PERFORMANCE OF AHI HOURLY AEROSOL OPTICAL PROPERTY DURING FREQUENT HAZE-FOG EVENTS: A CASE STUDY OF BEIJING

Abstract. The Advanced Himawari Imager (AHI) onboard Himawari-8, a next-generation geostationary meteorological satellite, provided firstly the full-disk aerosol observations every 10 min at sub-kilometer spatial resolution(5 km). This is responsible for retrieving the ground-level particulate matter of fewer than 2.5 micrometers and improving assimilation model. However, the representativeness of AHI L3 hourly Aerosol Optical Thickness (AOT) products remains unclear under different air quality conditions, Especially, over frequently polluted urban areas that feature complex surface characteristics and aerosol models. In this study, One-to-one comprehensive comparisons were conducted to evaluate the performance of three types of AHI L3 AOT products (version 3.0) based on the Aerosol Robotic NETwork (AERONET) aerosol measurements over Beijing. The overall comparisons of AHI and ground AOTs show the AHI merged AOT perform best, which the R is 0.87, RMSE is 0.25 and 52.5% of retrievals fall within the envelope of Expect Error (EE, ±(0.05 + 0.2 * AOTground)). For the different primary pollutants, the results suggested the three types AHI hourly AOT products are more suitable for the fine particulate matters (PM2.5) retrievals, especially the merged AOT with 0.87 of R, 0.29 of RMSE and 58.8% of within EE. Furthermore, when the slight and moderate pollution happened over Beijing, the AHI hourly AOT products perform well. And when the heavy pollution happened, the performance of the AHI merge AOT and L2 mean AOT is better. a case during low to high pollution suggested that AHI merged AOT can capture the similar spatial pattern to the MODIS (Deep Blue) DB or (Dark Target) DTDB merged AOT and has good consistency with ground-based air quality monitoring. These results demonstrate the AHI hourly merged AOT is a promising aerosol retrieval for air quality.

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Validation and Comparison of MODIS C6.1 and C6 Aerosol Products over Beijing, China

Remote Sensing ◽

10.3390/rs10122021 ◽

2018 ◽

Vol 10 (12) ◽

pp. 2021 ◽

Cited By ~ 17

Author(s):

Xinpeng Tian ◽

Qiang Liu ◽

Xiuhong Li ◽

Jing Wei

Keyword(s):

Optical Properties ◽

Urban Areas ◽

Surface Characteristics ◽

Complex Surface ◽

Deep Blue ◽

Spatial Coverage ◽

Moderate Resolution ◽

Moderate Resolution Imaging Spectroradiometer ◽

Beijing China ◽

Better Than

The operational Moderate Resolution Imaging Spectroradiometer (MODIS) Aerosol Products (APs) have provided long-term and wide-spatial-coverage aerosol optical properties across the globe, such as aerosol optical depth (AOD). However, the performance of the latest Collection 6.1 (C6.1) of MODIS APs is still unclear over urban areas that feature complex surface characteristics and aerosol models. The aim of this study was to validate and compare the performance of the MODIS C6.1 and C6 APs (MxD04, x = O for Terra, x = Y for Aqua) over Beijing, China. The results of the Dark Target (DT) and Deep Blue (DB) algorithms were validated against Aerosol Robotic Network (AERONET) ground-based observations at local sites. The retrieval uncertainties and accuracies were evaluated using the expected error (EE: ±0.05 + 15%) and the root-mean-square error (RMSE). It was found that the MODIS C6.1 DT products performed better than the C6 DT products, with a greater percentage (by about 13%–14%) of the retrievals falling within the EE. However, the DT retrievals collected from two collections were significantly overestimated in the Beijing region, with more than 64% and 48% of the samples falling above the EE for the Terra and Aqua satellites, respectively. The MODIS C6.1 DB products performed similarly to the C6 DB products, with 70%–73% of the retrievals matching within the EE and estimation uncertainties. Moreover, the DB algorithm performed much better than DT algorithm over urban areas, especially in winter where abundant missing pixels were found in DT products. To investigate the effects of factors on AOD retrievals, the variability in the assumed surface reflectance and the main optical properties applied in DT and DB algorithms are also analyzed.

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Air Quality Modeling in Dense Urban Areas at Ground Level—CFD, OSM or Gauss?

10.1007/978-3-662-63760-9_37 ◽

2021 ◽

pp. 265-270

Author(s):

Marie Haeger-Eugensson ◽

Christine Achberger ◽

Helen Nygren ◽

Erik Bäck ◽

Anna Bjurbäck ◽

...

