scholarly journals Abundance of NO3 Derived Organo-Nitrates and Their Importance in the Atmosphere

Atmosphere ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1381
Author(s):  
Amy Foulds ◽  
M. Anwar H. Khan ◽  
Thomas J. Bannan ◽  
Carl J. Percival ◽  
Mark H. Lowenberg ◽  
...  
Keyword(s):  
Air Quality ◽  
Significant Contribution ◽  
Transport Model ◽  
Temporal Analysis ◽  
Ozone Formation ◽  
Nitrate Radical ◽  
Night Time ◽  
Mixing Ratios ◽  
Model Measurement ◽  
Good Agreement

The chemistry of the nitrate radical and its contribution to organo-nitrate formation in the troposphere has been investigated using a mesoscale 3-D chemistry and transport model, WRF-Chem-CRI. The model-measurement comparisons of NO2, ozone and night-time N2O5 mixing ratios show good agreement supporting the model’s ability to represent nitrate (NO3) chemistry reasonably. Thirty-nine organo-nitrates in the model are formed exclusively either from the reaction of RO2 with NO or by the reaction of NO3 with alkenes. Temporal analysis highlighted a significant contribution of NO3-derived organo-nitrates, even during daylight hours. Night-time NO3-derived organo-nitrates were found to be 3-fold higher than that in the daytime. The reactivity of daytime NO3 could be more competitive than previously thought, with losses due to reaction with VOCs (and subsequent organo-nitrate formation) likely to be just as important as photolysis. This has highlighted the significance of NO3 in daytime organo-nitrate formation, with potential implications for air quality, climate and human health. Estimated atmospheric lifetimes of organo-nitrates showed that the organo-nitrates act as NOx reservoirs, with particularly short-lived species impacting on air quality as contributors to downwind ozone formation.

scholarly journals Modeling nitrous acid and its impact on ozone and hydroxyl radical during the Texas Air Quality Study 2006

2012 ◽  
Vol 12 (2) ◽  
pp. 5851-5880 ◽  
Author(s):  
B. H. Czader ◽  
B. Rappenglück ◽  
P. Percell ◽  
D. W. Byun ◽  
F. Ngan ◽  
...  
Keyword(s):  
Air Quality ◽  
Hydroxyl Radical ◽  
Gas Phase ◽  
Nitrous Acid ◽  
Organic Materials ◽  
Optical Absorption Spectroscopy ◽  
Ozone Formation ◽  
Mixing Ratios ◽  
Quality Study ◽  
Mist Chamber

Abstract. Nitrous acid (HONO) mixing ratios for the Houston metropolitan area were simulated with the Community Multiscale Air Quality (CMAQ) model for an episode during the Texas Air Quality Study (TexAQS) II in August/September 2006 and compared to in-situ MC/IC (mist-chamber/ion chromatograph) and long path DOAS (Differential Optical Absorption Spectroscopy) measurements at three different altitudes. Several HONO sources were accounted for in simulations, such as gas phase formation, direct emissions, nitrogen dioxide (NO2*) hydrolysis, photo-induced formation from excited NO2* and photo-induced conversion of NO2 into HONO on surfaces covered with organic materials. Compared to the gas-phase HONO formation there was about a tenfold increase in HONO mixing ratios when additional HONO sources were taken into account, which improved the correlation between modeled and measured values. Concentrations of HONO simulated with only gas phase chemistry did not change with altitude, while measured HONO concentrations decrease with height. A trend of decreasing HONO concentration with altitude was well captured with CMAQ predicted concentrations when heterogeneous chemistry and photolytic sources of HONO were taken into account. Heterogeneous HONO production mainly accelerated morning ozone formation, albeit slightly. Also HONO formation from excited NO2 only slightly affected HONO and ozone (O3) concentrations. Photo-induced conversion of NO2 into HONO on surfaces covered with organic materials turned out to be a strong source of daytime HONO. Since HONO immediately photo-dissociates during daytime its ambient mixing ratios were only marginally altered (up to 0.5 ppbv), but significant increase in the hydroxyl radical (OH) and ozone concentration was obtained. In contrast to heterogeneous HONO formation that mainly accelerated morning ozone formation, inclusion of photo-induced surface chemistry influenced ozone throughout the day.

