Search

Increasing emissions of aerosol and trace gases (e.g. nitrogen dioxide: NO2 and sulfur dioxide: SO2) have resulted in severe air pollution in China due to its rapid industrialization, economic growth, and urbanization. This resulted in numerous environmental and health problems, and poor air quality mainly in industrial areas and major cities. This study identifies long-term (2005‒2020) Ozone Monitoring Instrument (OMI) based NO2 and SO2 pollution hotspots across China by analyzing spatiotemporal distributions and variations, with characterization of polluted provinces, SO2/NO2 ratio, trend, and assessing how effective China's Air Pollution Control Policy (APCP) is on NO2 and SO2. Results show that NO2 and SO2 pollution hotspots were seen in China's central (Hubei), eastern (Anhui, Jiangsu, Shandong, Zhejiang), northern (Beijing, Hebei, Henan, Shanxi, Tianjin), northeast (Liaoning, Jilin), northwestern (Urumqi), southern (Guangdong, Hong Kong), and southwest (Chongqing, Sichuan). However, the pollution level was higher in winter, followed by autumn, spring, and summer. China's eight provinces (Tianjin, Shanghai, Shandong, Jiangsu, Beijing, Hebei, Hong Kong, and Henan) were identified as extremely polluted with high NO2 levels ranging from 16.86 − 9.75 (1015 molecules/cm2), whereas Shandong, Tianjin, Hebei, Beijing, Henan, Shanxi, Jiangsu, Shanghai, Anhui, and Liaoning were deemed to extremely polluted provinces with high SO2 levels ranging from 20.62 − 14.30 (1015 molecules/cm2). Moreover, the SO2/NO2 ratio for 27 Chinese provinces fluctuates between 1.02 to 4.98, indicating industries emit more SO2 than NO2. Finally, China's air pollution control policies (APCP) led to the largest annual reductions in NO2 during the 12th five-year plan (FYP) (6%‒94%) and SO2 during the 11th FYP (6%‒74%). The present study concludes, however, that China's APCP improved air quality by easing NO2 and SO2 emissions. This study recommends that the Chinese government may adopt a comprehensive strategy to reduce air pollution, including investing in clean energy, promoting electric vehicles, enforcing strict emission standards for industries, implementing green building practices, and raising public awareness about pollution reduction. [ABSTRACT FROM AUTHOR]

Forty percent of patients with acute coronary occlusion myocardial infarction (OMI) do not present with STEMI criteria, which delays their treatment and increases morbidity and mortality. The need to identify these patients promptly is crucial, and this sets the stage for the proposed reclassification. Many of these patients can be identified by other ECG and clinical features. Background/Objectives: We sought to evaluate cases of STEMI and NSTEMI that result in OMI. Additionally, we focused on the consequences of delayed revascularization in NSTEMI patients with acute coronary occlusion (NSTEMI-OMI). Methods: The study is a retrospective analysis conducted on 334 patients who underwent coronary angiography for acute coronary syndrome at UHC "Mother Teresa", Tirana, Albania, during January–May 2023. "OMI was defined as an acute culprit lesion with TIMI 0–2 flow, or an acute culprit lesion with TIMI 3 flow intervened upon and with highly elevated troponin (cTnI > 10.0 ng/mL, hs-cTnI > 5000 ng/L)". The presence or absence of STEMI criteria were determined in the final diagnosis written on the chart by a cardiologist using the third universal definition of MI. Ejection fraction (EF), total ischemia time, length of stay, and complications were compared between groups. Mechanical complications include acute ventricular failure, cardiogenic shock, rupture of the interventricular septum, rupture of the free wall, rupture of the papillary muscle, and pericarditis. Electrical complications include ventricular arrhythmias, supraventricular arrhythmias, and atrioventricular and interventricular blocks. Results: There were 334 patients included, 98 (29.3%) of whom were NSTEMI-OMI patients. Ninety-six patients (40%) of OMI patients did not fulfill the STEMI criteria. Only 11 patients (11%) of STEMI(−)OMI had PCI performed within the first 12 h vs. 76 patients (77%) with STEMI(+)OMI, p < 0.001. There was no difference in the percent of patients requiring PCI between the STEMI(+)OMI 98 patients (93%) and STEMI(−)OMI 87 patients (89%) (p = 0.496). The overall in-hospital mortality was 19 patients (5.7%), with subgroup mortality of 14 patients (4.2%) with STEMI(+)OMI, 2 patients (0.6%) with STEMI(+) NOMI, and 3 patients (0.9%) with STEMI(−)OMI, 0% STEMI(−)NOMI, (p = 0.013). Patients with mechanical complications included 67 patients (46.8%) with STEMI(+)OMI and 45 patients (46.4%) with STEMI(−)OMI. In addition, 26 patients (18.5%) with STEMI(+)OMI and 13 patients (13.1%) with STEMI(−)OMI developed electrical complications. Conclusions: STEMI(−)OMI patients had significant delays in catheterization, yet had angiographic findings, rates of PCI, and complications similar to STEMI(+)OMI. These data add further support to refocusing the paradigm of acute MI to improve recognition and rapid reperfusion of all OMIs, rather than only those with STEMI criteria. [ABSTRACT FROM AUTHOR]

This study presents new glyoxal (CHOCHO) products from the Ozone Monitoring Instrument (OMI) by utilizing updated level 1B irradiance/radiance data (Collection 4) and an updated glyoxal retrieval algorithm. The adoption of Collection 4 contributes to the reduction of artificial signals in differential glyoxal slant column densities (dSCDs) and improved fitting root mean square, and the updated retrieval settings result in fewer negative values of glyoxal dSCDs over oceans and less noisy dSCDs in the South Atlantic Anomaly. On‐line calculations of air mass factors consider interactive physical processes between input parameters. To address persistent trends in glyoxal SCDs over the Pacific Ocean that remain despite these updates, a trend correction is implemented. We evaluate the updated OMI glyoxal products using inter‐comparisons with GOME‐2A/2B glyoxal products. OMI glyoxal products exhibit good spatial and temporal agreement with GOME‐2A/2B, with correlation coefficients of 0.75–0.78 globally and 0.84–0.85 over source regions. Small biases are observed in OMI glyoxal vertical column densities, ranging from −0.2 ± 5.7% to 9 ± 3% in low and high glyoxal conditions, respectively, against GOME‐2A/2B. These advancements contribute to the reliability and accuracy of OMI glyoxal products, enhancing their utility for atmospheric studies and enabling a 20‐year‐long data record suitable for climate studies. Plain Language Summary: This research introduces new glyoxal (CHOCHO) products obtained from a satellite instrument called the Ozone Monitoring Instrument (OMI). For new glyoxal products, we use the updated OMI irradiance/radiance data and update the way we analyze the radiance data. As a result, new OMI glyoxal products show the reduction of errors caused by the instrument and consider interactive physical processes between the surface and atmosphere. The new data matches well with similar data from other satellite instruments (GOME‐2A/B), showing that the improvements are effective. This better data set helps scientists study the air quality over a long period of time. Key Points: We improve Ozone Monitoring Instrument (OMI) glyoxal column measurements with the new radiance data (Collection 4) and updated retrieval algorithmThe new glyoxal measurements show the stable spectral fitting through OMI's lifetimeCompared to GOME‐2A/B, OMI glyoxal products show good spatial (temporal) correlation coefficients of 0.75–0.78 (0.84–0.85), respectively [ABSTRACT FROM AUTHOR]