Keyword(s):

Air Quality ◽

Urban Areas ◽

Ground Level ◽

Air Quality Modeling ◽

Quality Modeling

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A Machine Learning Approach to Predict Air Quality in California

Complexity ◽

10.1155/2020/8049504 ◽

2020 ◽

Vol 2020 ◽

pp. 1-23 ◽

Cited By ~ 2

Author(s):

Mauro Castelli ◽

Fabiana Martins Clemente ◽

Aleš Popovič ◽

Sara Silva ◽

Leonardo Vanneschi

Keyword(s):

Machine Learning ◽

Air Quality ◽

Environmental Protection Agency ◽

Urban Areas ◽

Principal Component ◽

Ground Level ◽

Support Vector ◽

Validation Data ◽

Pollutant Concentrations ◽

Rbf Kernel

Predicting air quality is a complex task due to the dynamic nature, volatility, and high variability in time and space of pollutants and particulates. At the same time, being able to model, predict, and monitor air quality is becoming more and more relevant, especially in urban areas, due to the observed critical impact of air pollution on citizens’ health and the environment. In this paper, we employ a popular machine learning method, support vector regression (SVR), to forecast pollutant and particulate levels and to predict the air quality index (AQI). Among the various tested alternatives, radial basis function (RBF) was the type of kernel that allowed SVR to obtain the most accurate predictions. Using the whole set of available variables revealed a more successful strategy than selecting features using principal component analysis. The presented results demonstrate that SVR with RBF kernel allows us to accurately predict hourly pollutant concentrations, like carbon monoxide, sulfur dioxide, nitrogen dioxide, ground-level ozone, and particulate matter 2.5, as well as the hourly AQI for the state of California. Classification into six AQI categories defined by the US Environmental Protection Agency was performed with an accuracy of 94.1% on unseen validation data.

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The Effect of Nonlocal Vehicle Restriction Policy on Air Quality in Shanghai

Atmosphere ◽

10.3390/atmos9080299 ◽

2018 ◽

Vol 9 (8) ◽

pp. 299 ◽

Cited By ~ 7

Author(s):

Junjie Li ◽

Xiao-Bing Li ◽

Bai Li ◽

Zhong-Ren Peng

Keyword(s):

Air Quality ◽

Urban Areas ◽

Traffic Management ◽

Health And Safety ◽

Ground Level ◽

License Plate ◽

Traffic Emission ◽

Restriction Policy ◽

Co Concentration ◽

The Impact

In recent years, road space rationing policies have been increasingly applied as a traffic management solution to tackle congestion and traffic emission problems in big cities. Existing studies on the effect of traffic policy on air quality have mainly focused on the odd–even day traffic restriction policy or one-day-per-week restriction policy. There are few studies paying attention to the effect of nonlocal license plate restrictions on air quality in Shanghai. Restrictions toward nonlocal vehicles usually prohibit vehicles with nonlocal license plates from entering certain urban areas or using certain subsets of the road network (e.g., the elevated expressway) during specific time periods on workdays. To investigate the impact of such a policy on the residents’ exposure to pollutants, CO concentration and Air Quality Index (AQI) were compared during January and February in 2015, 2016 and 2017. Regression discontinuity (RD) was used to test the validity of nonlocal vehicle restriction on mitigating environmental pollution. Several conclusions can be made: (1) CO concentration was higher on ground-level roads on the restriction days than those in the nonrestriction days; (2) the extension of the restriction period exposed the commuters to high pollution for a longer time on the ground, which will do harm to them; and (3) the nonlocal vehicle restriction policy did play a role in improving the air quality in Shanghai when extending the evening rush period. Additionally, some suggestions are mentioned in order to improve air quality and passenger health and safety.

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REGIONAL-SCALE MODELING OZONE AIR QUALITY OVER THE CONTINENTAL SOUTH EAST ASIA

Science and Technology Development Journal ◽

10.32508/stdj.v12i2.2211 ◽

2009 ◽

Vol 12 (2) ◽

pp. 111-120

Author(s):

Nghiem Hoang Le ◽

Oanh Thi Kim Nguyen

Keyword(s):

