scholarly journals Insights into the abnormal increase of ozone during COVID-19 in a typical urban city of China

2021 ◽  
Author(s):  
Kun Zhang ◽  
Zhiqiang Liu ◽  
Xiaojuan Zhang ◽  
Qing Li ◽  
Andrew Jensen ◽  
...  
Keyword(s):  
Urban Areas ◽  
Proton Transfer Reaction ◽  
Yangtze River Delta ◽  
Air Pollutant ◽  
Photochemical Formation ◽  
Urban City ◽  
Pollutant Concentrations ◽  
Abnormal Increase ◽  
Air Pollutant Concentrations ◽  
The Relationship

Abstract. The outbreak of COVID-19 promoted strict restrictions to human activities in China, which led to dramatic decrease in most air pollutant concentrations (e.g., PM2.5, PM10, NOx, SO2, and CO). However, abnormal increase of ozone (O3) concentrations was found during the lockdown period in most urban areas of China. In this study, we conducted a field measurement targeting ozone and its key precursors by utilizing a novel proton transfer reaction time-of-flight mass spectrometer (PTR-TOF-MS) in Changzhou, which is representative for the Yangtze River Delta (YRD) city cluster of China. We further applied the integrated methodology including machine learning, observation-based model (OBM), and sensitivity analysis to get insights into the reasons causing the abnormal increase of ozone. Major findings include: (1) By deweathered calculation, we found changes in precursor emissions contributed 5.1 ppbv to the observed O3 during the Full-lockdown period, while meteorological conditions only contributed 0.5 ppbv to the O3 changes. (2) By using an OBM model, we found that although significant reduction of O3 precursors was observed during Full-lockdown period, the photochemical formation of O3 was stronger than that during the Pre-lockdown period. (3) The NOx / VOCs ratio dropped dramatically from 1.84 during Pre-lockdown to 0.79 in Full-lockdown period, which switched O3 formation from VOCs-limited regime to the conjunction of NOx- and VOC-limited regime. Additionally, the decrease in NOx / VOCs ratio during Full-lockdown period was supposed to increase the MeanO3 by 2.4 ppbv. Results of this study investigate insights into the relationship between O3 and its precursors in urban area, demonstrating reasons causing the abnormal increase of O3 in most urban areas of China during the COVID-19 lock-down period. This study also underlines the necessity of controlling anthropogenic OVOCs, alkenes, and aromatics in the sustained campaign of reducing O3 pollution in China.

Long-term Exposure to Low Air Pollutant Concentrations and the Relationship with All-Cause Mortality and Stroke in Older Men

Epidemiology ◽  
2019 ◽  
Vol 30 ◽  
pp. S82-S89 ◽  
Author(s):  
Mila Dirgawati ◽  
Andrea Hinwood ◽  
Lee Nedkoff ◽  
Graeme J. Hankey ◽  
Bu B. Yeap ◽  
...  
Keyword(s):  
Older Men ◽  
Air Pollutant ◽  
Pollutant Concentrations ◽  
All Cause Mortality ◽  
Air Pollutant Concentrations ◽  
The Relationship

scholarly journals Multitemporal analysis with statistical models: influence of the atmospheric condition on urban concentrations of particulate matter

2022 ◽  
Vol 2159 (1) ◽  
pp. 012003
Author(s):  
L Rodríguez-Garavito ◽  
K J Romero-Corredor ◽  
C A Zafra-Mejía
Keyword(s):  
Particulate Matter ◽  
Statistical Models ◽  
Urban Areas ◽  
Moving Average ◽  
Atmospheric Condition ◽  
Air Pollutant ◽  
Atmospheric Instability ◽  
Pollutant Concentrations ◽  
Multitemporal Analysis ◽  
Air Pollutant Concentrations