Aerosols have a significant impact on solar radiation, air quality deterioration, and climate change. To effectively assess the consequences of aerosols, we have to initially recognize the spatiotemporal distributions of their characteristics. This article uses OMI retrieved UVAI and Aqua MODIS retrieved AE data to analyze the spatiotemporal distributions and inter-annual trends of absorbing aerosol across Nigeria. Significant spatio-temporal variations in UVAI were observed high in northern and low in southern regions. The mean UVAI and AE over Nigeria shows an increasing and decreasing trend of 3.16% year−1 and − 1.62% year−1. Annually, UVAI showed an increasing trend of 7.59%, 9.79%, 5.19%, 6.27%, 7.65%, 4.87%, 7.17%, 4.99%, 4.10%, and 6.73% over Delta, Niger, Edo, Sokoto, Kwara, Osun, Kogi, Ondo, Oyo, and Ogun states respectively whereas AE is decreasing at the rate of − 0.53% year−1, − 2.50% year−1, − 0.84% year−1, − 1.18% year−1, − 2.12% year−1, − 1.19% year−1, − 1.12% year−1, − 0.85% year−1, − 1.77% year−1, and − 1.06% year−1 over Delta, Niger, Edo, Sokoto, Kwara, Osun, Kogi, Ondo, Oyo, and Ogun states respectively. UVAI was observed high during winter associated with dust storm activities. The HYSPLIT cluster analysis reveals the dominance of natural aerosols over northern and southern regions and Urban/industrial pollutants over the central regions of Nigeria. A strong positive correlation of UVAI with precipitation and temperature is observed in the northern regions of Nigeria. In accordance with the outcomes of this study, multiple methods such as planting more trees, improving fuel quality, etc. can be employed to lower the concentration of particle pollution. [ABSTRACT FROM AUTHOR]

The results of an analysis of long-term trends and interannual variations of the NO2 content in the atmosphere according to measurements with the Ozone Monitoring Instrument (OMI) aboard the EOS Aura satellite in 2004–2020 are compared to the results of a similar analysis of the NO2 content derived from independent spectrometric twilight NO2 measurements by zenith-scattered solar radiation at stations of the Network for the Detection of Atmospheric Composition Change (NDACC). According to both data, seasonally dependent estimates of linear NO2 trends and variations of the NO2 content under the influence of an 11-year cycle of solar activity and large-scale circulation factors such as the Arctic and Antarctic Oscillations, variations in ocean surface temperature in the Niño 3.4 zone, and the quasi-biennial oscillation in zonal wind in the equatorial stratosphere have been obtained. In general, a good qualitative and, in some cases, quantitative correspondence between estimates of interannual variations of NO2 has been obtained. For interannual variations of stratospheric NO2, the correspondence between estimates based on satellite and ground-based data on average for all stations is not bad, but the correspondence between trend estimates is noticeably worse. The best correspondence between the analysis results has been obtained for the Zvenigorod station. For stratospheric NO2, it was noted in 80–90% of cases, and the correspondence for tropospheric NO2 is practically 100%. [ABSTRACT FROM AUTHOR]

To study air pollution in the North China Plain (NCP), the Air Chemistry Research in Asia (ARIAs) campaign conducted airborne measurements of air pollutants in spring 2016. High pollutant concentrations, with O3 > 100 ppbv, CO > 500 ppbv, and NO2 > 10 ppbv, were observed. CMAQ simulations with the 2010 EDGAR emissions capture the spatial and temporal variations in ozone and its major precursors such as NO2 and VOCs, with significant underestimation. Differences between CMAQ simulations and satellite observations reflect changes in anthropogenic emissions, decreased NOx emissions in megacities such as Beijing, but slight increases in other cities and rural areas. CMAQ also underestimates HCHO and CO, suggesting adjustments of the 2010 EDGAR emissions are necessary. HCHO/NO2 column ratios derived from OMI measurements and CMAQ simulations show that VOC-sensitive chemistry dominates the ozone photochemical production in eastern China, suggesting the importance of tightening regulations on anthropogenic VOC emissions. After adjusting emissions based on satellite observations, better model performance was achieved. Because of the VOC-sensitive environment in ozone chemistry over the NCP, the underestimation of anthropogenic emissions could be important for CMAQ simulations, while future study and regulations should focus on VOC emissions with continuous controls on NOx emissions in China. [ABSTRACT FROM AUTHOR]

Nowadays, environmental problems have gradually become the focus of world attention. In recent years, heat waves in many parts of Europe have increased ozone concentrations, fuelling ozone pollution. Therefore, this paper investigates the spatial and temporal distribution of tropospheric column ozone concentrations in South-western Europe, future trend changes, influencing factors, and potential source regions based on remotely sensed monitoring data from the OMI (Ozone Monitoring Instrument) from 2011 to 2021. The results show that the areas of high tropospheric column ozone concentrations are mainly concentrated in the northwest, Poland, and southeast coastal areas. At the same time, the monthly variation curve of column ozone concentration is bimodal. Trend change analyses indicate an upward trend in future column ozone concentrations in the southeastern part of the study area. The potential for increases also exists in parts of Germany, France, and Poland, which will need to be monitored. Random forest model projections found a slight decrease in column ozone concentrations in 2022 and 2023 of about 1–4 DU compared to tropospheric column ozone concentrations in 2021. The health risk assessment found that the number of all-cause premature deaths due to exposure to ozone was the highest in Germany. During the summer, when ozone pollution is high, the potential source area in the southeastern part of the study area is located at the border of the three countries, and synergistic management is recommended. In exploring the correlation between the influencing factors and ozone, it was found that there is a significant difference between the long-time and short-time series. In addition, the pathway analysis shows that the population size, distribution density, and forested area in southwestern Europe may be more sensitive to the production of tropospheric ozone. [ABSTRACT FROM AUTHOR]

This study aims to generate a satellite-based qualitative emission source characterization for the heavily polluted eastern part of China in the 2010–2016 time period. The applied source identification technique relies on satellite-based NOx and SO2 emission estimates by OMI, their SO2:NOx ratio, and the MIX anthropogenic emission inventory to distinguish emissions from different emission categories (urban, industrial, natural) and characterize the dominant source per 0.25° × 0.25° grid cell in East China. Overall, we find good agreement between the satellite- and emission inventory–based spatiotemporal distribution and characterization of the dominant emission sources in East China in 2010–2016. In 2010, the satellite measurements suggest an emission distribution less dominated by industrial areas, a somewhat larger role for urban/transportation areas and agricultural activities, and more natural emissions in the southern part compared to the bottom-up emission categorization. In 2016, more than half of the classified emission categories over East China have remained the same. At the same time, there is a notable increase of agricultural lands and decrease of areas dominated by industry/transportation in 2016, suggestive of an overall decrease in heavy air pollution in East China over the course of 7 years. This is likely attributed to the sustained efforts of the Chinese government to drastically improve the air quality, especially since 2013 when the National Air Pollution Prevention and Control Action Plan was enacted. However, signs of urban expansion (urbanization) and rural–urban migration ("Go West" motion) stemmed from China's rapid economic growth and labour demand are evident; escalating industrialization (even with cleaner means) and the urban population growth in East China resulted in stronger emissions from sources representing consumption and transportation which are strongly related to NO2 and PM10 pollution (rather than SO2) and are directly influenced by the population size. This resulted to a shift of the emissions from the east mainly to the north and northwest of East China. Overall, although the effectiveness of the Chinese environmental control policies has been successful, the air pollution problem remains an important concern. [ABSTRACT FROM AUTHOR]

