prevent injury to plant and an imal life, prevent damage to property, and preserve visibility and scenic, esthetic and historic values of the state. ”

The mission of the Nevada Division of Environmental Protection (NDEP)

, and the Nevada Air P ollution Control Program (NAPCP, which comprises the Bureau of Air Quality Planning , BAQP, and B ureau of Air Pollution Control, BAPC) is to protect and enhance the environment in order to sustain healthy ecosystems and c ontribute to a vibrant economy. Our mission is accomplished through reasonable, fair, and consistent implementation of State and Federal air quality rules and regulations, with emphasis on objective and impartial responsiveness to the needs of a growing population and industrial base.

Air pollution comes from a variety of sources. These include "stationary sources," such as factories, power plants

, and smelters; smaller sources, such as dry cleaners and degreasing operations; "mobile sources," such as cars, trucks, buses, trains

, and planes ; and "natural sources," such as wildfires and
windblown dust.

The USEPA has set NAAQS for six principal pollutants , which are called "criteria" pollutants: carbon monoxide (CO), ground

- level ozone (O 3 ), particulate matter ( PM 2

. 5 , with an aerodynamic si ze les s than or equal to 2.5 microns, and PM 10 , with an aerodynamic size less than or equal to 10 microns), sulfur dioxide (SO 2 ), nitrogen dioxide (NO 2 ), and lead (Pb) . There are two forms of the NAAQS

– Primary and Secondary, and they are summarized in Ta ble 2.1. Primary standards are designed to protect human health, including sensitive populations such as children and the elderly. Secondary standards provide public welfare protection and are designed to protect against decreased visibility, damage to animals, crops, vegetation, and buildings

.

The primary purpose of NAPCP ’s ambient monitoring network i s to determine current and projected
concentrations of ambient air pollutants within the state, ensure current resource management strategies are wor king properly, and to develop new measures by which the ambient air quality
standards will continue to be attained

.

This document summarizes the ambient air data collected for the 1 1

- year period between 2000 and

2010 from the NAPCP monitoring network in N evada’s 15 Rural Counties. 1

1 Nevada’s 15 Rural Counties are Carson City, Churchill, Douglas, Elko, Esmeralda, Eureka, Humboldt, Lander, Lincoln, Lyon, Mineral, Nye, Pershing, Storey, and White Pine. Clark and Washoe counties operate and maintain monitoring networks separate from NAP CP and publish their findings independently.Nevada Air Quality Trend Report, 2000

- 2010

2 Review of l ong

- term monitoring data reveal s trends in the ambient air quality and provides feedback on
the effectiveness of measures utilized for managing the air resource.

NAPCP performs air monitoring throughout the stat e. The current active monitoring network consists of monitors located in the following towns:

 Carson City

– PM 10 , PM 2.5 , CO, and O 3

 Gardnerville

– PM 10 , PM 2.5 , and O 3

 Stateline

– CO

 Fernley

– PM 10 , PM 2.5 , and O 3

 Fallon

– PM 10 , and O 3

 Elko

– PM 10

 Pahrump

– multiple sites with PM 10 , and one site with PM 2.5

It should be noted that USEPA is actively reviewing and revising several of the NAAQS . Generally, these reviews are resulting in revised standards that are more stringent. More stringent standards may a ffect the future attainment status within Nevada’s 15 Rural Counties. As a result, NAPCP may be required to expand the State’s monitoring network. A brief discussion of all criteria pollutants under USEPA review is provided in Section 2.



### 1.2 N evada’s Air M oni toring N etwork

NAPCP operates a network of monitoring stations across Nevada’s 15 Rural Counties as shown in Figure
1.1. The monitors conform to all US EPA s iting criteria and are situated to measure air quality in both rural and the urbanized portions of Nevada’s 15 Rural Counties. In addition, NAPCP maintains two meteorological stations, one in Carson City and one in Pahrump, to provide meteorological information
for the monitoring conducted in these areas and to support stationary source permitting needs

. Detailed descriptions of both active and discontinued air quality monitoring stations are provided in Appendix A. A comprehensive list of monitoring data availability at NAPCP

- maintained monitoring stations is provided in Appendix B and monitoring data used in report preparation is in Appendix C

.

The monitoring conducted by NAPCP is established for the purposes of meeting federal monitoring requirements and for state informational and planning purposes. These two are categorized as : 1) State and Local Air Monitoring Stations (SLAMS) ; 2) Special Pu rpose Monitoring Stations (SPMS); and 3) Special Study Monitoring Stations (SSMS)

. SLAMS sites are federally required, long

- term air quality monitoring stations. SPMS sites are typically established to determine the air quality in a smaller,
localized area or to monitor on a temporary basis. These sites typically operate for six to 24 months, and are generally used to measure air quality in areas not previously monitored. They may also be established to monitor the effects of a specific air pollution source or group of sources on the surrounding air quality. Some sites within the network contain monitors to address both SLAMS and

SPMS

.

SLAMS monitoring is required once an area exceeds es tablished county population thresholds. Monitoring for Pb

, SO 2 and NO 2 , was not conducted during this reporting period as the population

- based thresholds were not reached in any of Nevada’s 15 Rural Counties. SPMS monitoring was also not
conducted for thes e three pollutants.Nevada Air Quality Trend Report, 2000

- 2010

3 This report presents the results of air quality monitoring conducted by NAPCP from 2000 to 2010

. Provided below is a summary of the pollutants monitored, their general trends, and a description of the conditions under which the polluta nts are typically found at their highest concentration.

Carbon Monoxide (CO): NAPCP ’s monitoring network shows that the highest concentrations of CO often occur in the winter during strong temperature inversions in basins surrounded by mountains. When

tem perature inversions occur, CO is trapped near ground level, causing elevated concentrations

. A mbient concentrations of CO have decreased and remained well below the current NAAQS

.

Ground

- Level Ozone (O 3 ): NAPCP ’s monitoring network shows that a mbient concentrations of O 3 have remained steady and below the current 2008 NAAQS. O 3 concentrations are typically affected by the quantity of pre

- cursor gases (NO
x and VOC’s) , temperature, and amount of sunlight available during the

summer.

Particulat e Matter ≤2.5 micrometers (PM 2.5 ): NAPCP ’s monitoring network shows that ambient
concentrations of PM 2.5 have trended upward in Gardnerville. No significant upward/downward linear trends were observed in the other monitored locations, and NAAQS were met i n all the years analyzed. However, both Carson City and Gardnerville were characterized by large fluctuations in PM 2.5 concentrations, which occasionally resulted in the daily maximum observations to be above the 1997 NAAQS and potentially could results in concentrations above the tighter 2006 NAAQS. NAPCP is in the process of analyzing samples to determine the cause(s) of the elevated levels. The highest
concentrations of PM 2.5 often occur in the winter during strong temperature inversions in basins

surrou nded by mountains. When temperature inversions occur, residential wood combustion is often at its peak and PM 2.5 is trapped near ground level, causing increases in ambient concentrations . Thus PM 2.5 trends may reflect the occurrence or absence of strong in versions during winter. However, these exceedance events in the daily maximum concentrations did not result in non

- attainment conditions, as both 1997 and 2006 standard are defined as the average of 3 consecutive years.

Particulate Matter ≤10 micrometers in diameter ( PM 10 ): During this reporting period, many of the PM 10 monitors in the NAPCP ’s network w ere taken offline because measurements remained well below the

PM 10 NAAQS. PM 10 monitoring conducted in Elko has shown no substantial change in ambient concentrations. Monitoring conducted in Pahrump shows that annual concentrations of PM 10 have
decreased in most of the monitored locations and remain well below the annual standard. The 24

- hour

PM 10 concentrations in Pahrump remain steady at or near the s tandard. However, the number of actual
exceedances of the 24

- hour standard have been reduced, most of which occurred during uncontrollable high wind events.Nevada Air Quality Trend Report, 2000

- 2010

4 Figure 1 : Location of NAPCP Monitoring Sites, 2000

- 2010, and N APCP planning areas.Nevada Air Quality Trend Report, 2000

- 2010

5 

### 1.3 A ttainment S tatus of A reas

NAPCP ’s Ambient Air Monitoring Branch is responsible for air quality surveillance in Nevada’s 15 Rural

Counties. In addition to NAPCP ’s monitoring network, air quality monitoring is being conducted through
the Interagency Monitoring of Protected Visual Environments (IMPROVE) network by federal land management agencies. At present, th ere are two active IMPROVE monitoring sites in Nevada; one
located in the Jarbidge Wilderness Area in northeastern corner of the state and the other near the
Lehman Caves Visitor Center in Great Basin National Park, along the eastern border of the state ne ar Baker

.

The NAAQS published by US EPA in 40 CFR Part 50 define the levels of air quality that USEPA ha s determined pr otect human health and welfare. An area is considered to be in nonattainment for a pollutant if it has violations for a particular NAAQS. Conversely, attainment areas are those where monitoring shows that no violation of the NAAQS have occur red. An area is considered unclassifiable if no monitoring has been conducted to determine its classification and NAAQS violations would not otherwise be expected. The extent of an area’s classification is defined by the Hydrographic Area
boundaries as es tablished in 1979 for the State of Nevada. The planning area boundaries are shown in Figure 1.1.

From 2000

- 2010, areas under the jurisdiction of NAPCP were classified as attainment or unclassifiable for all criteria pollutants, with one exception. The Nev ada side of the Lake Tahoe Basin was designated

nonattainment for CO in 1978, while the rest of Tahoe Basin within NAPCP ’s jurisdiction was designated attainment/unclassifiable

. 2 On October 27, 2003, NAPCP requested redesignation and USEPA approved the req uest on December 15, 2003

.

Clark and Washoe counties have their own independent ambient monitoring networks. Please c heck each county's web site for additional information.



### 1.4 Methodology for statistics analysis

Time

- series of pollutant concentration from each monitor station were tested for the presence of linear trend using non

- parametric algorithms. In particular, the Mann

- Kendall method was used to determine the significance of the trend and the Sen’s slope method (also known as Theil

- Sen method) was used to obtain the magnitude (i.e., the slope) of the linear trend. These methods provide a much more robust analysis than the traditional parametric approaches and are less sensitive to outlier values. In general, a

time

- series was considered having a significant trend if the significance value was equal or less than 5% (i.e., the probability of erroneou sly assuming a significant trend under actual no

- trend conditions is equal or less than 5%). However, as the 5% threshold is commonly used but somewhat arbitrary (as any other potential threshold), specific cases were discussed by reporting different signi ficance levels as well. It is important to recognize that results from statistical analyses were largely limited by the number of data points available, and, still, by outliers. In this respect, results from these analyses should not be
considered as absol ute proof (or disproof) for the presence (or absence) of significance trends in the
concentration datasets.

