scholarly journals Dry deposition of peroxyacetyl nitrate (PAN): Determination of its deposition velocity at night from measurements of the atmospheric PAN and222Radon concentration gradient

1996 ◽  
Vol 23 (24) ◽  
pp. 3599-3602 ◽  
Author(s):  
Wolfram Schrimpf ◽  
Karlheinz Lienaerts ◽  
Klaus Peter Müller ◽  
Jochen Rudolph ◽  
Rolf Neubert ◽  
...  
Keyword(s):  
Concentration Gradient ◽  
Dry Deposition ◽  
Deposition Velocity ◽  
Peroxyacetyl Nitrate

scholarly journals Influence of local air pollution on the deposition of peroxyacetyl nitrate to a nutrient-poor natural grassland ecosystem

2015 ◽  
Vol 15 (2) ◽  
pp. 899-911 ◽  
Author(s):  
A. Moravek ◽  
P. Stella ◽  
T. Foken ◽  
I. Trebs
Keyword(s):  
Dry Deposition ◽  
Deposition Velocity ◽  
Bowen Ratio ◽  
Grassland Ecosystem ◽  
Peroxyacetyl Nitrate ◽  
Autumn Period ◽  
Mixing Ratios ◽  
Underlying Mechanisms ◽  
The Impact ◽  
Natural Grassland

Abstract. Dry deposition of peroxyacetyl nitrate (PAN) is known to have a phytotoxic impact on plants under photochemical smog conditions, but it may also lead to higher productivity and threaten species richness of vulnerable ecosystems in remote regions. However, underlying mechanisms or controlling factors for PAN deposition are not well understood and studies on dry deposition of PAN are limited. In this study, we investigate the impact of PAN deposition on a nutrient-poor natural grassland ecosystem situated at the edge of an urban and industrialized region in Germany. PAN mixing ratios were measured within a 3.5 months summer to early autumn period. In addition, PAN fluxes were determined with the modified Bowen ratio technique for a selected period. The evaluation of both stomatal and non-stomatal deposition pathways was used to model PAN deposition over the entire summer–autumn period. We found that air masses at the site were influenced by two contrasting pollution regimes, which led to median diurnal PAN mixing ratios ranging between 50 and 300 ppt during unpolluted and between 200 and 600 ppt during polluted episodes. The measured PAN fluxes showed a clear diurnal cycle with maximal deposition fluxes of ~−0.1 nmol m−2 s−1 (corresponding to a deposition velocity of 0.3 cm s−1) during daytime and a significant non-stomatal contribution was found. The ratio of PAN to ozone deposition velocities was found to be ~0.1, which is much larger than assumed by current deposition models. The modelled PAN flux over the entire period revealed that PAN deposition over an entire day was 333 μg m−2 d−1 under unpolluted and 518 μg m−2 d−1 under polluted episodes. Additionally, thermochemical decomposition PAN deposition accounted for 32% under unpolluted episodes and 22% under polluted episodes of the total atmospheric PAN loss. However, the impact of PAN deposition as a nitrogen source to the nutrient-poor grassland was estimated to be only minor, under both unpolluted and polluted episodes.

Linear regression analyses with censored data: estimation of PAH washout ratios and dry deposition velocities to a snow surface

1995 ◽  
Vol 22 (4) ◽  
pp. 819-833 ◽  
Author(s):  
Mukesh Sharma ◽  
Neil R. Thomson ◽  
Edward A. McBean
Keyword(s):  
Least Squares ◽  
Censored Data ◽  
Dry Deposition ◽  
Least Squares Method ◽  
Deposition Velocity ◽  
Snow Surface ◽  
Regression Analyses ◽  
Doubly Censored Data ◽  
Doubly Censored ◽  
Censored Observations

Detection limits of analyzing instruments are the main reason for censored observations of pollutant concentrations. An iterative least squares method for regression analyses is developed to suit the doubly censored data commonly observed in environmental engineering. The modified iterative least squares method utilizes the expected values of censored observations estimated from the probability density function of doubly censored data in a regression process. The modified method is examined for bias in the estimation of the parameters of a linear model, and in the estimation of the standard deviation of the regression. A mechanistic model for atmospheric transport and deposition of polycyclic aromatic hydrocarbons (PAHs) to a snow surface is formulated by utilizing the long-term PAH retention property of deep snowpacks. The modified iterative least squares method is applied to estimate the deposition parameters (dry deposition velocity and washout ratio) for various PAH species, since some of the PAH deposition levels were below the minimum detection limit of the analyzing instrument. The estimated parameters are examined statistically, and compare favourably with previously reported estimates of these parameters. Key words: censored data, regression, iterative least squares, PAHs, dry deposition velocity, washout ratio.

scholarly journals Evaluation and improvements of two community models in simulating dry deposition velocities for peroxyacetyl nitrate (PAN) over a coniferous forest

