scholarly journals Air quality simulations of wildfires in the Pacific Northwest evaluated with surface and satellite observations during the summers of 2007 and 2008

2014 ◽  
Vol 14 (8) ◽  
pp. 11103-11152
Author(s):  
F. L. Herron-Thorpe ◽  
G. H. Mount ◽  
L. K. Emmons ◽  
B. K. Lamb ◽  
D. A. Jaffe ◽  
...  

Abstract. Evaluation of a regional air quality forecasting system for the Pacific Northwest was carried out for the 2007 and 2008 fire seasons using suite of surface and satellite observations. Wildfire events in the Pacific Northwest during the summers of 2007 and 2008 were simulated using the Air Information Report for Public Access and Community Tracking v.3 (AIRPACT-3) framework utilizing the Community Multi-scale Air Quality (CMAQ) model. Fire emissions were simulated using the BlueSky framework with fire locations determined by the Satellite Mapping Automated Reanalysis Tool for Fire Incident Reconciliation (SMARTFIRE). Plume rise was simulated using two different methods: the Fire Emission Production Simulator (FEPS) and the Sparse Matrix Operator Kernel Emissions (SMOKE) model. Predicted plume top heights were compared to the Cloud-Aerosol LIDAR with Orthogonal Polarization (CALIOP) instrument aboard the Cloud Aerosol LIDAR and Infrared Pathfinder Satellite Observation (CALIPSO) satellite. Carbon monoxide predictions were compared to the Atmospheric InfraRed Sounder (AIRS) instrument aboard the Aqua satellite. Horizontal distributions of column aerosol optical depth (AOD) were compared to retrievals by the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument aboard the Aqua satellite. Model tropospheric nitrogen dioxide distributions were compared to retrievals from the Ozone Monitoring Instrument (OMI) aboard the Aura satellite. Surface ozone and PM2.5 predictions were compared to surface observations. The AIRPACT-3 model captured the location and transport direction of fire events well, but sometimes missed the timing of fire events and overall underestimated the impact of wildfire events at regional surface monitor locations. During the 2007 fire period the fractional biases of AIRPACT-3 for average 24 h PM2.5, maximum daily average 8 h Ozone, AOD, total column CO, and tropospheric column NO2 were found to be −33%, −8%, −61%, −10%, and −39%, respectively; while during the 2008 fire period the fractional biases were −27%, +1%, −53%, −5%, and −28%, respectively. Fractional biases of AIRPACT-3 plume tops were found to be −46% above mean sea level (a.m.s.l.), but only −28% above ground level (a.g.l.), partly due to the under-estimation of AIRPACT-3 elevation in complex terrain that results from the 12 km grid-cell smoothing.

2014 ◽  
Vol 14 (22) ◽  
pp. 12533-12551 ◽  
Author(s):  
F. L. Herron-Thorpe ◽  
G. H. Mount ◽  
L. K. Emmons ◽  
B. K. Lamb ◽  
D. A. Jaffe ◽  
...  

