Articles | Volume 16, issue 18
Atmos. Chem. Phys., 16, 12329–12345, 2016
Atmos. Chem. Phys., 16, 12329–12345, 2016

Research article 29 Sep 2016

Research article | 29 Sep 2016

Colorado air quality impacted by long-range-transported aerosol: a set of case studies during the 2015 Pacific Northwest fires

Jessie M. Creamean1,2, Paul J. Neiman2, Timothy Coleman1,2, Christoph J. Senff1,3, Guillaume Kirgis1,3, Raul J. Alvarez3, and Atsushi Yamamoto4 Jessie M. Creamean et al.
  • 1University of Colorado at Boulder, Cooperative Institute for Research in Environmental Sciences, Boulder, CO 80309, USA
  • 2NOAA Earth System Research Laboratory, Physical Sciences Division, Boulder, CO 80305, USA
  • 3NOAA Earth System Research Laboratory, Chemical Sciences Division, Boulder, CO 80305, USA
  • 4HORIBA Instruments Inc., Process and Environmental, Irvine, CA 92618, USA

Abstract. Biomass burning plumes containing aerosols from forest fires can be transported long distances, which can ultimately impact climate and air quality in regions far from the source. Interestingly, these fires can inject aerosols other than smoke into the atmosphere, which very few studies have evidenced. Here, we demonstrate a set of case studies of long-range transport of mineral dust aerosols in addition to smoke from numerous fires (including predominantly forest fires and a few grass/shrub fires) in the Pacific Northwest to Colorado, US. These aerosols were detected in Boulder, Colorado, along the Front Range using beta-ray attenuation and energy-dispersive X-ray fluorescence spectroscopy, and corroborated with satellite-borne lidar observations of smoke and dust. Further, we examined the transport pathways of these aerosols using air mass trajectory analysis and regional- and synoptic-scale meteorological dynamics. Three separate events with poor air quality and increased mass concentrations of metals from biomass burning (S and K) and minerals (Al, Si, Ca, Fe, and Ti) occurred due to the introduction of smoke and dust from regional- and synoptic-scale winds. Cleaner time periods with good air quality and lesser concentrations of biomass burning and mineral metals between the haze events were due to the advection of smoke and dust away from the region. Dust and smoke present in biomass burning haze can have diverse impacts on visibility, health, cloud formation, and surface radiation. Thus, it is important to understand how aerosol populations can be influenced by long-range-transported aerosols, particularly those emitted from large source contributors such as wildfires.

Short summary
Aerosol particles that originate from wildfires can have a large impact on climate by affecting air quality, clouds, precipitation, and Earth's energy budget. We show how fires in the Pacific Northwest ejected mineral dust and smoke high into the troposphere, where they were transported to Colorado, affecting air quality in the Denver metro area. We also demonstrate how specific meteorological conditions were necessary to introduce and additionally clear out the dust and smoke aerosols.
Final-revised paper