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Quality of the Environment
The quality of life mirrors the quality of the environment. As a technology and knowledge-based society, we are more capable and vigilant than ever about managing and monitoring pollutants released into the air, water, and soil. Nevada state agencies are responsible for the implementation of  many laws intended to lessen impacts of activities that diminish environmental quality and impair the health and well being of people and other life forms.
Agency programs deal with discharges of pollutants from large and small sources into the air, water, and soil; the prudent allocation and conservative use of limited water supplies; and, the safe use, transportation, and storage of solid and hazardous waste and toxic substances. Some programs are mandatory and prescribe protective standards and practices. Many others are voluntary, and require individual, industry, and community involvement to be successful. State agencies most extensively involved are the Divisions of Environmental Protection (NDEP) and Water Resources (NDWR), and the Department of Agriculture.
The information presented in Part 2 provides an overview of Nevada's environmental quality status and some of the programs implemented to sustain favorable air, water, and soil conditions. Information from state and local agencies indicates environmental values are being maintained in many areas of the state. However, deteriorated environmental quality is evident where land and water resources are intensively developed for urban, agricultural, mining, and military land uses. In the past couple of decades, regulations have resulted in improved pollution controls at large, easily identified pollution sources.
Today, major threats to environmental quality come from numerous, dispersed, and smaller scale activities in both urban and rural areas. The expanding population and economy combined with the consumption habits of individuals, industries, and institutions make achievement of environmental standards dependent upon changes in the daily behaviors and choices of everyone.
Education is an important strategy for gaining the broad support needed to make environmental progress. Resource agencies can contribute to public education by sharing the results of environmental monitoring data and assessments of program effectiveness. Ultimately, high environmental quality depends upon each citizen, industry, and community learning how to modify our lifestyles, work practices, and recreational activities that negatively impact the air, water, and soil resources.
Air Quality
The quality of air throughout almost all of Nevada is better than government standards set to protect the health and welfare of humans and the environment. The clearest air in the nation is found in rural eastern Nevada, based on monitoring of airborne particulates at Great Basin National Park.
However, most of the state's population resides in two urbanized  areas that are designated as having moderate to serious air quality impairment, relative to air quality standards. Air quality is determined by measuring concentrations of common pollutants near ground level, where people live and work. If concentrations for a pollutant rise above air quality standards for a specified period of time and number of days, then the airshed can be classified as "nonattainment." In nonattainment areas, State Implementation Plans (SIP) must be prepared by the air quality management agency. The SIPs demonstrate how proposed strategies, technologies, practices, and regulations will reduce pollution, improve air quality sufficiently to achieve standards, and maintain improved conditions.
The State of Nevada has set air quality standards for criteria pollutants that are generally based on the federal standards for air quality. Air quality standards specify the maximum pollutant concentrations over specific averaging periods. The six criteria pollutants for which standards have been set are sulfur dioxide, carbon monoxide, nitrogen dioxide, ozone, particulate matter, and lead. These pollutants are relatively common and capable of causing mild discomfort or seriously affecting the health of people when elevated concentrations persist. Perhaps the greatest success of the Clean Air Act was the nationwide reduction in the level of atmospheric lead brought about by mandatory removal of lead from gasoline. The Nevada State Environmental Commission also has established an air quality standard for hydrogen sulfide (H2S), a toxic gas with a disagreeable odor.
Management of air quality in Nevada is handled by both state and county agencies. The Bureaus of Air Quality Planning (BAQP) and Air Pollution Control, within the NDEP, implement air quality programs for the state, with the exception of Clark and Washoe counties. The Washoe County District Health Department and the Clark County Department of Air Quality Management are responsible for the air pollution control programs and air quality monitoring in those jurisdictions.
Air Quality Status
Throughout the 1990s, the State of Nevada, Bureau of Air Quality periodically monitored air quality in Carson City, Minden, Gardnerville, Stateline, Zephyr Cove, Fernley, Fallon, Lovelock, Battle Mountain, Elko and McGill. Results indicate that generally good air quality occurs throughout Nevada. The BAQ reports that monitoring data show no deterioration in the air quality of these areas between 1989 and 1999 (Bureau of Air Quality, 2000). Air quality standards have been exceeded in the two most populated air basins - the Truckee Meadows and Las Vegas Valley (Table 2-1). Within the Truckee Meadows non-attainment area are the cities of Reno, Sparks, and the Nevada side of the Lake Tahoe Basin. The Las Vegas Valley nonattainment area includes the cities of Las Vegas, North Las Vegas, Henderson, and Boulder City. Overall, the annual number of days when air quality standards were exceeded declined during the 1990's.
Las Vegas Valley is designated a serious nonattainment area for carbon monoxide and particulate matter. The Truckee Meadows basin is designated as a moderate nonattainment area for carbon monoxide and a serious nonattainment area for particulate matter. Both areas experience elevated ozone concentrations during the summer months. Anticipated standard changes may result in the classification of both areas as nonattainment for ozone. Because Nevada is a highly urbanized state, about 80 percent of the state's population lives within the particulate matter and carbon monoxide nonattainment areas.
Primary human-derived sources of particulate pollution include windblown dust from construction sites, unpaved roads and trails, sand and gravel operations, and off-road recreational vehicles. Secondary sources include motor vehicle emissions, residential wood burning stoves and fireplaces, wildfire and brush/waste burning, tilled and fallowed agricultural fields, toxic chemicals, and industrial sources. Particulate matter also can form when gases emitted from motor vehicles and industry undergoes chemical reactions in the atmosphere.
