The mountain range, a prominent feature of the southern Appalachian region, derives its popular name from a naturally occurring phenomenon. A bluish haze frequently envelops the peaks and valleys, creating a visual effect reminiscent of smoke. This characteristic mist provides the basis for its widely recognized designation.
The pervasive haze is primarily attributed to volatile organic compounds (VOCs) released by the abundant vegetation within the area. These compounds, particularly isoprene produced by trees, react with sunlight to form aerosols. The resulting light scattering contributes significantly to the observed atmospheric opacity. The effect is enhanced by the region’s high humidity and elevation, leading to optimal conditions for the haze to persist and intensify. This enduring feature has shaped the region’s identity and contributed to its allure for visitors.
Understanding the origins of this unique attribute provides context for appreciating the ecological richness and environmental factors that define the area. The conditions that generate the visual phenomenon are integral to the area’s ecosystem and contribute to its status as a biodiversity hotspot. Further examination reveals the intricate interplay between vegetation, climate, and atmospheric chemistry that results in the captivating and enduring image associated with this mountain range.
1. Blue Haze
The persistent bluish haze that cloaks the mountain range is intrinsically linked to its familiar name. The presence of this haze is not merely coincidental; it is the primary reason for the mountains’ descriptive designation. The term “Smoky Mountains” directly reflects the visual impression created by this natural phenomenon. Without the presence of the characteristic blue haze, the mountains would likely be known by an entirely different name, perhaps one based on geological features or historical associations. The haze is thus foundational to the region’s identity.
The origin of the blue haze is complex, involving the interaction of biological and atmospheric elements. Vegetation, particularly deciduous trees abundant in the region, releases volatile organic compounds (VOCs), most notably isoprene. These compounds undergo photochemical reactions in the atmosphere, triggered by sunlight, resulting in the formation of light-scattering aerosols. These aerosols preferentially scatter blue light, creating the observed bluish hue. The effectiveness of this scattering is amplified by the regions high humidity, which increases the concentration of aerosols in the air. For example, during the summer months, when both VOC emissions and humidity levels are at their peak, the blue haze is often most pronounced, solidifying the area’s namesake characteristic.
In conclusion, the blue haze is not simply a visual attribute but a defining characteristic that informs the region’s identity. Understanding its origins through VOC emissions, photochemical reactions, and atmospheric conditions illuminates the scientific basis for the name “Smoky Mountains.” Recognizing this connection is crucial for appreciating the complex interplay of natural processes that shape this unique geographical area and perpetuates an understanding for the origin “why is it called the smoky mountains”.
2. VOC Emissions
Volatile Organic Compound (VOC) emissions constitute a crucial factor in understanding the origin of the name, “Smoky Mountains.” These emissions, released predominantly by the area’s dense vegetation, are the primary precursors to the atmospheric phenomenon that lends the mountains their distinctive, smoky appearance. Without the presence and subsequent chemical reactions of these VOCs, the characteristic blue haze would not form, thereby negating the basis for the mountains’ established moniker. The connection is, therefore, direct and causational: VOC emissions are a necessary component for the visual effect which informs the name.
The process begins with the release of VOCs, particularly isoprene, from deciduous trees prevalent in the region. These compounds, upon entering the atmosphere, react with sunlight in a complex series of photochemical reactions. The result is the formation of secondary organic aerosols (SOAs), tiny particles that scatter light. The scattering of shorter wavelengths, such as blue light, is more efficient, leading to the perceived bluish hue. High humidity levels further contribute to the haze by increasing the concentration of these aerosols. For instance, during the summer months, increased temperatures lead to heightened VOC emissions from the forests, resulting in a more pronounced haze, which is why the “smoky” effect is often most evident during this period. Understanding this interplay enables scientists to model air quality and predict visibility conditions in the region.
In summary, the “Smoky Mountains” are so named due to the visual phenomenon of a blue haze, which is directly linked to the emission and transformation of VOCs from the area’s vegetation. The intricate process involving isoprene, sunlight, aerosol formation, and light scattering elucidates the scientific basis for the name. This knowledge is not only academically important but also has practical significance for environmental management, air quality monitoring, and tourism, where the scenic views are a major attraction. Recognizing this connection is crucial for preserving the natural beauty of the area and mitigating the impact of human activities on the atmosphere.