The Outer Continental Shelf of the Gulf of Mexico (GOM) is populated with numerous oil and natural gas (ONG) platforms which produce NOx (NOx = NO + NO2), a major component of air pollution. The Bureau of Ocean Energy Management (BOEM) is mandated to ensure that the air quality of coastal states is not degraded by these emissions. As part of a NASA‐BOEM collaboration, we conducted a satellite data‐based analysis of nitrogen dioxide (NO2) patterns and trends in the GOM. Data from the OMI and TROPOMI sensors were used to obtain 18+ year records of tropospheric column (TrC) NO2 in three GOM regions: (a) Houston urban area, (b) near shore area off the Louisiana coast, and a (c) deepwater area off the Louisiana coast. The 2004–2022 time series show a decreasing trend for the urban (−0.027 DU/decade) and near shore (−0.0022 DU/decade) areas, and an increasing trend (0.0019 DU/decade) for the deepwater area. MERRA‐2 wind and TROPOMI NO2 data were used to reveal several NO2 hotspots (up to 25% above background values) under calm wind conditions near individual platforms. The NO2 signals from these deepwater platforms and the high density of shallow water platforms closer to shore were confirmed by TrC NO2 anomalies of up to 10%, taking into account the monthly TrC NO2 climatology over the GOM. The results presented in this study establish a baseline for future estimates of emissions from the ONG hotspots and provide a methodology for analyzing NO2 measurements from the new geostationary TEMPO instrument. Plain Language Summary: Oil and natural gas operations emit nitrogen oxides (NOx), which are major air pollutants and precursors to ground‐level ozone. The Bureau of Ocean Energy Management (BOEM) agency is responsible for managing planned oil and natural gas (ONG) activity on the outer continental shelf, and is mandated to ensure related emissions do not degrade air quality of coastal states. In collaboration with BOEM, we used satellite data from the OMI and TROPOMI sensors to construct an 18+ year record of tropospheric nitrogen dioxide (NO2), a proxy for NOx, in the Gulf Coast region. These time series focused on three areas: (a) Houston urban, (b) off the Louisiana coast, and (c) deepwater Gulf off Louisiana. These regions experienced changes in tropospheric column NO2 of −13.7%, −5.8%, and +5.4% per decade, respectively. We also identified NO2 hotspots from ONG platforms using TROPOMI NO2 averages under calm wind conditions. The ONG deepwater platforms enhance NO2 background amounts by 7%–13% on average, and up to 25% for the Mars and Olympus platforms combined. The results presented here will facilitate our work on emissions estimates from these sources and on applications to the recently launched TEMPO instrument. Key Points: Satellite NO2 records and trends of urban, coastal and deep water areas from 2005 to 2022, are presentedClassifying NO2 over the Gulf of Mexico (GOM) under various wind conditions highlights typical patterns in average NO2 valuesGOM NO2 hotspots from deepwater platforms were identified by TROPOMI under calm wind conditions, the largest of which is over Mars/Olympus [ABSTRACT FROM AUTHOR]

Here we focused on the co-occurrence pattern on regional and local scales, and on the niche differences of two species of congeneric beetles (Ochthebius quadricollis and O. lejolisii, Hydraenidae) exclusive of supratidal rockpools. Abundances of adults and larval stages from both species and environmental variables were obtained in 10 pools from 12 localities along the Iberian Mediterranean coast. To determine the local co-existence pattern, we monthly sampled two localities in an annual cycle. On regional and local scales, we found negative correlations between both species' pool abundances, which suggest spatio-temporal segregation based on their different environmental responses. The OMI analysis detected interspecific niche differences, larger in larvae than adults. The best regression models obtained for O. quadricollis larvae included depth, conductivity, and fine sediments as the main explanatory variables with a positive effect, and distance to sea and CPOM with a negative effect. For O. lejolisii larvae, the best models included CPOM and periphyton with positive effects, while pool area, depth and conductivity negatively affected. Our results suggest that subtle interspecific differences in ecological niches, mainly those related to pool hydroperiod and salinity, could determine spatio-temporal storage effects as the principal mechanisms of co-existence on local and regional scales. [ABSTRACT FROM AUTHOR]

Air quality has been one of the main concerns among Tehran residents for at least two decades. In this study, we investigated air quality in the metropolitan area of Tehran utilizing TROPOMI and OMI data based on the Google Earth Engine platform. Long-term analysis indicated slight negative trends in NO2, SO2, and HCHO over the last two decades, which are due to the development of urban transportation systems. Air quality parameters were classified based on spatiotemporal similarities. Urban pollutants include CO1, NO2, and HCHO, which were concentrated over the eastern part of Tehran and decreased radially towards the city border. Among the pollutants, CO1 showed a dependency with altitude. SO2 was controlled by both urban vehicles and nonurban industrial activities. SO2 was thus classified as an urban-industrial pollutant. The exterior parameters almost entirely controlled by external factors include O3, aerosols, and clouds. The spatial variations of the pollutants highly differed from a fraction to several times. All pollutants exhibited seasonality associated with fuel consumption and air conditions. However, the seasonality in the exterior parameters was associated with regional air masses. The Iranian New Year holiday significantly impacts air pollution. NO2, CO1, and SO2 experienced their annual minimum levels during this holiday period. COVID-19–related closures also led to negative trends in NO2, CO1, and SO2 after March 2020. However, the exterior parameters were not affected by these events. The results agreed with in situ measurements. As the final objective, we aimed to support urban management to reduce atmospheric pollution in Tehran. [ABSTRACT FROM AUTHOR]

The paper analyzes the trends in the average monthly concentrations of nitrogen dioxide in the period from 2005 to 2021 in 18 large cities in different geographical areas: St. Petersburg, Moscow, Kyiv, Donetsk, Helsinki, Warsaw, Istanbul, Athens, Rome, Milan, Barcelona, Madrid, Paris, London, and Amsterdam. It was found that, in all cities, the concentration of this gas decreases, but at different rates. The highest rate of change was recorded in cities with the highest gas content at the time of the initial stage—2005. A linear dependence of the average nitrogen dioxide concentration on the population and anthropogenic emissions was revealed according to HTAPv3 data. Approximately every 1 million people of the population of large cities is responsible for the formation of a gas concentration of ∼200 × 1015 molecules/cm2, regardless of the geographical location of the city. Every ∼10 000 t/month of nitrogen dioxide emissions based on HTAPv3 generate gas concentrations of ∼500 × 1015 molecules/cm2. Using these dependences, it is possible to estimate anthropogenic emissions of NO2 sources throughout the country, based on remote sensing data. The results of the study also indicate the possibility of verifying and correcting inventory databases of gas emissions based on satellite observations of the nitrogen dioxide content in the atmosphere. [ABSTRACT FROM AUTHOR]

