Wildfire atmospheric chemistry: climate and air quality impacts

In atmospheric chemistry, interactions between air pollution, the biosphere and human health, often through reaction mixtures from both natural and anthropogenic sources, are of growing interest. Massive pollution emissions in the Anthropocene have transformed atmospheric composition to the extent that biogeochemical cycles, air quality and climate have changed globally and partly profoundly. It is estimated that mortality attributable to outdoor air pollution amounts to 4.33 million individuals per year, associated with 123 million years of life lost. Worldwide, air pollution is the major environmental risk factor to human health, and strict air quality standards have the potential to strongly reduce morbidity and mortality. Preserving clean air should be considered a human right, and is fundamental to many sustainable development goals of the United Nations, such as good health, climate action, sustainable cities, clean energy, and protecting life on land and in the water. It would be appropriate to adopt “clean air” as a sustainable development goal.

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The Detailed Emissions Scaling, Isolation, and Diagnostic (DESID) module in the Community Multiscale Air Quality (CMAQ) Modeling System version 5.3

10.5194/gmd-2020-361 ◽

2020 ◽

Author(s):

Benjamin N. Murphy ◽

Christopher G. Nolte ◽

Fahim Sidi ◽

Jesse O. Bash ◽

K. Wyat Appel ◽

...

Keyword(s):

Air Quality ◽

Atmospheric Chemistry ◽

Chemical Species ◽

Energy System ◽

Reduced Form ◽

Chemistry Research ◽

Control Interface ◽

Source Contributions ◽

Areas Of Interest ◽

Multiple Chemical

Abstract. Air quality modeling for research and regulatory applications often involves executing many emissions sensitivity cases to quantify impacts of hypothetical scenarios, estimate source contributions or quantify uncertainties. Despite the prevalence of this task, conventional approaches for perturbing emissions in chemical transport models like the Community Multiscale Air Quality (CMAQ) model require extensive offline creation and finalization of alternative emissions input files. This workflow tends to be time-consuming, error-prone, inconsistent among model users and difficult to document while consuming increased computer storage space. The Detailed Emissions Scaling, Isolation, and Diagnostic (DESID) module, a component of CMAQv5.3 and beyond, addresses these limitations by performing these modifications online during the air quality simulation. Further, the model contains an Emission Control Interface which allows users to prescribe both simple and highly complex emissions scaling operations with control over individual or multiple chemical species, emissions sources, and spatial areas of interest. DESID further enhances the transparency of its operations with extensive error-checking and optional gridded output of processed emission fields. These new features are of high value to many air quality applications including routine perturbation studies, atmospheric chemistry research, and coupling with external models (e.g. energy system models, reduced-form models).

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First year of real-time VOC measurements at the SIRTA facility (Paris region, France): diurnal and seasonal variabilities, impact of lockdowns on air quality

10.5194/egusphere-egu21-8643 ◽

2021 ◽

Author(s):

Leïla Simon ◽

Valérie Gros ◽

Jean-Eudes Petit ◽

François Truong ◽

Roland Sarda-Esteve ◽

...

Keyword(s):

Air Quality ◽

Atmospheric Chemistry ◽

Seasonal Variability ◽

Anthropogenic Sources ◽

First Year ◽

Good Representation ◽

Atmospheric Measurements ◽

Paris Region ◽

The Impact

Volatile Organic Compounds (VOCs) have direct influences on air quality and climate. They also play a key role in atmospheric chemistry, as they are precursors of secondary pollutants, such as ozone (O3) and secondary organic aerosols (SOA).Long-term datasets of in-situ atmospheric measurements are crucial to characterize the variability of atmospheric chemical composition. Online and continuous measurements of O3, NOx and aerosols have been achieved at the SIRTA-ACTRIS facility (Paris region, France), since 2012. Regarding VOCs, they have been measured there for several years thanks to bi-weekly samplings followed by offline Gas Chromatography analysis. However, this method doesn&#8217;t provide a good representation of the temporal variability of VOC concentrations. To tackle this issue, online VOC measurements using a Proton-Transfer-Reaction Quadrupole Mass-Spectrometer (PTR-Q-MS) have been started in January 2020.The dataset acquired during the first year of online VOC measurements is analyzed, which gives insights on VOC seasonal variability. The additional long-term datasets obtained from co-located measurements (O3, NOx, aerosol physical and chemical properties, meteorological parameters) are also used for the sake of this study.Due to Covid-19 pandemic, the year 2020 notably comprised a total lockdown in France in Spring, and a lighter one in Autumn. Therefore, a focus can be made on the impact of these lockdowns on the VOC variability and sources. To this end, the diurnal cycles of VOCs considered markers for anthropogenic sources are carefully investigated. Results notably indicate that markers for traffic and wood burning sources behave quite differently during the Spring lockdown in comparison to the other periods. A source apportionment analysis using positive matrix factorization allows to further document the seasonal variability of VOC sources and the impacts on air quality associated with the lockdown measures.