2012 ◽  
Vol 117 (D4) ◽  
pp. n/a-n/a ◽  
Author(s):  
Zhiyong Wu ◽  
Xuemei Wang ◽  
Andrew A. Turnipseed ◽  
Fei Chen ◽  
Leiming Zhang ◽  
...  
Keyword(s):  
Dry Deposition ◽  
Coniferous Forest ◽  
Peroxyacetyl Nitrate ◽  
Deposition Velocities

scholarly journals Revising global ozone dry deposition estimates based on a new mechanistic parameterisation for air-sea exchange and the multi-year MACC composition reanalysis

2017 ◽  
Author(s):  
Ashok K. Luhar ◽  
Matthew T. Woodhouse ◽  
Ian E. Galbally
Keyword(s):  
Chemical Reaction ◽  
Dry Deposition ◽  
Tropospheric Ozone ◽  
Surface Resistance ◽  
Chemical Reactivity ◽  
Deposition Velocity ◽  
Water Layer ◽  
Turbulent Transfer ◽  
Dominant Term ◽  
Deposition Velocities

Abstract. Dry deposition at the Earth’s surface is an important sink of atmospheric ozone. Currently, dry deposition of ozone to the ocean surface in atmospheric chemistry models has the largest uncertainty compared to deposition to other surface types, with implications for global tropospheric ozone budget and associated radiative forcing. Most models assume that the dominant term of surface resistance in the parameterisation of ozone dry deposition velocity at the oceanic surface is constant. We present a consistent, process-based parameterisation scheme for air-sea exchange in which the surface resistance accounts for the simultaneous waterside processes of ozone solubility, molecular diffusion, turbulent transfer, and a first-order chemical reaction of ozone with dissolved iodide. The new scheme makes the following realistic assumptions: (a) the thickness of the top water layer is of the order of a reaction-diffusion length scale (a few micrometres) within which ozone loss is dominated by chemical reaction and the influence of waterside turbulent transfer is negligible; (b) in the water layer below, both chemical reaction and waterside turbulent transfer act together and are accounted for; and (c) iodide (hence chemical reactivity) is present through the depth of the oceanic mixing layer. The asymptotic behaviour of the new scheme is consistent with the known limits when either chemical reaction or turbulent transfer dominates. It has been incorporated into the ACCESS-UKCA global chemistry-climate model and the results are evaluated against dry deposition velocities from currently best available open-ocean measurements. In order to better quantify the global dry deposition loss and its interannual variability, the modelled 3-h ozone deposition velocities are combined with the 3-h MACC (Monitoring Atmospheric Composition and Climate) reanalysis ozone for the years 2003–2012. The resulting ozone dry deposition is found to be 98.4 ± 4.5 Tg O3 yr−1 for the ocean and 722.8 ± 20.9 O3 yr−1 globally. The new estimate of the ocean component is approximately a third of the current model estimates. This reduction corresponds to an approximately 20 % decrease in the total global ozone dry deposition, which is equivalent to an increase of approximately 5 % in the modelled tropospheric ozone burden and a similar increase in tropospheric ozone lifetime.

Detection of peroxyacetyl nitrate in air using chemiluminescence aerosol detector

2014 ◽  
Vol 68 (11) ◽  
Author(s):  
Pavel Mikuška ◽  
Lukáš Bružeňák ◽  
Zbyněk Večeřa
Keyword(s):  
Alkaline Solution ◽  
Limit Of Detection ◽  
Packed Column ◽  
Direct Reaction ◽  
Peroxyacetyl Nitrate ◽  
Brij 35 ◽  
Alternative Approach ◽  
Sensitive Determination ◽  
Triton X

AbstractA method for the rapid and sensitive determination of peroxyacetyl nitrate (PAN) in air based on a chemiluminescence reaction with an alkaline solution of luminol in the chemiluminescence aerosol detector is described. The PAN is chromatographically separated from nitrogen dioxide and ozone in a packed column filled with 5 % OV-1 on Chromosorb 30/60 and the eluted PAN is detected via the direct reaction with the luminol solution consisting of 0.002 mol L−1 luminol, 1 vol. % Brij-35 and 0.1 mol L−1 KOH. The limit of detection is 14.9 ng m−3 (3 ppt) of PAN. Alternatively, the PAN after separation is thermally converted to NO2 which is detected by the chemiluminescence reaction with a solution consisting of 0.002 mol L−1 luminol, 0.5 mol L−1 KOH, 0.2 mol L−1 Na2SO3, 0.1 mol L−1 KI, 0.05 mol L−1 EDTA and 0.5 vol. % triton X-100. The alternative approach affords the simultaneous determination of PAN and NO2. The limit of detection is 50 ppt of PAN and 50 ppt of NO2. The time resolution is 3 min. The method was applied to the measurement of ambient peroxyacetyl nitrate in air.

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