Sources and Characteristics of Summertime Organic Aerosol in the Colorado Front Range: Perspective from Measurements and WRF-Chem Modeling

Abstract

2O&G sector using the top-down approach, it was estimated that the O&G sector contributed to <5% of total OA, but up to 38% of anthropogenic SOA in the region. The best agreement between the measured and simulated median OA was achieved by limiting the extent of biogenic hydrocarbon aging and consequently biogenic SOA (bSOA) production. Despite a lower production of bSOA in this scenario, contribution of bSOA to total SOA remained high at 40-54%. Future studies aiming at a better emissions characterization of POA and intermediate volatility organic

Urban Oxidation Flow Reactor Measurements Reveal Significant Secondary Organic Aerosol Contributions from Volatile Emissions of Emerging Importance

“…5,54 We estimated HOA concentrations of 0.8, 0.3, and 0.1 μg m −3 in the street canyon, morning-time low-rise, and afternoon-time low-rise urban environments, respectively. These values are consistent with those reported previously for high-and low-source urban environments in the U.S. 21,22,55,56 OA and precursor levels were much higher (90 μg m −3 OA, 60 μg m −3 precursors) at the industrial site, because we sampled directly downwind of the Clairton coke works plant during a strong meteorological inversion, which can trap the pollutants near ground level. 57−60 These gas-and particle-phase measurements are consistent with previous fenceline measurements performed downwind of this industrial facility.…”

Air Quality in the Northern Colorado Front Range Metro Area: The Front Range Air Pollution and Photochemistry Éxperiment (FRAPPÉ)

“…The long‐range transport of wildfire emissions also impacted the Colorado Front Range for 1–2 days during, and this event was characterized by elevated concentrations of organic aerosol and of potassium. Bahreini et al () measured and simulated the distribution of organic aerosol (OA) during FRAPPÉ and found larger enhancements of oxygenated OA in air masses with large contributions of O&NG emissions, compared to air masses dominated by urban emissions, but modeling the observed OA distributions proved difficult.…”

“…Many of the forecast products have been evaluated and have been and remain an essential piece of information in post‐campaign analysis (e.g., Battye et al, ; Pfister et al, ; Sullivan et al, ; Sullivan et al, ; Vu et al, ). Additional model simulations have also been conducted after the campaign in support of the analysis of observations (e.g., Abdi‐Oskouei et al, ; Bahreini et al, ; Kaser et al, ; Kille et al, ; Pfister & Flocke, ).…”

Vertical Transport, Entrainment, and Scavenging Processes Affecting Trace Gases in a Modeled and Observed SEAC4RS Case Study

“…Many of those studies suggest that the model‐measurement discrepancies and differences among emission inventories approach a factor of two or more. To represent anthropogenic emissions during weekdays and weekend, the simulation uses the National Emission Inventory (NEI—2011), version 2 which correct VOC speciation profiles for oil and gas sources (Bahreini et al, 2018; McDonald et al, 2018). A Sunday emission inventory was used to represent the Monday of 2 September, which was the U.S. Labor Day holiday.…”