Gas-particle interactions above a Dutch heathland: III. Modelling the influence of the NH&amp;lt;sub&amp;gt;3&amp;lt;/sub&amp;gt;-HNO&amp;lt;sub&amp;gt;3&amp;lt;/sub&amp;gt;-NH&amp;lt;sub&amp;gt;4&amp;lt;/sub&amp;gt;NO&amp;lt;sub&amp;gt;3&amp;lt;/sub&amp;gt; equilibrium on size-segregated particle fluxes

Nemitz, Eiko; Sutton, Mark A.

doi:10.5194/acp-4-1025-2004

Cited by 68 publications

(52 citation statements)

References 47 publications

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“…However, due to the drying procedure in this study, the error due to hygroscopic growth was estimated to be below 10%. In addition to water vapor, semi-volatile organic and inorganic vapors may result in particle growth and shrinkage, leading to spurious number fluxes for fixed sizebins, as pointed out by Nemitz and Sutton (2004) and Nemitz et al (2009). Due to the very large uncertainty in particle growth rates in the Amazon Basin , these potential errors are harder to quantify, though.…”

Section: Flux Measurementsmentioning

confidence: 94%

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Emission and dry deposition of accumulation mode particles in the Amazon Basin

et al. 2010

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Abstract. Size-resolved vertical aerosol number fluxes of particles in the diameter range 0.25-2.5 µm were measured with the eddy covariance method from a 53 m high tower over the Amazon rain forest, 60 km NNW of Manaus, Brazil. This study focuses on data measured during the relatively clean wet season, but a shorter measurement period from the more polluted dry season is used as a comparison. Size-resolved net particle fluxes of the five lowest size bins, representing 0.25-0.45 µm in diameter, were in general dominated by deposition in more or less all wind sectors in the wet season. This is an indication that the source of primary biogenic aerosol particles may be small in this particle size range. Transfer velocities within this particle size range were observed to increase linearly with increasing friction velocity and increasing particle diameter.In the diameter range 0.5-2.5 µm, vertical particle fluxes were highly dependent on wind direction. In wind sectors where anthropogenic influence was low, net upward fluxes were observed. However, in wind sectors associated with higher anthropogenic influence, deposition fluxes dominated. The net upward fluxes were interpreted as a result of primary biogenic aerosol emission, but deposition of anthropogenic particles seems to have masked this emission in wind sectors with higher anthropogenic influence. The net emission fluxes were at maximum in the afternoon when the mixed layer is well developed, and were best correlated with horizontal wind speed according to the equationwhere F is the net emission number flux of 0.5-2.5 µm particles [m −2 s −1 ] and U is the horizontal wind speed [ms −1 ] at the top of the tower.

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Section: Flux Measurementsmentioning

confidence: 94%

“…Several biogenic related elements (e.g. K, P, S, Zn) in plants are present in the fluids circulating in plants and can be released from the plant during transpiration (Nemeruyk, 1970). The latent heat flux is at maximum at 12:00 LT and is much lower at 15:00 LT (Fig.…”

Section: Diurnal Cycles Of Fluxes Of Particles With Diametersmentioning

confidence: 99%

Emission and dry deposition of accumulation mode particles in the Amazon Basin

et al. 2010

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“…3.1. Nemitz and Sutton (2004) modelled the effect of NH 4 NO 3 evaporation on the apparent deposition velocity and found that, for some scenarios, the evaporation can lead to apparent emission of small particles. In one scenario, false positive fluxes were seen for particles less than 300 nm at a height of 10 m. Here, we investigation the extent of false fluxes due to ammonium-nitrate evaporation.…”

Section: Ammonium-nitrate Evaporationmentioning

confidence: 99%

“…The equilibrium mass concentration of NH 4 NO 3 , M, is a function of temperature, T , and relative humidity, S R , as well as the concentrations of NH 4 NO 3 , NH 3 , and HNO 3 , (cf. Mozurekwich, 1993;Nemitz and Sutton, 2004). Assuming all aerosol particles contain some NH 4 NO 3 , the change in mass of particles (with diameter D) due to the evaporation or condensation of NH 4 NO 3 is…”

Section: Ammonium-nitrate Evaporationmentioning

confidence: 99%

Aerosol flux measurements above a mixed forest at Borden, Ontario

et al. 2011

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Abstract. Aerosol fluxes were measured above a mixed forest by Eddy Covariance (EC) with a Fast Mobility Particle Sizer (FMPS) at the Borden Forest Research Station in Ontario, Canada between 13 July and 12 August 2009. Chemically speciated flux measurements were made at a height of 29 m at the same location between 19 July and 2 August, 2006 using a Quadrupole Aerosol Mass Spectrometer (Q-AMS). The Q-AMS measured an average sulphate deposition velocity of 0.3 mm s −1 and an average nitrate deposition velocity of 4.8 mm s −1 . The FMPS, mounted at a height of 33 m (approximately 10 m above the canopy top) and housed in a temperature controlled enclosure, measured sizeresolved particle concentrations from 3 to 410 nm diameter at a rate of 1 Hz. For the size range 18 < D < 452 nm, 60 % of fluxes were upward. The exchange velocity was between −0.5 and 2.0 mm s −1 , with median values near 0.5 mm s −1 for all sizes between 22 and 310 nm. The size distribution of the apparent production rate of particles at 33 m peaked at a diameter of 75 nm. Results indicate a decoupling of the above and below canopy spaces, whereby particles are stored in the canopy space at night, and are then diluted with cleaner air above during the day.