scholarly journals Interpreting the variability of CO<sub>2</sub> columns over North America using a chemistry transport model: application to SCIAMACHY data

2008 ◽  
Vol 8 (2) ◽  
pp. 7339-7371 ◽  
Author(s):  
P. I. Palmer ◽  
M. P. Barkley ◽  
P. S. Monks
Keyword(s):  
North America ◽  
North American ◽  
Significant Contribution ◽  
Transport Model ◽  
Model Bias ◽  
Chemistry Transport Model ◽  
Mixing Ratios ◽  
Non Local ◽  
Flux Estimation ◽  
Kernel Model

Abstract. We use the GEOS-Chem chemistry transport model to interpret variability of CO2 columns and associated column-averaged volume mixing ratios (CVMRs) observed by the SCIAMACHY satellite instrument during the 2003 North American growing season, accounting for the instrument averaging kernel. Model and observed columns, largely determined by surface topography, averaged on a 2°×2.5° grid, are in excellent agreement (model bias=3%, r>0.9), as expected. Model and observed CVMRs, determined by scaling column CO2 by surface pressure data, are on average within 3% but are only weakly correlated, reflecting a large positive model bias (10–15 ppmv) at 50–70° N during midsummer at the peak of biospheric uptake. GEOS-Chem generally reproduces the magnitude and seasonal cycle of observed CO2 surface VMRs across North America. During midsummer we find that model CVMRs and surface VMRs converge, reflecting the instrument vertical sensitivity and the strong influence of the land biosphere on lower tropospheric CO2 columns. We use model tagged tracers to show that local fluxes largely determine CVMR variability over North America, with the largest individual CVMR contributions (1.1%) from the land biosphere. Fuel sources are relatively constant while biomass burning make a significant contribution only during midsummer. We also show that non-local sources contribute significantly to total CVMRs over North America, with the boreal Asian land biosphere contributing close to 1% in midsummer at high latitudes. We used the monthly-mean Jacobian matrix for North America to illustrate that: 1) North American CVMRs represent a superposition of many weak flux signatures, but differences in flux distributions should permit independent flux estimation; and 2) the atmospheric e-folding lifetimes for many of these flux signatures are 3–4 months, beyond which time they are too well-mixed to interpret.

scholarly journals Temperature response measurements from eucalypts give insight into the impact of Australian isoprene emissions on air quality in 2050

2020 ◽  
Vol 20 (10) ◽  
pp. 6193-6206
Author(s):  
Kathryn M. Emmerson ◽  
Malcolm Possell ◽  
Michael J. Aspinwall ◽  
Sebastian Pfautsch ◽  
Mark G. Tjoelker
Keyword(s):  
Air Quality ◽  
Transport Model ◽  
Temperature Response ◽  
Emission Factors ◽  
Eucalyptus Species ◽  
Chemical Transport Model ◽  
Mixing Ratios ◽  
The Impact ◽  
Temperature Responses ◽  
Insight Into