Abstract. Evaluation of a regional air quality forecasting system for the Pacific Northwest was carried out using a suite of surface and satellite observations. Wildfire events for the 2007 and 2008 fire seasons were simulated using the Air Information Report for Public Access and Community Tracking v.3 (AIRPACT-3) framework utilizing the Community Multi-scale Air Quality (CMAQ) model. Fire emissions were simulated using the BlueSky framework with fire locations determined by the Satellite Mapping Automated Reanalysis Tool for Fire Incident Reconciliation (SMARTFIRE). Plume rise was simulated using two different methods: the Fire Emission Production Simulator (FEPS) and the Sparse Matrix Operator Kernel Emissions (SMOKE) model. Predicted plume top heights were compared to the Cloud-Aerosol LIDAR with Orthogonal Polarization (CALIOP) instrument aboard the Cloud Aerosol LIDAR and Infrared Pathfinder Satellite Observation (CALIPSO) satellite. Carbon monoxide predictions were compared to the Atmospheric InfraRed Sounder (AIRS) instrument aboard the Aqua satellite. Horizontal distributions of column aerosol optical depth (AOD) were compared to retrievals by the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument aboard the Aqua satellite. Model tropospheric nitrogen dioxide distributions were compared to retrievals from the Ozone Monitoring Instrument (OMI) aboard the Aura satellite. Surface ozone and PM2.5 predictions were compared to surface observations. The AIRPACT-3 model captured the location and transport direction of fire events well, but sometimes missed the timing of fire events and overall underestimated the PM2.5 impact of wildfire events at surface monitor locations. During the 2007 (2008) fire period, the fractional biases (FBs) of AIRPACT-3 for various pollutant observations included: average 24 h PM2.5 FB = −33% (−27%); maximum daily average 8 h ozone FB = −8% (+1%); AOD FB = −61% (−53%); total column CO FB = −10% (−5%); and tropospheric column NO2 FB = −39% (−28%). The bias in total column CO is within the range of expected error. Fractional biases of AIRPACT-3 plume tops were found to be −46% when compared in terms of above mean sea level, but only −28% when compared in terms of above ground level, partly due to the under-estimation of AIRPACT-3 ground height in complex terrain that results from the 12 km grid-cell smoothing. We conclude that aerosol predictions were too low for locations greater than ~100–300 km downwind from wildfire sources and that model predictions are likely under-predicting secondary organic aerosol (SOA) production, due to a combination of very low volatile organic compound (VOC) emission factors used in the United States Forest Service Consume model, an incomplete speciation of VOC to SOA precursors in SMOKE, and under-prediction by the SOA parameterization within CMAQ.


2020 ◽  
Vol 237 ◽  
pp. 03012
Author(s):  
Christoph Senff ◽  
Andrew Langford ◽  
Raul Alvarez ◽  
Tim Bonin ◽  
Alan Brewer ◽  
...  

Recently, two air quality campaigns were conducted in the southwestern United States to study the impact of transported ozone, stratospheric intrusions, and fire emissions on ground-level ozone concentrations. The California Baseline Ozone Transport Study (CABOTS) took place in May – August 2016 covering the central California coast and San Joaquin Valley, and the Fires, Asian, and Stratospheric Transport Las Vegas Ozone Study (FAST-LVOS) was conducted in the greater Las Vegas, Nevada area in May – June 2017. During these studies, nearly 1000 hours of ozone and aerosol profile data were collected with the NOAA TOPAZ lidar. A Doppler wind lidar and a radar wind profiler provided continuous observations of atmospheric turbulence, horizontal winds, and mixed layer height. These measurements allowed us to directly observe the degree to which ozone transport layers aloft were entrained into the boundary layer and to quantify the resulting impact on surface ozone levels. Mixed layer heights in the San Joaquin Valley during CABOTS were generally below 1 km above ground level (AGL), while boundary layer heights in Las Vegas during FAST-LVOS routinely exceeded 3 km AGL and occasionally reached up to 4.5 km AGL. Consequently, boundary layer entrainment was more often observed during FAST-LVOS, while most elevated ozone layers passed untapped over the San Joaquin Valley during CABOTS.


2020 ◽  
Vol 12 (6) ◽  
pp. 913 ◽  
Author(s):  
Zhining Tao ◽  
Hao He ◽  
Chao Sun ◽  
Daniel Tong ◽  
Xin-Zhong Liang

A regional modeling system that integrates the state-of-the-art emissions processing (SMOKE), climate (CWRF), and air quality (CMAQ) models has been combined with satellite measurements of fire activities to assess the impact of fire emissions on the contiguous United States (CONUS) air quality during 1997–2016. The system realistically reproduced the spatiotemporal distributions of the observed meteorology and surface air quality, with a slight overestimate of surface ozone (O3) by ~4% and underestimate of surface PM2.5 by ~10%. The system simulation showed that the fire impacts on primary pollutants such as CO were generally confined to the fire source areas but its effects on secondary pollutants like O3 spread more broadly. The fire contribution to air quality varied greatly during 1997-2016 and occasionally accounted for more than 100 ppbv of monthly mean surface CO and over 20 µg m−3 of monthly mean PM2.5 in the Northwest U.S. and Northern California, two regions susceptible to frequent fires. Fire emissions also had implications on air quality compliance. From 1997 to 2016, fire emissions increased surface 8-hour O3 standard exceedances by 10% and 24-hour PM2.5 exceedances by 33% over CONUS.