2 The Nevada side of the Lake Tahoe Basin is formally known as Hydrographic Area 90 which includes portions of Carson City County, Douglas County, and Washoe County.Nevada Air Quality Trend Report, 2000

- 2010

6 

## 2 C riteria Pollutants

2.1 N ational A mbient A ir Q uality S tandards

The federal Clean Air Act (CAA), which was last amended in 1990, requires USEPA to set NAAQS for pollutants considered a danger to public health and welfare . The CAA established two types of NAAQS:

Primary standards set limits to protect public health, including the health of se nsitive populations such as children, the elderly, and asthmatics. Secondary standards set limits to protect public welfare, including protection against decreased visibility, damage to animals, crops, vegetation, and buildings.

Criteria pollutants are monitored with federal reference (FRM) or equivalent (FEM) methods that USEPA has approved. For each criteria pollutant, USEPA specifies the monitoring objectives that define the parameters by which health exposure and public welfar e are assessed, and the measurement scale classifications that describe the influence of atmospheric movement at a given location.

Table 1 : Current National Ambient Air Quality Standards ( http://www.epa.gov/air/criteria.html )

.

Pollutant Averaging time Form NAAQS

- Primary NAAQS

– Secondary

Carbon Monoxide (CO) 8

- hour Not to exceed more than

once per year 9ppm N/A

1

- hour Not to exceed more than

once per year 35 ppm

Lead (Pb) Rolling 3

- month Not to exceed, over a period of 3 years, 0.15 μg m - 3 Same as primary

Nitrogen Dioxide ( NO 2 ) 1

- hour 98 th percentile of daily maximum distribution, averaged over 3 years,
not to exceed 100 ppb N/A

Annual Mean Not to exceed 53 ppb Same as primary

Ozone (O 3 ) 8

- hour Annual fourth

- highest daily maximum, averaged over 3 years, not to
exceed 0.075ppm Same as primary

Particle Pollution

≤ 2.5 μm (PM 2.5 ) Annual * Averaged over 3 year not
to exceed 15 μg/m 3 Same as Primary

24

- hour 98 th percentile, averaged

over 3 year, not to exceed 35 μg/m 3 Same as Primary

Particle pollution

≤ 10 μm (PM 10 ) 24

- hour Not to exceed more than

once per year, on average over 3 year 150 μg/m 3 Same as Primary

Sulfur Dioxide ( SO 2 ) 1

- hour 99 th percentile of daily maximum, averaged over 3 years, not to exceed 75 ppb

3

- hour Not to exceed more than

once per year 0.5 ppm

* The annual NAAQS for PM 2.5 was revised from 15 μg/m 3 to 12 μg/m 3 in December 2012Nevada Air Quality Trend Report, 2000

- 2010

7 

### 2.2 C arbon M onoxide

Carbon monoxide (CO) is a colorless, odorless, gas that is typically produced by the incomplete combustion of fuels. Compliance with the CO NAAQS is met when the 8

- hour and the 1

- hour average don’t exceed 9 ppm and 35 ppm, respectively, more than once per year. The CO NAAQS have not changed since they were originally promulgated in 1971; however, they are currently under USEPA

review.

NAPCP MONITORING NETWORK:

Between 2000 and 2010, NAPCP measured ambient concentrations of CO at 2 monitors:

 Long Street in Carson City: 2000

- 2009 (discontinued site)

 Harvey’s Resort Hotel in Stateline: 2000

- 2010

ATTAINMENT STATUS:

From 2000

- 2010, areas under the jurisdiction of NAPCP were classified as attainment or unclassifiable for CO except for the Nevada side of the Lak e Tahoe Basin. This portion of the Basin was designated nonattainment for CO in 1978, while the rest of Tahoe Basin within NAPCP ’s jurisdiction was designated attainment/unclassifiable. The nonattainment designation was based on monitoring conducted in

Sta teline during the 1970s. On October 27, 2003, NAPCP requested redesignation of the Nevada side of
the Basin to attainment of the CO standards. NAPCP ’s redesignation request for the Nevada side of the Lake Tahoe Basin was based on ambient air quality monito ring data that showed no violations for calendar years 2001 through 2002. On December 15, 2003, USEPA published a final rule ( http://www.federalregister.gov/articles/2003/12/15/03

- 30369/approval

- and

- promulgation

- of

implementation

- plans

- state

- of

- nevada

- designation

- of

- areas

- for

- air#p

- 48 ) effective February 13, 2004 redesignating th e Nevada side of the Lake Tahoe Basin attainment for CO.

2.2.1 N ational C arbon M onoxide T rend

Nationally, average CO concentrations have decreased substantially over the years. Based on the annual

2 nd highest value of the 8

- hour average, national CO average co ncentration decreased 82% from 1980 to 2010 ( Figure 2 and http://www.epa.gov/airtrends/carbon.html ) . From 2000 to 2010, national CO average concentration decreased 54%, with a significant trend (based on the Mann

- Kendal and Sen’s slope statistics) of

- 0.2 ppm per year. The decrease in average CO concentrations is largely the result of improved pollution control technology in on

- road vehicles that has significantly reduced CO emissions. Since 1970, CO emissions from on

- road vehicles have been cut by more than 40 percent nationwide.Nevada Air Quality Trend Report, 2000

- 2010

8 Figure 2 : National average carbon monoxide trend from 1980 to 2010. The black dashed line is the average 2 nd
highest value (based on the 8

- hour averages) from 104 (1980

- 1989), 170 (1990

- 1999), and 265 (2000

- 2010) monitoring sites ( http://www.epa.gov/airtrends/carbon.html ). The blue area delimits the 10 th and 90 th percentile of the annual observation distributions. Red dotted line is the national standard (9 ppm).

2.2.2 C arbon M onoxide T rends in NAPCP ’s M onitoring N etwork

For the entire 2000

- 2010 period, a mbient concentrations of CO ( 8

- hour and 1

- hour average) have
trended downward and remained, in most cases, well below the NAAQS ( Figure 3 Figure 4 )

. The Long Street monitor site in C arson City showed a significant downward trend in the 1 st highest value
of both the 8

- hour and 1

- hour average (

- 0.2 ppm per year and

- 0.6 ppm per year, respectively). In particular, the trend in the 1 st highest value of the 8

- hour average mirrored the 2 nd

- highest value of 8

- hour average national trend ( Figure 2 ). Results from the Harvey’s Resort Hotel monitor in Stateline also
show a downward trend in the 1 st highest values of the 8

- hour and 1

- hour average , although less consistent trend. The peak i n 2002 was observed during the July 2002 Gondola Fire; a timber wildfire that burned 673 acres at the Heavenly Ski Resort a short distance from the monitor. Trends at the Harvey’s Resort Hotel monitor site were not significant at the 5% confidence interval . However, they were significant at the 10% confidence interval, suggesting that a downward, though not very strong,
trend existed. The 2 nd

- highest values of the 8

- hour average are shown in Figure 4 as well. This is to confirm that while the highest 8

- hour average CO concentration (8.8 ppm) went close to the NAAQS in 2002 (9 ppm), the 2 nd

- highest value recorded in the same time series was well below tha t threshold (6.1 ppm). 0 2 4 6 8 10 12 14 16

1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 Concentration (ppm) USA, 2nd Highest NAAQSNevada Air Quality Trend Report, 2000

- 2010

9 Figure 3 : Carbon Monoxide (1

- hour Average) for the Long St. and Harvey’s Resort H otel (HRH) monitoring stations. The 1 st highest values, are shown for both monitor sites. NAAQS (35 ppm) is shown with a red dashed

line.

Figure 4 : Carbon Monoxide (8

- hour Average) for the Long St. and Harvey’s Resort Hotel (HRH) monitoring stations. Annual 1st

- highest values are shown for both stations, while annual 2nd

- highest concentrations are shown for HRH only. The national average for annual 2nd highest concentration (as in Figure 2 ) is shown with a dashed black line. NAAQS (9 ppm) is shown with a red dashed line.

0 5 10 15 20 25 30 35 40

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 Concentration (ppm) 

### Long St, 1st Max. HRH, 1st Max. NAAQS

0 1 2 3 4 5 6 7 8 9 10

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 Concentration (ppm) Long St, 1st Max. HRH, 1st Max. HRH, 2nd Max.

USA, 2nd Max. NAAQSNevada Air Quality Trend Report, 2000

- 2010

10 

### 2.3 L ead

Lead ( Pb ) is a metal found naturally in the environment . It is also mined and processed for use in
manufactured products such as lead

- acid batteries, old lead

- based paint, ammunition, and gasoline

. From 1978 through 2008, the design value for Pb had been the calendar quarterly average, with a NAAQS established at 1.5 μg/m 3 . Effective January 12, 2009 , US

- EPA changed the design value to a 3

- month rolling average, evaluated over a 3 year period, and tightened both the primary and secondary
NAAQS to 0.15 μg/m 3 . Therefore, c ompliance with the P b NAAQS is met when daily concentrations averaged for 3 adjacent months do not exceed 0.15 μg/m 3 over a period of 3 years.

NAPCP MONITORING NETWORK : During the reporting period, NAPCP did not conduct ambient monitoring for Pb because monitoring
thresholds established by USEPA have not been met in any of Nevada’s 15 Rural Counties. In addition,
the revised NAAQS now require Pb monitoring near sources such as industrial facilities that emit one

half ton or more of Pb per year and in Core Based Statistical Areas (CBSA) with populations greater than 500,000. 3 In Nevada’s 15 Rural Counties there are no sources that emit one

- half ton or more of Pb per

year and no CBSA’s with po pulations greater than 500,000.

ATTAINMENT STATUS:

US

- EPA designed all areas in Nevada’s 15 Rural Counties as unclassifiable, since NAPC P is not required to monitor for lead and these areas are expected to be meeting the 2008 NAAQS ( http://www.epa.gov/leaddesignations/2008standards/final/region9f.html ).

