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Ground‐level ozone (O3) was unusually high in northern Colorado in the summer of 2021 with maximum daily 8‐hr average (MDA8) concentrations 6 to 8 parts‐per‐billion by volume (ppbv) higher than in 2019, 2020, or 2022. One or more of the monitors on the Colorado Front Range exceeded the 2015 U.S. National Ambient Air Quality Standard (NAAQS) of 70 ppbv on 66 of the 122 days from 1 June to 30 September, and this record number of exceedances coincided with the near daily presence of dispersed smoke haze from wildfires in Arizona, California, and the Pacific Northwest. In this paper, we use regulatory and non‐regulatory surface O3 and PM2.5 measurements in conjunction with ground‐based lidar observations to estimate how much O3 was associated with the wildfire smoke. Analyses of the surface measurements suggest that pyrogenic O3 transported to northern Colorado with the smoke increased the surface concentrations in northern Colorado by an average of 8 ppbv in July, 3 ppbv in August, and 2 ppbv in September. Analysis of the lidar measurements showed these contributions to be as large as 12 ppbv on some days. Production of O3 from reactions of pyrogenic VOCs and locally emitted NOx appears to have been minimal (<3 ppbv) in the Boulder area, but may have been much larger in the suburbs southwest of downtown Denver. Plain Language Summary: Northern Colorado experienced unusually poor air quality in the summer of 2021 with frequent high ozone (O3) episodes and hazy skies caused by smoke from wildfires in Arizona, California, and the Pacific Northwest. In this study, we use surface and lidar measurements to explore the connection between the two. Our analysis suggests that the unusually high O3 was caused primarily by a combination of O3 transported to Colorado with the wildfire smoke and enhancement of local photochemical production by unusually clear skies and warm temperatures coupled with weak winds that led to localized O3 accumulations and fewer than normal thunderstorms that might otherwise have dispersed the O3. Production of O3 by reactions of locally emitted NOx with VOCs in the wildfire smoke may also have been significant in Southwest Denver. Key Points: The impacts of the 2021 western wildfires on ozone in the Denver metropolitan area and rural northern Colorado in 2021 are examinedOzone transported in the smoke from distant wildfires increased the 8‐hr concentrations in northern Colorado by an average of 8 ppbv in JulyUnusual meteorology, including fewer thunderstorms, allowed ozone produced locally to accumulate along the foothills west of Denver [ABSTRACT FROM AUTHOR]

Greenhouse gas (GHG) accounting for individual cities in large metropolitan areas is confounded by spatial scale and boundary effects that impact the allocation of transportation fuels used for surface transport and airline travel. This paper expands on a demand-based methodology to spatially allocate transportation fuel use (surface and airline) among colocated cities in the United States that are part of a larger metropolitan area commutershed on the basis of demand for surface vehicle miles traveled (VMT) exerted by individual cities. By using travel demand models for metropolitan planning organizations, the demand method was first applied as part of the city of Denver's GHG inventory in 2005 to develop a material flow analysis (MFA) of gasoline, diesel, and jet fuel consumption at the city scale. This paper reports on the application of the same method to six major metropolitan regions across the United States and a detailed analysis of all 27 cities within the larger Denver metro region. The analysis of six metropolitan areas in the United States demonstrated (1) the demand method produces VMT estimates allocated to cities across the commutershed that are similar (within 6%) to the boundary-limited polygon approach (linear correlation coefficient R2=0.82; slope m=0.98); (2) airline travel allocation by vehicular trip count ratios to the regional airport from colocated cities produces results similar to regional airline travel allocation by population ratios (linear correlation coefficient R2=0.96; slope m=0.99); and (3) the method is replicable with necessary data available from all cities in this study through their corresponding metropolitan planning organizations. In addition, the demand-VMT allocation method is found to be more responsive to future simulated mass transit growth. Further, the method is sensitive to local travel demand features of the individual cities, of which employment intensity was found to have the largest impact on per capita VMT allocated to a city. Within the Denver commutershed, daily VMT per capita estimates ranged from 13-129 km/capita/day (8-80 mi/capita/day) among the 27 communities, with a strong positive correlation with employment intensity (employment/capita; R2=0.97) and employment density (employment/kilometer; R2=0.59). [ABSTRACT FROM AUTHOR]