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AerChemMIP: quantifying the effects of chemistry and aerosols in CMIP6

Geoscientific Model Development ◽

10.5194/gmd-10-585-2017 ◽

2017 ◽

Vol 10 (2) ◽

pp. 585-607 ◽

Cited By ~ 66

Author(s):

William J. Collins ◽

Jean-François Lamarque ◽

Michael Schulz ◽

Olivier Boucher ◽

Veronika Eyring ◽

...

Keyword(s):

Air Quality ◽

Atmospheric Chemistry ◽

Radiative Forcing ◽

Climate Models ◽

Coupled Model ◽

Climate Impacts ◽

Atmospheric Composition ◽

Historical Period ◽

Model Intercomparison ◽

Intercomparison Project

Abstract. The Aerosol Chemistry Model Intercomparison Project (AerChemMIP) is endorsed by the Coupled-Model Intercomparison Project 6 (CMIP6) and is designed to quantify the climate and air quality impacts of aerosols and chemically reactive gases. These are specifically near-term climate forcers (NTCFs: methane, tropospheric ozone and aerosols, and their precursors), nitrous oxide and ozone-depleting halocarbons. The aim of AerChemMIP is to answer four scientific questions. 1. How have anthropogenic emissions contributed to global radiative forcing and affected regional climate over the historical period? 2. How might future policies (on climate, air quality and land use) affect the abundances of NTCFs and their climate impacts? 3.How do uncertainties in historical NTCF emissions affect radiative forcing estimates? 4. How important are climate feedbacks to natural NTCF emissions, atmospheric composition, and radiative effects? These questions will be addressed through targeted simulations with CMIP6 climate models that include an interactive representation of tropospheric aerosols and atmospheric chemistry. These simulations build on the CMIP6 Diagnostic, Evaluation and Characterization of Klima (DECK) experiments, the CMIP6 historical simulations, and future projections performed elsewhere in CMIP6, allowing the contributions from aerosols and/or chemistry to be quantified. Specific diagnostics are requested as part of the CMIP6 data request to highlight the chemical composition of the atmosphere, to evaluate the performance of the models, and to understand differences in behaviour between them.

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Integrating in situ Measurements and City Scale Modelling to Assess the COVID–19 Lockdown Effects on Emissions and Air Quality in Athens, Greece

Atmosphere ◽

10.3390/atmos11111174 ◽

2020 ◽

Vol 11 (11) ◽

pp. 1174 ◽

Cited By ~ 3

Author(s):

Georgios Grivas ◽

Eleni Athanasopoulou ◽

Anastasia Kakouri ◽

Jennifer Bailey ◽

Eleni Liakakou ◽

...

Keyword(s):

Air Quality ◽

Atmospheric Chemistry ◽

Traffic Management ◽

Management Strategies ◽

Road Transport ◽

Scale Model ◽

Ambient Exposure ◽

Mean Concentration ◽

Reduced Emissions

The lockdown measures implemented worldwide to slow the spread of the COVID–19 pandemic have allowed for a unique real-world experiment, regarding the impacts of drastic emission cutbacks on urban air quality. In this study we assess the effects of a 7-week (23 March–10 May 2020) lockdown in the Greater Area of Athens, coupling in situ observations with estimations from a meteorology-atmospheric chemistry model. Measurements in central Athens during the lockdown were compared with levels during the pre- and post-lockdown 3-week periods and with respective levels in the four previous years. We examined regulatory pollutants as well as CO2, black carbon (BC) and source-specific BC components. Models were run for pre-lockdown and lockdown periods, under baseline and reduced-emissions scenarios. The in-situ results indicate mean concentration reductions of 30–35% for traffic-related pollutants in Athens (NO2, CO, BC from fossil fuel combustion), compared to the pre-lockdown period. A large reduction (53%) was observed also for the urban CO2 enhancement while the reduction for PM2.5 was subtler (18%). Significant reductions were also observed when comparing the 2020 lockdown period with past years. However, levels rebounded immediately following the lift of the general lockdown. The decrease in measured NO2 concentrations was reproduced by the implementation of the city scale model, under a realistic reduced-emissions scenario for the lockdown period, anchored at a 46% decline of road transport activity. The model permitted the assessment of air quality improvements on a spatial scale, indicating that NO2 mean concentration reductions in areas of the Athens basin reached up to 50%. The findings suggest a potential for local traffic management strategies to reduce ambient exposure and to minimize exceedances of air quality standards for primary pollutants.