3. Isoprene Production
The correlation between isoprene production and the mountain range’s designation stems from its role as a primary precursor in the formation of the characteristic atmospheric haze. Isoprene, a volatile organic compound emitted by many species of trees prevalent in the region, undergoes photochemical reactions in the atmosphere, leading to the creation of secondary organic aerosols (SOAs). These SOAs scatter light, particularly blue light, resulting in the perceived bluish haze that visually characterizes the area. Without substantial isoprene production, this haze would be significantly diminished, weakening the association with the mountains’ descriptive name. The abundance of isoprene-emitting vegetation directly contributes to the persistent visual effect, thus underscoring the importance of isoprene production as a component of “why is it called the smoky mountains.” For instance, deciduous forests, known for high isoprene emissions, dominate the landscape, reinforcing the link between vegetation type, isoprene release, and the mountains’ atmospheric character.
Further analysis reveals the practical significance of understanding the isoprene-haze connection. Monitoring isoprene emissions provides valuable data for assessing air quality and visibility conditions. Models that incorporate isoprene production rates can predict the intensity of the haze under various environmental conditions, such as temperature and humidity levels. This information is crucial for managing tourism, as the scenic vistas are a key attraction. Additionally, this understanding is relevant for evaluating the impact of climate change on the region. Alterations in temperature and precipitation patterns could influence isoprene emissions, potentially modifying the haze and impacting the aesthetic value of the mountains. For example, studies have shown that increasing temperatures can lead to higher isoprene emissions, but drought conditions can reduce vegetation growth and, consequently, isoprene production.
In summary, the name is inextricably linked to the natural processes that occur due to the region’s unique environmental features. Isoprene production is a key determinant, facilitating the formation of the bluish haze that defines the range. Understanding the relationship between isoprene, atmospheric chemistry, and visibility is essential for environmental monitoring, resource management, and ensuring the long-term preservation of the visual characteristics that give the mountain region its name and appeal. Challenges include accurately modeling isoprene emissions across diverse landscapes and predicting the impacts of future climate scenarios on the area’s air quality and scenic vistas.
4. Sunlight Reaction
The phenomenon central to the name is intricately connected to atmospheric photochemical reactions. Sunlight serves as the catalyst, driving the transformation of volatile organic compounds (VOCs) into secondary organic aerosols (SOAs). This process is fundamental to creating the visually distinct haze.
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Photochemical Oxidation
VOCs, such as isoprene emitted by vegetation, undergo oxidation when exposed to sunlight. This chemical transformation alters their molecular structure, leading to the formation of new compounds. For example, isoprene reacts with hydroxyl radicals (OH), formed through the interaction of sunlight with ozone and water vapor, initiating a series of oxidation steps. This oxidation is critical as it converts gaseous VOCs into particles that contribute to the haze.
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Aerosol Formation
The oxidized VOCs nucleate and condense, forming secondary organic aerosols (SOAs). These aerosols are microscopic particles suspended in the atmosphere. Their size and composition determine their light-scattering properties. The abundance of SOAs is directly related to the intensity of sunlight, with increased solar radiation leading to greater aerosol formation. This is evident in summer months when haze is more pronounced.
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Light Scattering Properties
SOAs effectively scatter sunlight, and the scattering efficiency is wavelength-dependent. Smaller particles preferentially scatter shorter wavelengths, such as blue light. This selective scattering causes the overall haze to appear bluish when viewed from a distance. The visual effect is enhanced by the density of the aerosol cloud, a result of continuous VOC emissions and efficient sunlight-driven conversion to SOAs.
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Atmospheric Stability
The stability of the atmospheric conditions influences the persistence of the haze. Stable atmospheric layers can trap VOCs and SOAs, allowing them to accumulate and enhance light scattering. Inversions, where a layer of warm air sits above cooler air, prevent vertical mixing and contribute to the formation of concentrated haze layers. Consequently, the interplay between sunlight, VOC emissions, and atmospheric stability determines the prominence and duration of the characteristic haze.