Abstract. Predicting future air quality in Australian cities dominated by eucalypt emissions requires an understanding of their emission potentials in a warmer climate. Here we measure the temperature response in isoprene emissions from saplings of four different Eucalyptus species grown under current and future average summertime temperature conditions. The future conditions represent a 2050 climate under Representative Concentration Pathway 8.5, with average daytime temperatures of 294.5 K. Ramping the temperature from 293 to 328 K resulted in these eucalypts emitting isoprene at temperatures 4–9 K higher than the default maximum emission temperature in the Model of Emissions of Gases and Aerosols from Nature (MEGAN). New basal emission rate measurements were obtained at the standard conditions of 303 K leaf temperature and 1000 µmol m−2 s−1 photosynthetically active radiation and converted into landscape emission factors. We applied the eucalypt temperature responses and emission factors to Australian trees within MEGAN and ran the CSIRO Chemical Transport Model for three summertime campaigns in Australia. Compared to the default model, the new temperature responses resulted in less isoprene emission in the morning and more during hot afternoons, improving the statistical fit of modelled to observed ambient isoprene. Compared to current conditions, an additional 2 ppb of isoprene is predicted in 2050, causing hourly increases up to 21 ppb of ozone and 24-hourly increases of 0.4 µg m−3 of aerosol in Sydney. A 550 ppm CO2 atmosphere in 2050 mitigates these peak Sydney ozone mixing ratios by 4 ppb. Nevertheless, these forecasted increases in ozone are up to one-fifth of the hourly Australian air quality limit, suggesting that anthropogenic NOx should be further reduced to maintain healthy air quality in future.

scholarly journals Long-Term Variations of Air Quality Influenced by Surface Ozone in a Coastal Site in India: Association with Synoptic Meteorological Conditions with Model Simulations

Atmosphere ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 193 ◽  
Author(s):  
Resmi C T ◽  
Nishanth T ◽  
Satheesh Kumar M K ◽  
Balachandramohan M ◽  
Valsaraj K T
Keyword(s):  
Air Quality ◽  
Surface Ozone ◽  
Atmospheric Temperature ◽  
Night Time ◽  
Coastal Site ◽  
Model Study ◽  
Different Seasons ◽  
Surface O3 ◽  
Good Agreement

Atmospheric ozone (O3) in the surface level plays a central role in determining air quality and atmospheric oxidizing capacity. In this paper, we review our comprehensive results of simultaneous measurements of surface ozone (O3) and its precursor gas (NOx) and weather parameters that were carried out continuously for a span of six years (January 2013–December 2018) at a typical rural coastal site, Kannur (11.9° N, 75.4° E) in South India. Surface O3 concentration reached its maximum during daytime hours and minimum during the night time. The influence of solar radiation and water content on variations of O3 are discussed. A Multi-Layer Perceptron (MLP) artificial neural network technique has been used to understand the effect of atmospheric temperature on the increase in O3 over the past six years. This has been found that temperature has been a major contributor to the increase in O3 levels over the years. The National Centre for Atmospheric Research- Master Mechanism (NCAR-MM) Photochemical box model study was conducted to validate the variations of O3 in different seasons and years, and the results were shown to be in good agreement with observed trends.

scholarly journals Air quality over Europe: modelling gaseous and particulate pollutants

2013 ◽  
Vol 13 (18) ◽  
pp. 9661-9673 ◽  
Author(s):  
E. Tagaris ◽  
R. E. P. Sotiropoulou ◽  
N. Gounaris ◽  
S. Andronopoulos ◽  
D. Vlachogiannis
Keyword(s):  
Air Quality ◽  
Western Europe ◽  
Anthropogenic Emissions ◽  
Southern Europe ◽  
Mixing Ratios ◽  
Particulate Pollutants ◽  
Predicted Values ◽  
Eastern And Western Europe ◽  
Modelling System ◽  
Good Agreement

Abstract. Air quality over Europe using Models-3 (i.e., CMAQ, MM5, SMOKE) modelling system is performed for winter (i.e., January 2006) and summer (i.e., July 2006) months with the 2006 TNO gridded anthropogenic emissions database. Higher ozone mixing ratios are predicted in southern Europe while higher NO2 levels are simulated over western Europe. Elevated SO2 values are simulated over eastern Europe and higher PM2.5 concentrations over eastern and western Europe. Regional average results suggest that NO2 and PM2.5 are underpredicted, SO2 is overpredicted, while Max8hrO3 is overpredicted for low mixing ratios and is underpredicted for the higher mixing ratios. However, in a number of countries observed and predicted values are in good agreement for the pollutants examined here. Speciated PM2.5 components suggest that NO3 is dominant during winter over western Europe and in a few eastern countries due to the high NO2 mixing ratios. During summer NO3 is dominant only in regions with elevated NH3 emissions. For the rest of the domain SO4 is dominant. Low OC concentrations are simulated mainly due to the uncertain representation of SOA formation.

