scholarly journals Nonlinear response of ozone to precursor emission changes in China: a modeling study using response surface methodology

2011 ◽  
Vol 11 (10) ◽  
pp. 5027-5044 ◽  
Author(s):  
J. Xing ◽  
S. X. Wang ◽  
C. Jang ◽  
Y. Zhu ◽  
J. M. Hao
Keyword(s):  
Response Surface Methodology ◽  
Air Quality ◽  
Response Surface ◽  
Surface Ozone ◽  
Emission Control ◽  
Nox Emission ◽  
Ozone Sensitivity ◽  
Nox Control ◽  
Ozone Levels ◽  
Modeling Study

Abstract. Statistical response surface methodology (RSM) is successfully applied for a Community Multi-scale Air Quality model (CMAQ) analysis of ozone sensitivity studies. Prediction performance has been demonstrated through cross validation, out-of-sample validation and isopleth validation. Sample methods and key parameters, including the maximum numbers of variables involved in statistical interpolation and training samples have been tested and selected through computational experiments. Overall impacts from individual source categories which include local/regional NOx and VOC emission sources and NOx emissions from power plants for three megacities – Beijing, Shanghai and Guangzhou – were evaluated using an RSM analysis of a July 2005 modeling study. NOx control appears to be beneficial for ozone reduction in the downwind areas which usually experience high ozone levels, and NOx control is likely to be more effective than anthropogenic VOC control during periods of heavy photochemical pollution. Regional NOx source categories are strong contributors to surface ozone mixing ratios in three megacities. Local NOx emission control without regional involvement may raise the risk of increasing urban ozone levels due to the VOC-limited conditions. However, local NOx control provides considerable reduction of ozone in upper layers (up to 1 km where the ozone chemistry is NOx-limited) and helps improve regional air quality in downwind areas. Stricter NOx emission control has a substantial effect on ozone reduction because of the shift from VOC-limited to NOx-limited chemistry. Therefore, NOx emission control should be significantly enhanced to reduce ozone pollution in China.

scholarly journals Nonlinear response of ozone to precursor emission changes in China: a modeling study using response surface methodology

2010 ◽  
Vol 10 (12) ◽  
pp. 29809-29851 ◽  
Author(s):  
J. Xing ◽  
S. X. Wang ◽  
C. Jang ◽  
Y. Zhu ◽  
J. M. Hao
Keyword(s):  
Air Quality ◽  
Response Surface ◽  
Power Plants ◽  
Surface Ozone ◽  
Emission Control ◽  
Nox Emission ◽  
Sample Number ◽  
Ozone Sensitivity ◽  
Ozone Levels ◽  
Modeling Study

Abstract. Statistical response surface method (RSM) is successfully applied in Community Multi-scale Air Quality model (CMAQ) analysis on ozone sensitivity studies. Prediction performance has been validated through cross validation, out of sample validation and isopleths validation. Sample methods and key parameters including the maximum numbers for variables involving in statistic interpolation as well as training sample number have been tested and selected through computational experiments. Overall impacts from individual sources including local/regional NOx and VOC emission sources and NOx emissions from power plants for three megacities as Beijing, Shanghai and Guangzhou have been evaluated through RSM analysis under a July 2005 modeling study. NOx control appears to be beneficial for ozone reduction in the downwind areas where usually have higher ozone levels, and it's likely to be more effective than anthropogenic VOC control during heavy photochemical pollution period. Regional NOx sources are strong contributors to surface ozone mixing. Local NOx emission control without regional involvement may bring the risk of increasing urban ozone levels due to the VOC-limited conditions, but it gives considerable control benefit for ozone in upper layers (up to 1 km, where the ozone chemistry is changed to NOx-limited condition) and helps to improve regional air quality in the downwind areas. Effectiveness of NOx emission control is growing along with stricter control efforts, therefore an integrated regional and multi-pollutant control policy is necessary to mitigate ozone problem in China.

scholarly journals Coupling between surface ozone and leaf area index in a chemical transport model: strength of feedback and implications for ozone air quality and vegetation health

2018 ◽  
Vol 18 (19) ◽  
pp. 14133-14148 ◽  
Author(s):  
Shan S. Zhou ◽  
Amos P. K. Tai ◽  
Shihan Sun ◽  
Mehliyar Sadiq ◽  
Colette L. Heald ◽  
...  
Keyword(s):  
Air Quality ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Dry Deposition ◽  
Transport Model ◽  
Surface Ozone ◽  
Chemical Transport ◽  
Chemical Transport Model ◽  
Area Index ◽  
Ozone Levels