The name is thus a direct reflection of the atmospheric photochemical processes initiated by solar radiation. Sunlight drives the conversion of VOCs into light-scattering aerosols, creating the visual haze. Without this process, the mountains would not possess their signature characteristic. This underscores the central role of sunlight in shaping the visual identity and the naming of the mountain range, emphasizing the link “why is it called the smoky mountains”.
5. Aerosol Formation
The presence of a characteristic bluish haze, visually defining the mountain range and influencing its name, is inextricably linked to the process of aerosol formation. This process, wherein gaseous precursors transform into particulate matter, is pivotal in generating the light-scattering properties responsible for the observed atmospheric effect.
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VOC Oxidation and Nucleation
Volatile organic compounds (VOCs), emitted by vegetation, undergo oxidation in the atmosphere. Sunlight initiates these reactions, leading to the creation of oxidized organic molecules. These molecules subsequently nucleate, meaning they aggregate and condense, forming ultra-fine particles. These initial particles are crucial seeds for further aerosol growth. This process is a significant source of secondary organic aerosols (SOAs) in the region. For instance, isoprene, a common VOC, reacts with ozone and hydroxyl radicals to form SOAs. The prevalence of deciduous forests ensures a continuous supply of isoprene, facilitating aerosol formation.
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Condensational Growth
Once initial aerosol particles are formed, they grow through condensation. Additional oxidized organic molecules and other atmospheric trace gases condense onto these existing particles, increasing their size. Larger particles are more effective at scattering light. Condensational growth is influenced by temperature, humidity, and the availability of condensable material. For example, high humidity promotes the uptake of water vapor by aerosols, further increasing their size and scattering efficiency. This process directly connects VOC emissions to the atmospheric visual effect.
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Chemical Composition and Properties
The chemical composition of aerosols dictates their light-scattering properties. Secondary organic aerosols often contain a complex mixture of organic compounds, including carboxylic acids, aldehydes, and ketones. These compounds affect the refractive index of the aerosol, which determines how effectively it scatters light. Some aerosols may also contain inorganic salts, such as sulfates and nitrates, which contribute to their hygroscopic properties. The chemical composition varies with location and time of year, affecting the overall haze characteristics. For instance, aerosols formed during wildfires may contain black carbon, which absorbs light, leading to a different visual effect.
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Influence of Meteorological Conditions
Meteorological conditions significantly influence aerosol formation and transport. Stable atmospheric conditions, such as temperature inversions, trap aerosols near the surface, increasing their concentration and enhancing the haze. Wind patterns distribute aerosols over the region, affecting visibility. Precipitation can remove aerosols from the atmosphere through wet deposition. Regional weather patterns, therefore, play a critical role in determining the spatial and temporal variability of the haze. For example, stagnant air masses during summer months promote the accumulation of aerosols, leading to more pronounced hazy conditions.
In summary, the mountainous region owes its name to the visual effect produced by aerosols. The oxidation and subsequent condensation of VOCs, coupled with favorable meteorological conditions, contribute to the formation of a persistent haze. The process directly explains “why is it called the smoky mountains”. Understanding this phenomenon is essential for managing air quality, predicting visibility conditions, and preserving the scenic beauty of the area.
6. Light Scattering
The optical phenomenon of light scattering is fundamental to understanding the rationale behind the naming of the mountainous region. The pervasive bluish haze, which is the source of the name, arises directly from the interaction of sunlight with particulate matter suspended in the atmosphere. This interaction, governed by principles of light scattering, determines the color and intensity of the observed haze and, consequently, the association with the name.
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Rayleigh Scattering and Particle Size
Rayleigh scattering, a dominant mechanism in clear atmospheric conditions, occurs when light interacts with particles smaller than the wavelength of the light. In the context of the mountain region, secondary organic aerosols (SOAs), formed from volatile organic compounds (VOCs) emitted by vegetation, fall within this size range. Rayleigh scattering is most efficient at shorter wavelengths, such as blue light, causing preferential scattering of blue light in all directions. This explains the bluish hue of the haze. For example, the high concentration of SOAs, coupled with the abundance of blue light in the solar spectrum, results in a visible blue haze that contributes significantly to the area’s name.