Carbon monoxide typically is higher during calm periods. A large amount of carbon monoxide comes from motor vehicles and wood burning for home heating. Other sources include lawn mowers, off-road vehicles and construction equipment. Federal rules have required placement of pollution controls on automobiles, thereby lowering emission rates from a portion of the vehicle mix. However, onboard emission controls have not been required on trucks and buses yet.
Air quality improvements from lower auto emissions may not be maintained due to demographic trends. Between 1991 and 1999, the amount of vehicle miles traveled (VMT) in Nevada increased 6.8 billion miles to 17.4 billion miles, a 65 percent increase (Nevada Department of Transportation, 2001). Population increased about 30 percent during the same period. A portion of the increased VMT may be attributable to tourism and suburban sprawl.
More residential developments built distant from core urban areas translate into more workers and shoppers driving longer distances. Sprawl works against the local economy of scale to fund mass transit services, a pollution reduction strategy used in other metropolitan areas. An inspection and maintenance program for vehicles in the Reno and Las Vegas area helps to reduce vehicle tailpipe emissions. The use of oxygenated fuels, cleaner alternative fueled vehicles, vapor recovery at gas service stations, and improved on-board emission controls also lower pollutant emissions.
Air Quality Management
State and county air quality management agencies administer permitting programs to control and track emissions of the six criteria pollutants from a wide variety of sources. Emissions of volatile organic compounds (VOCs) are also regulated and tracked because this group of chemicals (e.g., petroleum based solvents) contributes to formation of ozone and some pose serious human and environmental health threats. Major stationary sources and hazardous pollutant emission sources are subject to stringent permits that
specify the amount of emissions allowed, minimum pollution control measures, and monitoring and reporting requirements. Source emissions data is collected or estimated periodically and analyzed to check on permit compliance.
The state's BAPC issues permits for Nevada electric generating stations that burn fossil fuels. Although coal remains the primary fuel for electricity generation in Nevada (56 percent), natural gas fueled generation has increased to 20% over the past decade. More geothermal power plants have also been added to the state's generation mix, helping hold down pollutant emission increases. From 1988 to 1998, power plants in Nevada produced fewer tons of sulfur dioxide, declining from 61,000 to 54,000 tons (Table 2-2). However, nitrogen dioxide emissions rose from 69,000 to 76,000 tons. Carbon dioxide, a greenhouse gas associated with accelerated climate change and global warming concerns, also increased modestly.
Air toxics, or hazardous air pollutants (HAPs) are compounds known or suspected to cause serious health effects or environmental effects. Common HAP's include benzene and toluene from gasoline, perchloroethylene from dry cleaning facilities, and methylene chloride from paint stripping compounds. Others are dioxin, asbestos, and metallic compounds (e.g., those with cadmium, mercury, chromium, and lead). HAP's that are persistent, such as mercury, may accumulate in the food chain, reaching higher levels than in the surrounding environment. Most HAP's originate from mobile sources. Forest fires may release large quantities. Stationary sources of air toxics are divided into major and area source categories. Few major sources, which include chemical plants, steel mills, oil refineries, hazardous waste incinerators, and power plants, are located in Nevada. Area sources, such as dry cleaners and gas stations, release smaller amounts, which though small, can be of concern where concentrated. The 1996 National Toxics Inventory data from the EPA show that mobile sources contribute 50 percent of our country's HAP's emissions, major stationary sources 26 percent, and area and other sources 24 percent.
Greenhouse Gases and Climate Change
The atmosphere contains gases that trap re-radiated energy from the sun, warming the earth, similar to a greenhouse trapping heat. "Greenhouse gases" - primarily carbon dioxide, methane, and nitrous oxide - make up a fraction of one percent of all atmospheric gases. Without them, the earth's surface would be 34o F cooler. Because a small amount of gases exerts such a strong global effect, the continuing rise in greenhouse gas concentrations during the past century has generated intense scientific interest.
Measurements taken directly from the atmosphere since the 1930's confirm that carbon dioxide (CO2), the most plentiful greenhouse gas, has been increasing. Carbon dioxide levels for earlier times are inferred from measurements of CO2 trapped in air bubbles in glacial or polar ice. Concentrations have varied naturally throughout Earth's history, however, the 30% increase observed since pre-industrial times cannot be explained by natural causes. Carbon dioxide concentrations are higher now than in the past 450,000 years (U.S. Environmental Protection Agency, 2002). Table 2-3 shows calculated changes in greenhouse gas emissions in Nevada from 1990 to 1995. Total emissions increased 16.5 percent, corresponding with population and economic growth (Nevada Energy Office, 1998).
Climate scientists predict that average temperatures for the U.S. will warm 7°F by 2090. This change appears small compared to short-term weather. For global climate, such a warming would be larger and faster than any changes in the past 10,000 years. The global average temperature this past century has warmed 1o F. Computer climate models that evaluate the potential effect of expected warming on western water resources give insight into potential effects in the Sierra Nevada and Great Basin ranges. Possible impacts include: less snowfall and more rain; a shorter snowfall season; and accelerated snow pack runoff. Flashier, earlier, and greater spring runoff would lower supply availability during the growing season. Higher evaporation would reduce water storage in reservoirs, aquifer recharge, and soil moisture. Longer dry seasons would present new challenges to managers of Nevada's water supplies and aquatic ecosystems (Frederick and Gleick, 1999).
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