Sub-Saharan Africa (SSA) is one of the regions most affected by climate change and health problems caused by atmospheric pollution are becoming increasingly serious. Based on the daily data of OMI/AURA UVAI from 2010 to 2021, this study derived the spatial and temporal distribution patterns of UVAI levels in SSA over a long time series. By using big data, slope, and GTWR analysis methods, the influencing factors are explored and discussed. Studies have shown the following: (1) year-to-year UVAI levels values in SSA are high in the north and low in the south. The average annual variation of UVAI displayed a wave-like structure with a gradually increasing minimum over time. (2) The monthly UVAI column volume pattern in the study area is distinct, with a peak in June and an inverted "V" shape. (3) The correlations of each variable with UVAI levels in the study area are negative for NDVI> precipitation> water content> 10m wind speed, positive for correlation on u-directional wind> v-directional wind> air temperature, and almost independent for barometric pressure. (4) During the study, the dynamic UVAI change pattern in SSA has shown a substantial drop in the north, and a significant increase in the south. Finally, the authors concluded that air pollution in the region is closely related to climate change; moreover, the strengthening of composite studies in regard of air pollution and climate change will be the main work to be conducted in the future. [ABSTRACT FROM AUTHOR]

This study uses ozone in the atmosphere column collected by the Aura satellite's ozone monitoring instrument (OMI), to evaluate the ozone pollution status of Japan. Mann–Kendall and slope trend analysis, Hurst index analysis, the potential source contribution factor algorithm, GTWR (geographically and temporally weighted regression model), and the random forest regression model were used in this paper to investigate ozone column concentrations in Japan from 2010 through 2021. The results showed that ozone column concentrations had a significant latitudinal trend over the past 12 years, i.e., concentrations increased with increasing latitude. And the slope has showed a small upward trend over the years (slope = 0.01). The interannual maximum and minimum ozone column concentrations are in 2021 (387.57 DU) and 2015 (241.27 DU), respectively. The monthly maximum and minimum values occur in March (361.60 DU) and October (286.96 DU), with seasonal concentrations in the order of Spring (352.94 DU) > Winter (336.01 DU) > Summer (306.78 DU) > Autumn (296.30 DU). Column ozone concentrations have increased in 69.82% of Japan over the past 12 years. In 2022, the maximum, minimum, and mean ozone column concentrations based on random forest forecasts are 372DU, 278DU, and 334DU, respectively. Pollution sources in Japan are largely derived from pollutants that are transported across borders from the seas around the country or from other countries in the world, with the largest potential source areas being located in the Kanto region. Relative humidity, lift index, and air temperature (in all three seasons except winter) have a negative effect on ozone column concentrations. The positive effects of precipitable water and nitrogen dioxide on ozone column concentrations in the Hokkaido locality and southern Japan were more significant. The contribution of population density and GDP to ozone is small. [ABSTRACT FROM AUTHOR]

Agung, Bromo, and Sinabung Volcanoes have high volcanic activity over the last decade, and have different eruption characteristics. Hence, it would be fascinating to study the characteristics of their volcanic activity patterns based on SO2 emission rates and thermal anomaly correlated with the seismicity data. The SO2 emission rate measurement was carried out using the Differential Optical Absorption Spectroscopy (DOAS), and calculated based on SO2 column density, distance of measurement, wind speed, and wind direction. In addition, SO2 emission was detected using Ozone Monitoring Instrument (OMI) images with daily global coverage. Thermal anomaly detection was performed using Advance Spaceborne Thermal Emission and Reflection Radiometer (ASTER) of Thermal Infrared (TIR) subsystem with high spatial resolution (90x90 m). ASTER TIR images were corrected for radiometric and thermal atmospheric. The emissivity and brightness temperature separation algorithm was applied to obtain surface temperature of Agung, Bromo, and Sinabung Volcanoes. All the data were correlated with the seismicity of each volcano. The SO2 emission rates correlate with the magma ascent to the shallow depth in an open system volcano (Bromo Volcano). In the closed-system volcanoes (early phase of Agung and Sinabung), SO2 emission was detected after the transition of closed to open system. Magmatic injection from the reservoir to the shallow depth was detected as thermal anomalies, such as in Agung Volcano. Whereas in Bromo Volcano, the thermal anomaly was insignificant since Bromo Volcano has an explosive eruption at a short period, so the ASTER image could not observe the thermal anomaly on the eruption time. Thermal anomaly pattern in Sinabung Volcano was the manifestation of new magmatic injection to the shallow depth. Therefore, their increase serves as indicators for the increasing magmatic activity prior to the eruptions. [ABSTRACT FROM AUTHOR]

The research on formaldehyde is of great significance to preventing ozone pollution under high temperatures in the future and protecting people's health. Brazil is the largest economy and trading power in South America, in recent years, air pollution, especially the emission of volatile organic compounds (VOCs), has increased. This paper takes formaldehyde (HCHO) as an example to monitor its pollution distribution and provide a basis for its treatment. Based on this, the temporal and spatial distribution characteristics and influencing factors of formaldehyde in Brazil from 2012 to 2021 were analyzed, and the future trend of formaldehyde was discussed. The results showed that the formaldehyde column concentration (31.1 × 1015 molec/cm2) was the highest in August and the lowest in December was 6.8 × 1015 molec/cm2. The formaldehyde column concentration in dry season was higher than that in rainy season. Formaldehyde showed a decreasing trend from southwest to northeast. The correlation coefficients between HCHO and the normalized vegetation index (NDVI) and leaf area index (LAI) were − 0.84 ~ 0.84 and − 0.86 ~ 0.82, respectively. In addition, the mean annual water content (MAWC) and mean annual temperature (MAT) also had some effects. The path coefficient was used to analyze the influence of human activities on HCHO, and it was found that the contribution rates of total energy consumption (1.3592), GDP (1.1499), and electricity consumption (− 1.1113) were high, while the impact of coal consumption was relatively small (0.6425). It is expected that formaldehyde in Brazil may continue to show a weak persistence reduction trend in the future. [ABSTRACT FROM AUTHOR]

This research report investigated the impacts of the COVID-19 lockdown restrictions on CO, SO2, and NO2 trends in Durban from 2019 to 2021. The COVID-19 lockdown restrictions proved to decrease greenhouse gas (GHG) emissions globally; however, the decrease in GHG emissions was for a short period only. Space-borne technology has been used by researchers to understand the spatial and temporal trends of GHGs. This study used Sentinel-5P to map the spatial distribution of CO, SO2, and NO2. Use was also made of the Atmospheric Infrared Sounder (AIRS), Modern-Era Retrospective Analysis for Research and Applications, Version 2 (MERRA-2), and the Ozone Monitoring Instrument (OMI) to understand the temporal trends of CO, SO2, and NO2, respectively. To validate the results of this study, we used the Sequential Mann–Kendall (SQMK) test. This study indicated that there were no significant changes in all the investigated gases. Therefore, this study failed to reject the null hypothesis of the SQMK test that there was no significant trend for all investigated gasses. Increasing trends were observed for CO, SO2, and NO2 trends during winter months throughout the study period, whereas a decreasing trend was observed in all investigated gases during the spring months. This shows that meteorological factors play a significant role in the accumulation of air pollutants in the atmosphere. Most importantly, this study has noted that there was an inverse relationship between the trends of all investigated gases and the COVID-19 lockdown restrictions. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Remote Sensing is the property of Editorial Office of Journal of Remote Sensing & Science Publishing Co. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study investigated the impact of Octomodal Mental Imagery (OMI) and management dimensions on shoppers' experiences and mall loyalty. The study was collected through "Questionnaire Star," and 358 valid data points were obtained. The data were analyzed using SPSS27 and AMOS28. The results showed that sensory attributes such as visual, tactile, gustatory, and olfactory attributes positively influenced shoppers' experiences in OMI, while the auditory attribute had no significant effect. Spatial, a structural attribute of OMI, positively influenced shoppers' experiences, whereas autonomy and kinesthetics did not have a considerable effect. Tenant mix and entertainment positively impacted shoppers' experiences in management, while accessibility had no significant effect. The study also found that shoppers' experiences positively impacted mall loyalty, while hedonistic motivation had a more substantial effect than utilitarian motivation. This study is the first to examine the impact of OMI on shoppers' experiences. It fills a gap in the literature on this relationship. It also examines the combined impact of management dimensions (accessibility, tenant mix, and entertainment) on the overall shopper's experience, filling a gap in the Chinese shopping mall literature and extending the generalizability of the theory. The study further explores the relationship between shoppers' experiences and mall loyalty and the moderating effect of incentive orientation. The results of this study have critical implications for mall managers. Strengthening the mental image and management dimensions of the shopping mall will enhance shoppers' experiences and build loyalty, allowing brick-and-mortar malls to remain competitive and sustainable in today's highly competitive and popular e-commerce environment. [ABSTRACT FROM AUTHOR]