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Mie Scattering and Aerosol Concentration
Mie scattering occurs when light interacts with particles of comparable size to the wavelength of the light. While less dominant than Rayleigh scattering in clear conditions, Mie scattering can become significant at higher aerosol concentrations. Increased aerosol loading enhances the overall scattering of light, regardless of wavelength, leading to a more opaque appearance. This effect can be observed during periods of increased VOC emissions or atmospheric stagnation. For example, under stagnant air conditions, aerosol concentrations can build up, increasing Mie scattering and intensifying the perceived haze, reinforcing the image.
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Wavelength Dependence and Color Perception
The wavelength dependence of light scattering directly influences color perception. Rayleigh scattering favors blue light, while Mie scattering is less wavelength-dependent and can contribute to the scattering of other colors. The interplay between these two mechanisms determines the final color of the haze. Variations in aerosol composition and size distribution can shift the balance between Rayleigh and Mie scattering, altering the perceived color. The fact is that most of the time, blue scattering dominates as the wavelength to be seen by a human eye to give that color
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Visibility and Atmospheric Conditions
Light scattering also affects visibility. High aerosol concentrations reduce visibility by scattering light away from the line of sight. The extent of this reduction depends on the aerosol loading and atmospheric conditions. High humidity can exacerbate the reduction in visibility by increasing the size of hygroscopic aerosols. Poor visibility is often associated with increased aerosol concentrations, reinforcing the visual association .
The mountain range owes its descriptive designation to the interaction of light with atmospheric particles, a process governed by the principles of light scattering. The dominance of Rayleigh scattering, due to the abundance of small SOAs, explains the characteristic bluish hue. Atmospheric conditions, such as humidity and stagnation, influence aerosol concentrations and scattering efficiency. Understanding these mechanisms provides a scientific basis for comprehending the origin of the name.
7. High Humidity
Elevated levels of atmospheric moisture play a significant, though indirect, role in the naming of the mountainous region. While not the primary cause of the haze, high humidity exacerbates the conditions that create it, influencing both the formation and persistence of the visual effect that defines the region. The area’s geographical characteristics contribute to its higher-than-average humidity, creating an environment conducive to haze development. This influence underscores the importance of considering humidity as a contributing factor to “why is it called the smoky mountains.”
High humidity affects haze formation through several mechanisms. First, water vapor can condense onto existing aerosol particles, increasing their size and, consequently, their light-scattering efficiency. Larger, more hydrated aerosols scatter light more effectively than smaller, dry aerosols, amplifying the bluish haze. Second, high humidity promotes the formation of secondary organic aerosols (SOAs) by enhancing the uptake of volatile organic compounds (VOCs) by cloud droplets. For example, during periods of high humidity, the increased water content in the atmosphere facilitates the conversion of gaseous VOCs to particulate form, increasing the overall aerosol loading. Third, high humidity often coincides with stable atmospheric conditions, such as inversions, which trap aerosols near the surface, further enhancing the haze. The persistent vegetation due to high humidity also perpetuates the VOC emissions.
Understanding the connection between high humidity and the visual effect has practical significance for environmental management and tourism. Forecasting models that incorporate humidity data can more accurately predict haze intensity and visibility conditions. This information is valuable for planning outdoor activities and managing resources during periods of high visitation. Furthermore, understanding the role of humidity in haze formation is important for assessing the impacts of climate change on the region’s atmospheric characteristics. For example, changes in temperature and precipitation patterns could alter humidity levels, potentially affecting the intensity and frequency of the haze, with consequences for the region’s aesthetic value and tourism industry. In summary, while VOC emissions and photochemical reactions initiate the haze, high humidity serves as an amplifying factor, contributing to the distinctive atmospheric phenomenon and reinforcing the connection.