2.3.1 N ational L ead T rend

Nationally, average Pb concentrations have decreased substantially over the years. From 1980 to 2010
there was an 89 % decrease in the national Pb average, based on the same 31 monitor sites measured during the 1980

- 1989 period. From 20 00 to 20 10 , there was a 61% reduction in the national Pb average,
based on 92 monitor sites. The reduction in average Pb concentrations is mainly the result of r emoving
Pb from gasoline used in on

- road vehicles , and additional source control programs for stationary sources in those areas that did not meet the national standards ( http://www.epa.gov/airtrends/lead.html ).

3 Core Based Statistical Area (CBSA) is a United States Census Bureau term that became effective in 2000 and refers collectively to metropolitan and micropolitan statistical areas. The 2000 census criteria provide that each CBSA must contain at least one urban area of 10,000 or more people . Each metropolitan statistical area must have at least one urbanized area of 50,000 or more inhabitants. Each micropolitan statistical area must have at least one urban cluster of at least 10,000 but less than 50,000 people

.Nevada Air Quality Trend Report, 2000

- 2010

11 Figure 5 : National lead trend, 1980

- 2010. The black dashe d line is the annual 1 st

- highest value (i.e., the annual maximum) based on 3

- month average from 31 (1980

- 1989), 62 (1990

- 1999), and 92 (2000

- 2010) monitoring sites ( http://www.epa.gov/airtrends/lead.html ). The blue area delimits the 10 th and 90 th percentile of the annual observation distributions. Red dotted line is the 2008 national standard (0.15 ppm).

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 Concentration (ppm) USA, 3-Month Average, Annual Max NAAQSNevada Air Quality Trend Report, 2000

- 2010

12 

### 2.4 N itrogen D ioxide

Nitrogen dioxide ( NO 2 ) belongs to a group of reactive gases known as nitrogen oxides. 4 Other nitrogen
oxides include nitric oxide (NO) and nitrous oxide (N 2 O). In the environment NO 2 is the predominant
form. 5 NO 2 forms rapidly, primarily resulting from fuel combustion sources

.

The NO 2 standard was first established in 1971 and defined attainment conditions when the average annual concentration does not exceed 53 ppb (or 0.053 ppm)

. 6 Effective April 12, 2010, USEPA
established a new 1

- hour based primary NAAQS. Compliance with the 1

- hour standard is achieved when

3

- year average of the 98 th percentile of the daily maximum distribution (1

- hour average) does not exceed 100 ppb (or 0.1 ppm).

NAPCP MONITORING NETWORK : NAPCP does not currently monitor for NO 2 . Historical NO 2 monitoring at Stateline and Carson City was terminated in 1997 due to very low monitored concentrations. During the reporting period, NAPCP did not conduct ambient monitoring for NO 2 because monitoring thresholds established by USEPA have not been met in any of Nevad a’s Rural Counties.

ATTAINMENT STATUS:

USE PA has designated all areas in Nevada’s 15 Rural Counties as unclassifiable , based on the 2010 standards ( http://www.epa.gov/no2designations/ region/region9.html ).

2.4.1 National Nitrogen Dioxide Trend

Nationally, average NO 2 concentrations have decreased substantially over the years. From 1980 to 2 010
there was a 52 % decrease in the national NO 2 average (based on the annual arithmetic average and on the 81 monitoring sites initially established in the 1990

- 1999 period). From 2000 to 20 10 , there was a

38% reduction in the national NO 2 average (based on 283 monitoring sites). The decrease in averag e NO 2 concentrations is largely the result of improved pollution control technology in on

- road vehicles that has significantly reduced NO 2 emissions

. Moreover, NO 2 concentrations are expected to continue to
decrease as a result of a number of new mobile so urce regulations ( http://www.epa.gov/airtrends/nitrogen.html )

.

4 Nitrogen oxides are also referred to as oxides of nitrogen.

5 NO 2 is the monitored indicator for the larger group of nitrogen oxides

. 6 The official level of the annual NO 2 s tandard is 0.053 ppm, equal to 53 ppb, which is shown here for the purpose of clearer comparison to the 1

- hour standard.Nevada Air Quality Trend Report, 2000

- 2010

13 Figure 6 : National nitrogen dioxide trend, 1980

- 2010. The black dashed line is the annual arithmetic average based on 81 (1980

- 1989), 150 (1990

- 1999), and 283 (2000

- 2010) monitoring sites (http://www.epa.gov/airtrends/nitrogen.html). The
blue area delimits the 10 th and 90 th percentile of the annual observation distributions. Red dotted line is the nation standard (53 ppm).

0 10 20 30 40 50 60 70 Concentration (ppm) 

### Annual Arithmetic Average NAAQSNevada Air Quality Trend Report, 2000

- 2010

14 

### 2.5 G round

- L evel O zone

Ozone (O 3 ) in different layers of the atmosphere (i.e., ground

- level O 3 versus stratospheric O 3 ) exhibits
different effects . W hile the physical substance remains the same

, ground

- level O 3 affects hu man s adversely and therefore is consi dered a harmful pollutant. On the other hand, s tratospheric O 3 is
essential to human survival and prevent s harmful ultraviolet solar radiation from reaching the earth's
surface. Ground

- level ozone is a reactive, oxidant gas and is the primary constituent of photochemical

smog

. O 3 is formed by reactions between nitrogen oxides and volatile organic compounds ( VOC s) in the presence of sunlight. T he actual photo chemical reaction that produces O 3 can take place far awa y from
where the precursor gases are emitted. In addition, natural sources such as vegetation, soil, wildfires, and lightning emit nitrogen oxides and VOC s that lead to the form ation of O 3 . Another source of
localized O 3 is downward mixing of O 3 from the stratosphere , known as stratospheric O 3 intrusion ( especially at high mountain locations )

.

The O 3 NAAQS was first established in 1979 and based on hourly average concentrations. Primary and secondary standards were met when the number of days per calendar year with maximum hourly

average concentrations above 0.12 ppm wa s less than or equal to 1. In 1997 USEPA created new primary and secondary O 3 standards, based on the 8

- hour average and set at 0.08 ppm

. The se standards are met when the 3

- year average of the annual 4 th

- highest value of daily maximum distribution is less than or equal to 0.08 ppm

. O n June 15, 2005, USEPA revoked the 1

- hour O 3 standard established in 1979.
Effective May 27, 2008, USEPA tightened the primary and secondary 8

- h our O 3 NAAQS from 0.08 ppm to 0.075 ppm 7

. USEPA is pursuing a review of the O 3 NAAQS on its normal 5 year review cycle. A proposed rule is expected to be released by the end of 2013 ( http://www.epa.gov/glo/acti ons.html ).

NAPCP MONITORING NETWORK:

Between 2000 and 2010, NAPCP measured ambient concentrations of O 3 at 7 monitors:

 Fifth Street in Carson City: from 2008

 Long Street in Carson City: 1998

- 2007 (discontinued site)

 West End Elementary School in Fallon: from 2005

 Fire Station in Fernley: 1998

- 2003 (discontinued site)

 Intermediate School in Fernley: from 2007

 Cave Rock State Park in Zephyr Cove : 1999

- 2004 (discontinued site)

 IMPROVE Site in Great Basin National Park: from 1998 8

ATTAINMENT STATUS:
All ar eas within Nevada’s 15 Rural Counties are currently designated attainment/unclassifiable for the

1997 1

- hour O 3 NAAQS and the 2008 8

- hour O 3 NAAQS ( http://www.epa.gov/ozo nedesignations/2008standards/final/region9f.htm ).

7 For more information on the history of O 3 regulation, visit USEPA ’s webpage: Ozone & Health

– A Timeline

. 8 Great Basin National Park IMPROVE monitoring site is maintained by the National Park Service.Nevada Air Quality Trend Report, 2000

- 2010

15 2.5.1 N ational G round

- L evel O zone T rend

Nationally, average ground

- level O 3 showed a decline of 29% from 1980 to 2010 (based on the annual

4 th

- highest value of the 8

- hour average, Figure 7 and http://www.epa.gov/airtrends/ozone.html ), with a significant trend of

- 0.817 p pb/year. The 2000

- 2010 period showed the largest rate in concentration decline, 60% larger than the one observed in the 1980

- 1999 period (

- 1.21 ppb/year and

- 0.75 ppb/year
for 2000

- 2010 and 1980

- 1999, respectively). However, it’s only in 2004 that the nati onal O 3 average concentration fell below the 2008 NAAQS (0.075 ppm) for the first time. Across the United States, programs have been and are being implemented to reduce NOx and VOC s emissions from motor vehicles, industrial facilities, and power plants. VO Cs emissions are used as a surrogate for O 3 since O 3 is not directly emitted by sources. M itigation strategies also include reducing the emission of O 3 precursor

gases by reformulating fuels as well as consumer/commercial products such as paints and chemical
solvents that contain VOCs.

Figure 7 : National ozone trend, 1980

- 2010. The black dashed line is the annual 4 th highest value of the 8

- hour average concentration based on 247 (1980

- 1989), 507 (1990

- 1999), and 946 (2000

- 2010) monitoring sites (http://www.epa.gov/airtrends/ozone.html). The blue area delimits the 10 th and 90 th percentile of the annual observation
dist ributions. Red dashed line is the current 8

- hour national standard (0.075 ppm, accordingly to the 2008 NAAQS). From 1997 to 2008, the 8

- hour NAAQS was 0.080 ppm. From 1979 to 1997, only the 1

- hour NAAQS was used.

2.5.2 O zone T rends in NAPCP ’s M onitoring N etwork

Because of the multiple historical changes in O 3 NAAQS, trends based on both the 1

- hour and 8

- hour standards are presented in this report for all the monitor stations. For the 2000

- 2010 period a mbient
concentrations of ground

- level O 3 have remained relatively constant and below the revoked 1

- hour based NAAQS in all active and discontinued stations ( Figure 8 ). The only exceptions are the sites located at the Cave Rock State Park (discontinued in 2005) and Fifth St in Carson City (active from 2008), which
both showed noticeable concentration reduc tions during the monitored periods
The time

- series of the annual 4 th

- highest daily maximum (based on the 8

- hour average) and its 3

- year average (the design value) fell below the NAAQS (pre

- and after

- 2008 threshold) in all monitor sites ( Figure 9 and Figure 10 ). In 2010, the highest concentratio ns were observed at the Great Basin National 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 Concentration (ppm) 

### 8-hour average, 4th highest 2008 NAAQS (current)Nevada Air Quality Trend Report, 2000

- 2010

16 Park. A study is currently being conducted by NDEP

- NAPCP and University of Nevada in Reno to investigate the causes for such high O 3 concentrations in the area 9

. USEPA is pursuing a review of the O 3 NAAQS on its normal 5 year review cycle. A proposed rule is expected to be released by the end of 2013 ( http://www.epa.gov/glo/actions.html ) and it may result in
lower O 3 NAAQS.