COVID-19 lockdown has given us an opportunity to investigate the pollutant concentrations in response to the restricted anthropogenic activities. The atmospheric concentration levels of nitrogen dioxide (NO2), carbon monoxide (CO) and ozone (O3) have been analysed for the periods during the first wave of COVID-19 lockdown in 2020 (25th March–31st May 2020) and during the partial lockdowns due to second wave in 2021 (25th March–15th June 2021) across India. The trace gas measurements from Ozone Monitoring Instrument (OMI) and Atmosphere InfraRed Sounder (AIRS) satellites have been used. An overall decrease in the concentration of O3 (5–10%) and NO2 (20–40%) have been observed during the 2020 lockdown when compared with business as usual (BAU) period in 2019, 2018 and 2017. However, the CO concentration increased up to 10–25% especially in the central-west region. O3 and NO2 slightly increased or had no change in 2021 lockdown when compared with the BAU period, but CO showed a mixed variation prominently influenced by the biomass burning/forest fire activities. The changes in trace gas levels during 2020 lockdown have been predominantly due to the reduction in the anthropogenic activities, whereas in 2021, the changes have been mostly due to natural factors like meteorology and long-range transport, as the emission levels have been similar to that of BAU. Later phases of 2021 lockdown saw the dominant effect of rainfall events resulting in washout of pollutants. This study reveals that partial or local lockdowns have very less impact on reducing pollution levels on a regional scale as natural factors like atmospheric long-range transport and meteorology play deciding roles on their concentration levels. [ABSTRACT FROM AUTHOR]

Air pollution has become one of the factors that most affect the quality of life, human health, and the environment. Gaseous pollutants from motor vehicles have a significantly harmful effect on air quality in the Metropolitan Area of São Paulo (MASP)—Brazil. Motor vehicles emit large amounts of particulate matter (PM), carbon monoxide (CO), nitrogen oxides (NOx), and volatile organic compounds (VOCs), the last three acting as the main tropospheric ozone (O3) precursors. In this study, we evaluated the effects of these pollutants on air quality in the MASP during the partial lockdown that was imposed to ensure the social distancing necessitated by the COVID-19 pandemic. We compared the monthly data for nitrogen dioxide (NO2) from the Ozone Monitoring Instrument (OMI) and CO, SO2, and BC from MERRA-2 for the period between April and May 2020 (during the pandemic) with the average for the same period for the (pre-pandemic) years 2017 to 2019 in the southeast region of Brazil. The meteorological and pollutant concentration data from the CETESB air quality monitoring stations for the MASP were compared with the diurnal cycle of three previous years, with regard to the monthly averages of April and May (2017, 2018, and 2019) and the same period in 2020, when the partial lockdown was first imposed in southeast Brazil. Our findings showed that there was a decrease in NO2 concentrations ranging from 10% to more than 60% in the MASP and the Metropolitan Area of Rio de Janeiro (MARJ), whereas in the Metropolitan Area of Belo Horizonte and Vitoria (MABH and MAV, respectively), there was a reduction of around 10%. In the case of the concentrations of CO and BC from MERRA-2, there was a considerable decrease (approx. 10%) during the period of partial lockdown caused by COVID-19 throughout almost the entire state of São Paulo, particularly in the region bordering the state of Rio de Janeiro. The concentration of SO2 from MERRA-2 was 5 to 10% lower in the MASP and MARJ and the west of the MABH, and there was a decrease of 30 to 50% on the border between the states of São Paulo and Rio de Janeiro, while in the MAV region, there was an increase in pollutant levels, as this region was not significantly affected by the COVID-19 pandemic. Sharp reductions in the average hourly concentrations of CO (38.8%), NO (44.9%), NO2 (38.7%), and PM2.5 (6%) were noted at the CETESB air quality monitoring stations in the MASP during the partial lockdown in 2020 compared with the hourly average rate in the pre-pandemic period. In contrast, there was an increase of approximately 16.0% in O3 concentrations in urban areas that are seriously affected by vehicular emissions, which is probably related to a decrease in NOx. [ABSTRACT FROM AUTHOR]

The response of tropospheric column nitrogen dioxide (NO2) variations under the background of Major Function Oriented Zones (MFOZs) over eastern China is analyzed in this study. There is an increasing and then decreasing trend in the average annual value of NO2 in eastern China, with the highest values in 2011 and the lowest in 2017. As serious polluted regions, three regions (Jing-Jin-Ji, Yangtze River Delta, and Pearl River Delta) all show decrease trend, the average concentration of NO2 in the Jing-Jin-Ji region is the highest, and the decrease rate is also the highest. By analyzing the variation characteristics of NO2 concentration in MFOZs, there is a maximum in optimized zones and a minimum is the key ecological safety zones, each region shows a downward trend, and the optimized zones has the highest decrease rate. Population and gross domestic product (GDP) distribution are the key factors affecting NO2 concentration, changes of NO2 concentration are consistent with the population and GDP density, the regions with higher population and GDP density also have higher NO2 concentration (like the optimized zones and the prioritized zones), and the regions with lower population and GDP density also have lower NO2 concentration (like the ecological safety zones). [ABSTRACT FROM AUTHOR]

Air pollution is a global issue causing major health hazards. By proper monitoring of air quality, actions can be taken to control air pollution. Satellite remote sensing is an effective way to monitor global atmosphere. Various sensors and instruments fitted to satellites and airplanes are used to obtain the radar images. These images are quite complex with various wavelength differentiated by very close color differences. Clustering of such images based on its wavelengths can provide the much-needed relief in better understanding of these complex images. Such task related to image segmentation is a universal optimization issue that can be resolved with evolutionary techniques. Differential Evolution (DE) is a fairly fast and operative parallel search algorithm. Though classical DE algorithm is popular, there is a need for varying the mutation strategy for enhancing the performance for varied applications. Several alternatives of classical DE are considered by altering the trial vector and control parameter. In this work, a new alteration of DE technique labeled as DiDE (Divergent Differential Evolution Algorithm) is anticipated. The outcomes of this algorithm were tested and verified with the traditional DE techniques using fifteen benchmark functions. The new variant DiDE exhibited much superior outcomes compared to traditional approaches. The novel approach was then applied on remote sensing imagery collected form TEMIS, a web based service for atmospheric satellite images and the image was segmented. Fuzzy Tsallis entropy method of multi-level thresholding technique is applied over DiDE to develop image segmentation. The outcomes obtained were related with the segmented results using traditional DE and the outcome attained was found to be improved profoundly. Experimental results illustrate that by acquainting DiDE in multilevel thresholding, the computational delay was greatly condensed and the image quality was significantly improved. [ABSTRACT FROM AUTHOR]