Abstract This paper shows a multitemporal analysis with autoregressive integrated moving average models of the influence of atmospheric condition on concentrations of particulate matter ≤ 10 µm in Bogotá city, Colombia. Information was collected from six monitoring stations distributed throughout the city. The study period was nine years. Autoregressive component of the models suggests that urban areas with greater atmospheric instability show a lower hourly persistence of particulate matter (one hour) compared to urban areas with lower atmospheric instability (two hours). Moving average component of the models hints those urban areas with greater atmospheric instability show greater hourly variability in particulate matter concentrations (5-10 hours). The models also suggest that a high degree of air pollution decreases the temporal influence of the atmospheric condition on particulate matter concentrations; in this case, the temporal behavior of particulate matter possibly depends on the urban emission sources of this pollutant rather than on the existing atmospheric condition. This study is relevant to deepen the knowledge in relation to the following aspects of atmospheric physics: The use of statistical models for the time series analysis of atmospheric condition, and the analysis by statistical models of the influence of atmospheric condition on air pollutant concentrations.

scholarly journals Mobile-Platform Measurement of Air Pollutant Concentrations in California: Performance Assessment, Statistical Methods for Evaluating Spatial Variations, and Spatial Representativeness

2020 ◽  
Author(s):  
Paul A. Solomon ◽  
Dena Vallano ◽  
Melissa Lunden ◽  
Brian LaFranchi ◽  
Charles L. Blanchard ◽  
...  
Keyword(s):  
Los Angeles ◽  
San Francisco ◽  
Urban Areas ◽  
Spatial Variations ◽  
Air Pollutant ◽  
Mobile Platform ◽  
Pollutant Concentrations ◽  
Accuracy And Precision ◽  
Research Grade ◽  
Air Pollutant Concentrations

Abstract. Mobile platform measurements provide new opportunities for characterizing spatial variations of air pollution within urban areas, identifying emission sources, and enhancing knowledge of atmospheric processes. The Aclima, Inc. mobile measurement and data acquisition platform was used to equip Google Street View cars with research-grade instruments. On-road measurements of air quality were made between May 2016 and September 2017 at high (i.e., 1-second [s]) temporal and spatial resolution at several California locations: Los Angeles, San Francisco, and the northern San Joaquin Valley (including non-urban roads and the cities of Tracy, Stockton, Manteca, Merced, Modesto, and Turlock). The results demonstrate that the approach is effective for quantifying spatial variations of air pollutant concentrations over measurement periods as short as two weeks. Measurement accuracy and precision are evaluated using results of weekly performance checks and periodic audits conducted through the sampler inlets, which show that research instruments in stationary vehicles are capable of reliably measuring nitric oxide (NO), nitrogen dioxide (NO2), ozone (O3), methane (CH4) black carbon (BC), and particle number (PN) concentration with bias and precision ranging from

scholarly journals Investigation the influence of some meteorological factors on shipping air emissions in the Istanbul Strait

2021 ◽  
Vol XXIV (1) ◽  
pp. 184-192
Author(s):  
TOKUSLU Aydin
Keyword(s):  
Human Health ◽  
Meteorological Parameters ◽  
Air Pollutant ◽  
Stepwise Multiple Regression ◽  
Pollutant Concentrations ◽  
Air Pollutant Concentrations ◽  
Relationship Of ◽  
Exhaust Gas Emissions ◽  
The Relationship ◽  
Harmful Effects

Shipping emissions are one of the most important environmental problems in Istanbul city and people living around the Bosphorus are unprotected from these effects every day. 35% of the population of Istanbul city (about 15 million people) live at a distance of approximately 4/5 km to the Bosphorus. Exhaust gas emissions (NOX, SOX, and PM) generated from transit ships have direct harmful effects on human health, the ecosystem, and the environment. Meteorological conditions play an important role in affecting air quality and human health due to seasonal changes and are closely related to air pollutant concentrations. In this study, the relationship of meteorological parameters (such as wind speed, temperature, relative humidity, pressure, precipitation) on the distribution of transit ship emissions was investigated using stepwise multiple regression and correlation analysis. A "good relationship" between the pollutants (NOX, SOX, PM) concentrations and meteorological parameters have been found.

scholarly journals Rapid ventilation of the Mexico City basin and regional fate of the urban plume

2006 ◽  
Vol 6 (1) ◽  
pp. 839-877 ◽  
Author(s):  
B. de Foy ◽  
J. R. Varela ◽  
L. T. Molina ◽  
M. J. Molina
Keyword(s):  
Mexico City ◽  
Urban Areas ◽  
Vertical Mixing ◽  
Air Pollutant ◽  
Residence Times ◽  
Meteorological Model ◽  
Pollutant Concentrations ◽  
Urban Plume ◽  
Air Pollutant Concentrations ◽  
Carry Over