Figure 8 : Ground level ozone trend. The annual 1 st highest values from hourly average concentrations are shown. Red dashed line is the National Standard (0. 12ppm), which was revoked by US

- EPA in June 2005.

9 “Nevada Rural Ozone Iniziative”

– Principal Investi gator: Dr. Mae Gustin

– Department of Natural Resources and Environmental Sciences, UNR 0.05 0.06 0.07 0.08 0.09 0.10 0.11 0.12 0.13 Concentration (ppm) Fifth St. West End Element. Sch. Fernley Intermed. Sch.

Great Basin Ntnl Park Long St. Fernley Fire Stat.

Cave Rock State Park NAAQSNevada Air Quality Trend Report, 2000

- 2010

17 Figure 9 : Ground

- level ozone trend

. The annual 4 th

- highest daily maximum from the 8

- hour averages are shown. The red dashed line is the National Standard, which was revised from 0.08 ppm to 0.075 ppm in May 2008. Black dashed line is the national average (see also Figure 7 )

.

Figure 10 : Design values for ground

- level ozone (3

- year average of the annual 4 th

- highest daily maximum, based on

the 8

- hour average, as in Figure 8 ). Red dotted line is the National Ambient Air Quality Standard, which was revised from 0.08 ppm to 0.075 ppm in May 2008. 0.050 0.055 0.060 0.065 0.070 0.075 0.080 0.085 Concentration (ppm) Fifth St. West End Element. Sch. Fernley Intermed. Sch.

Great Basin Ntnl Park Long St. Fernley Fire Stat.

Cave Rock State Park NAAQS

0.050 0.055 0.060 0.065 0.070 0.075 0.080 0.085

99-01 00-02 01-03 02-04 03-05 04-06 05-07 06-08 07-09 08-10 09-11 Concentration (ppm) Fifth St. West End Element. Sch. Fernley Intermed. Sch.

Great Basin Ntnl Park Long St. Fernley Fire Stat.

Cave Rock State Park USA NAAQSNevada Air Quality Trend Report, 2000

- 2010

18 

### 2.6 P articulate Matter

Particulate matter (PM) generally consist s of a mixture of particles of dust, pollen, ash, soot, metals and other various solid and liquid chemicals found in the atmosphere. 10 There are two categories of particle matter pollutants: PM 2.5 and PM 10 . PM 2.5 (also known as “fine particulate”) is particulate matter 2.5 microns or smaller in aerodynamic diameter

. PM 10 (also known as “inhalable coarse particulate”) is particulate matte r 10 microns or sma ller in aerodynamic diameter. For reference, t en microns is about

one

- seventh the diameter of human hair.

PM 2.5 can be directly emitted fr om sources such as fires, construction sites, r esidential wood combustion, or unpaved roads. PM 1 0 emissions are from sources such as seas salt, unpaved roads, construction/demolition dust, and rock processing. These particles are referred to as primary particles, as they are directly emitted by the sources. PM 2.5 and PM 10 can also form as the result of the interaction
of gaseous pollutants ( such as SO 2 , NOx , and VOCs, emitted, among others, from power plants, industries and automobiles) in the atmosphere. These particles are referred to as secondary particles. Given the small size, PM 2.5 can remain suspended in the air and be transported extremely long distances. Meteorological conditions (e.g., inversion, rain, wind) can have a significant effect on ambient particulate concentrations

.

US EPA first issued standards for total suspended pa rticles in 1971 and revised the m in 1987 (for PM 10 only), 1997 (for PM 10 and PM 2.5 ), 2006 and 2012.

PM 2.5 : In September 1997, new standards were established, based on 24

- hour and annual averages. The

24

- hour average

- based NAAQS is met when the 98 th perce ntile of the annual distribution, averaged over 3 years, does not exceed 65 μg/m 3 . The annual NAAQS is met when the 3

- year average of the annual weighted mean concentration is less or equal to 15 μg/m 3

. In December 2006, USEPA tightened the 24

- hour PM 2.5 NAAQS from 65 μg/m 3 to 35 μg/m 3 . In December 2012, the annual

- average

- based primary standard was tightened from 1 5 μg/m 3 to 12 μg/m 3

.

PM 10 : new standards were established in 1987, based on 24

- hour and annual averages. The annual

based NAAQS is met when t he 3

- year average of the 98th percentile 24

- hour concentration is less than or equal to 50 μg/m 3 . The annual NAAQS was revoked in 2006. The primary and secondary 24

- hour PM 10 NAAQS are met when the expected number of days per calendar year above 150 μg/m 3 is less than or equal to one, over a 3

- year period.

NAPCP MONITORING NETWORK : Between 2000 and 2010, NAPCP measured ambient concentrations of PM 2.5 at 5 monitor sites:

 Fifth Street in Carson City: 2009

- 2010 (special study monitoring station)

 Long Street in Carson City: 2000

- 2009 (discontinued)

 Intermediate School in Fernley: 2000

- 2010

 Gardnerville Ranchos in Gardnerville: 2000

- 2010

 Cave Rock State Park in Zephyr Cove: 2000

- 2001 (discontinued)

10 The majority of compounds that form particle pollution can be grouped into five categories: sulfates, nitrates, elemental carbon, organic carbon, and “crustal” materi al.Nevada Air Quality Trend Report, 2000

- 2010

19 The Fifth Street, Gardnerville Ranchos, and Fernley Intermedi ate School monitors are maintained within

NAPCP ’s network for special study purposes.

Between 2000 and 2010, NAPCP measured ambient concentrations of PM 10 at 10 monitor sites:

 High School in Battle Mountain: 2000

- 2002 (discontinued)

 State Offices Building in Elko: 2000

- 2008 (discontinued)

 Grammar School No. 2 in Elko: 2008

- 2010

 Community Pool in Pahrump: 2001

- 2004 (discontinued)

 Linda Street in Pahrump: 2004

- 2010

 Willow Creek in Pahrump: 2004

- 2009 (discontinued)

 Church in Pahrump: 2004

- 2010

 Glenoaks Street in Pahrump: 2009

- 2010

 Manse Elementary School in Pahrump: 2005

- 2010

 Cave Rock State Park in Zephyr Cove (Lake Tahoe): 2000

- 2001 (discontinued)

The Community Pool site in Pahrump was relocated to the Manse Elementary School site because the
site location did not conform to USEPA siting criteria and for a lack of continued maintenance access.

ATTAINMENT STATUS: On April 5, 2005, USEPA designated all areas within Nevada’s 15 Rural Counties as attainment/unclassifiable for the 1997 24

- hour and annual PM 2.5 NAAQS. On December 13, 2009, USEPA designated all areas within Nevada’s 15 Rural Counties as attainment/unclassifiable for the revised 2006

24

- hour PM 2.5 NAAQS. On November 15, 1990, USEPA designated all areas within Nevada’s 15 Rural
Counties as unclassif iable for PM 10 .

Beginning in 2001, NAPCP began special purpose monitoring in the Pahrump Valley in Nye County . This monitoring indicated exceedances of the PM 10 NAAQS ( Figure 17 and Table 2 ). To correct the problem

US EPA, NAPCP

, the Pahrump Town Board

, and Nye County agreed to implement control measures throughout the valley to address the exceedances. The measures generally are targeted at decreasing the sources and causes for PM emissions, such as increasing the fraction of paved roads, land
disturban ce mitigation, and dust control enforcement. Continued monitoring in the area indicates that the implemented control strategies have resulted in significant reductions in the number of monitored

PM 10 exceedances ( Figure 17 and Table 2 ). Remaining exceedances are attributed to uncontrollable high

- win d events, or “exceptional events”. The NDEP has submitted evidence of these exceptional

events to the USEPA and is awaiting EPA’s concurrence.

2.6.1 N ational PM 2.5 T rend

Nationally, average PM 2.5 concentrations have significantly decreased since 2000 ( Figure 11 , and http://www.epa.gov/airtrends/pm.html )

. From 2000 to 2010 there was a 27 % decrease i n the national

PM 2.5 average, based on the seasonally

- weighted average and 646 sites. The reduction in average PM 2.5 concentrations is mainly the result of regional and national rules that have been and are being implemented to reduce emissions of pollutan ts that form PM 2.5 . In addition, a number of voluntary programs also are helping to reduce PM 2.5 pollution ( http://www.epa.gov/air/particlepollution/reducing.html ).Nevada Air Quality Trend Report, 2000

- 2010

20 Figure 11 : National PM 2.5 Trend, 2000

- 2010 b ased on seasonally

- weighted average (black dashed line) and 646 sites ( http://www.epa.gov/airtrends/pm.html ). National monitoring of PM 2.5 star ted in 1999. The 2006 NAAQS for annual

- average is shown as a reference (15 μ g/m 3 , red dashed line). The blue area delimits the 10 th and 90 th percentiles of the distribution of annual values reported by the monitor sites nationwide.

2.6.2 PM 2.5 T rends in NAPCP ’s M onitoring Network

PM 2.5 trends across the state showed high degree of variability ( Figure 12

, Figure 13

, Figure 14

, Figure 15 ) and likely reflect localized conditions such as wintertime temperature inversion s. The time

- series of the

98 th percentile of the annual 24

- hour average distribution ( Figure 12 ) do not present any significant trend. However, the monitor stations on Long St. (Carson City) and at Gardnerville Ranchos (Gardnerville) showed a substantial peak i n 2005. Even though the 2005 values in these locations exceeded the 1997 NAAQS, attainment conditions were met, as the 24

- hour

- based USEPA NAAQS for

PM 2.5 is defined as the average of three consecutive years ( Figure 13 ). Under this definition, none of the stations reported values higher than the implemented NAAQS ( Figure 13 ). 0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00 20.00

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 Concentration ( μg m - 3 ) 

### Annual Average NAAQSNevada Air Quality Trend Report, 2000

- 2010

21 Figure 12 : 24

- hour 98th percentile trend for PM 2.5 . The NAAQS are shown as a reference as well. However,

exceedance events in these time

- series do not indicate non

- compliant conditions, as both 1997 and 2006 standard are defined as the average of 3 consecutive years (as in Figure 13 ).