The results of measuring the NO2 content in vertical columns of the stratosphere and troposphere using the Ozone Monitoring Instrument (OMI) on board the EOS Aura satellite in 2004–2020 are compared with the results of ground-based measurements at stations of the Network for the Detection of Atmospheric Composition Change (NDACC), first and foremost, with the results of measurements at the Zvenigorod Scientific Station (ZSS) of the Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences. The comparison between the satellite data and the ZSS data is performed using the two products of satellite measurements: the NO2 contents in stratospheric and tropospheric columns. When comparing the OMI data with ground-based measurements at other stations, satellite values of the NO2 content in the stratospheric column are compared to values of the total content (TC) of NO2 obtained from ground-based measurements. The correspondence between the results of satellite and ground-based measurements is characterized by the magnitude of difference between them, the linear correlation coefficients, and regression coefficients. The difference has a noticeable seasonal variation. The correlation and regression coefficients depend significantly on the season. Characteristic patterns of correlation coefficient changes with latitude, as well as specific features of correlation between satellite and ground-based data in the polar and middle latitudes of the Southern Hemisphere in spring, have been revealed. For some stations, the dependence of quantitative characteristics of the correspondence between the results of satellite and ground-based measurements on cloudiness has been found. Under cloudless conditions at the ZSS, a weakening of the correlation between the satellite and ground-based values of the stratospheric NO2 content and an increase in the correlation between the values of the tropospheric NO2 content is observed. The dependence of the correspondence characteristics between the data of satellite and ground-based measurements on the level of pollution of the lower troposphere by nitrogen oxides is revealed. The correlation between the values of the tropospheric NO2 content in the vicinity of ZSS under strong pollution increases, while the correlation between the values of the stratospheric NO2 content decreases. Based on the results of the comparison of satellite and ground-based data, estimates of the upper threshold values of the tropospheric NO2 content at different stations are found. The lowest values are obtained for polar stations, and the highest value are obtained for the ZSS, which is most susceptible to anthropogenic pollution due to its proximity to the Moscow megapolis. [ABSTRACT FROM AUTHOR]

The Chinese government introduced regulations to control emissions and reduce the level of NOx pollutants for the first time with the 12th Five-Year Plan in 2011. Since then, the changes in NOx emissions have been assessed using various approaches to evaluate the impact of the regulations. Complementary to the previous studies, this study estimates anthropogenic NOx emissions in 2015 and 2019 over Eastern China using as a reference the Hemispheric Transport of Air Pollution (HTAP) v2.2 emission inventory for 2010 and the new variational inversion system the Community Inversion Framework (CIF) interfaced with the CHIMERE regional chemistry transport model and OMI satellite observations. We also compared the estimated NOx emissions with the independent Multi-resolution Emission Inventory for China (MEIC) v1.3, from 2015. The inversions show a slight global decrease in NOx emissions (in 2015 and 2019 compared to 2010), mainly limited to the most urbanized and industrialized locations. In the locations such as Baotou, Pearl River Delta, and Wuhan, the estimations in 2015 compared to 2010 are consistent with the target reduction (10%) of the 12th Five-Year Plan. Comparisons between our emission estimates and MEIC emissions in 2015 suggest that our estimates likely underestimate the emission reductions between 2010 and 2015 in the most polluted locations of Eastern China. However, our estimates suggest that the MEIC inventory overestimates emissions in regions where MEIC indicates an increase of the emissions compared to 2010. [ABSTRACT FROM AUTHOR]

Absorbing aerosols, consisting of smoke (black carbon (BC) and other organics) and dust (from windblown sources), can have a strong warming effect on the climate and impact atmospheric circulation due to localized heating. To investigate the spatiotemporal and vertical changes of absorbing aerosols across Asia, collocation data from OMI, MODIS, and CALIPSO were used to compare two periods: 2006–2013 and 2014–2021. This study revealed a significant temporal and spatial contrast of aerosol loading over the study region, with a drop in total aerosol concentration and anthropogenic smoke concentration recorded across the Eastern China region (all seasons) and a concurrent increase in the Indian sub-continent region (especially in autumn). The range of aerosol diffusion is affected by the height of the smoke and aerosol plumes, as well as the wind force, and is dispersed eastwards because of the Hadley circulation patterns in the Northern Hemisphere. Smoke from Southeast Asia typically rises to a height of 3 km and affects the largest area in contrast to other popular anthropogenic zones, where it is found to be around 1.5–2 km. The dust in Inner Mongolia had the lowest plume height of 2 km (typically in spring) compared to other locations across the study region where it reached 2–5 km in the summer. This study showed, by comparison with AERONET measurements, that combining data from MODIS and OMI generates more accuracy in detecting aerosol AOD from smoke than using the instruments singularly. This study has provided a comprehensive assessment of absorbing aerosol in Asia by utilizing multiplatform remote-sensed data and has summarized long-term changes in the spatiotemporal distribution and vertical structure of absorbing aerosols. [ABSTRACT FROM AUTHOR]

Using a series of characteristic analyses of HCHO, SO2, NO2, O3, and absorptive aerosols (ultraviolet aerosol index—UVAI) in the atmosphere of the study area from 2011 to 2021, this paper reviews the pollutants present in Jiangsu, Shandong, Henan, and Anhui provinces, which are the key regions for air pollution control in China. Furthermore, the correlation between various air pollutants and O3 is also examined. The results obtained show the following: (1) Within the research areas, temporal pollutant variations can be observed from 2011 to 2021. NO2 and HCHO only modestly decrease, SO2 sharply declines, while UVAI remains stable. During the study period, HCHO and O3 first increase and subsequently decline, whereas the other three pollutants exhibit the opposite behavior. (2) Among the examined pollutants, SO2 is the most unstable. (3) Our research discovered that the atmospheric transport paths at high-value points significantly vary between seasons using the public backward trajectory model. (4) Through the correlation analysis we performed, this research reveals the different degrees of spatial correlations between O3 and other pollutants. (5) Using the FNR index method, the sensitivity of O3 to its precursors (NOx and VOCs) is investigated. Based on the results, we provide some suggestions concerning the primary control pollutants and relative control strategies in different seasons and regions. [ABSTRACT FROM AUTHOR]

Copyright of Medizinische Klinik: Intensivmedizin & Notfallmedizin is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ozone (O3) pollution is one of the predominant environmental problems, and exposure to high O3 concentrations has a significant negative influence on both human health and ecosystems. Therefore, it is essential to analyze spatio-temporal characteristics of O3 distribution and to evaluate O3 exposure levels. In this study, O3 monitoring and satellite data were used to estimate O3 daily, seasonal and one-year exposure levels based on the Bayesian maximum entropy (BME) model with a spatial resolution of 1 km × 1 km in the Beijing-Tianjin-Hebei (BTH) region, China. Leave-one-out cross-validation (LOOCV) results showed that R2 for daily and one-year exposure levels were 0.81 and 0.69, respectively, and the corresponding values for RMSE were 19.58 μg/m3 and 4.40 μg/m3, respectively. The simulation results showed that the heavily polluted areas included Tianjin, Cangzhou, Hengshui, Xingtai, and Handan, while the clean areas were mainly located in Chengde, Qinhuangdao, Baoding, and Zhangjiakou. O3 pollution in summer was the most severe with an average concentration of 134.5 μg/m3. In summer, O3 concentrations in 87.7% of the grids were more than 100 μg/m3. In contrast, winter was the cleanest season in the BTH region, with an average concentration of 51.1 μg/m3. [ABSTRACT FROM AUTHOR]