Abstract. Tropospheric ozone is an air pollutant that substantially harms vegetation and is also strongly dependent on various vegetation-mediated processes. The interdependence between ozone and vegetation may constitute feedback mechanisms that can alter ozone concentration itself but have not been considered in most studies to date. In this study we examine the importance of dynamic coupling between surface ozone and leaf area index (LAI) in shaping ozone air quality and vegetation. We first implement an empirical scheme for ozone damage on vegetation in the Community Land Model (CLM) and simulate the steady-state responses of LAI to long-term exposure to a range of prescribed ozone levels (from 0 to 100 ppb). We find that most plant functional types suffer a substantial decline in LAI as ozone level increases. Based on the CLM-simulated results, we develop and implement in the GEOS-Chem chemical transport model a parameterization that computes fractional changes in monthly LAI as a function of local mean ozone levels. By forcing LAI to respond to ozone concentrations on a monthly timescale, the model simulates ozone–LAI coupling dynamically via biogeochemical processes including biogenic volatile organic compound (VOC) emissions and dry deposition, without the complication from meteorological changes. We find that ozone-induced damage on LAI can lead to changes in ozone concentrations by −1.8 to +3 ppb in boreal summer, with a corresponding ozone feedback factor of −0.1 to +0.6 that represents an overall self-amplifying effect from ozone–LAI coupling. Substantially higher simulated ozone due to strong positive feedbacks is found in most tropical forests, mainly due to the ozone-induced reductions in LAI and dry deposition velocity, whereas reduced isoprene emission plays a lesser role in these low-NOx environments. In high-NOx regions such as the eastern US, Europe, and China, however, the feedback effect is much weaker and even negative in some regions, reflecting the compensating effects of reduced dry deposition and reduced isoprene emission (which reduces ozone in high-NOx environments). In remote, low-LAI regions, including most of the Southern Hemisphere, the ozone feedback is generally slightly negative due to the reduced transport of NOx–VOC reaction products that serve as NOx reservoirs. This study represents the first step to accounting for dynamic ozone–vegetation coupling in a chemical transport model with ramifications for a more realistic joint assessment of ozone air quality and ecosystem health.

scholarly journals Impact of the 2008 Global Recession on air quality over the United States: Implications for surface ozone levels from changes in NOxemissions

2016 ◽  
Vol 43 (17) ◽  
pp. 9280-9288 ◽  
Author(s):  
Daniel Tong ◽  
Li Pan ◽  
Weiwei Chen ◽  
Lok Lamsal ◽  
Pius Lee ◽  
...  
Keyword(s):  
United States ◽  
Air Quality ◽  
Surface Ozone ◽  
The United States ◽  
Global Recession ◽  
Ozone Levels

scholarly journals Sensitivities of NO<sub>x</sub> transformation and the effects on surface ozone and nitrate

2014 ◽  
Vol 14 (3) ◽  
pp. 1385-1396 ◽  
Author(s):  
H. Lei ◽  
J. X. L. Wang
Keyword(s):  
Air Quality ◽  
Los Angeles ◽  
Surface Ozone ◽  
Nox Emission ◽  
Ozone Production ◽  
Limited Area ◽  
Transformation Rate ◽  
Nox Emissions ◽  
Increase Rate ◽  
Industrial Regions

Abstract. As precursors to tropospheric ozone and nitrate, nitrogen oxide (NOx) in the present atmosphere and its transformation in response to emission and climate perturbations are studied by using the CAM-Chem model and air quality measurements from the National Emissions Inventory (NEI), Clean Air Status and Trends Network (CASTNET), and Environmental Protection Agency Air Quality System (EPA AQS). It is found that NOx transformations in present atmospheric conditions show different sensitivities over industrial and non-industrial regions. As a result, the surface ozone and nitrate formations can be divided into several regimes associated with the dominant emission types and relative levels of NOx and volatile organic compounds (VOC). Ozone production in industrial regions (the main NOx emission source areas) increases in warmer conditions and slightly decreases following an increase in NOx emissions due to NOx titration, which is opposite to the response in non-industrial regions. The ozone decrease following a temperature increase in non-industrial regions indicates that ozone production in regions that lack NOx emission sources may be sensitive to NOx transformation in remote source regions. The increase in NO2 from NOx titration over industrial regions results in an increase rate of total nitrate that remains higher than the increase rate of NOx emissions. The presented findings indicate that a change in the ozone concentration is more directly affected by changes in climate and precursor emissions, while a change in the nitrate concentration is affected by local ozone production types and their seasonal transfer. The sensitivity to temperature perturbations shows that a warmer climate accelerates the decomposition of odd nitrogen (NOy) during the night. As a result, the transformation rate of NOx to nitrate decreases. Examinations of the historical emissions and air quality records of a typical NOx-limited area, such as Atlanta and a VOC-limited area, such as Los Angeles further confirm the conclusions drawn from the modeling experiments.