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Nitrate radicals and biogenic volatile organic compounds: oxidation, mechanisms and organic aerosol

10.5194/acp-2016-734 ◽

2016 ◽

Cited By ~ 3

Author(s):

N. L. Ng ◽

S. S. Brown ◽

A. T. Archibald ◽

E. Atlas ◽

R. C. Cohen ◽

...

Keyword(s):

Air Quality ◽

Volatile Organic Compounds ◽

Organic Compounds ◽

Atmospheric Chemistry ◽

Climate Models ◽

Large Body ◽

Organic Aerosol ◽

Organic Nitrate ◽

Biogenic Volatile Organic Compounds ◽

Volatile Organic

Abstract. Oxidation of biogenic volatile organic compounds (BVOC) by the nitrate radical (NO3) represents one of the important interactions between anthropogenic emissions related to combustion and natural emissions from the biosphere. This interaction has been recognized for more than three decades, during which time a large body of research has emerged from laboratory, field and modeling studies. NO3-BVOC reactions influence air quality, climate and visibility through regional and global budgets for reactive nitrogen (particularly organic nitrates), ozone and organic aerosol. Despite its long history of research and the significance of this topic in atmospheric chemistry, a number of important uncertainties remain. These include an incomplete understanding of the rates, mechanisms and organic aerosol yields for NO3-BVOC reactions, lack of constraints on the role of heterogeneous oxidative processes associated with the NO3 radical, the difficulty of characterizing the spatial distributions of BVOC and NO3 within the poorly mixed nocturnal atmosphere and the challenge of constructing appropriate boundary layer schemes and non-photochemical mechanisms for use in state-of-the-art chemical transport and chemistry-climate models. This review is the result of a workshop of the same title held at the Georgia Institute of Technology in June 2015. The first section summarizes the current literature on NO3-BVOC chemistry, with a particular focus on recent advances in instrumentation and models, and in organic nitrate and secondary organic aerosol (SOA) formation chemistry. Building on this current understanding, the second half of the review outlines impacts of NO3-BVOC chemistry on air quality and climate, and suggests critical research needs to better constrain this interaction to improve the predictive capabilities of atmospheric models.

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The contribution of marine organics to the air quality of the western United States

Atmospheric Chemistry and Physics ◽

10.5194/acp-10-7415-2010 ◽

2010 ◽

Vol 10 (15) ◽

pp. 7415-7423 ◽

Cited By ~ 17

Author(s):

B. Gantt ◽

N. Meskhidze ◽

A. G. Carlton

Keyword(s):

United States ◽

Air Quality ◽

San Francisco ◽

Atmospheric Chemistry ◽

Environmental Protection Agency ◽

Regional Scale ◽

The United States ◽

Coastal Areas ◽

Western United States ◽

The Us

Abstract. The contribution of marine organic emissions to the air quality in coastal areas of the western United States is studied using the latest version of the US Environmental Protection Agency (EPA) regional-scale Community Multiscale Air Quality (CMAQv4.7) modeling system. Emissions of marine isoprene, monoterpenes, and primary organic matter (POM) from the ocean are implemented into the model to provide a comprehensive view of the connection between ocean biology and atmospheric chemistry and air pollution. Model simulations show that marine organics can increase the concentration of PM2.5 by 0.1–0.3 μg m−3 (up to 5%) in some coastal cities such as San Francisco, CA. This increase in the PM2.5 concentration is primarily attributed to the POM emissions, with small contributions from the marine isoprene and monoterpenes. When marine organic emissions are included, organic carbon (OC) concentrations over the remote ocean are increased by up to 50% (25% in coastal areas), values consistent with recent observational findings. This study is the first to quantify the air quality impacts from marine POM and monoterpenes for the United States, and it highlights the need for inclusion of marine organic emissions in air quality models.

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Alkane autoxidation and aerosol formation: new insights from combustion engines to the atmosphere

10.5194/egusphere-egu2020-20144 ◽

2020 ◽

Author(s):

Mikael Ehn ◽

Zhandong Wang ◽

Matti Rissanen ◽

Olga Garmash ◽

Lauriane Quéléver ◽

...