To mitigate tropospheric ozone (O3) pollution with proper and effective emission regulations, diagnostics for the O3-sensitive regime are critical. In this study, we analyzed the satellite-measured formaldehyde (HCHO) and nitrogen dioxide (NO2) column densities and derived the HCHO to NO2 ratio (FNR) from 2005 to 2019. Over China, there was a clear increase in the NO2 column during the first 5-year period and a subsequent decrease after 2010. Over the Republic of Korea and Japan, there was a continuous decline in the NO2 column over 15 years. Over the entire East Asia, a substantial increase in the HCHO column was identified during 2015–2019. Therefore, FNR increased over almost all of East Asia, especially during 2015–2019. This increasing trend in FNR indicated the gradual shift from a volatile organic compound (VOC)-sensitive to a nitrogen oxide (NOx)-sensitive regime. The long-term changes in HCHO and NO2 columns generally corresponded to anthropogenic non-methane VOC (NMVOC) and NOx emissions trends; however, anthropogenic sources did not explain the increasing HCHO column during 2015–2019. Because of the reduction in anthropogenic sources, the relative importance of biogenic NMVOC sources has been increasing and could have a larger impact on changing the O3-sensitive regime over East Asia. [ABSTRACT FROM AUTHOR]

Based on satellite remote sensing data acquired by the ozone monitoring instrument (OMI), this study used pixel space analysis, a coefficient of variation, stability analysis, and an atmospheric transmission model to determine the concentration of tropospheric ozone (O3), NO2, HCHO, and SO2 columns in Lanzhou from 2010 to 2019. A series of analyses were carried out on the temporal and spatial distribution of concentration, influencing factors and atmospheric transmission path. The results show that the air pollutants in this area present multi-dimensional characteristics and have a complex spatial distribution. In terms of inter-annual changes, in addition to the increase in the concentration of the HCHO column, the ozone, NO2, and SO2 column concentrations have all decreased over time. In terms of monthly average changes, these four pollutants reached their maximum values in April, December, June, and January, respectively. These four types of pollution had a strong spatial correlation, among which HCHO and SO2 had a significant positive correlation, with a correlation coefficient of 0.76. Many factors affect the atmospheric pollutant in Lanzhou. Among them, pollutants are closely related to urbanization and to the activities of coal-burning industries. Moreover, temperature, precipitation, and sunshine also have certain effects on air quality. The proliferation of pollutants in Gansu Province was one of the sources of pollutants in Lanzhou, while long-distance transportation in the atmosphere from outside the province (Qinghai, Sichuan, and Shaanxi) also exacerbated the pollution in Lanzhou. [ABSTRACT FROM AUTHOR]

The unprecedented increase in anthropogenic activities, coupled with the prevailing climatic conditions, has increased the aerosol load over East Africa (EA). Given this, the present study examined the trends in total, absorption, scattering, and total aerosol extinction optical depth (TAOD, AAOD, SAOD, and TAEOD) over EA, alongside trends in single scattering albedo (SSA). For this purpose, the AOD of different optical properties retrieved from multiple sensors and the Modern-Era Retrospective Analysis for Research and Applications (MERRA-2) model between January 2001 to December 2019 were utilized to estimate trends and assess their statistical significance. The spatial patterns of seasonal mean AOD from the Moderate-resolution Imaging Spectroradiometer (MODIS) sensor and MERRA-2 model were generally characterized with high (>0.35) and low (<0.2) AOD centers over EA observed during the local dry and wet seasons, respectively. Also, the spatial trend analysis revealed a general increase in TAOD, being positive and significant over the arid and semi-arid zones of the northeastern part of EA, which is majorly dominated by locally derived dust. The local dry (wet) months generally experienced positive (negative) trends in TAOD, associated with seasonal cycles of rainfall. High and significant positive trends in AAOD were dominated over the study domain, attributed to an increased amount of biomass burning, variations in soil moisture, and changes in the rainfall pattern. The trends in TAEOD showed a distinct pattern, except over some months that depicted significant increasing trends attributed to changes in climatic conditions and anthropogenic activities. At last, the study domain exhibited decreasing trends in SSA, signifying strong absorption of direct solar radiation resulting in a warming effect. The study revealed patterns of trends in aerosol optical properties and forms the basis for further research in aerosols over EA. [ABSTRACT FROM AUTHOR]

Various indices have been defined to characterize the phase and amplitude of the Madden‐Julian oscillation (MJO). One widely used index is the outgoing longwave radiation (OLR) based MJO index (OMI), which is calculated using the spatial pattern of 30–96‐day eastward‐filtered OLR. The empirical orthogonal functions (EOFs) used to calculate the OMI in observations are prone to degeneracy and exhibit oscillations on the order of 10–20 days, despite initial filtering of the OLR. We propose a simple modification to the OMI that involves aligning the EOFs between neighboring days while retaining the spatial pattern described by the EOFs. This rotation method is implemented as a postprocessing procedure of the current OMI calculation and cleanly removes the spurious oscillations and degeneracy issues seen in the standard method. A similar rotation procedure can be implemented in calculations of other MJO indices. Plain Language Summary: Characterization of the Madden‐Julian oscillation (MJO) is important for subseasonal weather forecasting. However, the indices often used to characterize the MJO are projected onto a basis that includes unphysical day‐to‐day variations and noise that arise from the mathematical procedure used to calculate the basis, rather than the atmosphere itself. We propose a modified postprocessing procedure to the standard method that removes spurious oscillations in the index basis while maintaining the broad structures of the original index. Key Points: Current methods used to calculate Madden‐Julian oscillation (MJO) indices result in degeneracy and unphysical oscillatory behaviorA simple projection and rotation algorithm is derived as a postprocessing step to current MJO index calculationsAdding a simple rotation results in a slowly varying index basis that retains the broad structure of the original index [ABSTRACT FROM AUTHOR]

This study examines uncertainties in the retrieval of the Aerosol Optical Depth (AOD) for different aerosol types, which are obtained from different satellite-borne aerosol retrieval products over North Africa, California, Germany, and India and Pakistan in the years 2007–2019. In particular, we compared the aerosol types reported as part of the AOD retrieval from MODIS/MAIAC and CALIOP, with the latter reporting richer aerosol types than the former, and from the Ozone Monitoring Instrument (OMI) and MODIS Deep Blue (DB), which retrieve aerosol products at a lower spatial resolution than MODIS/MAIAC. Whereas MODIS and OMI provide aerosol products nearly every day over of the study areas, CALIOP has only a limited surface footprint, which limits using its data products together with aerosol products from other platforms for, e.g., estimation of surface particulate matter (PM) concentrations. In general, CALIOP and MAIAC AOD showed good agreement with the AERONET AOD (r: 0.708, 0.883; RMSE: 0.317, 0.123, respectively), but both CALIOP and MAIAC AOD retrievals were overestimated (36–57%) with respect to the AERONET AOD. The aerosol type reported by CALIOP (an active sensor) and by MODIS/MAIAC (a passive sensor) were examined against aerosol types derived from a combination of satellite data products retrieved by MODIS/DB (Angstrom Exponent, AE) and OMI (Aerosols Index, AI, the aerosol absorption at the UV band). Together, the OMI-DB (AI-AE) classification, which has wide spatiotemporal cover, unlike aerosol types reported by CALIOP or derived from AERONET measurements, was examined as auxiliary data for a better interpretation of the MAIAC aerosol type classification. Our results suggest that the systematic differences we found between CALIOP and MODIS/MAIAC AOD were closely related to the reported aerosol types. Hence, accounting for the aerosol type may be useful when predicting surface PM and may allow for the improved quantification of the broader environmental impacts of aerosols, including on air pollution and haze, visibility, climate change and radiative forcing, and human health. [ABSTRACT FROM AUTHOR]

