Simultaneous concentrations of ammonia and nitric acid in a polluted atmosphere and their equilibrium relationship to particulate ammonium nitrate

Doyle, George J.; Tuazon, Ernesto C.; Graham, Richard; Mischke, Thomas M.; Winer, Arthur M.; Pitts, James N.

doi:10.1021/es60159a010

Cited by 85 publications

(37 citation statements)

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“…Stelson et al (1979) and Doyle et al (1979) have shown that measurements of gaseous nitric acid and ammonia often are consistent with the upper limit on those concentrations predicted if the gases were in equilibrium with pure solid NH 4 No 3 • In those studies, the aerosol phase was not characterized completely, and little insight is gained into the cause of those cases where the atmospheric concentration products of NH 3 and HN0 3 fall below the equilibrium dissociation constant for pure NH 4 No 3 • The hypothesis that NH 3 , HN0 3 , and NH 4 No 3 are in equilibrium also has been pursued i n cool humid atmospheres (Harrison and Pio, 1983) and at the low concentrations present in rural atmospheres (Cadle et al, 1982). Very little work has been published to date that examines the agreement between equilibrium-based calculation schemes and field observations in cases where the ionic components in the aerosol are treated as being more complex than pure NH 4 No 3 • A step in this direction is provided by Tanner (1982), who compared the thermodynamics of aqueous mixed sulfate-nitrate solutions and solid ammonium nitrate to field experiments under conditions present on Long Island, New York.…”

Section: Introductionmentioning

confidence: 99%

Ammonia and Nitric Acid Concentrations in Equilibrium With Atmospheric Aerosols: Experiment vs Theory

HILDEMANN¹,

RUSSELL²,

CASS³

1984

CACGP Symposium on Tropospheric Chemistry With Emphasis on Sulphur and Nitrogen Cycles and the Chemistry of Clouds and Precipit

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The equilibrium between gaseous ammonia, nitric acid, and aerosol nitrate is discussed on the basis of a recent field experiment in Southern California.Comparison is drawn between theoretical equilibrium calculations and simultaneous measurements of nitric acid, ammonia, ammonium ion, nitrate ion, sulfate ion, other ionic species, temperature and dewpoint. Particulate .and gaseous pollutant concentrations at some inland sampling sites are readily explained if the aerosol is assumed to exist as an external mixture with all particulate nitrate and ammonium available to form pure NR 4 No 3 • At other monitoring sites, especially near the coast, aerosol nitrate is found in the presence of NR 3 and RN0 3 concentrations that thermodynamic calculations show are too low to produce pure NR 4 No 3 • This can be explained when the amount of aerosol nitrate that can be derived from reaction of nitric acid with sea salt and soil dust is taken into account. A calculation approach that accounts for the presence of mixed sulfate and nitrate salts improves the agreement between predicted and observed pollutant concentrations in the majority of cases studied. Uncertainties in these calculations arise from a number of sources including the thermodynamic quantities, and the effect of these uncertainties on the comparison between theory and experiment is discussed.

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Section: Introductionmentioning

confidence: 99%

Ammonia and Nitric Acid Concentrations in Equilibrium With Atmospheric Aerosols: Experiment vs Theory

HILDEMANN¹,

RUSSELL²,

CASS³

1984

CACGP Symposium on Tropospheric Chemistry With Emphasis on Sulphur and Nitrogen Cycles and the Chemistry of Clouds and Precipit

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“…Ammonium nitrate tends to form after sulfuric acid is completely neutralized. Atmospheric ammonium nitrate generally obeys thermodynamic equilibrium with gaseous nitric acid and ammonia (Stelson et al, 1979;Doyle et al, 1979;Seinfeld, 1982a, 1982b;Russell et al, 1983;Hildemann et al, 1984;Zhang et al, 2002;Takahama et al, 2004;Yu et al, 2005), although some studies have pointed out that factors such as mass transport limitations can, at times, result in departures from equilibrium (Wexler and Seinfeld, 1992;Meng and Seinfeld, 1996;. The equilibrium between particulate ammonium nitrate and gaseous nitric acid and ammonia shifts to the gas phase as ambient temperature increases, and RH decreases.…”