Figure 13 : 24

- hour 98th percentile trend for PM 2.5 , averaged over 3 consecutive years (i.e. the design values). The NAAQS are shown as well. Design values for monitors in Cave Rock State Park are not shown, as less than 3 consecutive years of data were available. 0 10 20 30 40 50 60 70 80 Concentration ( μg m - 3 ) 

### Long St. Fernley Intermed. Sch. Gardnerville Ranchos



### Fifth St. Cave Rock State Park NAAQS

0 10 20 30 40 50 60 70 80 Concentration ( μg m 3 ) 

### Long St. Fernley Intermed. Sch. Gardnerville Ranchos

NAAQS Fifth St.Nevada Air Quality Trend Report, 2000

- 2010

22 The annual average time

- series present similar results ( Figure 14 ), with all but one station showing no significant trends. The exception is represented by the Gardnerville Rancho station, where a positive trend of approximately 0.7 μ g/m 3 is detected. Annua l and 3

- year

- averaged values are well below the 1997 NAAQS (15 μ g/m 3 ). However, if the 2012 NAAQS are applied (12 μ g/m 3 ), annual values are above the threshold in 2010 ( Figure 14 ), though the 3

- year average would maintain attainment ( Figure 15 ).

Figure 14 : Annual averages of PM 2.5 concentrations. The 1997 NAAQS (15 μ g/m 3 ) is shown as well.

Figure 15 : 3

- year average of annual mean PM 2.5 concentrations (i.e., the design values)

. The 1997 NAAQS (15 μ g/m 3 ) is shown as well. Cave Rock State Park stations is not shown, as less than 3 consecutive years of data were available. 0 2 4 6 8 10 12 14 16 Concentration ( μg m - 3 ) 

### Long St. Fernley Intermed. Sch. Gardnerville Ranchos
Fifth St. Cave Rock State Park NAAQS

0 5 10 15 Concentration ( μg m 3 ) 

### Long St. Fernley Intermed. Sch. Gardnerville Ranchos Fifth St. NAAQSNevada Air Quality Trend Report, 2000

- 2010

23 2.6.3 N ational PM 10 T rend

Nationally, average PM 10 concentration has decreased significantly over the years. From 1990 to 2010

t here was a 38 % decrease in the national PM 10 average (based on 279 sites). From 2000 to 2010, the reduction in concentration was 29%, based on 601 sites ( Figure 16 and http://www.epa.gov/airtrends/pm.html ). The reduction in average PM 10 concentrations is mainly the
result of regional and national rules that have been and are being implemented to reduce emissions of pollutants that form PM 10 . In addition, a number of voluntary programs also are helping to reduce PM 10 pollution ( http://www.epa.gov/air/particlepollution/reducing.html ).

Figure 16 : National PM 10 Trend, 2000

- 2010 b ased on the annual 2 nd highest value of the 24

- hour average and 279 sites (1990

- 1999) and 601 sites (2000

- 2010, http://www.epa.gov/airtrends/pm.html ). National monitoring of PM 10 started in 1990. Black dashed line is the average from all the sites nationwide, and blue area delimits the 10 th and 90 th percentiles of the data distribution. Red dashed line is the National Ambient Air Quality Standard (150 μ g m 3 ). The addition o f 322 new sites in 2000 caused an increase in average PM 10 concentration. This increase is likely due to a better representation of PM 10 concentration across the Country.

2.6.4 PM 10 T rends in NAPCP ’s Monitoring Network

PM 10 measurements are typically influenced by local conditions and often by “exceptional meteorological evens”, such as high

- winds

. For this reason, annual mean concentrations provide a good
indicator of ambient PM 10 trends and they are here presented together with the 24

- hour averages ( used with the NAAQS).

In general, 24

- hour concentrations of PM 10 in Elko, Battle Mountain and Lake Tahoe have remained below the standard, with very few exceptions ( Figure 17 ). Based on PM 10 NAAQS, which require a 3

- year average period, all of these sites met the requirements for attainment ( Table 2 ). None of these sites present significant linear trend in the annual averages or were not active long enough to allow statistical analysis ( Figure 18 ). Monitor sites in Pahrump showed 24

- hour concentrations above the NAAQS at the

0 20 40 60 80 100 120 140 160 180

1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 Concentration ( μg m 3 ) 

### Annual Average (279 sites) Annual Average (601 sites) NAAQSNevada Air Quality Trend Report, 2000

- 2010

24 Manse Elementary School, Willow Creek, and Community Pool stations ( Figure 17 and Table 2 ).
However, t he Community Pool site was relocated to the Manse Elementary School site because the site location did not conform to USEPA siting criteria and for a lack of continued access.

Strong linear trends are detected in the annual average time

- series of several of these sites. The Church
station showed a trend of about

- 1.3 μ g/m 3 per year. The site at the Manse Elementary School showed a
decline of about

- 4.7 μ g/m 3 per year; this tren d, while not significant at the 5% confidence interval, is significant at the 10% confidence interval.

The apparent contradiction between the observed strong decline in concentrations and low statistical significance of the trend is likely due to the cho ice of the statistical approach and overall number of data points, rather than lack of trend in the observations. The Mann

- Kendall algorithm is quite robust towards outliers (or spikes) in the dataset. The Manse ES time

- series presents a strong decline in concentrations between 2005 (i.e. the first point of the series) and 2006, and a more consistent, but weaker, downwards trend thereafter ( Figure 18 ). I t is quite possible that the Mann

- Kendall algorithm
‘underestimated’ the effect of the 2005

- 2006 decline in the time

- series, therefore decreasing the
confidence level of the overall detected linear trend. A re

- analysis of the time

- series using a more
stand ard parametric, but less robust approach, revealed a significant linear trend. The Manse ES station is currently active, and it is likely that the addition of more data points from more recent years may help in determining the actual pattern of the trend. A similar situation was found at the Willlow Creek site; a strong decline in PM 10 concentration was observed in the last year of monitoring (2009), following a somewhat weaker downwards trend in the previous 4 years ( Figure 18 ). Given the relatively short period the station was active (5 years), the statistical procedure failed in detecting a linear trend, even though it is very likely that an improveme nt in air quality occurred.

The station on Linda St. is the only station in Pahrump that displayed a significant positive trend of about

2.5 μ g/m 3 per year. As explained earlier in this report, USEPA NAPCP , the Pahrump Town Board , and Nye County have b een implementing control measures throughout the valley to address the high PM 10 concentrations measured in this area. Continued monitoring in the area indicates that the implemented control strategies have resulted in significant reductions in the number of monitored PM 10 exceedances ( Figure 17 and Table 2 ). Remaining exceedances are attributed to uncontrollable high

- wind events, or “exceptional events”. The NDEP has submitted evidence of these exceptional events to the USEPA and are awaiting EPA’s concurrence.Nevada Air Quality Trend Report, 2000

- 2010

25 Figure 17 : Annual 1st

- highest value (1st H) for PM 10 , based on the 24

- hour average

. The 2 nd

- highest values (2nd H.) are shown for those stations where the 1 st highest is above the NAAQS (red dashed line, 150 μ g m 3 ). The design value is defined as the average number of times that the 24

- hour average exceeds the NAAQS over 3 years. To comply with the NAAQS, this number cannot exceed 1.

The following acronyms were used for the stations : Elko Grammar School #2 : Elko GS #2 Battle Mountain High School: BM HS Willow Creek: WC Manse Elementary School: Manse ES State Office Buildings: SOB Community Pool: CP
Cave Rock State Park: Cave Rock SP

Active Monitors

Discontinued Monitors 0 20 40 60 80 100 120 140 160

2004 2006 2008 2010 Concentration ( μ g m - 3 ) Elko GS #2 Linda St.

Church NAAQS

0 20 40 60 80 100 120 140 160

2004 2006 2008 2010 Concentration (μg m - 3 ) Manse ES - 1st H. 2nd H.

Glenoaks St.

0 50 100 150 200 250 300

2000 2002 2004 2006 2008 Concentration (μg m - 3 ) BM HS - 1st H. 2nd H.

WC - 1st H. 2nd H.

0 50 100 150 200 250 300 350 400

2000 2002 2004 2006 2008 Concentration (μg m - 3 ) SOB - 1st H. 2nd H.

CP - 2nd H. 2nd H.

Cave Rock SPNevada Air Quality Trend Report, 2000

- 2010

26 Table 2 : Total number of exceedances of the PM 10 24

- Hour Standard, between 2000 and 2010.
Reported, are the total exceedances for each station and the average of each 3

- year period (i.e., the design value). Compliance with the NAAQ is met w hen the average number of exceedances in the 3

- year period is less or equal to 1. Numbers in red
indicate exceedance conditions.

Elko

Grammar
School #2 Linda Street Church Manse Elementary
School Glenoaks

Street

2004

- 2006

--- 0 0

--- --- 2005

- 2007

--- 0 0 0

--- 2006

- 2008

--- 0 0 0

--- 2007

- 2009 0 0 0 0

--- 2008

- 2010 0 0 0 0 0

Battle

Mountain High School State Offices

Building Community

Pool Willow Creek

1998

- 2000 1 (0.3) 0

--- --- 1999

- 2001 1 (0.3) 0 4 (1.3)

--- 2000

- 2002 1 (0.3) 1 (0.3) 18 (6.0)

--- 2001

- 2003

--- 1 (0.3) 21 (7.0)

--- 2002

- 2004

--- 1 (0.3) 14 (4.7)

--- 2003

- 2005

--- 0 19 (6.3)

--- 2004

- 2006

--- 0 2 (0.7) 2 (0.7)

2005

- 2007

--- 0

--- 1 (0.3)

2006

- 2008

--- 0

--- 1 (0.3)Nevada Air Quality Trend Report, 2000

- 2010

27 Figure 18 : Annual average for PM 10 from active (above) and discontinued (below) monitors

0 10 20 30 40 50 60

2000 2002 2004 2006 2008 2010 Concentration ( μ g m - 3 ) Elko Grammar School #2 Linda Street Church Manse Elementary School Glenoaks Street

0 10 20 30 40 50 60

2000 2002 2004 2006 2008 2010 Concentration (μg m - 3 ) Battle Mountain High School State Offices Building Community Pool

Willow Creek Cave Rock State ParkNevada Air Quality Trend Report, 2000

- 2010

28 

### 2.7 S ulfur D ioxide

Sulfur oxides (SO 2 ) commonly orig inate from burning fossil fuels and are also produced from various
industrial processes . SO 2 is the measured criteria pollutant of concern. In the air, SO 2 reacts with oxygen, ammonia and other compounds, including water vapor, to form sulfate salts and sulfuric acid mist.

