Fig 4 - uploaded by Phan Hong Danh Pham
Content may be subject to copyright.
a The scattergram of the five ground stations' observations and b The spatial distribution of the estimated PM 2.5 mass concentration on January 5, 2020 in HCMC
Source publication
Air pollution,
especially PM2.5 mass concentration is one of big problems in Ho Chi Minh City in recent years. This study focuses on deriving a linear regression model based on a relationship between ground-level PM2.5 mass concentration measurements and satellite aerosol optical depth (AOD) values. The PM2.5 measurements were collected from 25 gro...
Contexts in source publication
Context 1
... coefficient of 0.85 and a RMSE of 6.439 (μg/m 3 ), as presented in Table 3. The multivariable linear regression was presented by Eq. (2). For validating the model, the observations from the 5 ground stations was substituted into Eq. (2), and the result indicated a correlation coefficient of 0.88 and a RMSE of 5.567 (μg/m 3 ), as described in Fig. 4a. The relationship between ground-level PM 2.5 measurements and MODIS blue band and green band AOD values was shown in Eq. (2). Accordingly, the two MODIS blue band and green band AOD images on January 5, 2020 were substituted into the model. As a result, the PM 2.5 mass concentration in the whole HCMC was estimated, as illustrated in ...
Context 2
... in Fig. 4a. The relationship between ground-level PM 2.5 measurements and MODIS blue band and green band AOD values was shown in Eq. (2). Accordingly, the two MODIS blue band and green band AOD images on January 5, 2020 were substituted into the model. As a result, the PM 2.5 mass concentration in the whole HCMC was estimated, as illustrated in Fig. 4b. The observations on this day were used to verify the model, and the result indicated correlation of 0.63 and a RMSE of 5.149 (μg/m 3 ). Subsequently, estimated PM 2.5 mass concentration was approximate from 20 to 50 (μg/m 3 ) in the whole HCMC, but it presented a range of (30-35) (μg/m 3 ) in most of the study area in green color. ...
Citations
... In case of AOD in Blue band and Green band retrived from Terra satellite, the image datasets are filtered by the upper and lower boundaries, to eliminate anomalies caused by the effect of clouds and bad weather condition. The ground-level values of PM2.5 mass concentration can be estimated from AOD observations based on their correlation, illustrated as a linear regression [27][28][29][30]. In this paper, the PM2.5 mass concentration values are computed using the multivariable linear regression model from Equation (1), built from the MODIS Blue and Green band AOD images and the PM2.5 mass concentration measurements of the 25 PAM-Air ground stations in HCMC in 2020 [30]. ...
... The ground-level values of PM2.5 mass concentration can be estimated from AOD observations based on their correlation, illustrated as a linear regression [27][28][29][30]. In this paper, the PM2.5 mass concentration values are computed using the multivariable linear regression model from Equation (1), built from the MODIS Blue and Green band AOD images and the PM2.5 mass concentration measurements of the 25 PAM-Air ground stations in HCMC in 2020 [30]. After processing process, the data is divided into timeframe of dry season and wet season from 2019 to 2022 for the study to analyze the spatiotemporal distribution in air pollutants and its change due to the affect of the Covid-19 pandemic in HCMC. ...
The Corona virus disease in 2019 (Covid-19) has come up with serious consequences in public health all over the world, and especially in Ho Chi Minh City (HCMC). During the pandemic, the city needs to do quarantine activities to control the spread of the virus. This study focuses on exploring the impact of the Covid-19 outbreaks on the air quality by the concentration of pollutants including Sulphur Dioxide (SO2), Nitrogen Dioxide (NO2), and Ozone (O3) derived from Sentinel-5P TROPOMI data, and Particulate matter is at and under 2.5 mm of diameter (PM2.5) estimated from MODIS Aerosol Optical Depth (AOD) data. The duration of the research is from 1st January 2020 to 31st December 2022, and separated into 2 parts, based on the dry season and the wet season for the case study of Ho Chi Minh city. As a result, it shows the decrease in different level of air pollutants, including the significant decline in NO2 (up to 15.27%), SO2 (up to 46%), and PM2.5 (up to 25.46%), while the O3 layer suffered minor change of 1.75% in increasing. The results are expected to provide an understanding of the geospatial distribution of the air pollutants before and after the Covid-19 lockdown periods in HCMC. Moreover, it also confirms that deploying air quality monitoring systems with ground stations and satellite observations is effective.