scholarly journals Midlatitude ClO during the maximum atmospheric chlorine burden: in situ balloon measurements and model simulations

2005 ◽  
Vol 5 (1) ◽  
pp. 875-909
Author(s):  
B. Vogel ◽  
R. Müller ◽  
A. Engel ◽  
J.-U. Grooß ◽  
D. Toohey ◽  
...  
Keyword(s):  
Stratospheric Ozone ◽  
Potential Temperature ◽  
Lagrangian Model ◽  
Night Time ◽  
Model Simulations ◽  
Mixing Ratios ◽  
Chlorine Monoxide ◽  
Similar Good ◽  
Good Agreement

Abstract. Chlorine monoxide (ClO) plays a key role in stratospheric ozone loss processes at midlatitudes. We present two balloonborne in situ measurements of ClO conducted in northern hemisphere midlatitudes during the period of the maximum of total inorganic chlorine loading in the atmosphere. Both ClO measurements were conducted on board the TRIPLE balloon payload, launched in November 1996 in León, Spain, and in May 1999 in Aire sur l'Adour, France. For both flights a ClO daylight and night time vertical profile could be derived over an altitude range of approximately 15–31 km. ClO mixing ratios are compared to model simulations performed with the photochemical box model version of the Chemical Lagrangian Model of the Stratosphere (CLaMS). Simulations along 24-h backward trajectories were performed to study the diurnal variation of ClO in the midlatitude lower stratosphere. Model simulations for the flight launched in Aire sur l'Adour 1999 show a good agreement with the ClO measurements. For the flight launched in León 1996, a similar good agreement is found, except at around ≈650 K potential temperature (≈26 km altitude). However, a tendency is found that for solar zenith angles greater than 86°–87° the simulated ClO mixing ratios substantially overestimate measured ClO by approximately a factor of 2.5 or more for both flights. Therefore we conclude that no indication can be deduced from the presented ClO measurements that substantial uncertainties exist in midlatitude chlorine chemistry of the stratosphere. An exception is the situation at solar zenith angles greater than 86°–87° where model simulations substantial overestimate ClO observations.

scholarly journals Interpreting the variability of space-borne CO<sub>2</sub> column-averaged volume mixing ratios over North America using a chemistry transport model

2008 ◽  
Vol 8 (19) ◽  
pp. 5855-5868 ◽  
Author(s):  
P. I. Palmer ◽  
M. P. Barkley ◽  
P. S. Monks
Keyword(s):  
North America ◽  
North American ◽  
Significant Contribution ◽  
Transport Model ◽  
Co2 Flux ◽  
Chemistry Transport Model ◽  
Sources And Sinks ◽  
Mixing Ratios ◽  
Non Local ◽  
Flux Estimation

Abstract. We use the GEOS-Chem chemistry transport model to interpret the sources and sinks of CO2 that determine variability of column-averaged volume mixing ratios (CVMRs), as observed by the SCIAMACHY satellite instrument, during the 2003 North American growing season. GEOS-Chem generally reproduces the magnitude and seasonal cycle of observed CO2 surface VMRs across North America and is quantitatively consistent with column VMRs in later years. However, it cannot reproduce the magnitude or variability of FSI-WFM-DOAS SCIAMACHY CVMRs. We use model tagged tracers to show that local fluxes largely determine CVMR variability over North America, with the largest individual CVMR contributions (1.1%) from the land biosphere. Fuel sources are relatively constant while biomass burning makes a significant contribution only during midsummer. We also show that non-local sources contribute significantly to total CVMRs over North America, with the boreal Asian land biosphere contributing close to 1% in midsummer at high latitudes. We used the monthly-mean Jacobian matrix for North America to illustrate that:~1) North American CVMRs represent a superposition of many weak flux signatures, but differences in flux distributions should permit independent flux estimation; and 2) the atmospheric e-folding lifetimes for many of these flux signatures are 3–4 months, beyond which time they are too well-mixed to interpret. These long lifetimes will improve the efficacy of observed CVMRs as surface CO2 flux constraints.

