Long-term variability and source signature of gases emitted from oil & natural gas and cattle feedlot operations in the Colorado front range

Multiple tropospheric gases are analyzed in ten years of observations (2010–2019) using a high-resolution ground-based solar absorption Fourier Transform InfraRed (FTIR) instrument the Colorado Northern Front Range (CNFR). The first year measurements 2010 coincides with start remarkable increase oil and natural (O&NG) extraction region. We show seasonal variations trends atmospheric related to O&NG (C2H6), cattle feedlot activities (NH3), urban emissions (CO, C2H2), biomass burning (HCN), volatile organic compounds photochemistry ozone production (H2CO, HCOOH). long-term time series C2H6 shows clear episodic peak-enhancements local that contribute positive trend 0.9 ± 0.3% ?yr?1. NH3 also enhancements has greatest rate change for studied here (2.7 0.7% ?yr?1). Simulations all presented Community Atmosphere Model chemistry (CAM-chem) within Earth System (CESM) framework. Modeled compared different combinations global order determine best combination CNFR. For most gases, emissions, annual obtained CAM-chem agrees FTIR observations, except NH3, which is underestimated by factor 6. Nevertheless, simulations due decrease its removal via reaction H2SO4 from reduction coal power plant emissions. generally well represented model, although magnitudes often underestimated. anthropogenic CO, C2H2, about 20%, 40%, 65%, respectively, independent emission inventories. While summer values significantly, other months low relative mean difference between simulations. Excellent agreement found H2CO, but HCOOH 2–3 needed match pointing significant missing source. HCN, tracer reproduced NCAR Fire Inventory (FINN). Furthermore, we simple approach identify nearby concentrated animal feeding operations. These above ambient levels used estimate ratios (ER) C2H6, CO air masses. A median ER (and standard deviation) 0.48 0.41, 0.26 0.15, 0.13 0.09 [ppb/ppb] estimated HCOOH, respectively representative observations. can be factors (EF), need well-known. To complement results derived airborne during Air Pollution Photochemical Experiment (FRAPPE) 2014. Even though FRAPPE not easily they both yield similar ER. Finally, plumes fires originated western United States August 2015 were identified EF estimated.