Abstract. Urban areas can be large emitters of air pollutants leading to negative health effects and environmental degradation. The rate of venting of these airsheds determines the pollutant loading for given emission levels, and also determines the regional impacts of the urban plume. Mexico City has approximately 20 million people living in a high altitude basin with air pollutant concentrations above the health limits most days of the year. A mesoscale meteorological model (MM5) and a particle trajectory model (FLEXPART) are used to simulate air flow within the Mexico City basin and the fate of the urban plume during the MCMA-2003 field campaign. The simulated trajectories are validated against pilot balloon and radiosonde trajectories. The residence time of air within the basin and the impacted areas are identified by episode type. Three specific cases are analysed to identify the meteorological processes involved. For most days, residence times in the basin are less than 12 h with little carry-over from day to day and little recirculation of air back into the basin. Very efficient vertical mixing leads to a vertically diluted plume which, in April, is transported predominantly towards the Gulf of Mexico. Regional accumulation was found to take place for some days however, with urban emissions sometimes staying over Mexico for more than 6 days. Knowledge of the residence times, recirculation patterns and venting mechanisms will be useful in guiding policies for improving the air quality of the MCMA.

scholarly journals Photocatalytic self-cleaning facades in architectural design

2018 ◽  
Vol 16 (3) ◽  
pp. 425-436
Author(s):  
Aleksandra Curcic
Keyword(s):  
Energy Efficiency ◽  
Urban Areas ◽  
Architectural Design ◽  
Building Materials ◽  
Air Pollutant ◽  
Gaseous Emissions ◽  
Pollutant Concentrations ◽  
Sustainable Value ◽  
Self Cleaning ◽  
Air Pollutant Concentrations

Sustainable and affordable technologies are an important aspect of environment and energy efficiency. Environmental pollution in urban areas is one of the causes for poor air quality. Gaseous emissions from daily traffic are continuously increasing often exceeding the allowable concentration in the atmosphere. The development of self cleaning materials photocatalytic building materials-particularly when applied to facades, can contribute to providing the clean the air and to improvement of sustainability levels. They represents one of the most promising solutions for reducing air pollutant concentrations in urban areas, proving to be really effective and showing a real eco-sustainable value. The paper explains the mechanism of self-cleaning of fa?ades, their types in architectural design and the importance of their application.

scholarly journals Rapid ventilation of the Mexico City basin and regional fate of the urban plume

2006 ◽  
Vol 6 (8) ◽  
pp. 2321-2335 ◽  
Author(s):  
B. de Foy ◽  
J. R. Varela ◽  
L. T. Molina ◽  
M. J. Molina
Keyword(s):  
Mexico City ◽  
Urban Areas ◽  
Vertical Mixing ◽  
Air Pollutant ◽  
Residence Times ◽  
Meteorological Model ◽  
Pollutant Concentrations ◽  
Urban Plume ◽  
Air Pollutant Concentrations ◽  
Carry Over

Abstract. Urban areas can be large emitters of air pollutants leading to negative health effects and environmental degradation. The rate of venting of these airsheds determines the pollutant loading for given emission levels, and also determines the regional impacts of the urban plume. Mexico City has approximately 20 million people living in a high altitude basin with air pollutant concentrations above the health limits most days of the year. A mesoscale meteorological model (MM5) and a particle trajectory model (FLEXPART) are used to simulate air flow within the Mexico City basin and the fate of the urban plume during the MCMA-2003 field campaign. The simulated trajectories are validated against pilot balloon and radiosonde trajectories. The residence time of air within the basin and the impacted areas are identified by episode type. Three specific cases are analysed to identify the meteorological processes involved. For most days, residence times in the basin are less than 12 h with little carry-over from day to day and little recirculation of air back into the basin. Very efficient vertical mixing leads to a vertically diluted plume which, in April, is transported predominantly towards the Gulf of Mexico. Regional accumulation was found to take place for some days however, with urban emissions sometimes staying over Mexico for more than 6 days. Knowledge of the residence times, recirculation patterns and venting mechanisms will be useful in guiding policies for improving the air quality of the MCMA.

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