2021 ◽  
Vol 20 (1-2) ◽  
pp. 632-638
Author(s):  
Stephanie A Bryson

This reflexive essay examines the adoption of an intentional ‘ethic of care’ by social work administrators in a large social work school located in the Pacific Northwest. An ethic of care foregrounds networks of human interdependence that collapse the public/private divide. Moreover, rooted in the political theory of recognition, a care ethic responds to crisis by attending to individuals’ uniqueness and ‘whole particularity.’ Foremost, it rejects indifference. Through the personal recollections of one academic administrator, the impact of rejecting indifference in spring term 2020 is described. The essay concludes by linking the rejection of indifference to the national political landscape.


2013 ◽  
Vol 13 (24) ◽  
pp. 12215-12231 ◽  
Author(s):  
Z. S. Stock ◽  
M. R. Russo ◽  
T. M. Butler ◽  
A. T. Archibald ◽  
M. G. Lawrence ◽  
...  

Abstract. We examine the effects of ozone precursor emissions from megacities on present-day air quality using the global chemistry–climate model UM-UKCA (UK Met Office Unified Model coupled to the UK Chemistry and Aerosols model). The sensitivity of megacity and regional ozone to local emissions, both from within the megacity and from surrounding regions, is important for determining air quality across many scales, which in turn is key for reducing human exposure to high levels of pollutants. We use two methods, perturbation and tagging, to quantify the impact of megacity emissions on global ozone. We also completely redistribute the anthropogenic emissions from megacities, to compare changes in local air quality going from centralised, densely populated megacities to decentralised, lower density urban areas. Focus is placed not only on how changes to megacity emissions affect regional and global NOx and O3, but also on changes to NOy deposition and to local chemical environments which are perturbed by the emission changes. The perturbation and tagging methods show broadly similar megacity impacts on total ozone, with the perturbation method underestimating the contribution partially because it perturbs the background chemical environment. The total redistribution of megacity emissions locally shifts the chemical environment towards more NOx-limited conditions in the megacities, which is more conducive to ozone production, and monthly mean surface ozone is found to increase up to 30% in megacities, depending on latitude and season. However, the displacement of emissions has little effect on the global annual ozone burden (0.12% change). Globally, megacity emissions are shown to contribute ~3% of total NOy deposition. The changes in O3, NOx and NOy deposition described here are useful for quantifying megacity impacts and for understanding the sensitivity of megacity regions to local emissions. The small global effects of the 100% redistribution carried out in this study suggest that the distribution of emissions on the local scale is unlikely to have large implications for chemistry–climate processes on the global scale.


2019 ◽  
Author(s):  
Lang Wang ◽  
Amos P. K. Tai ◽  
Chi-Yung Tam ◽  
Mehliyar Sadiq ◽  
Peng Wang ◽  
...  