Field sampling was performed at a number of residential structures in the Denver metropolitan area for the purpose of assessing the extent of wetting below residential structures after construction and commencement of landscape irrigation. Total suction measurements using filter paper methods were undertaken on undisturbed samples. A similar data set from sites without previous development or irrigation was used to estimate the suction profile before the imposition of residential construction and landscape irrigation. Comparison of the postdevelopment profile measured at the residential structures to the predevelopment profile estimated using a site-specific procedure was used to assess the depth of wetting at each structure. Cumulative probability curves are presented for the depth of wetting arising from common residential landscape schemes and site drainage for the Denver area. The Denver-area data set was used to develop a method for assessment of depth of wetting. This method can be used to assess depth of wetting from residential development for other regions having different climatic conditions and landscape practices. [ABSTRACT FROM AUTHOR]

The rise of the city-region concept has focused attention on the nature of territorial politics underpinning city-regionalism. This paper investigates the relationship between territorial politics, city-regionalism and the collective provision of mass transport infrastructure in the USA. It deploys a case study of the Denver region, examining the state and governance structures driving forward FasTracks, a long-term project to expand the Denver Regional Transportation District’s light and commuter rail system. FasTracks represents a programme to retrofit the Denver city-region for integrated mass transit but its funding has fostered tensions around new regionalist governance arrangements. The paper uses the findings of the case study to reflect upon the balance of bottom–up versus top–down geopolitical forces shaping the landscape of city-regionalism in the USA. It emphasises the variety of ways in which struggles around infrastructure provision shape the emergence of new city-regionalist structures inside the competition state. [ABSTRACT FROM PUBLISHER]

Many of the larger US metropolitan regions promote polycentric development as a way of fostering livability, accessibility, and sustainability. Polycentric urban structures can increase transit ridership, promote active transportation, and decrease vehicle miles traveled (VMT) and CO2 emissions. Although many regions include ambitious polycentric aspirations in their plans, only a few follow up with rigorous implementation and see their efforts come to fruition. The topic of implementation is also widely omitted from scholarly inquiry. This research aims to explore three examples of successful implementation of urban polycentricity: Portland, Oregon; Seattle, Washington; and Denver, Colorado. Each region employs a very distinct polycentric development model, but each relies heavily on its regional governance organization for direction, guidance, and even command in the implementation process. To understand specific strategies and methods used by each region, the authors conducted interviews with metropolitan planning organizations, central cities, and transit agencies in the three regions and used qualitative techniques to analyze the interview transcripts and collected documents. As regional governance organizations play a crucial role in implementing regional plans, their policies and practices were also investigated by the authors. Based on collected data and insights, we conclude that the three regions are great examples of an advanced implementation of polycentric development. This research can be helpful to other US metropolitan regions that wish to promote polycentric development. The lessons learned from the three case studies can provide guidance and possible paths to successful implementation. [ABSTRACT FROM AUTHOR]

Increases in nitrogen (N) inputs to the biosphere can exacerbate the introduction and spread of invasive non-native plant species. Often, with elevated soil N levels, invasive plants establish and further enrich soil N pools, changing overall ecosystem function. This study examined the relationship between soil N cycling and an increasingly prevalent, invasive plant species, tall oatgrass (Arrhenatherum elatius subsp. elatius), in foothills ecosystems between the Colorado Rocky Mountains and the Denver-Boulder Metropolitan area—similar to many Western US grasslands and woodlands. It focused on investigating differences in soil N transformations, inorganic N pools, and vegetation characteristics across invaded and uninvaded plots at three sites in two seasons (summer and autumn). There was a statistically significant effect of invasion on rates of net N mineralization, but it was dependent on site and season (p = 0.046). Site had a statistically significant effect on soil moisture and aboveground biomass C:N (p < 0.04). The interactions of invasion x site were statistically significant for ammonium pools (p < 0.03). These findings suggest that A. elatius invasion can be associated with accelerated N cycling, but that the nature of the relationship differs by location and season in the foothills. More broadly, this study contributes to determining how the N cycle is shifting in grassland ecosystems subject to increasing pressures from anthropogenic change. [ABSTRACT FROM AUTHOR]