S ources of SO 2 include metal smelters, oil refineries, and large oil

- or coal

- fired power plants. Ac ross the United States, the largest sources of SO 2 emissions are from fossil fuel combustion at power plants (66%) and other industrial facilities (29%). Smaller sources of SO 2 emissions include industrial processes such as extracting metal from ore as wel l as the burning of high sulfur containing fuels by locomotives, large ships, and nonroad equipment . Since 2010, USEPA recognizes a 1

- hour primary standard for SO 2 at a level of 75 ppb, and a 3

- hour average secondary standard. To attain the primary standa rd, the 3

- year average of the 99 th percentile of daily maximum distribution (based on 1

- hour average s) must not exceed 75 ppb. To attain the secondary standard, the 3

- hour average concentration cannot exceed 0.5 ppm more than once per year.

NAPCP MONITORING NETWORK: During the reporting period, NAPCP did not conduct ambient monitoring for SO 2 because monitoring threshols established by USEP have not been met in any of Nevada’s 15 Rural Counties. However, the US

Forest Service monitors SO 2 at the J arbidge Wilderness area through the IMPROVE network ( http://vista.cira.colostate.edu/improve/Overview/Overview.htm ).

ATTAINMENT STATUS: With the exception of the central Stept oe Valley (near Ely), USE PA has designated all areas in Nevada’s 15 Rural Counties as unclassifiable. Prior to 2002, the central Steptoe Valley was designated by USEPA

as SO 2 non

- attainment due to the historic operation of a copper smelter at McGill. The smelter ceased operation in 1983 and NAPCP requested reclassification of the area to attainment. USEPA approved the request on April 12, 2002. USEPA will designate areas for the 2010 standard in 201 3 ( h ttp://www.epa.gov/so2designations/ ). NAPCP expects its jurisdiction to remain unclassifiable

.Nevada Air Quality Trend Report, 2000

- 2010

29 2.7.1 N ational S ulfur D ioxide Trend

Nationally, average SO 2 concentrations have decreased over the years. From 1980 to 2010 there was an
81% decrease in the national SO 2 average. From 2000 to 20 10 there was a 52% decrease in the national

SO 2 average. The reduction in average SO 2 concentrations is mainly the result of switching to low sulfur
fossil fuels especially in on

- road and off

- road vehicles ( http://www.epa.gov/airtrends/sulfur.html )

.

Figure 19 : Annual national average for SO 2 from 1980 to 2010 (black dashed line), based on 121 (1980

- 1989), 229 (1990

- 1999), and 341 site (2000

- 2010). Blue area delimits the 10 th and 90 th percentile of the annual distribution of concentrations reported by all sites nationwide ( http://www.epa.gov/airtrends/sulfur.html ).

0 5 10 15 20 25 30 Concentration ( ppb ) 

### Annual AverageNevada Air Quality Trend Report, 2000

- 2010

30 

## 3 Appendixes

3.1 Monitoring Station Description

Monitoring stations active at any time during the 2000

- 2010 period are described in this section. A synopsis of all stations and data availability is presented at in section 3.2

.



# High School, Battle Mountain

32

- 015

- 0004 (SLAMS)

Pollutant(s) Monitored

CO NO 2 O 3 PM 2.5 PM 10 1998

- 2002

Project Type = Population Oriented Surveillance

Measurement Scale = Neighborhood

Located at 625 Weaver Avenue in Battle Mountain, this PM 10 site was on the grounds of Battle Mountain High School. This site was at the edge of a residential neighborhood, near the intersection of Interstate Highway 80 and Nevada Highway 305. The TEOM continuous PM 10 monitor was sited on the
announcer's tower at the school’s athletic field. Monitoring commenced on August 20, 1998 and was
discontinued in 2002.Nevada Air Quality Trend Report, 2000

- 2010

31 

# Fifth Street, Carson City

32

- 510

- 0002 (SLAMS/SS MS)

Pollutant(s) Monitored

CO NO 2 O 3 PM 2.5 PM 10

1981

- 1989 1974

- 1989,

2008

- 2010 2009

- 2010 1991

- 1997

Project Type = Population Oriented Surveillance (Typical Concentration)

Measurement Scale = Neighborhood

Located at 3300 East Fifth Street in Carson City, this CO, O 3 , and PM 2.5 site is near the Carson City Public Works Department maintenance yard. In ad dition, meteorological data is collected at the Fifth Street site. This site is situated in a transition area that is adjacent to the maintenance yard, a sewage treatment plant, residential neighborhoods, wetlands, and the new extension of Highway 580. CO and

O 3 were monitored from 1974 through 1989. PM 10 monitoring commenced in March 1991 and was discontinued at the end of February 1997. In 2006, an existing meteorological station was restarted. In 2008, O 3 monitoring commenced at the Fifth Street site. In 2009, PM 2.5 monitoring commenced at the
Fifth Street site 11

. This station was discontinued and relocated in December 2012.

11 The O 3 and PM 2.5 monitors were relocated from the Long Street site.Nevada Air Quality Trend Report, 2000

- 2010

32 

# Long Street, Carson City

32

- 510

- 0004 (SLAMS /SSMS)

Pollutant(s) Monitored

CO NO 2 O 3 PM 2.5 PM 10 1997

- 2008 1997

- 1998 1997

- 2007 1998

- 2009 1997

- 1998

Project Type = Highest Concentration and Population Oriented Surveillance (Typical Concentrations)

Measurement Scale = Neighborhood (Urban) (Middle)

Located at 875 East Long Street in Carson City, this CO, O 3 , NO 2 , PM 2.5 , and PM 10 site was in the Sierra Pacific Power Company yard. This site monitored highest concentrations and population exposure downwind of the main traffic corridors and the commercial part of the city. This site began monitoring for CO, O 3 , NO 2 , and PM 10 in 1997. PM 2.5 monitoring commenced in January 1998. NO 2 monitoring was
discontinued in October 1997 and PM 10 sampling was discontinued at the end of June 1998. The Long

Street O 3 monitor was relocated to the Fifth Street site after the 2007 O 3 season. 12 In 2008, N APCP requested USEPA for discontinuation of CO monitoring based upon no violations of the NAAQS from 2002 to 2007. USEPA allowed CO monitoring to be discontinued at the end of 2008. In the summer of 2009, the Long Street site was discontinued and the speci al study PM 2.5 monitor was relocated to the
Fifth Street.

12 The Long Street O 3 monitor was relocated due to concern that trees adjacent to the site may have been interfering with the O 3 sampling.Nevada Air Quality Trend Report, 2000

- 2010

33 

# State Offices Building, Elko

32

- 007

- 0004 (SLAMS)

Pollutant(s) Monitored

CO NO 2 O 3 PM 2.5 PM 10 1992

- 2008

Project Type = Population Oriented Surveillance

Measurement Scale = Urban

Located at 850 Elm Street in Elko, this continuous PM 10 site was on the roof of the state offices building. This site was situated in a predominantly residential area. PM 10 sampling commenced at this site in November 1992. This monitor was previously located at the Fire Station at 723 Railroad Street (ID #32

- 007

- 0003) in a commercial area. It was moved to the State Offices Building at 850 Elm Street in
November 1992. At the end of 1998, the manual PM 10 sampler was replaced with a TEOM continuous

PM 10 monitor. In September 2008, the TEOM monitor was closed and a new beta attenuation monitor
was sited at the Elko Grammar School #2.Nevada Air Quality Trend Report, 2000

- 2010

34 

# Elko Grammar School #2, Elko

32

- 007

- 0005 (SLAMS)

Pollutant(s) Monitored

CO NO 2 O 3 PM 2.5 PM 10 2008

- 2010

Project Type = Population Oriented Surveillance (Typical Concentration)

Measurement Scale = Neighborhood

Located at 1055 7 th Street in Elko, this PM 10 site is on the grounds of Elko Grammar School #2. This site is
situated in a residential neighborhood . PM 10 monitoring commenced at this site in September 2008
when the beta attenuation monitor was installed.Nevada Air Quality Trend Report, 2000

- 2010

35 

# West End Elementary School, Fallon

32

- 001

- 0002 (SLAMS )

Pollutant(s) Monitored

CO NO 2 O 3 PM 2.5 PM 10 1999

- 2010 1993

- 1998

Project Type = Population Oriented Surveillance

Measurement Scale = Urban

Located at 280 South Russell Street in Fallon, this O 3 and PM 10 site is on the grounds of the West End Elementary School. This site is situated in a residential neighborhood that may at times be affected by agricultural operations surrounding the town. PM 10 sampling (SLAMS) commenced at this site in May
1993 and was d iscontinued at the end of June 1998. Monitoring for O 3 began in October 1999 as an O 3 transport site downwind of Reno and Fernley. In 2008, t he O 3 monitor was reclassified as a SLAMS.Nevada Air Quality Trend Report, 2000

- 2010

36 

# Fire Station, Fernley
(SPMS)

Pollutant(s) Monitored

CO NO 2 O 3 PM 2.5 PM 10 1998

- 2003

Project Type = Highest Concentration and Population Oriented Surveillance

Measurement Scale = Urban

Located at 195 East Main Street in Fernley, this O 3 site was at the North Lyon County Fire Protection District Station. This site was generally downwind from Reno at the end of a canyon corridor that includes large industrial sources. O 3 monitoring commenced in September 1997 and was discontinued at
the en d of September 2003.Nevada Air Quality Trend Report, 2000

- 2010

37 

# Intermediate School, Fernley

32

- 019

- 0006 (SLAMS /SSMS )