scholarly journals Modeling nitrous acid and its impact on ozone and hydroxyl radical during the Texas Air Quality Study 2006

2012 ◽  
Vol 12 (15) ◽  
pp. 6939-6951 ◽  
Author(s):  
B. H. Czader ◽  
B. Rappenglück ◽  
P. Percell ◽  
D. W. Byun ◽  
F. Ngan ◽  
...  
Keyword(s):  
Air Quality ◽  
Hydroxyl Radical ◽  
Gas Phase ◽  
Nitrous Acid ◽  
Organic Materials ◽  
Optical Absorption Spectroscopy ◽  
Ozone Formation ◽  
Mixing Ratios ◽  
Quality Study ◽  
Mist Chamber

Abstract. Nitrous acid (HONO) mixing ratios for the Houston metropolitan area were simulated with the Community Multiscale Air Quality (CMAQ) Model for an episode during the Texas Air Quality Study (TexAQS) II in August/September 2006 and compared to in-situ MC/IC (mist-chamber/ion chromatograph) and long path DOAS (Differential Optical Absorption Spectroscopy) measurements at three different altitude ranges. Several HONO sources were accounted for in simulations, such as gas phase formation, direct emissions, nitrogen dioxide (NO2) hydrolysis, photo-induced formation from excited NO2 and photo-induced conversion of NO2 into HONO on surfaces covered with organic materials. Compared to the gas-phase HONO formation there was about a tenfold increase in HONO mixing ratios when additional HONO sources were taken into account, which improved the correlation between modeled and measured values. Concentrations of HONO simulated with only gas phase chemistry did not change with altitude, while measured HONO concentrations decrease with height. A trend of decreasing HONO concentration with altitude was well captured with CMAQ predicted concentrations when heterogeneous chemistry and photolytic sources of HONO were taken into account. Heterogeneous HONO production mainly accelerated morning ozone formation, albeit slightly. Also HONO formation from excited NO2 only slightly affected HONO and ozone (O3) concentrations. Photo-induced conversion of NO2 into HONO on surfaces covered with organic materials turned out to be a strong source of daytime HONO. Since HONO immediately photo-dissociates during daytime its ambient mixing ratios were only marginally altered (up to 0.5 ppbv), but significant increase in the hydroxyl radical (OH) and ozone concentration was obtained. In contrast to heterogeneous HONO formation that mainly accelerated morning ozone formation, inclusion of photo-induced surface chemistry influenced ozone throughout the day.

Effect of nitryl chloride chemistry on oxidants concentrations during the KORUS-AQ campaign

2020 ◽  
Author(s):  
Hyeonmmin Kim ◽  
Rokjin Park ◽  
Jaein Jeong ◽  
Saewung Kim ◽  
Daun Jeong ◽  
...  
Keyword(s):  
Air Quality ◽  
East Asia ◽  
Transport Model ◽  
Night Time ◽  
Radical Species ◽  
Chemistry Transport Model ◽  
Nitryl Chloride ◽  
Regional Air Quality ◽  
Ozone Photochemistry ◽  
Nitrate Aerosol