This paper examines geographic patterns of firm relocation in the Denver metropolitan area and factors responsible for the decision to move. A sample of 106 manufacturing, commercial, and service enterprises that relocated between 1974 and 1976 are analyzed. Major relationships between selected business operational characteristics, distance moved, and reasons for relocation are discussed. A comparative analysis of firms is undertaken to examine significant differences in relocation and new site selection factors by origin-destination, type of industry, and type of operation. Firm growth is identified as the primary stimulus for relocations and as an important force limiting spatial searches for alternative locations. Market centrality, site economics, and agglomeration economies are shown to be major constraints governing the selection of new sites. Several major issues associated with governmental policy influences upon firm relocations are considered briefly within the context of the empirical results. [ABSTRACT FROM AUTHOR]

The growing and continued popularity of light rail transit systems in major United States metropolitan areas is leading to growing research on land use impacts, value generation, and contributions to gentrification. While various studies explore the fiscal and environmental influences of light rail transit development in the Denver Metropolitan Area, only recently have scholars turned their attention to gentrification and social influences. This paper analyzes how one station shapes residents' sense of place, providing more nuanced understandings of the role light rail and transit-oriented development affects perceptions of neighborhood character and place attachment. We argue that gentrification can be measured and understood not only quantitatively, but also by how people feel light rail influences their attachment to place. Residents within half a mile of the Evans Light Rail Station were randomly and anonymously surveyed with a series of demographic questions and asked to provide their experiences, observations, and opinions. With 166 household responses, we examine residents' perceptions of Evans Station and sense of place to investigate relationships between factors such as race, age, income, education, length of residency, and walking distance from the light rail station. Analysis of their responses creates a more nuanced understanding of the ways that light rail contributes to positive, neutral, and negative emotions associated with gentrification ranging from appreciation of increased accessibility, younger residents, increased property values, and new commercial development to complaints about increased density, higher rents, traffic, noise, and loss of community. [ABSTRACT FROM AUTHOR]

This article empirically examines the segmentation of house price risk across 99 ZIP-code-delineated neighborhoods in metropolitan Denver. The house price risk in each neighborhood is measured with the temporal variation of quarterly appreciation rates of the neighborhood house price index over the 2002-2007 period. Cross-sectional regressions of neighborhood house price risk on the median household income and the percentage of population in poverty from the 2000 census data for the same neighborhoods provide strong evidence that the house price risk is significantly higher in low-income/poor neighborhoods. Subperiod analyses further indicate that the risk segmentation exists in both a booming period (pre 2005:2) and a busting period (post 2005:3). The results indicate that homeownership can be a much riskier investment for low-income/poor households. [ABSTRACT FROM AUTHOR]

Discusses the results of a case study on equity and accountability In Colorado's Denver Metropolitan Area, a local government funded by the National Academy of Public Administration. Background on equity in the Denver urban area; Per capita county revenue; Accountability and responsiveness; Factors affecting efforts to achieve equity and accountability.

The purpose of the study was to assess the economic impact of the Denver Broncos Football Club on the Denver Metropolitan Area economy. Primary data required to determine the economic impact was collected from three main sources. First, a two page survey questionnaire was mailed to 9,519 randomly selected season ticket holders with 4,810 returned questionnaires. The City and County of Denver provided financial management information reports for all home games as the second source of primary data. Finally, the Denver Broncos administration provided financial information pertaining to operational expenditures. The total industrial output or economic impact was calculated at &dollar;117,801,500 for the economic activity associated with the Denver Broncos Football Club for the 1989-1990 season. Direct economic impact was shown to be &dollar;64,282,200 and indirect and induced effects corresponding to the multipliers generated by the model was an additional &dollar;53,519,300. Employee compensation was &dollar;47,213,300 and property income provided &dollar;16,732,000 to the Denver metropolitan economy. Indirect business taxes totaling &dollar;7,118,300 went to local, county, state and federal government. The economic activity produced 1,828 jobs directly and indirectly resulting from Broncos activity in the metropolitan area. [ABSTRACT FROM AUTHOR]

Geographers can provide information that is important to the establishment and revision of air quality standards. A spatial approach to the description of air quality can pinpoint segments of the population that are disproportionately exposed to potential health hazards. Temporal trends in the spatial distribution of given levels of pollutant concentration may not be the same as those determined from one monitoring site or from station-averaged data. These points are demonstrated for the Total Suspended Particulate pollutant in the Denver metropolitan area for the years 1977 through 1981. The reported findings have major implications for the contentious processes of establishing and revising air quality standards. [ABSTRACT FROM AUTHOR]