Next Issue
Previous Issue

E-Mail Alert

Add your e-mail address to receive forthcoming issues of this journal:

Journal Browser

Journal Browser

Table of Contents

Atmosphere, Volume 2, Issue 4 (December 2011), Pages 567-741

  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Readerexternal link to open them.
View options order results:
result details:
Displaying articles 1-8
Export citation of selected articles as:

Research

Open AccessArticle Cloud Processing of Gases and Aerosols in Air Quality Modeling
Atmosphere 2011, 2(4), 567-616; doi:10.3390/atmos2040567
Received: 10 June 2011 / Revised: 15 September 2011 / Accepted: 16 September 2011 / Published: 10 October 2011
Cited by 18 | PDF Full-text (943 KB) | HTML Full-text | XML Full-text
Abstract
The representations of cloud processing of gases and aerosols in some of the current state-of-the-art regional air quality models in North America and Europe are reviewed. Key processes reviewed include aerosol activation (or nucleation scavenging of aerosols), aqueous-phase chemistry, and wet deposition/removal of
[...] Read more.
The representations of cloud processing of gases and aerosols in some of the current state-of-the-art regional air quality models in North America and Europe are reviewed. Key processes reviewed include aerosol activation (or nucleation scavenging of aerosols), aqueous-phase chemistry, and wet deposition/removal of atmospheric tracers. It was found that models vary considerably in the parameterizations or algorithms used in representing these processes. As an emerging area of research, the current understanding of the uptake of water soluble organics by cloud droplets and the potential aqueous-phase reaction pathways leading to the atmospheric secondary organic aerosol (SOA) formation is also reviewed. Sensitivity tests using the AURAMS model have been conducted in order to assess the impact on modeled regional particulate matter (PM) from: (1) the different aerosol activation schemes, (2) the different below-cloud particle scavenging algorithms, and (3) the inclusion of cloud processing of water soluble organics as a potential pathway for the formation of atmospheric SOA. It was found that the modeled droplet number concentrations and ambient PM size distributions were strongly affected by the use of different aerosol activation schemes. The impact on the modeled average ambient PM mass concentration was found to be limited in terms of averaged PM2.5 concentration (~a few percents) but more significant in terms of PM1.0 (up to 10 percents). The modeled ambient PM was found to be moderately sensitive to the below-cloud particle scavenging algorithms, with relative differences up to 10% and 20% in terms of PM2.5 and PM10, respectively, when using the two different algorithms for the scavenging coefficient (Λ) corresponding to the lower and upper bounds in the parameterization for Λ. The model simulation with the additional cloud uptake and processing of water-soluble organic gases was shown to improve the evaluation statistics for modeled PM2.5 OA compared to the IMPROVE network data, and it was demonstrated that the cloud processing of water-soluble organics can indeed be an important mechanism in addition to the traditional secondary organic gas uptake to the particle organic phase. Full article
(This article belongs to the Special Issue Air Pollution Modeling: Reviews of Science Process Algorithms)
Open AccessArticle Emission Ratios of the Tropospheric Ozone Precursors Nitrogen Dioxide and Formaldehyde from Australia’s Black Saturday Fires