Pollutant(s) Monitored

CO NO 2 O 3 PM 2.5 PM 10 2004,

2007

- 2010 1999

- 2 010 1995

- 1998

Project Type = Population Oriented Surveillance

Measurement Scale = Urban

Located at 320 Hardie Lane in Fernley, this O 3 , PM 2.5 , and PM 10 site is on the grounds of Fernley Intermediate School. This site is situated in a residential and agricultural area that has experienced recent industrial growth. Sampling for PM 10 commenced at this site in May 1995 to determine agricultural and industrial source impacts and population exposure. PM 10 sampling was discontinued in
November 1998. PM 2.5 special study monitoring (SS MS) commenced in June 1999. O 3 monitoring (SLAMS) occurr ed during 2004 and resumed in July 2007.Nevada Air Quality Trend Report, 2000

- 2010

38 

# Gardnerville Ranchos, Gardnerville

32

- 005

- 0007 (SLAMS /SSMS )

Pollutant(s) Monitored

CO NO 2 O 3 PM 2.5 PM 10 1998

- 20 10 1995

- 1998

Project Type = Population Oriented Surveillance (Typical Concentration)

Measurement Scale = Neighborhood

Located at 820 Lyell Way in Gardnerville, this PM 2.5 and PM 10 site is in Aspen Park in the Gardnerville Ranchos. This site is situated in a residential neighborhood. PM 10 monitoring (SLAMS) commenced at
this site in December 1995 and was discontinued at the end of June 1998

. Special study m onitoring for

PM 2.5 ( SS MS) commenced in January 1998.Nevada Air Quality Trend Report, 2000

- 2010

39 

# IMPROVE Site, Great Basin National Park

32

- 033

- 0101 (SLAMS)

Pollutant(s) Monitored

CO NO 2 O 3 PM 2.5 PM 10 1998

- 2010

Project Type = Background

Measurement Scale = Regional

The IMPROVE (Interagency Monitoring of Protected Visual Environments) program implement an extensive long term monitoring program to establish the current visibility conditions, track changes in visibility and determine causal mechanisms for the visibility impairment in the National Parks and Wilderness Areas ( http://vista.cira.colostate.edu/im prove/ ). This monitoring station is l ocated at the
Lehman Caves in the Great Basin National Park near Baker. T he National Park Service started O 3 sampling in 1998.Nevada Air Quality Trend Report, 2000

- 2010

40 

# Community Pool, Pahrump
(32

- 023

- 0010 SLAMS )

Pollutant(s) Monitored

CO NO 2 O 3 PM 2.5 PM 10 2001

- 2004

Project Type = Highest Concentration

Measurement Scale = Neighborhood

Located at 250 North Highway 160 in Pahrump, this PM 10 site was on the grounds of the municipal swimming pool and recreation complex. The continuous beta attenuated monitor was sited on the roof of a dressing room. This site was situated in a commercial neighborhood behind the County offices. PM 10 monitoring commenced in January 2001 and ended in November 2004. The site was closed due to reconstruction of the pool

- building from a flat to a pitched roof.Nevada Air Quality Trend Report, 2000

- 2010

41 

# Linda Street, Pahrump
(32

- 023

- 0011 SLAMS)

Pollutant(s) Monitored

CO NO 2 O 3 PM 2.5 PM 10 2003

- 2010

Project Type = Background

Measurement Scale = Regional

Located at 8825 North Linda Street in Pahrump, this PM 10 site is on the premises of a private residence.
The continuous beta attenuated monitor is sited on the roof of an old railroad box car. This location is
the most rural and northern

- most site in the Pahrump Valley monitoring network. There are some
residen tial plats surrounding this site, but the area mainly consists of native desert vegetation with little or no land surface disturbances. There are gravel roads in the area, but they experience little traffic.

PM 10 monitoring commenced in May 2003.Nevada Air Quality Trend Report, 2000

- 2010

42 

# Willow Creek, Pahrump
(32

- 023

- 0012 SLAMS)

Pollutant(s) Monitored

CO NO 2 O 3 PM 2.5 PM 10 2004

- 2009

Project Type = Highest Concentration and Population Oriented Surveillance (Typical Concentration)

Measurement Scale = Urban

Located at 1500 Red Butte in Pahrump, this PM 10 site was on the Willow Creek Golf Course. The continuous beta attenuated monitor was sited on the roof of a pump house for the golf course between fairways. PM 10 monitoring commenced in December 2003. The Willow Creek Golf Course is surrounded by residential plats and vacant land. While the Community Pool site was in operation, the purpose of the Willow Creek site was to determine population exposure in central Pahrump. After the Community Pool site was closed in November 2004, the pu rpose of the Willow Creek site became monitoring the highest concentrations. In July 2009, the Willow Creek site was relocated to a new site on the golf course, 410 South Glenoaks Street, approximately one

- third of a mile southwest of the original site.Nevada Air Quality Trend Report, 2000

- 2010

43 

# Church, Pahrump
(32

- 023

- 0013 SLAMS)

Pollutant(s) Monitored

CO NO 2 O 3 PM 2.5 PM 10 2004

- 2010

Project Type = Source Impact

Measurement Scale = Neighborhood

Located at 781 East Gamebird in Pahrump, this PM 10 site is on the grounds of Our Lady of the Valley
Catholic Church. The continuous beta attenuated monitor is sited in the southeast corner of the Catholic Church lot. This site is situated in a residential area with some commercial plats and native desert. There is a mix of paved and dirt roads in the vicinity. The Church Site began operation in 2004 to complement the existing three other sites in the Pahrump Valley monitoring network. This PM 10 site is the southern

most monitoring site in the Pahrump Valley.Nevada Air Quality Trend Report, 2000

- 2010

44 

# Manse Elementary School, Pahrump

(32

- 023

- 0014 SLAMS)

Pollutant(s) Monitored

CO NO 2 O 3 PM 2.5 PM 10 2005

- 2010

Project Type = Highest Concentration

Measurement Scale = Middle

Located at 1020 East Wilson Road in Pahrump, this PM 10 site is on the grounds of the Manse Elementary School. This site replaced the Community Pool site. The continuous beta attenuated monitor is sited on the roof of the school. This site is situated adjacent to the busiest activity area of Pahrump in a mostl y commercial area, with some residential plats. This PM 10 site is located downwind from land surface disturbances such as residential construction developments that have cleared large swaths of ground and agricultural lands. There is a mix of paved and dirt roads in the vicinity

.Nevada Air Quality Trend Report, 2000

- 2010

45 

# Glenoaks Street, Pahrump
(32

- 023

- 0015 SLAMS)

Pollutant(s) Monitored

CO NO 2 O 3 PM 2.5 PM 10 2009

- 2010

Project Type = Population Oriented Surveillance (Typical Concentration)

Measurement Scale = Neighborhood

Located at 410 South Glenoaks Street in Pahrump, this PM 10 monitor is on the Willow Creek Golf Course. In July 2009, this site replaced the original Willow Creek site which was located approximately one

- third
of a mile to the northeast. The continuous beta attenua ted monitor is sited on the grounds of the wastewater treatment plant. PM 10 monitoring commenced in October 2009.Nevada Air Quality Trend Report, 2000

- 2010

46 

# Harvey’s Resort Hotel, Stateline
(32

- 005

- 0009 SLAMS)

Pollutant(s) Monitored

CO NO 2 O 3 PM 2.5 PM 10 1999

- 2010

Monitoring Objective = Highest Concentration

Measurement Scale = Micro

Located at 18 Highway 50 in Stateline, this CO site is on the 1 st level of Harvey’s Resort and Hotel’s parking garage facing the highway. This is a "micro

- scale" monitoring site for CO in the core of the Stateline casino hotel area at Lake Tahoe. The site is designed to monitor the highest CO concentrations at Lake Tahoe, and is taken to be representative of both the California and Nevada sides of the south
shore casino district. CO monitoring at this site commenced in October 1999 and was previously is conducted by the California Air Resources Board by multi

- agency cooperative agreement. Starting in July 2006, NDEP took over the monitoring responsibility for this site under a maintenance agreement with

EPA . In June 30 th 2012 , this monitoring station was discontinued, after 33 years of data below the
NAAQS.Nevada Air Quality Trend Report, 2000

- 2010

47 

# Cave Rock State Park, Zephyr Cove

32

- 005

- 0008 (SLAMS)

Pollutant(s) Monitored

CO NO 2 O 3 PM 2.5 PM 10 1999

- 2004 2000

- 2001 2000

- 2001

Project Type = Regional Transport

Measurement Scale = Regional

Located at Cave Rock State Park in Zephyr Cove, this O 3 , PM 2.5 , and PM 10 site was on the boat launch facility. This site monitored O 3 transport from upwind California urban areas. O 3 monitoring commenced in July 1999 and was discontinued at the end of February 2004. PM 2.5 and PM 10 monitoring commenced
at the end of 1999. PM 2.5 monitoring was discontinued on January 15, 2002. PM 10 monitoring was discontinued on January 22, 2002.Nevada Air Quality Trend Report, 2000

- 2010

48 

### 3.2 M onitoring Data Avail ability

The following table lists years during which air quality monitors were operated for the pollutant indicated. A blank space indicates that the specific pollutant has not been monitored for at that site.