Abstract. Surface ozone (O3) is an important air pollutant and greenhouse gas. Land use and land cover (LULC) is one of the critical factors influencing ozone, in addition to anthropogenic emissions and climate. LULC change can on the one hand affect ozone biogeochemically, i.e., via dry deposition and biogenic emissions of volatile organic compounds (VOCs). LULC change can on the other hand alter regional- to large-scale climate through modifying albedo and evapotranspiration, which can lead to changes in surface temperature, hydrometeorology and atmospheric circulation that can ultimately impact ozone biogeophysically over local and remote areas. Such biogeophysical effects of LULC on ozone are largely understudied. This study investigates the individual and combined biogeophysical and biogeochemical effects of LULC on ozone, and explicitly examines the critical pathway for how LULC change impacts ozone pollution. A global coupled atmosphere–chemistry–land model is driven by projected LULC changes from the present day (2000) to future (2050) under RCP4.5 and RCP8.5 scenarios, focusing on the boreal summer. Results reveal that when considering biogeochemical effects only, surface ozone is predicted to have slight changes by up to 2 ppbv maximum in some areas due to LULC changes. It is primarily driven by changes in isoprene emission and dry deposition counteracting each other in shaping ozone. In contrast, when considering the integrated effect of LULC, ozone is more substantially altered by up to 6 ppbv over several regions, reflecting the importance of biogeophysical effects on ozone changes. Furthermore, large areas of these ozone changes are found over the regions without LULC changes where the biogeophysical effect is the only pathway for such changes. The mechanism is likely that LULC change induces a regional circulation response, in particular the formation of anomalous stationary high-pressure systems, shifting of moisture transport, and near-surface warming over the middle-to-high northern latitudes in boreal summer, owing to associated changes in albedo and surface energy budget. Such temperature changes then alter ozone substantially. We conclude that the biogeophysical effect of LULC is an important pathway for the influence of LULC change on ozone air quality over both local and remote regions, even in locations without significant LULC changes. Overlooking the impact of biogeophysical effect may cause evident underestimation of the impacts of LULC change on ozone pollution.


Author(s):  
Ernesto Pino-Cortés ◽  
Samuel Carrasco ◽  
Luis A. Díaz-Robles ◽  
Francisco Cubillos ◽  
Fidel Vallejo ◽  
...  

Wildfires generate large amounts of atmospheric pollutants yearly. The development of an emissions inventory for this activity is a challenge today, mainly to perform modeling of air quality. There are free available databases with historical information about this source. The main goal of this study was to process the results of biomass burning emissions for the year 2014 from the Global Fire Assimilation System (GFAS). The pollutants studied were the black carbon, the organic carbon, fine and coarse particulate matter, respectively. The inputs were pre-formatted to enter to the simulation software of the emission inventory. In this case, the Sparse Matrix Operator Kernel Emissions (SMOKE) was used and the values obtained in various cities were analyzed. As a result, the spatial distribution of the forest fire emissions in the Southern Hemisphere was achieved, with the polar stereographic projection. The highest emissions were located in the African continent, followed by the northern region of Australia. Future air quality modeling at a local level could apply the results and the methodology of this study. The biomass burning emissions could add a better performance of the results and more knowledge on the effect of this source.


2009 ◽  
Vol 9 (12) ◽  
pp. 4115-4129 ◽  
Author(s):  
N. Unger ◽  
S. Menon ◽  
D. M. Koch ◽  
D. T. Shindell

Abstract. The development of effective emissions control policies that are beneficial to both climate and air quality requires a detailed understanding of all the feedbacks in the atmospheric composition and climate system. We perform sensitivity studies with a global atmospheric composition-climate model to assess the impact of aerosols on tropospheric chemistry through their modification on clouds, aerosol-cloud interactions (ACI). The model includes coupling between both tropospheric gas-phase and aerosol chemistry and aerosols and liquid-phase clouds. We investigate past impacts from preindustrial (PI) to present day (PD) and future impacts from PD to 2050 (for the moderate IPCC A1B scenario) that embrace a wide spectrum of precursor emission changes and consequential ACI. The aerosol indirect effect (AIE) is estimated to be −2.0 Wm−2 for PD-PI and −0.6 Wm−2 for 2050-PD, at the high end of current estimates. Inclusion of ACI substantially impacts changes in global mean methane lifetime across both time periods, enhancing the past and future increases by 10% and 30%, respectively. In regions where pollution emissions increase, inclusion of ACI leads to 20% enhancements in in-cloud sulfate production and ~10% enhancements in sulfate wet deposition that is displaced away from the immediate source regions. The enhanced in-cloud sulfate formation leads to larger increases in surface sulfate across polluted regions (~10–30%). Nitric acid wet deposition is dampened by 15–20% across the industrialized regions due to ACI allowing additional re-release of reactive nitrogen that contributes to 1–2 ppbv increases in surface ozone in outflow regions. Our model findings indicate that ACI must be considered in studies of methane trends and projections of future changes to particulate matter air quality.


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