scholarly journals Unraveling the complex local-scale flows influencing ozone patterns in the southern Great Lakes of North America

2010 ◽  
Vol 10 (8) ◽  
pp. 19763-19810 ◽  
Author(s):  
I. Levy ◽  
P. A. Makar ◽  
D. Sills ◽  
J. Zhang ◽  
K. L. Hayden ◽  
...  
Keyword(s):  
Air Quality ◽  
North America ◽  
Great Lakes ◽  
Lake Erie ◽  
Surface Ozone ◽  
Inversion Layer ◽  
Air Quality Model ◽  
Large Reservoir ◽  
Mixing Ratios ◽  
Ozone Levels

Abstract. This study examines the complexity of various processes influencing summertime ozone levels in the southern Great Lakes region of North America. Results from the Border Air Quality and Meteorology (BAQS-Met) field campaign in the summer of 2007 are examined with respect to land-lake differences and local meteorology using a large array of ground-based measurements, aircraft data and simulation results from a high resolution (2.5 km) regional air-quality model, AURAMS. Analyses of average ozone mixing ratio from the entire BAQS-Met intensive campaign period support previous findings that ozone levels are higher over the southern Great Lakes than over the adjacent land. However, there is great heterogeneity in the spatial distribution of surface ozone over the lakes, particularly over Lake Erie during the day, with higher levels located over the southwestern end of the lake. Results suggest that some of these increased ozone levels are due to local emission sources in large nearby urban centers. The land-lake differences in ozone mixing ratios are most pronounced during the night in a shallow inversion layer of about 200 m above the surface. After sunrise, these differences have a limited effect on the total mass of ozone over the lakes during the day time, though they may cause elevated ozone levels in the lake breeze air. A large reservoir layer of ozone is predicted by the AURAMS model over Lake Erie at night, centered between 600–1000 m above ground and extending into the land over Cleveland. The model also predicts a vertical circulation during the day with an updraft over Detroit-Windsor and downdraft over Lake St. Clair, which transports ozone up to 1500 m above ground and results in high ozone over the lake. Oscillations in ground level ozone mixing ratios were observed on several nights and several ground monitoring sites, with amplitudes of up to 40 ppbv and time periods of 15–40 min.

scholarly journals Unraveling the complex local-scale flows influencing ozone patterns in the southern Great Lakes of North America

2010 ◽  
Vol 10 (22) ◽  
pp. 10895-10915 ◽  
Author(s):  
I. Levy ◽  
P. A. Makar ◽  
D. Sills ◽  
J. Zhang ◽  
K. L. Hayden ◽  
...  
Keyword(s):  
Air Quality ◽  
North America ◽  
Great Lakes ◽  
Lake Erie ◽  
Surface Ozone ◽  
Inversion Layer ◽  
Air Quality Model ◽  
Quality Model ◽  
Mixing Ratios ◽  
Ozone Levels

Abstract. This study examines the complexity of various processes influencing summertime ozone levels in the southern Great Lakes region of North America. Results from the Border Air Quality and Meteorology (BAQS-Met) field campaign in the summer of 2007 are examined with respect to land-lake differences and local meteorology using a large array of ground-based measurements, aircraft data, and simulation results from a high resolution (2.5 km) regional air-quality model, AURAMS. Analyses of average ozone mixing ratio from the entire BAQS-Met intensive campaign period support previous findings that ozone levels are higher over the southern Great Lakes than over the adjacent land. However, there is great heterogeneity in the spatial distribution of surface ozone over the lakes, particularly over Lake Erie during the day, with higher levels located over the southwestern end of the lake. Model results suggest that some of these increased ozone levels are due to local emission sources in large nearby urban centers. While an ozone reservoir layer is predicted by the AURAMS model over Lake Erie at night, the land-lake differences in ozone mixing ratios are most pronounced during the night in a shallow inversion layer of about 200 m above the surface. After sunrise, these differences have a limited effect on the total mass of ozone over the lakes and land during the day, though they do cause elevated ozone levels in the lake-breeze air in some locations. The model also predicts a mean vertical circulation during the day with an updraft over Detroit-Windsor and downdraft over Lake St. Clair, which transports ozone up to 1500 m above ground and results in high ozone over the lake. Oscillations in ground-level ozone mixing ratios were observed on several nights and at several ground monitoring sites, with amplitudes of up to 40 ppbv and time periods of 15–40 min. Several possible mechanisms for these oscillations are discussed, but a complete understanding of their causes is not possible given current data and knowledge.

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