Air Quality ◽

East Asia ◽

Urban Areas ◽

Regional Scale ◽

Ground Level ◽

South East Asia ◽

Modeling Tools ◽

Ozone Concentrations ◽

Ozone Levels ◽

Monitoring Stations

Long range transport of ozone and its precursors can significantly impact the air quality in downwind regions. The problem of regional transport of ozone has been studied for more than three decades in Europe and U.S but not yet in Southeast Asia. This study investigated the regional scale distribution of tropospheric ozone over the Continental South East Asia Region (CSEA) of Thailand, Burma, Cambodia, Lao and Vietnam. The Models-3 Community Multi-scale Air Quality (CMAQ modeling system, driven by the NCAR/Penn State Fifth-Generation Mesoscale Model (MM5), is used for the purpose. The model domain covers the longitude range from 91'E to 111°E and the latitude range from 5°N to 25°N. Two most recent ozone episodes of March 24-26, 2004 and January 2-4, 2005 were selected which represent the typical meteorological conditions for high ozone concentrations periods of a year. The episode analysis was made based on available data from 10 and 4 monitoring stations located in Bangkok of Thailand and Ho Chi Minh City (HCMC) of Vietnam, respectively. The episodes were characterized with hourly ozone levels above the National Ambient Air Quality Standards of Thailand and Vietnam of 100 ppb at a number of the monitoring stations. The maximum ground level concentrations of ozone for March 2004 and January 2005 episodes reached 173 ppb and 157 ppb, respectively, in the urban plume of the Bangkok Metropolitan Region (BMR). The simulations were performed with 0.5o 0.5° emission input data which was prepared from the regional anthropogenic emission inventory used in the Transport and Chemical Evolution over the Pacific (TRACE-P), and the biogenic emissions obtained from the Global Emissions Inventory Activity (GEIA). The simulated overall picture of ground level ozone concentrations over CSEA domain shows that the concentrations were high at the downwind areas at a considerable distance from large urban areas such as BMR and HCMC. During March 2004 episode the ozone plume moved northeastward following the Southwesterly monsoon and the maximum width of the modeled plume with the ozone above 100 ppb was about 70 km from BMR. For HCMC the ozone plume moved northward and the concentration in the city plume was lower with the width of isopleth of 50ppb of around 40 km. During the Jan 2005 episode the ozone plume moved southwestward following the Northeasterly monsoon and the width of the modeled plume with the ozone concentration above 100 ppb in BMR was 50 km while for HCMC the width of the 40ppb isopleth was about 30 km. The model performance was evaluated on the available observed hourly ozone concentrations. The model system was shown to be able to reproduce the peak ozone levels that occurred during the episodes at these two large urban areas, and capture the day by day variations during the selected episodes. The performance statistics MNBE, NGE, and UPA for the simulated ozone concentrations are within U.S. EPA guidance criteria and are comparable to those reported previous for other regional ozone simulations. It is shown that the MM5/CMAQ system is the suitable modeling tools for ozone prediction over the CSEA.

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Evaluation of MODIS-Retrieved Aerosol Optical Depth in Alaska: Implications for Surface Air Quality Applications

10.20944/preprints201805.0123.v1 ◽

2018 ◽

Author(s):

Alyson McPhetres ◽

Srijan Aggarwal

Keyword(s):

Air Quality ◽

Aerosol Optical Depth ◽

Optical Depth ◽

National Parks ◽

Urban Areas ◽

Ground Level ◽

Modis Data ◽

Particulate Pollution ◽

Modis Aod ◽

Pollution Concentrations

The air quality monitoring network in Alaska is currently limited to ground-based observations in urban areas and national parks leaving a large proportion of the state unmonitored. The use of MODIS aerosol optical depth (AOD) to estimate ground-level particulate pollution concentrations has been successfully demonstrated around the world, and could potentially be used in Alaska. In this work, MODIS AOD measurements at 550 nm were validated against AOD derived from AERONET ground-based sunphotometers in Barrow and Bonanza Creek to determine if MODIS AOD from the Terra and Aqua satellites could be used to estimate ground-level particulate pollution concentrations. The MODIS AOD was obtained from MODIS collection 6 using the dark target Land and Ocean algorithms from 2000 to 2014. MODIS data could only be obtained between the months of April and October; therefore, it could only be validated for those months. Individual and combined Terra and Aqua MODIS data were considered. The results showed that MODIS collection 6 products at 10 km resolution for Terra and Aqua combined are not valid over land but are valid over the ocean. On the other hand, the individual Terra and Aqua MODIS collection 6 AOD products at 10 km resolution are valid over land individually but not when combined. Results also suggest the MODIS collection 6 AOD products at 3 km resolution are valid over land and ocean and perform better over land than the 10-km product. These findings indicate that MODIS collection 6 AOD products can be used quantitatively in air quality applications in Alaska during the summer months.

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Air Inequality: Global Divergence in Urban Fine Particulate Matter Trends

10.26434/chemrxiv.14671908 ◽

2021 ◽

Author(s):

Joshua Apte ◽

Sarah Seraj ◽

Sarah Chambliss ◽

Melanie Hammer ◽

Veronica Southerland ◽

...