8. Elevation Influence
Elevation plays a multifaceted role in shaping the atmospheric conditions that lead to the characteristic haze, thereby influencing the reasons it is called the Smoky Mountains. Higher altitudes affect temperature, humidity, and vegetation patterns, all of which contribute to the formation and persistence of the bluish haze that defines the region’s visual identity.
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Temperature Gradients and Stability
Temperature typically decreases with increasing elevation, creating temperature gradients that can influence atmospheric stability. Stable atmospheric conditions, characterized by warmer air aloft and cooler air near the surface, inhibit vertical mixing. This trapping of air near the surface concentrates volatile organic compounds (VOCs) emitted by vegetation, promoting the formation of secondary organic aerosols (SOAs) responsible for the haze. For example, mountain valleys often experience temperature inversions, enhancing the accumulation of pollutants and intensifying the haze. Higher elevations themselves can also promote cloud formation, which participates in the aerosol-creation process.
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Orographic Lift and Cloud Formation
As air masses are forced to rise over mountainous terrain (orographic lift), they cool and condense, leading to cloud formation. Clouds can act as reaction vessels for the formation of SOAs. Water droplets within clouds absorb VOCs and promote chemical reactions that transform them into particulate matter. Moreover, clouds can enhance the scattering of light, contributing to the overall opacity of the atmosphere. The mountain range’s elevation promotes orographic lift, increasing cloud formation and enhancing the haze. The process is essential to why it is called the smoky mountains.
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Vegetation Distribution and VOC Emissions
Elevation influences the distribution of vegetation types. Different plant species emit different amounts and types of VOCs. Higher elevations may support coniferous forests, while lower elevations may be dominated by deciduous trees. The mix of vegetation types affects the overall VOC emissions profile and, consequently, the composition of the haze. The region, with its diverse elevational gradients, supports a wide range of vegetation, leading to complex VOC emissions patterns and a unique atmospheric signature. The elevation differences thus influence the specific chemical compounds responsible for the appearance. This variation contributes to the complexity of aerosol formation.
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Precipitation Patterns and Air Scavenging
Elevation affects precipitation patterns. Higher elevations typically receive more precipitation than lower elevations. Precipitation can remove aerosols from the atmosphere through wet deposition, reducing haze intensity. However, precipitation can also influence VOC emissions by affecting vegetation growth and stress levels. The balance between aerosol removal and VOC emissions determines the overall impact of precipitation on haze formation. This is why seasonal variations in precipitation levels can significantly impact visual quality.
In conclusion, the name is intricately linked to the area’s topography, because it is a contributor to how light and aerosol interact. Understanding the multifaceted role of elevation in shaping temperature gradients, cloud formation, vegetation distribution, and precipitation patterns is crucial for comprehending the origin of the designation. Recognizing these factors allows for a more comprehensive appreciation of the natural processes that define the visual identity of the area and informs environmental management efforts aimed at preserving its unique atmospheric characteristics.
Frequently Asked Questions
The following addresses common inquiries regarding the origin and scientific basis behind the name applied to this prominent Appalachian range.
Question 1: What is the primary reason the mountain range is called by its popular designation?
The designation stems from the pervasive bluish haze that frequently shrouds the peaks and valleys. This haze creates a visual effect reminiscent of smoke, providing the basis for the mountains’ recognized name.
Question 2: What causes the characteristic bluish haze?
The haze is primarily attributed to volatile organic compounds (VOCs) released by vegetation. These compounds react with sunlight to form aerosols, which scatter light, resulting in the observed bluish hue.
Question 3: What role does isoprene play in the formation of the haze?
Isoprene, a VOC emitted by many tree species, is a key precursor to the secondary organic aerosols (SOAs) that scatter light. Its abundance in the region contributes significantly to the haze.
Question 4: How does sunlight contribute to the atmospheric effect?
Sunlight acts as a catalyst, driving photochemical reactions that transform VOCs into SOAs. Without sunlight, the conversion of gaseous VOCs to light-scattering particles would be significantly reduced.
Question 5: How does humidity influence the appearance of the mountains?