Keyword(s):

Air Quality ◽

Atmospheric Chemistry ◽

Internal Combustion Engines ◽

Combustion Engines ◽

Aerosol Formation ◽

Engine Operation ◽

Alkoxy Radicals ◽

Chemical Mechanisms ◽

Engine Efficiency ◽

New Information

Autoxidation is a process whereby organic compounds become oxidized by molecular oxygen (O2). It is ubiquitous in various reaction systems, contributing to the spoilage of food and wine, ignition in internal combustion engines, and formation of atmospheric secondary organic aerosol (SOA) from volatile emissions. Autoxidation thus greatly influences both engine operation and efficiency, and, via SOA, climate and air quality. Recent progress in atmospheric chemistry has identified double bonds and oxygen-containing moieties as structural facilitators for efficient autoxidation, and subsequent OA formation. Lacking either of these functionalities, alkanes, the primary molecular class in fuels for combustion engines and an important class of urban trace gases, have been expected to have low susceptibility to undergo autoxidation. In this work, we show that alkanes can indeed undergo efficient autoxidation both under combustion-relevant and atmospheric temperatures, consequently producing more highly oxygenated species than previously expected. By bridging methodologies and knowledge from both combustion and atmospheric chemistry, we mapped the autoxidation potential of a range of alkane structures under various conditions, from the combustion domain to the atmospheric domain. We identified the importance of isomerization steps driven by both peroxy and alkoxy radicals, and show that isomerization and production of low-volatile condensable vapors is efficient even under highly polluted ([NO]>10ppb) conditions. Our findings, currently under review, provide insights into the underlying chemical mechanisms causing highly variable SOA yields from alkanes, which were observed in previous atmospheric studies. The results of this inter-disciplinary effort provide crucial new information on oxidation processes in both combustion engines and the atmosphere, with direct implications for engine efficiency and urban air quality.

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Characterizing two distinct biomass burning regimes over Southeast Asia and their impacts on regional air quality

10.5194/egusphere-egu2020-7653 ◽

2020 ◽

Author(s):

Margaret Marvin ◽

Paul Palmer ◽

Fei Yao ◽

Barry Latter ◽

Richard Siddans ◽

...

Keyword(s):

Air Quality ◽

Southeast Asia ◽

Biomass Burning ◽

Atmospheric Chemistry ◽

Agricultural Waste ◽

Critical Evaluation ◽

Dry Season ◽

Mitigation Strategies ◽

Atmospheric Composition ◽

Regional Air Quality

Mainland and maritime Southeast Asia is home to more than 655 million people, representing nearly 10% of the global population. The dry season in this region is typically associated with intense biomass burning activity, which leads to a significant increase in surface air pollutants that are harmful to human health, including ozone (O3) and fine (radii smaller than 2.5 microns) particulate matter (PM2.5). Latitude-based differences in dry season timing and land use distinguish two regional biomass burning regimes: (1) agricultural waste burning on the peninsular mainland from February through April and (2) coastal peat burning across the equatorial islands in September and October. The type and amount of material burned determines the chemical composition of emissions and subsequently their impact on regional air quality. Understanding the individual and collective roles of these biomass burning regimes is a crucial step towards developing effective air quality mitigation strategies for Southeast Asia. Here, we use the nested GEOS-Chem atmospheric chemistry transport model (horizontal resolution of 0.25&#176; x 0.3125&#176;) to simulate fire-atmosphere interactions over Southeast Asia during March and September of 2014, when emissions peak from the two regional burning seasons. Based on our analysis of model output, we report how these two distinct biomass burning regimes impact the photochemical environment over Southeast Asia and what the resulting consequences are for surface air quality. We will also present a critical evaluation of our model using ground-based and satellite observations of atmospheric composition across the region.

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Air quality modelling, simulation, and computational methods: a review

Environmental Reviews ◽

10.1139/er-2012-0056 ◽

2013 ◽

Vol 21 (3) ◽

pp. 149-179 ◽

Cited By ~ 22

Author(s):

Mohanad El-Harbawi

Keyword(s):

Air Quality ◽

Computational Methods ◽

Atmospheric Chemistry ◽

Web Sites ◽

Remote Sensing Data ◽

Reference Source ◽

Air Quality Modelling ◽

Quality Models ◽

Wide Range ◽

Recent Developments

The objective of this paper is to provide a comprehensive theoretical review with regard to history, existing approaches, recent developments, major research, associated computational methods, and applications of air quality models. A wide range of topics is covered, focusing on sources of air pollution, primary and secondary pollutants, atmospheric chemistry, atmospheric chemical transport models, computer programs for dispersion modelling, online and offline air quality modelling, data assimilation, parallel computing, applications of geographic information system in air quality modelling, air quality index, as well as the use of satellite and remote sensing data in air quality modelling. Each of these elements is comprehensively discussed, covered, and reviewed with respect to various literature and methods related to air quality modelling and applications. Several major commercial and noncommercial dispersion packages are extensively reviewed and detailed advantages and limitations of their applications are highlighted. The paper includes several comparison summaries among various models used in air quality study. Furthermore, the paper provides useful web sites, where readers can obtain further information regarding air quality models and (or) software. Lastly, current generation of air quality models and future directions are also discussed. This paper may serve as a compendium for scientists who work in air quality modelling field. Some topics are generally treated; therefore, the paper may also be used as a reference source by many scientists working with air quality modelling.

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