Keyword(s):

Air Quality ◽

Urban Areas ◽

Urban Population ◽

Fine Particulate Matter ◽

Ground Level ◽

World Health ◽

Global Environmental ◽

Key Policy ◽

Health Organization

Fine particle air pollution (PM2.5) is the largest global environmental risk factor for ill-health and is implicated in >7% of all human deaths. Improved air quality is a key policy goal for cities, yet in-situ PM2.5 measurements are missing for >50% of the world’s urban population. Here, we apply satellite remote sensing to develop a 21-year time series of ground-level PM2.5 concentrations for the 4231 urban areas with populations >100,000 (2.9 billion people) from 1998 -2018. Globally, we find the most polluted cities are generally small (<1 million population) and lack PM2.5 monitors. Since 1998, we observe a growing divide in urban air quality between cities in lower and higher-income regions, with the PM2.5 disparity increasing by >50% (from 25 to 39 µg m-3) between the highest- and lowest income quartiles of world cities. Within Asia, a sharp divergence is underway, with sustained PM2.5 increases in South Asian cities (+48%) contrasted against dramatic improvements in Chinese cities (-40% since 2011). While 85% of the world’s urban population experiences PM2.5 higher than World Health Organization guidelines, urban PM2.5 concentrations are tightly linked to regional conditions, suggesting that city-level efforts alone may be insufficient to address this major health threat.

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3D Spatial Analysis of Particulate Matter (PM10, PM2.5 and PM1.0) and Gaseous Pollutants (H2S, SO2 and VOC) in Urban Areas Surrounding a Large Heat and Power Plant

Energies ◽

10.3390/en14144070 ◽

2021 ◽

Vol 14 (14) ◽

pp. 4070

Author(s):

Robert Cichowicz ◽

Maciej Dobrzański

Keyword(s):

Particulate Matter ◽

Air Quality ◽

Power Plant ◽

Urban Areas ◽

Ground Level ◽

Industrial Plant ◽

Gaseous Pollutants ◽

Winter Period ◽

Housing Estate ◽

The Impact

In many regions of the world, the winter period is a time of poor air quality, due primarily to the increased use of individual and district heating systems. As a consequence, the atmospheric air contains increased concentrations of both particulate matter and gaseous pollutants (as a result of “low” emissions at altitudes of up to 40 m and “high” emissions more than 40 m above ground level). In winter, the increased pollution is very often exacerbated by meteorological conditions, including air temperature, pressure, air speed, wind direction, and thermal inversion. Here, we analyze the concentrations of particulate matter (PM10, PM2.5, and PM1.0) and gaseous pollutants (H2S, SO2, and VOC) in the immediate vicinity of a large solid fuel-fired heat and power plant located in an urban agglomeration. Two locations were selected for analysis. The first was close to an air quality measurement station in the center of a multi-family housing estate. The second was the intersection of two main communication routes. To determine the impact of “low” and “high” emissions on air quality, the selected pollutants were measured at heights of between 2 and 50 m using an unmanned aerial vehicle. The results were compared with permissible standards for the concentration of pollutants. Temperature inversion was found to have a strong influence on the level of pollutants at various heights, with higher concentrations of particulate matter registered at altitudes above 40 m. The source of PM, H2S, and SO2 pollutants was confirmed to be “low emission” from local transport, industrial plant areas, and the housing estate comprising detached houses located in the vicinity of the measuring points. “High emission” was found to be responsible for the high concentrations of VOC at altitudes of more than 40 m above the intersection and in the area of the housing estate.

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The impact of air pollution on terrestrial managed and natural vegetation

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2019.0317 ◽

2020 ◽

Vol 378 (2183) ◽

pp. 20190317 ◽

Cited By ~ 3

Author(s):

C. J. Stevens ◽

J. N. B. Bell ◽

P. Brimblecombe ◽

C. M. Clark ◽

N. B. Dise ◽

...

Keyword(s):

Twentieth Century ◽

Air Pollution ◽

Air Quality ◽

Urban Areas ◽

Industrial Revolution ◽

Ground Level ◽

Natural Vegetation ◽

Natural Ecosystems ◽

The Uk ◽

The Impact

Although awareness that air pollution can damage vegetation dates back at least to the 1600s, the processes and mechanisms of damage were not rigorously studied until the late twentieth century. In the UK following the Industrial Revolution, urban air quality became very poor, with highly phytotoxic SO 2 and NO 2 concentrations, and remained that way until the mid-twentieth century. Since then both air quality, and our understanding of pollutants and their impacts, have greatly improved. Air pollutants remain a threat to natural and managed ecosystems. Air pollution imparts impacts through four major threats to vegetation are discussed through in a series of case studies. Gas-phase effects by the primary emissions of SO 2 and NO 2 are discussed in the context of impacts on lichens in urban areas. The effects of wet and dry deposited acidity from sulfur and nitrogen compounds are considered with a particular focus on forest decline. Ecosystem eutrophication by nitrogen deposition focuses on heathland decline in the Netherlands, and ground-level ozone at phytotoxic concentrations is discussed by considering impacts on semi-natural vegetation. We find that, although air is getting cleaner, there is much room for additional improvement, especially for the effects of eutrophication on managed and natural ecosystems. This article is part of a discussion meeting issue ‘Air quality, past present and future’.

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