&lt;p&gt;Nitryl chloride (ClNO&lt;sub&gt;2&lt;/sub&gt;) plays an important role as a night-time reservoir of NO&lt;sub&gt;X&lt;/sub&gt; and the source of Cl radical during the daytime, which consequently affects the ozone photochemistry. Its impacts on regional air quality in East Asia, however, are not fully understood so far. We here use extensive observations during the international KORea-US cooperative Air Quality field study in Korea (KORUS-AQ), which occurred in May-June 2016, with a 3-D chemistry transport model to examine the impacts of ClNO&lt;sub&gt;2&lt;/sub&gt; chemistry on radical species and total nitrate concentrations in East Asia. We first update the model by implementing chlorine chemistry and latest anthropogenic chlorine emissions of China and South Korea. We conduct model simulations for May-June, 2016 and validate the model by comparing against the observations from the KORUS-AQ campaign. We find that the ClNO&lt;sub&gt;2&lt;/sub&gt; chemistry in the model results in an increase of ozone by ~1.4 ppbv (~2.5%), Cl radical by ~ 4.6x10&lt;sup&gt;3&lt;/sup&gt; molec cm&lt;sup&gt;-3&lt;/sup&gt; (~3600%), OH ~8.2x10&lt;sup&gt;4&lt;/sup&gt; molec cm&lt;sup&gt;-3&lt;/sup&gt; (~5.3%), HO&lt;sub&gt;2&lt;/sub&gt; ~6.6 molec cm&lt;sup&gt;-3&lt;/sup&gt; (~3.0%), a decrease of TNO&lt;sub&gt;3&lt;/sub&gt; (HNO&lt;sub&gt;3&lt;/sub&gt; + nitrate aerosol) concentrations by ~2 &amp;#956;g m&lt;sup&gt;-3&lt;/sup&gt; on a daily mean basis during the campaign. Overall, the enhanced conversion of NO to NO&lt;sub&gt;2&lt;/sub&gt; driven by ClNO&lt;sub&gt;2&lt;/sub&gt; chemistry contributes to higher oxidant concentrations in the model. As a result, the updated model shows a better agreement with the observations in Korea during the KORUS-AQ campaign.&lt;/p&gt;

scholarly journals Midlatitude ClO during the maximum atmospheric chlorine burden: in situ balloon measurements and model simulations

2005 ◽  
Vol 5 (6) ◽  
pp. 1623-1638 ◽  
Author(s):  
B. Vogel ◽  
R. Müller ◽  
A. Engel ◽  
J.-U. Grooß ◽  
D. Toohey ◽  
...  
Keyword(s):  
Lower Stratosphere ◽  
Stratospheric Ozone ◽  
Lagrangian Model ◽  
Night Time ◽  
Model Simulations ◽  
Mixing Ratios ◽  
Chlorine Monoxide ◽  
Good Agreement ◽  
Balloon Measurements

Abstract. Chlorine monoxide (ClO) plays a key role in stratospheric ozone loss processes at midlatitudes. We present two balloon-borne in situ measurements of ClO conducted in northern hemisphere midlatitudes during the period of the maximum of total inorganic chlorine loading in the atmosphere. Both ClO measurements were conducted on board the TRIPLE balloon payload, launched in November 1996 in León, Spain, and in May 1999 in Aire sur l'Adour, France. For both flights a ClO daylight and night-time vertical profile was derived over an altitude range of approximately 15-35 km. ClO mixing ratios are compared to model simulations performed with the photochemical box model version of the Chemical Lagrangian Model of the Stratosphere (CLaMS). Simulations along 24-hour backward trajectories were performed to study the diurnal variation of ClO in the midlatitude lower stratosphere. Model simulations for the flight launched in Aire sur l'Adour 1999 show an excellent agreement with the ClO measurements. For the flight launched in León 1996, an overall good agreement is found, whereas the flight is characterized by a more complex dynamical situation due to a possible mixture of vortex and non-vortex air. We note that for both flights at solar zenith angles greater than 86°-87° simulated ClO mixing ratios are higher than observed ClO mixing ratios. However, the present findings indicate that no substantial uncertainties exist in midlatitude chlorine chemistry of the stratosphere.

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