The Clark County Department of Air Quality and Environmental Management (DAQEM) manages air quality monitoring stations and develops implementation plans to achieve air quality standards compliance within the county. Compliance requires that air quality levels for monitored pollutants do not exceed the National Ambient Air Quality Standards published by the Environmental Protection Agency (EPA) within delineated airsheds (Appendix C, National Ambient Air Quality Standards).

Walking Box Ranch is not located in a non-attainment boundary and falls directly to the south of the Eldorado Valley hydrographic basin #167, which stretches from Boulder City to Searchlight. The closest air quality monitoring site is located northwest of Walking Box Ranch in Jean, Nevada. The Jean monitoring station was primarily established by Clark County to monitor transport pollution from southern California, ozone, and particulate matter, but is also used to establish general background concentration levels (Clark County 2009). The Jean monitoring station has reported yearly fourth highest 8-hour average concentration ozone trend levels above the current EPA 8-hour standard (75 ppb) for every year between 1998 and 2007 (Clark County 2009). The Jean station has also reported one of the lowest annual mean particulate matter readings in Continuous PM₁₀ Trends, the lowest readings in Filter-Based PM_2.5 FRM Trends between 1999 and 2008, and one of the lowest readings for Continuous PM_2.5 Annual Mean Trends for 2008 (Clark County 2009). The next closest monitoring station in Boulder City has reported yearly fourth highest 8-hour average concentration ozone trend levels above the current EPA 8-hour standard for 5 years, non-continuously, between 1998 and 2008 (Clark County 2009).

A non-attainment area designation indicates that a defined region, such as a hydrographic basin, has exceeded safe levels for one or more criteria pollutants as set forth by the National Ambient Air Quality Standards (NAAQS) that contribute to poor air quality, and which may affect human health and the environment. The Eldorado Valley airshed is in attainment for air quality, unlike the Las Vegas Valley airshed directly to the north. As of 2008 in Clark County, all monitored pollutants with an EPA -designated 8-hour standard have been recorded at all monitoring stations in the county as below the standard, with the exception of ozone. The levels of most pollutants have remained constant. There have been no recorded exceedances of carbon monoxide (CO) in the last 10 years, so Clark County has sought redesignation to maintenance status with the EPA .

Ground-level ozone ( O₃ ) is a toxic gas, which is naturally found as a component of ambient air that reaches hazardous levels due to human activities. O₃ levels are monitored as an average concentration over an 8-hour period. Unlike other pollutants, O₃ is not produced by any specific source; rather it is formed in the air through reactions between other airborne man-made chemicals in the presence of sunlight. Sources of contributing chemical components primarily stem from gasoline vapors, but also include other fuel and solvent vapors and consumer products. Emissions from these sources can be carried over hundreds of miles, forming high ground-level O₃ concentrations over very large areas and in locations other than the source areas. Weather and temperature affects the production of O₃ ; warm, sunny days increase the levels of O₃ . In Clark County, ground-level ozone is predicted to be at moderate levels throughout the warmer months (May-Sept.), particularly within the Las Vegas Valley north of Walking Box Ranch, with occasionally higher, unhealthy levels occurring in the afternoons when breezy conditions do not exist to move the air.

Coarse or fine particulate matter as a pollutant can be any type of material substance suspended in air, either liquid or solid. Particulate pollutant levels are monitored as the total weight of matter collected over a 24-hour period, every sixth day. Particles are typically classified into two size categories: coarse particles smaller than 10 microns in size ( PM₁₀ ), and fine particles smaller than 2.5 microns in size ( PM_2.5 ). Coarse particle emissions typically occur from processes such as travel over paved or unpaved roads, dust blown from open desert or vacant lands, rock and gravel mining, or processing or construction activities (Clark County 2007). Weather activity can contribute to higher levels of suspended particulate matter, such as high winds over lands naturally or artificially cleared of vegetation or desert soils which have been disturbed and have a loose surface or broken soil crusts (Clark County 2007). Fine particle sources include liquids and solids from all types of fuel combustion, and pollutants that are formed in the air from interactions between airborne chemicals and compounds. The majority of monitored fine particulates monitored in the county consist of sulfates, organic and elemental carbon, carbonaceous compounds such as CO, and low levels of nitrates (DRI 2002).

Current uses of Walking Box Ranch include field studies, caretaker occupation, and state police accommodations/stationing. The primary contributor to air quality issues is the use of vehicles to access the ranch from the main highway north of the study area. Road access and the area around the ranch buildings consist of packed dirt, which is blown up as vehicles travel over it. Current vehicular uses at Walking Box Ranch may contribute moderate amounts to the coarse particulate matter in the immediate area of the ranch as well as minor amounts of fine particulates, and may be carried off site depending on weather patterns. Additional air quality contaminants can come from air conditioning units used by the caretaker and officers, and are dependent on the types of equipment in use.