High humidity increases the concentration of aerosols in the air, intensifying the light-scattering effect. It also facilitates the condensation of water vapor onto aerosols, further increasing their size and scattering efficiency.
Question 6: Does elevation have any bearing on why the mountain range is called by its widely known name?
Elevation influences temperature gradients, cloud formation, and vegetation patterns, all of which affect the production and distribution of VOCs and aerosols. Mountainous terrain also promotes orographic lift, which can lead to increased cloud formation and haze intensity. These factors, influenced by elevation, contribute to the visual phenomena associated with the region.
In summary, the mountains are recognized because of the pervasive bluish haze. A complex interplay of biological, atmospheric, and geographical factors influences its formation. This distinctive characteristic shaped the mountains identity.
The next section will explore the environmental and conservation efforts undertaken to preserve the unique qualities of this natural wonder.
Insights Regarding the Mountain Range Name
The following provides informative guidance for researchers, environmental scientists, and interested parties seeking a deeper understanding of the natural processes associated with the atmospheric phenomenon that gives the mountain region its distinctive moniker.
Tip 1: Analyze Vegetation Composition: Thoroughly investigate the dominant plant species within the region, as different species emit varying quantities and types of volatile organic compounds (VOCs). Quantify the emission rates of isoprene and other key VOCs from these species to establish a comprehensive emissions inventory.
Tip 2: Model Photochemical Reactions: Construct detailed photochemical models to simulate the transformation of VOCs into secondary organic aerosols (SOAs). These models should account for factors such as solar radiation intensity, temperature, humidity, and the presence of atmospheric oxidants like ozone and hydroxyl radicals.
Tip 3: Characterize Aerosol Properties: Conduct comprehensive measurements of aerosol size distribution, chemical composition, and optical properties. This includes determining the refractive index of aerosols and their ability to scatter light at different wavelengths.
Tip 4: Monitor Atmospheric Conditions: Continuously monitor meteorological parameters such as temperature, humidity, wind speed, and atmospheric stability. Correlate these data with VOC emissions, aerosol concentrations, and visibility measurements to assess the influence of atmospheric conditions on haze formation.
Tip 5: Evaluate the Impact of Human Activities: Assess the influence of human activities on VOC emissions and air quality in the region. This includes evaluating the contribution of vehicle emissions, industrial sources, and agricultural practices to the overall haze. Consider implementing mitigation strategies to reduce anthropogenic emissions.
Tip 6: Examine Historical Data: Analyze historical records of visibility, temperature, and precipitation to identify long-term trends and potential impacts of climate change on haze formation. The comparison can yield valuable information. Examine tree ring data to assess the past productivity of isoprene emissions.
Tip 7: Consider Regional Air Transport: Evaluate the contribution of long-range transport of pollutants to the region’s air quality. Assess how emissions from distant sources may affect the local formation. Employ back trajectory analysis to identify major source regions contributing to the mountain range haze.
Understanding the connection between vegetation, atmospheric processes, and human activities is crucial for preserving the mountain region’s aesthetic qualities and protecting its environment. Effective resource management requires sustained research, careful monitoring, and informed decision-making.
The subsequent section will offer concluding remarks, synthesizing the key findings and highlighting the long-term implications for the conservation of this natural wonder.
Why is it called the Smoky Mountains
The exploration reveals that the name is directly linked to a complex interplay of environmental factors. The characteristic bluish haze, observed consistently throughout the region, originates from volatile organic compounds (VOCs) released by vegetation. These VOCs undergo photochemical reactions in the atmosphere, forming secondary organic aerosols (SOAs) that scatter light, resulting in the distinctive visual effect. The process is influenced by elevation, humidity, and atmospheric stability, all of which contribute to the mountains name.
Sustained efforts are required to preserve the natural processes responsible for the atmospheric phenomenon, safeguarding the mountains’ identity for future generations. Continued research, responsible environmental management, and heightened awareness are essential to mitigate potential impacts from human activities and climate change. Protecting the range’s air quality ensures the enduring legacy of the mountains’ descriptive name.