Atmosphere 2011, 2(4), 617-632; doi:10.3390/atmos2040617
Received: 5 September 2011 / Revised: 19 October 2011 / Accepted: 19 October 2011 / Published: 31 October 2011
Cited by 6 | PDF Full-text (2929 KB) | HTML Full-text | XML Full-text
Abstract
The ‘Black Saturday’ fires were a series of devastating forest fires that burned across Victoria, Australia, during February and March of 2009. In this study we have used satellite data made publically available by NASA from the Ozone Monitoring Instrument (OMI) and the
[...] Read more.
The ‘Black Saturday’ fires were a series of devastating forest fires that burned across Victoria, Australia, during February and March of 2009. In this study we have used satellite data made publically available by NASA from the Ozone Monitoring Instrument (OMI) and the Atmospheric InfraRed Sounder (AIRS) to track the smoke plume from the Black Saturday firestorm and explore the chemical aging of the smoke plume in the first days after emission. We also determined emission ratios for formaldehyde and nitrogen dioxide within smoke from fires actively burning across Victoria between 7 and 17 February 2009. The mean emission ratios with respect to carbon monoxide derived for these two tropospheric ozone precursors are (0.016 ± 0.004 mol.mol−1) for formaldehyde and (0.005 ± 0.002 mol.mol−1) for nitrogen dioxide. The mean emission ratio for formaldehyde with respect to CO is in broad agreement with values previously quoted in the literature for temperate forest fires. However, to our knowledge there are no previous measurements of emission ratios for nitrogen dioxide from Australian temperate forest fires. Full article
(This article belongs to the Special Issue Biomass Emissions)
Open AccessArticle Emission Ratios for Ammonia and Formic Acid and Observations of Peroxy Acetyl Nitrate (PAN) and Ethylene in Biomass Burning Smoke as Seen by the Tropospheric Emission Spectrometer (TES)
Atmosphere 2011, 2(4), 633-654; doi:10.3390/atmos2040633
Received: 26 August 2011 / Revised: 22 October 2011 / Accepted: 1 November 2011 / Published: 9 November 2011
Cited by 13 | PDF Full-text (2840 KB) | HTML Full-text | XML Full-text
Abstract
We use the Tropospheric Emission Spectrometer (TES) aboard the NASA Aura satellite to determine the concentrations of the trace gases ammonia (NH3) and formic acid (HCOOH) within boreal biomass burning plumes, and present the first detection of peroxy acetyl nitrate (PAN)
[...] Read more.
We use the Tropospheric Emission Spectrometer (TES) aboard the NASA Aura satellite to determine the concentrations of the trace gases ammonia (NH3) and formic acid (HCOOH) within boreal biomass burning plumes, and present the first detection of peroxy acetyl nitrate (PAN) and ethylene (C2H4) by TES. We focus on two fresh Canadian plumes observed by TES in the summer of 2008 as part of the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS-B) campaign. We use TES retrievals of NH3 and HCOOH within the smoke plumes to calculate their emission ratios (1.0% ± 0.5% and 0.31% ± 0.21%, respectively) relative to CO for these Canadian fires. The TES derived emission ratios for these gases agree well with previous aircraft and satellite estimates, and can complement ground-based studies that have greater surface sensitivity. We find that TES observes PAN mixing ratios of ~2 ppb within these mid-tropospheric boreal biomass burning plumes when the average cloud optical depth is low ( < 0.1) and that TES can detect C2H4 mixing ratios of ~2 ppb in fresh biomass burning smoke plumes. Full article
(This article belongs to the Special Issue Biomass Emissions)
Figures