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confidence: 99%

Comprehensive airborne characterization of aerosol from a major bovine source

et al. 2008

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Abstract. We report an extensive airborne characterization of aerosol downwind of a massive bovine source in the San Joaquin Valley (California) on two flights during July 2007. The Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter probed chemical composition, particle size distribution, mixing state, sub-and supersaturated water uptake behavior, light scattering properties, and the interrelationship between these parameters and meteorology. Total PM 1.0 levels and concentrations of organics, nitrate, and ammonium were enhanced in the plume from the source as compared to the background aerosol. Organics dominated the plume aerosol mass (∼56-64%), followed either by sulfate or nitrate, and then ammonium. Particulate amines were detected in the plume aerosol by a particleinto-liquid sampler (PILS) and via mass spectral markers in the Aerodyne C-ToF-AMS. Amines were found to be a significant atmospheric base even in the presence of ammonia; particulate amine concentrations are estimated as at least 14-23% of that of ammonium in the plume. Enhanced sub-and supersaturated water uptake and reduced refractive indices were coincident with lower organic mass fractions, higher nitrate mass fractions, and the detection of amines. The likelihood of suppressed droplet growth owing to kinetic limitations from hydrophobic organic material is explored. After removing effects associated with size distribution and mixing state, the normalized activated fraction of cloud condensation nuclei (CCN) increased as a function of the subsaturated Correspondence to: J. H. Seinfeld (seinfeld@caltech.edu) hygroscopic growth factor, with the highest activated fractions being consistent with relatively lower organic mass fractions and higher nitrate mass fractions. Subsaturated hygroscopic growth factors for the organic fraction of the aerosol are estimated based on employing the ZdanovskiiStokes Robinson (ZSR) mixing rule. Representative values for a parameterization treating particle water uptake in both the sub-and supersaturated regimes are reported for incorporation into atmospheric models.

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“…At a given temperature, in situ spectroscopic measurements have shown the equilibrium constant to be quite variable in ambient air, although regression plots against the inverse of absolute temperature yielded free energy and enthalpy changes consistent with laboratory studies. 4 The variability may be due to humidity and whether the aerosol is internally or externally mixed. [5][6][7] After NH 4 NO 3 is collected on a filter, it is subject to these equilibrium shifts, which can increase or decrease the amount of NH 4 NO 3 retained on the filter.…”

Section: Introductionmentioning

confidence: 99%

“…8 Both NH 3 and HNO 3 gases are also subject to acid-base reactions with previously collected particulate matter, resulting in ion formation and, therefore, transformation to the particulate phase. In order to accurately sample HNO 3 , NH 3 , NO 3 -, and NH 4 + in the phases as they exist in the atmosphere, diffusion denuding techniques have been developed. [9][10][11][12][13] Diffusion denuders are devices that remove gaseous components while allowing particles to pass through them.…”

Section: Introductionmentioning

confidence: 99%

“…Since SO 4 2-is a non-volatile particulate species, the amount of SO 4 2-collected by each denuder compared to the sulfate on the Teflon front filter (or the sum of the SO 4 2-on the back Teflon filter plus all of the preceding denuders) provides a measure of the penetration of fine particulate matter through the denuder. This approach also assumes that NO 3 -and SO 4 2-have a similar size distribution.…”

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A Fabric Denuder for Sampling Semi-Volatile Species

Fitz

Motallebi

2000

Journal of the Air & Waste Management Association

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A new style of diffusion denuder has been evaluated specifically for sampling HNO 3 . A coated fabric is used as the denuder substrate, which can be loaded directly into a standard filter holder. This approach allows direct denuder sampling with no additional capital costs over filter sampling and simplifies the coating and extraction process.Potential denuder materials and coatings were evaluated in the laboratory to test the removal efficiency. NaCl coatings were used to assess more than 20 materials for HNO 3 collection efficiency. Particle retention, which would cause a denuder to have a positive bias for gas concentration measurements, was evaluated by ambient air sampling using particulate sulfate as the reference aerosol. Particle retention varied from 0 to 15%, depending on the denuder material tested. The best performing material showed an average particle retention of less than 3%.Denuder efficiency of four fabric materials was tested under ambient conditions to determine removal efficiency. The fabric denuder method was compared with a long path-length Fourier transform infrared (FTIR) spectrometer, a tunable diode laser absorption spectrometer (TDLAS), and a denuder difference sampler to independently measure HNO 3 . HNO 3 collection efficiency was typically 90% for the denuders, whether coated with NaCl or not. For 10-L/min sampling rates with the fabric denuder, the square of the correlation coefficient with IMPLICATIONS A simple fabric material used as a diffusion denuder has been shown to be an effective and inexpensive method to measure species such as HNO 3 and NH 3 which partition into both gaseous and particulate phases. The low cost of this approach compared with other types of denuders may encourage more measurements of these air pollutants. With a larger database available, the environmental and health effects of these species may be better assessed.the FTIR spectrometer was 0.73, compared to 0.24 with the TDLAS. INTRODUCTIONBackground HNO 3 in the atmosphere may pose a significant health risk and environmental hazard. In the atmosphere, HNO 3 and NH 3 are in equilibrium with NH 4 NO 3 particulate matter. These particles are primarily in the PM 2.5 size range, a particulate range for which a new federal ambient air quality standard has been promulgated.

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Simultaneous concentrations of ammonia and nitric acid in a polluted atmosphere and their equilibrium relationship to particulate ammonium nitrate

Cited by 85 publications

References 3 publications

Ammonia and Nitric Acid Concentrations in Equilibrium With Atmospheric Aerosols: Experiment vs Theory

Ammonia and Nitric Acid Concentrations in Equilibrium With Atmospheric Aerosols: Experiment vs Theory

Comprehensive airborne characterization of aerosol from a major bovine source

A Fabric Denuder for Sampling Semi-Volatile Species

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