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“…Both short-and long-term NH 3 measurement studies have been undertaken in Europe over many years (e.g., Burkhardt et al, 1998;Horvath and Sutton, 1998;Sutton et al, 2001Sutton et al, , 2009Huber and Kreutzer, 2002), but long-term measurements in the U.S. have been limited. Due to the relatively rapid equilibration of NH 3 with ambient ammonium nitrate (NH 4 NO 3 ) aerosol (Meng and Seinfeld, 1996;Nemitz and Sutton, 2004), measurements of gaseous NH 3 alone are not sufficient to fully characterize its nature. To do so requires simultaneous measurements of both gas-phase NH 3 and particle-phase NH 4 + (predominately in the fine particle fraction), preferably at similar temporal resolutions.…”

Section: Introductionmentioning

confidence: 99%

Recent trends in gas-phase ammonia and PM_2.5 ammonium in the Southeast United States

Saylor

Myles

Sibble

et al. 2014

Journal of the Air & Waste Management Association

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Ammonia measurements from the Southeastern Aerosol Research and Characterization (SEARCH) study network were analyzed for trends over 9 yr (2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012) of observations. Total ammonia concentrations, defined as the sum of gas-phase ammonia and fine particle ammonium, were found to be decreasing by 1-4% yr −1 and were qualitatively consistent with ammonia emission estimates for the SEARCH states of Alabama, Georgia, Mississippi, and Florida. On the other hand, gas-phase ammonia mixing ratios were found to be slightly rising or steady over the region, leading to the observation that the gas-phase fraction of total ammonia has steadily increased over 2004-2012 as a result of declining emissions of the strong acid precursor species sulfur dioxide (SO 2 ) and nitrogen oxides (NO x ) and consequent reduced partitioning of ammonia to the fine particle phase. Because gas-phase ammonia is removed from the atmosphere more rapidly than fine particle ammonium, an increase in the gas-phase fraction of total ammonia may result in shifted deposition patterns as more ammonia is deposited closer to sources rather than transported downwind in fine particles. Additional long-term measurements and modeling studies are needed to determine if similar transitions of total ammonia to the gas phase are occurring outside of the Southeast and to assess if these changes are impacting plants and ecosystems near major ammonia sources. Unusually high ammonia concentrations observed in 2007 in the SEARCH measurements are hypothesized to be linked to emissions from wildfires that were much more prevalent across the Southeast during that year due to elevated temperatures and widespread drought. Although wildfires are currently estimated to be a relatively small fraction (3-10%) of total ammonia emissions in the Southeast, the projected increased incidence of wildfires in this region as a result of global climate change may lead to this source's increased importance over the rest of the 21st century.Implications: Ammonia concentrations from the Southeastern Aerosol Research and Characterization study (SEARCH) network are analyzed over the 9-yr period 2004-2012. Total ammonia (gaseous ammonia + PM 2.5 ammonium) concentrations declined at a rate of 1-4% yr −1 , consistent with U.S. Environmental Protection Agency (EPA) emission estimates for the Southeast United States, but the fraction of ammonia in the gas phase has risen steadily (+1-3% yr −1 ) over the time period. Declining emissions of SO 2 and NO x resulting from imposed air quality regulations have resulted in decreased atmospheric strong acids and less ammonia partitioning to the particle phase, which may impact the amount and overall pattern of ammonia deposition.

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Gas-particle interactions above a Dutch heathland: III. Modelling the influence of the NH<sub>3</sub>-HNO<sub>3</sub>-NH<sub>4</sub>NO<sub>3</sub> equilibrium on size-segregated particle fluxes

Cited by 68 publications

References 47 publications

Emission and dry deposition of accumulation mode particles in the Amazon Basin

Emission and dry deposition of accumulation mode particles in the Amazon Basin

Aerosol flux measurements above a mixed forest at Borden, Ontario

Recent trends in gas-phase ammonia and PM_2.5 ammonium in the Southeast United States

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Gas-particle interactions above a Dutch heathland: III. Modelling the influence of the NH&lt;sub&gt;3&lt;/sub&gt;-HNO&lt;sub&gt;3&lt;/sub&gt;-NH&lt;sub&gt;4&lt;/sub&gt;NO&lt;sub&gt;3&lt;/sub&gt; equilibrium on size-segregated particle fluxes

Cited by 68 publications

References 47 publications

Emission and dry deposition of accumulation mode particles in the Amazon Basin

Emission and dry deposition of accumulation mode particles in the Amazon Basin

Aerosol flux measurements above a mixed forest at Borden, Ontario

Recent trends in gas-phase ammonia and PM2.5 ammonium in the Southeast United States

Contact Info

Product

Resources

About

Gas-particle interactions above a Dutch heathland: III. Modelling the influence of the NH<sub>3</sub>-HNO<sub>3</sub>-NH<sub>4</sub>NO<sub>3</sub> equilibrium on size-segregated particle fluxes

Recent trends in gas-phase ammonia and PM_2.5 ammonium in the Southeast United States