Open AccessArticle Influence of Reduced Nitrogen Diets on Ammonia Emissions from Cattle Feedlot Pens
Atmosphere 2011, 2(4), 655-670; doi:10.3390/atmos2040655
Received: 19 September 2011 / Revised: 10 October 2011 / Accepted: 21 October 2011 / Published: 11 November 2011
Cited by 2 | PDF Full-text (705 KB) | HTML Full-text | XML Full-text
Abstract
Reducing crude protein (CP) in livestock diets may lower ammonia emissions. A feeding trial was conducted with crossbred steers at the Southeast Colorado Research Center in Lamar, Colorado from December 2009 to March 2010. Three diet treatments were investigated: Reduced (11.6% CP), Oscillating
[...] Read more.
Reducing crude protein (CP) in livestock diets may lower ammonia emissions. A feeding trial was conducted with crossbred steers at the Southeast Colorado Research Center in Lamar, Colorado from December 2009 to March 2010. Three diet treatments were investigated: Reduced (11.6% CP), Oscillating (13.5% crude protein 4 days/week and 11.6% CP 3 days/week) and Control (13.5% CP). Intact soil core samples (n = 36 per sampling date) were collected from the pen surfaces on three dates corresponding to 45, 92, and 148 days into the feeding cycle. Four pens from each diet treatment were sampled. Cores were placed into flow-through laboratory chambers for seven days and ammonia fluxes were trapped in acid bubblers that were refreshed every 24 h. Average daily ammonia emissions for the Control diet ranged from 6.6 to 9.4 g NH3 m−2·day−1; average daily emission for the Oscillating diet ranged from 6.3 to 8.8 g NH3 m−2·day−1; and average daily flux for the Reduced diet ranged from 4.1 to 5.8 g NH3 m−2·day−1. Ammonia fluxes from the reduced N treatment were significantly lower (21% to 40%) than from the control diet on the first two sample dates. There was no significant difference between the Oscillating and Control treatments. Reducing CP in cattle feedlot diets may be an effective method for reducing ammonia emissions from pen surfaces. More research is needed to validate these results at commercial scales in different environments to determine if reductions in ammonia can be sustained with lower CP diets without affecting rate of gain, feed efficiency and health. Full article
(This article belongs to the Special Issue Atmospheric Emissions from Agricultural Practices)
Open AccessArticle Desorption of Herbicides from Atmospheric Particulates During High-Volume Air Sampling
Atmosphere 2011, 2(4), 671-687; doi:10.3390/atmos2040671
Received: 25 July 2011 / Revised: 20 October 2011 / Accepted: 24 October 2011 / Published: 14 November 2011
PDF Full-text (234 KB) | HTML Full-text | XML Full-text
Abstract
Pesticides can be present in the atmosphere either as vapours and/or in association with suspended particles. High-volume air sampling, in which air is aspirated first through a glass fibre filter to capture pesticides associated with atmospheric particulates and then polyurethane foam (PUF), often
[...] Read more.
Pesticides can be present in the atmosphere either as vapours and/or in association with suspended particles. High-volume air sampling, in which air is aspirated first through a glass fibre filter to capture pesticides associated with atmospheric particulates and then polyurethane foam (PUF), often in combination with an adsorbent resin such as XAD-2, to capture pesticides present as vapours, is generally employed during atmospheric monitoring for pesticides. However, the particulate fraction may be underestimated because some pesticides may be stripped or desorbed from captured particulates due to the pressure drop created by the high flow of air through the filter. This possibility was investigated with ten herbicide active ingredients commonly used on the Canadian prairies (dimethylamine salts of 2,4-D, MCPA and dicamba, 2,4-D 2-ethylhexyl ester, bromoxynil octanoate, diclofop methyl ester, fenoxaprop ethyl ester, trifluralin, triallate and ethalfluralin) and seven hydrolysis products (2,4-D, MCPA, dicamba, bromoxynil, diclofop, clopyralid and mecoprop). Finely ground heavy clay soil fortified with active ingredients/hydrolysis products was evenly distributed on the glass fibre filters of high-volume air samplers and air aspirated through the samplers at a flow rate of 12.5 m3/h for a 7-day period. The proportion desorbed as vapour from the fortified soil was determined by analysis of the PUF/XAD-2 resin composite cartridges. The extent of desorption from the fortified soil applied to the filters varied from 0% for each of the dimethylamine salts of 2,4-D, MCPA and dicamba to approximately 50% for trifluralin, triallate and ethalfluralin. Full article
(This article belongs to the Special Issue Atmospheric Emissions from Agricultural Practices)
Open AccessArticle A Comparison of Risk Estimates for the Effect of Short-Term Exposure to PM, NO2 and CO on Cardiovascular Hospitalizations and Emergency Department Visits: Effect Size Modeling of Study Findings
Atmosphere 2011, 2(4), 688-701; doi:10.3390/atmos2040688
Received: 15 September 2011 / Revised: 19 November 2011 / Accepted: 22 November 2011 / Published: 6 December 2011
Cited by 1 | PDF Full-text (436 KB) | HTML Full-text | XML Full-text
Abstract
Although particulate matter (PM), nitrogen dioxide (NO2) and carbon monoxide (CO) typically exist as part of a complex air pollution mixture, the evidence linking these pollutants to health effects is evaluated separately in the scientific and policy reviews of the National