Station Name Location Site # O 3 NO 2 CO PM 10 PM 2.5 Battle Mountain

Police & Fire Station 25 E. Second St. 32

- 015

- 0002 85

- 98 High School 625 Weaver Ave. 32

- 015

- 0004 98

- 02 Carson City

Fifth Street 13 3300 E. Fifth St. 32

- 510

- 0002 74

- 98,08

- 12 81

- 89 91

- 97 09

- 12
Bordewich School 110 Thompson Dr. 32

- 510

- 0003 94

- 98 Long Street 875 E. Long St. 32

- 510

- 0004 97

- 07 97

- 98 97

- 08 97

- 98 98

- 09
Ann Street E Ann St. SPMS 90

- 93
Roberts House Hwy 395 & Corbett St. SPMS 89,94

- 96 Elko State Offices Building 850 Elm St. 32

- 007

- 0004 92

- 08
Grammar School No. 2 1055 Seventh St. 32

- 007

- 0005 08

- 12 Fallon

West End School 280 S. Russell St. 32

- 001

- 0002 99

- 12 93

- 98 Fernley

Intermediate School 320 Hardie Lane 32

- 019

- 0006 07

- 12 95

- 98 99

- 12
Fire Station 163 E. Main St. SPMS 98

- 03 Gardnerville

Mitch Drive 931 Mitch Dr. 32

- 005

- 0006 94

- 96 Gardnerville Ranchos 820 Lyell Way 32

- 005

- 0007 95

- 98 98

- 12 Great Basin National Park

Lehman Caves Maintenance Bldg. 32

- 033

- 0007 93

- 95 Lehman Caves IMPROVE site 32

- 033

- 0008 95

- 97 Lehman Caves IMPROVE site 32

- 033

- 0101 93

- 12 Lovelock

Post Office Main St. & Dartmouth Ave. 32

- 027

- 0002 91

- 97 High School 1215 Franklin Ave. 32

- 027

- 0003 * McGill Elementary School 25 F Ave. 32

- 033

- 0002 93

- 98 Minden Dispatch Center 1615 Eight St. 32

- 005

- 0005 93

- 98
Law Enforcement Bldg. 1625 Eight St. SPMS 98

- 99
Pahrump Community Pool 250 N. Hwy 160 32

- 023

- 0010 01

- 04
Linda Street 8825 N. Linda St. 32

- 023

- 0011 03

- 12
Willow Creek 1500 Red Butte 32

- 023

- 0012 04

- 09 Church 781 E. Gamebird Rd. 32

- 023

- 0013 04

- 12
Manse School 1020 E. Wilson Rd. 32

- 023

- 0014 05

- 12
Glenoaks Street 41

- S. Glenoaks St. 32

- 023

- 0015 09

- 12 Stateline

Horizon Casino Resort 50 Hwy 50 32

- 005

- 0004 81

- 99 90

- 97 82

- 99 88

- 9 Harvey’s Resort
Hotel 14 18 Hwy 50 32

- 005

- 0009 99

- 12
Zephyr Cove

Cave Rock State Park Boat Ramp 32

- 005

- 0008 99

- 04 00

- 01 00

- 01

*Data collected was deemed invalid by USEPA

13 This station was discontinued and relocate d to a different location in December 2012.

14 This station was discontinued in June 2012.Nevada Air Quality Trend Report, 2000

- 2010

49 

### 3.3 Monitoring Data



## M onitoring Methods Used in Nevada, 2000

- 2010

Pollutant Method Units

CO Gas Nondispersive Infrared Radiation ppm

O 3 UV Absorption ppm

PM 2.5 Met

- One BAM 1020 μg/m 3

PM 2.5 Met

- One ES

- 640 μg/m 3

PM 10 Reference

- Hi Vol Andersen/GMW 1200 μg/m 3

PM 10 R&P TEOM Mass Transducer μg/m 3Nevada Air Quality Trend Report, 2000

- 2010

50 

# Carbon Monoxide

There was one active CO monitor under NDEP’s jurisdiction

, Harvey’s Resort Hotel in Stateline (discontinued in 2012). Between 2000 and 2010 CO data was also collected at the monitor station on Long Street in Carson City from 1997 to 2008.Nevada Air Quality Trend Report, 2000

- 2010

51 Compliance with the current CO NAAQS is met when:

 The 8

- hour average does not exceed 9 ppm more than once per year

 The 1

- hour average does not exceed 35 ppm more than once per year

Table 3 : Carbon monoxide. Annual maxima ( p pm) and number of exceedances (in parenthesis) for each NAAQS for the Long Street and Harvey’s Resort Hotel in the 2000

- 2010 period

.

Long Street Harvey’s Resort Hotel

8

- hour 1

- hour 8

- hour 1

- hour

2000 3.8 (0) 8.0 (0) 4.4 (0) 13.0 (0)

2001 3.9 (0) 7.0 (0) 3.7 (0) 7.6 (0)

2002 3.9 (0) 8.3 (0) 8.8 (0) 17.2 (0)

2003 3.3 (0) 5.5 (0) 7.3 (0) 13.0 (0)

2004 3.3 (0) 6.0 (0) 4.4 (0) 12.0 (0)

2005 2.9 (0) 4.3 (0) 3.8 (0) 12.7 (0)

2006 2.8 (0) 4.8 (0) 3.1 (0) 5.2 (0)

2007 2.8 (0) 4.8 (0) 4.5 (0) 7.8 (0)

2008 2.2 (0) 2.9 (0) 2.6 (0) 5.8 (0)

2009 3.4 (0) 10.5 (0)

2010 3.2 (0) 5.8 (0)Nevada Air Quality Trend Report, 2000

- 2010

52 

# Ground

- Level Ozone Monitoring Data

There were three active O 3 monitors under NDEP’s jurisdiction, Fifth Street in Carson City (discontinued and relocated in December 2012)

, West End Elementary School in Fallon, and Intermediate School in Fernley. In addition, O 3 data is collected by the National Park Service at the IMPROVE Site in Great Basin National Park. Between 2000 and 2010, O 3 data was also collected at four other monit ors, Long Street in Carson City, Fire Station in Fernley, Horizon Casino Resort in Stateline, and Cave Rock State Park in Zephyr Cove.Nevada Air Quality Trend Report, 2000

- 2010

53 Compliance with the current O 3 NAAQS is met when the 3

- year average of the annual 4 th

- highest daily

maximum value, based on the 8

- hour average, does not exceed 0.1 ppm.

Table 4 : Ozone: 3

- year average of the annual 4 th

- highest daily maximum value, based on the 8

- hour average, for all the stations measuring O 3 between 2000 and 2010.

Fifth

St. West End Elem.

Sch. Fernley Int.

Sch. Great Basin

NP Long

St. Fernley Fire

St. Cave Rock

SP
2000

- 2002 0.073 0.07 0.067 0.073

2001

- 2003 0.071 0.069 0.066 0.071

2002

- 2004 0.072 0.067 0.064

2003

- 2005 0.072 0.064

2004

- 2006 0.072 0.066

2005

- 2007 0.064 0.073 0.066

2006

- 2008 0.068 0.073

2007

- 2009 0.066 0.063 0.072

2008

- 2010 0.069 0.063 0.06 3 0.070

2009

- 2011 0.066 0.059 0.064 0.070Nevada Air Quality Trend Report, 2000

- 2010

54 

# PM 2.5 

# Monitoring Data

There were three active PM 2.5 monitors under NDEP’s jurisdiction, Fifth Street in Carson City (discontinued and relocated in December 2012), Intermediate School in Fernley, and Gardnerville
Ranchos in Gardnerville. Between 2000 and 2010, PM 2.5 data was also collected at two other moni tors, Long Street in Carson City and Cave Rock State Park in Zephyr Cove.Nevada Air Quality Trend Report, 2000

- 2010

55 Compliance with the current PM 2.5 NAAQS is met when

 The 3

- year average of the annual mean does not exceed 15 μ g/m 3

 The 3

- year average of the 98 th percentile value of the 24

- hour average, does not exceed 35

μ g/m 3

Table 5 : PM10 : 3

- year average for annual mean and annual 98th percentile of 24

- hour average. Fifth Street and Cave Rock NP stations are not shown as they did not h ave 3 consecutive years of data. The threshold for the 24

- hour NAAQS was changed from 65 μg/m 3 to 35 μg/m 3 in 2007, therefore all stations were in compliance during the 2000

- 2010 period.

Long St. Fifth St. Fernley Inter. Sch. Gardnerville Ranchos

Annual

mean 98 th perctl. Annual

mean 98 th perctl. Annual

mean 98 th perctl. Annual

mean 98 th perctl.

2000

- 2002 4.78 23.90 5.03 21.70 6.17 29.43

2001

- 2003 4.39 20.53 4.47 18.53 6.08 28.33

2002

- 2004 4.11 20.97 3.91 15.00 6.45 30.47

2003

- 2005 4.81 36.23 * 3.85 14.10 7.00 45.20 *

2004

- 2006 4.78 36.43 * 13.80 8.91 46.10 *

2005

- 2007 5.39 34.90 12.83 10.19 42.20 *

2006

- 2008 21.30 10.60 11.37 26.97

2007

- 2009 24.83 4.20 14.47 11.15 28.43

2008

- 2010 4.43 15.43 11.73 29.17

2009

- 2011 13.40 27.00 4.78 15.20 10.89 29.30

* NAAQS threshold was 35 μg/m 3Nevada Air Quality Trend Report, 2000

- 2010

56 

# PM 10 

# Monitoring Data

There are five active PM 10 monitors under NDEP’s jurisdiction, Grammar School #2 in Elko as well as
Linda Street

, Church

, Manse Elementary School , and Glenoaks Street in Pahrump. Between 2000 and 2010, PM 10 data was also collected at 5 other monitoring sites, Battle Mountain High School in Battle Mountain, State Offices Building in Elko, Community Pool in Pahrump, Willow Creek in Pahrump, and
Cave Rock State Park in Zephyr Cove.Nevada Air Quality Trend Report, 2000

- 2010

57 Compliance with the current PM 10 is met when the 24

- hour average does not exceed 150 μ g/m 3 more than once per year, on a 3

- year average basis.

Table 6 : Total number of exceedances of the PM10 24

- Hour Stand ard, between 2000 and 2010.
Reported, are the total exceedances for each station and the average of each 3

- year period (i.e., the design value). Compliance with the NAAQ is met when the average number of exceedances in the 3

- year period is less or equal to 1. Numbers in red
indicate exceedance conditions.

Elko Grammar
School #2 Linda Street Church Manse Elementary
School Glenoaks

Street

2004

- 2006

--- 0 0

--- --- 2005

- 2007

--- 0 0 0

--- 2006

- 2008

--- 0 0 0

--- 2007

- 2009 0 0 0 0

--- 2008

- 2010 0 0 0 0 0

Battle Mountain High
School State Offices

Building Community

Pool Willow Creek

1998

- 2000 1 (0.3) 0

--- --- 1999

- 2001 1 (0.3) 0 4 (1.3)

--- 2000

- 2002 1 (0.3) 1 (0.3) 18 (6.0)

--- 2001

- 2003

--- 1 (0.3) 21 (7.0)

--- 2002

- 2004

--- 1 (0.3) 14 (4.7)

--- 2003

- 2005

--- 0 19 (6.3)

--- 2004

- 2006

--- 0 2 (0.7) 2 (0.7)

2005

- 2007

--- 0

--- 1 (0.3)

2006

- 2008

--- 0

--- 1 (0.3)