Determining the Impact of CDOT Roadway Construction Projects on Air Quality

Details

• Creators:
  Coffey, Evan ; Cortez, Gabriela ; Schmidt, Madelyn ; Amaro, Carlos Rodriguez ; Hannigan, Michael P. ; Techera, Ulises D.
• Corporate Creators:
  University of Colorado Boulder
• Corporate Contributors:
  Colorado Department of Transportation. Office of Applied Research ; United States. Department of Transportation. Federal Highway Administration
• Subject/TRT Terms:
  Air Pollution Sources Air Quality Management Construction Data Collection Earthwork Environmental Impacts Environmental Monitoring Hot Mix Asphalt Pollution Control Road Construction Rural Areas Traffic

  More +
• Publication/ Report Number:
  CDOT-2025-10
• Resource Type:
  Tech Report
• Geographical Coverage:
  United States
• Edition:
  Final Report
• Corporate Publisher:
  Colorado. Department of Transportation
• Abstract:
  Elevated concentrations of air pollutants can have serious impacts on human health, the environment, and Colorado’s ecosystems. The Colorado Department of Transportation (CDOT) has prioritized protecting air quality in accordance with the Colorado Air Pollution Prevention and Control Act (Section 25-7-101 et seq., C.R.S., 2017). This research quantified exposure to air pollutants as a function of construction activity type, distance from the project site, traffic, and weather conditions. A methodology was developed to monitor pollutant concentrations using low-cost, multi-sensor air quality systems (“Pods”) strategically positioned along and near CDOT construction sites. Traffic, construction activities, and environmental variables were monitored to identify major pollution sources and the factors influencing dispersion and concentration. The protocol was first implemented as a pilot on a rural highway and later applied to an urban project (CDOT US 6 Clifton Improvements) and a rural project (Passing Lane project on US 40 near Kremmling, CO). Data collected between August 2023 and November 2024 produced an unprecedented, high-quality dataset. The modeling framework—incorporating dynamic background subtraction, Generalized Linear Mixed Models (GLMM), pruned decision trees, and random forests—proved effective in explaining observed concentrations, predicting pollutant levels, and identifying key variables driving them at each site. Asphalt Milling increased PM₁₀, coarse PM, PM₂.₅, and total volatile organic compounds ((t)VOCs); Earthwork elevated NO, NOₓ, PM₁₀, coarse PM, and PM₂.₅; and Hot Mix Asphalt (HMA) paving increased CO, NO, NOₓ, (t)VOCs, PM₁₀, coarse PM, and PM₂.₅. Concrete saw-cutting, sidewalk and shoulder work, and striping activities also enhanced several pollutants, particularly PM₂.₅, CO, and NOₓ. Across all activities, pollutant enhancements were primarily influenced by environmental variables and traffic volumes. Future research in this area is both necessary and promising. This study has established a foundation for collecting, analyzing, and reporting data to better understand how road construction activities influence local air quality. The next steps involve validating the methodology and modeling framework developed here to reliably predict construction-related air quality impacts, and subsequently applying the validated model to evaluate potential mitigation strategies. Advancing these efforts would position CDOT at the forefront of managing air pollution during construction and maintenance activities.
• Format:
  PDF
• Funding:
  R123.04
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:617fb9622cc7b8610b036636a883d82c0a2f4a3eb82a3ec12c6ad656a176d8bf2b32cca6ef32072105edde433bf4fa5a24db1f07a0ecf5bdf8d479f2375e4dad
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/88887/dot_88887_DS1.pdf
• File Type:
  [PDF - 9.75 MB ]