[...] Read more.
Although particulate matter (PM), nitrogen dioxide (NO2) and carbon monoxide (CO) typically exist as part of a complex air pollution mixture, the evidence linking these pollutants to health effects is evaluated separately in the scientific and policy reviews of the National Ambient Air Quality Standards (NAAQS). The objective of this analysis was to use meta-regression methods to model effect estimates for several individual yet correlated NAAQS pollutants in an effort to identify factors that explain differences in the effect sizes across studies and across pollutants. We expected that our consideration of the evidence for several correlated pollutants in parallel could lead to insights regarding exposure to the pollutant mixture. We focused on studies of hospital admissions for congestive heart failure (CHF) and ischemic heart disease (IHD), which have played an important role in the evaluation of the scientific evidence communicated in the PM, NO2, and CO Integrated Science Assessments (ISAs). Of the studies evaluated, 11 CHF studies and 21 IHD studies met our inclusion requirements. The size of the risk estimates was explained by factors related to the pollution mixture, study methods, and monitoring network characteristics. Our findings suggest that additional analyses focusing on understanding differences in effect sizes across geographic areas with different pollution mixtures and monitor network designs may improve our understanding of the independent and combined effects of correlated pollutants. Full article
(This article belongs to the Special Issue Health Effects of Air Pollution)
Open AccessArticle Carbon Dioxide and Methane at a Desert Site—A Case Study at Railroad Valley Playa, Nevada, USA
Atmosphere 2011, 2(4), 702-714; doi:10.3390/atmos2040702
Received: 19 July 2011 / Revised: 1 November 2011 / Accepted: 25 November 2011 / Published: 8 December 2011
Cited by 4 | PDF Full-text (527 KB) | HTML Full-text | XML Full-text
Abstract
Ground based in-situ measurements of carbon dioxide (CO2) and methane (CH4) at the dry lakebed at Railroad Valley (RRV) playa, Nevada, USA (38°30.234′ N, 115°41.604′ W, elevation 1437 m) were conducted over a five day period from 20–25 June
[...] Read more.
Ground based in-situ measurements of carbon dioxide (CO2) and methane (CH4) at the dry lakebed at Railroad Valley (RRV) playa, Nevada, USA (38°30.234′ N, 115°41.604′ W, elevation 1437 m) were conducted over a five day period from 20–25 June 2010. The playa is a flat, desert site with virtually no vegetation, an overall size of 15 km × 15 km and is approximately 110 km south-west of the nearest city, Ely (elevation 1962 m, inhabitants 4000). The measurements were taken in support of the vicarious calibration experiment to validate column-averaged dry air mole fractions of CO2 and CH4 (XCO2 and XCH4) retrieved from the Greenhouse Gases Observing Satellite (GOSAT) which was launched in January 2009. This work reports on ground-based in-situ measurements of CO2 and CH4 from RRV playa and describes comparisons made between in-situ data and XCO2 and XCH4 from GOSAT. Full article
Open AccessArticle Case Study of Pollutants Concentration Sensitivity to Meteorological Fields and Land Use Parameters over Douala (Cameroon) Using AERMOD Dispersion Model
Atmosphere 2011, 2(4), 715-741; doi:10.3390/atmos2040715
Received: 3 August 2011 / Revised: 14 October 2011 / Accepted: 14 October 2011 / Published: 14 December 2011
PDF Full-text (3270 KB) | HTML Full-text | XML Full-text
Abstract
This paper deals with the simulation of the NOx concentration over Douala for the period 2002–2006 by means of the American Meteorological Society (AMS)/Environmental Protection Agency (EPA) Regulatory Model (AERMOD) model, version 07026. Its sensitivity to local meteorological fields and land use parameters
[...] Read more.
This paper deals with the simulation of the NOx concentration over Douala for the period 2002–2006 by means of the American Meteorological Society (AMS)/Environmental Protection Agency (EPA) Regulatory Model (AERMOD) model, version 07026. Its sensitivity to local meteorological fields and land use parameters are investigated by selecting different buildings (receptors) specific direction and distance from the source and by making changes in land use parameters. Results reveal variations in concentration patterns depending on the roughness length, albedo and the Bowen ratio. Changes in the albedo as well as the Bowen ratio only alter the concentration patterns during convective conditions. For a short averaging time, changes in albedo and Bowen ratio have the same effects on the concentration patterns. These results not only help to accurately choose the indicated areas for implanting industrial sites, to manage risk assessment exposure to pollutants in Douala city and addressing recommendations to policies makers. Full article
(This article belongs to the Special Issue Air Pollution Modeling: Reviews of Science Process Algorithms)

Journal Contact

MDPI AG
Atmosphere Editorial Office
St. Alban-Anlage 66, 4052 Basel, Switzerland
atmosphere@mdpi.com
Tel. +41 61 683 77 34
Fax: +41 61 302 89 18
Editorial Board
Contact Details Submit to Atmosphere
Back to Top