Author
A. Febo
Bio: A. Febo is an academic researcher from National Research Council. The author has contributed to research in topics: Nitrous acid & Nitric acid. The author has an hindex of 16, co-authored 29 publications receiving 1600 citations.
Topics: Nitrous acid, Nitric acid, Sampling (statistics), Nitrite, Nitrate
Papers
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TL;DR: In this paper, an annular geometry-based diffusion denuder made of two concentric short tubes was developed and tested for laminar air flows as high as 20lmin−1.
288 citations
TL;DR: In this paper, the authors presented measurements of the HONO UV-visible absorption cross sections with a spectral resolution better than 0.1 nm and a high signal-to-noise ratio.
Abstract: Nitrous acid, HONO, is a source of OH radicals in the polluted atmosphere. Although the atmospheric chemistry of HONO is qualitatively understood, not much quantitative information exists. The magnitude of the OH production by HONO photolysis depends on the spectrum of its absorption cross sections; therefore the knowledge of σ'HONO(λ) is essential. The spectrum of the differential cross sections σ'HONO(λ) is needed to detect HONO in the atmosphere by differential optical absorption spectroscopy (DOAS). Here we present measurements of the HONO UV-visible absorption cross sections with a spectral resolution better than 0.1 nm and a high signal-to-noise ratio. The maximum value of the absorption cross sections is σHONO (354 nm) = (5.19±0.26) × 10−19 cm2 and agrees well with literature data. Nevertheless, calculations based on data from this work and on literature data reveal that an uncertainty of ∼15% remains for the HONO photolysis rates. The new σHONO(λ) has been employed in DOAS measurements in Milan, Italy.
198 citations
TL;DR: The annular denuder method (ADM) as discussed by the authors was developed to measure several gaseous and aerosol species without sampling artifacts, and it has been applied to the determination of gas phase and particulate matter.
144 citations
University of California, Los Angeles1, California Air Resources Board2, Research Triangle Park3, California Health and Human Services Agency4, University of South Florida5, California Institute of Technology6, Brigham Young University7, Southern California Edison8, National Oceanic and Atmospheric Administration9, University of Calgary10, Ford Motor Company11, Battelle Memorial Institute12, University of Denver13, University of California, Riverside14
TL;DR: The results from the three annular denuders do not agree; the ratios of means to the DDM value are 1.0, 0.8 and 0.6 as mentioned in this paper.
121 citations
TL;DR: In the NITROCAT ground-based field experiment in May/June 2001, the highest HNO2 concentrations were found under high-pressure conditions with high nocturnal atmospheric stability and high values of pollutants as discussed by the authors.
115 citations
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TL;DR: OH, NO3, and O3 are shown to play a central role in the formation and fate of airborne toxic chemicals, mutagenic polycyclic aromatic hydrocarbons, and fine particles.
Abstract: Tropospheric air pollution has impacts on scales ranging from local to global. Reactive intermediates in the oxidation of mixtures of volatile organic compounds (VOCs) and oxides of nitrogen (NOx) play central roles: the hydroxyl radical (OH), during the day; the nitrate radical (NO3), at night; and ozone (O3), which contributes during the day and night. Halogen atoms can also play a role during the day. Here the implications of the complex VOC-NOx chemistry for O3 control are discussed. In addition, OH, NO3, and O3 are shown to play a central role in the formation and fate of airborne toxic chemicals, mutagenic polycyclic aromatic hydrocarbons, and fine particles.
1,065 citations
TL;DR: Simpler models representing transport, limiting precursor pollutants, and gas-to-particle equilibrium should be used to understand where and when emission reductions will be effective, rather than large complex models that have insufficient input and validation measurements.
Abstract: The 1999 Regional Haze Rule provides a context for this review of visibility, the science that describes it, and the use of that science in regulatory guidance The scientific basis for the 1999 regulation is adequate The deciview metric that tracks progress is an imperfect but objective measure of what people see near the prevailing visual range The definition of natural visibility conditions is adequate for current planning, but it will need to be refined as visibility improves Emissions from other countries will set achievable levels above those produced by natural sources Some natural events, notably dust storms and wildfires, are episodic and cannot be represented by annual average background values or emission estimates Sulfur dioxide (SO2) emission reductions correspond with lower sulfate (SO4 2−) concentrations and visibility im-provements in the regions where these have occurred Non-road emissions have been growing more rapidly than emissions from other sources, which have remained
964 citations
TL;DR: An extensive view on the role of hydroxyl radical in different environmental compartments and in laboratory systems is provided, with the aim of drawing more attention to this emerging issue of great concern.
Abstract: The hydroxyl radical (•OH) is one of the most powerful oxidizing agents, able to react unselectively and instantaneously with the surrounding chemicals, including organic pollutants and inhibitors. The •OH radicals are omnipresent in the environment (natural waters, atmosphere, interstellar space, etc.), including biological systems where •OH has an important role in immunity metabolism. We provide an extensive view on the role of hydroxyl radical in different environmental compartments and in laboratory systems, with the aim of drawing more attention to this emerging issue. Further research on processes related to the hydroxyl radical chemistry in the environmental compartments is highly demanded. A comprehensive understanding of the sources and sinks of •OH radicals including their implications in the natural waters and in the atmosphere is of crucial importance, including the way irradiated chromophoric dissolved organic matter in surface waters yields •OH through the H2O2-independent pathway, and the ...
892 citations
812 citations
TL;DR: A review of recent developments in atmospheric aerosol measurements can be found in this article, which focuses on measurements of aerosol integral properties (total number concentration, CCN concentration, optical coefficients, etc.), aerosol physical chemical properties (density, refractive index, equilibrium water content, etc.).
806 citations