In recent years, ozone pollution has been increasing in some parts of the world. In this study, we used the Beijing–Tianjin–Tangshan (BJ-TJ-TS) urban agglomeration region as a case study and used satellite remotely sensed inversion data and hourly ground monitoring observations of surface ozone concentrations, meteorological data, and other factors from 2016 to 2019 to explore the spatiotemporal dynamic characteristics of surface ozone concentration and its pollution levels. We also investigated their coupling relationships with meteorological factors, including temperature, pressure, relative humidity, wind velocity, and sunshine duration, in order to support the development of effective control measures for regional ozone pollution. The results revealed that the surface ozone concentration throughout the BJ-TJ-TS region from 2016 to 2019 exhibited an overall pattern of high values in the northwest and low values in the southeast, as well as an obvious difference between built-up and non-built-up areas (especially in Beijing). Meanwhile, a notable increasing trend of ozone levels was discovered in the BJ and TJ areas from 2016 to 2019, whereas this upward trend was not evident in the TS area. In all three areas, the highest monthly average ozone values occurred in the summer month of June, while the lowest monthly average levels occurred in the winter month of December. Their diurnal variation values reached a maximum value at approximately 3:00–4:00 p.m. and a minimum value at approximately 7:00 a.m. It is clear that high temperature, long sunshine duration, low atmospheric pressure, and weak wind velocity conditions, as well as certain relative humidity levels, readily led to high-concentration ozone pollution. Meanwhile, the daily average values of the five meteorological factors on days with Grade I and Grade II ozone pollution displayed different characteristics. [ABSTRACT FROM AUTHOR]

The spatial and temporal variation of satellite derived pre-monsoonal Aerosol Optical Depth (AOD) over the Indian region has been studied using long-term (2005–2021) satellite data from Moderate Resolution Imaging Spectroradiometer (MODIS) and Ozone Monitoring Instrument (OMI). In particular, three zones were selected, based on the dominance of natural, anthropogenic and mixture of both types of aerosols. The seasonal average of AOD (MODIS, OMI) was found to be (~ 0.40, ~ 0.35) for the entire Indian landmass. We found that the trends are increasing (and are statistically significant) over the Indian region and the increase is at a faster rate in the last 8 years compared to the previous ones. Trend from MODIS (OMI) was found to be 0.011 (0.002) year−1 and 0.014 (0.006) year−1 for the periods 2005–2012 and 2013–2021, respectively, over the Indian region. Increasing trends of AOD for zones selected in Indo-Gangetic Plains and South-India were found during 2005–2021, whereas for the desert zone, AOD trend has contrastingly became negative (2005–2012) to positive (2013–2021) in the recent years. [ABSTRACT FROM AUTHOR]

This study uses the daily product data of the concentration of ozone in the atmospheric column (ozone column concentration) collected by the Aura satellite's Ozone Monitoring Instrument (OMI), to evaluate the ozone pollution status of the Fenwei Plain in east-central China, by employing pixel-based spatial analysis, an θslope trend index, a Hurst index, and grey correlation. The following results were found. (1) The spatial distribution of ozone in the atmosphere of the Fenwei Plain was higher in the north and lower in the south, with high values appearing in Jinzhong, Lvliang, and other cities. (2) The changes in ozone column concentration periodically and seasonally in the Fenwei Plain. Seasonally, the ozone column concentration was highest in spring, followed by summer, winter, and autumn. (3) The pixel-based trend change of the ozone slope (θslope) indicated that the ozone concentration in the region was in a downward trend, while the long-term correlation of the time series trend Hurst index found that the region should expect to see a weak rebound in the ozone column concentration in the future, so that routine monitoring should be strengthened. (4) The present study on the factors influencing the ozone concentration found that the concentration is relatively closely related to temperature, air pressure, humidity, grain sowing area, highway mileage, and secondary industry. [ABSTRACT FROM AUTHOR]

A bulk of evidence from in situ observations and lab experiments suggests that brown carbon (light-absorbing organic compounds in particles) can provide a significant yet highly variable contribution to the overall light absorption by aerosol particles from biomass burning (BB). Partly stemming from the complexity of the atmospheric evolution of organic aerosol (OA), the variability in brown carbon (BrC) absorption makes it difficult to partition the radiative effects of BrC and black carbon (BC) in atmospheric and climate models; as such, there are calls for satellite-based methods that could provide a statistical characterization of BrC absorption and its evolution in different regions of the world, especially in remote BB regions, such as Siberia. This study examined the feasibility of the statistical characterization of the evolution of BrC absorption and related parameters of BB aerosol in smoke plumes from intense wildfires in Siberia through the analysis of a combination of data from three satellite instruments: OMI (Ozone Monitoring Instrument), MISR (Multi-Angle Imaging SpectroRadiometer), and MODIS (Moderate Resolution Imaging Spectroradiometer). Using a Monte Carlo method, which related the satellite retrievals of the absorption and extinction aerosol optical depths to Mie theory calculations of the optical properties of BB aerosol, we found that the BrC absorption, as well as the imaginary refractive index for the OA, decreased significantly in Siberian BB smoke plumes during about 30 h of the daylight evolution, nevertheless remaining considerable until at least 70 h of the daylight evolution. Overall, the study indicated that the analysis of multi-platform satellite observations of BB plumes can provide useful insights into the atmospheric evolution of BrC absorption and the partitioning of BrC and BC contributions to the total light absorption by BB aerosol. [ABSTRACT FROM AUTHOR]

The tropospheric vertical column density of NO2 (Trop NO2 VCD) can be obtained using satellite remote sensing, but it has been discovered that the Trop NO2 VCD is affected by uncertainties such as the cloud fraction, terrain reflectivity, and aerosol optical depth. A certain error occurs in terms of data inversion accuracy, necessitating additional ground observation verification. This study uses surface NO2 mass concentrations from the China National Environmental Monitoring Center (CNEMC) sites in Jiangsu Province, China in 2019 and the Trop NO2 VCD measured by MAX-DOAS, respectively, to verify the Trop NO2 VCD product (daily and monthly average data), that comes from the TROPOspheric Monitoring Instrument (TROPOMI) and Ozone Monitoring Instrument (OMI). The results show that the spatial distributions of NO2 in TROPOMI and OMI exhibit a similar tendency and seasonality, showing the characteristics of being high in spring and winter and low in summer and autumn. On the whole, the concentration of NO2 in the south of Jiangsu Province is higher than that in the north. The Pearson correlation coefficient (r) between the monthly average TROPOMI VCD NO2 and the CNEMC NO2 mass concentration is 0.9, which is greater than the r (0.78) between OMI and CNEMC; the r (0.69) between TROPOMI and the MAX-DOAS VCD NO2 is greater than the r (0.59) between OMI and the MAX-DOAS. As such, the TROPOMI is better than the previous generation of OMI at representing the spatio-temporal distribution of NO2 in the regional scope. On the other hand, the uncertainties of the satellite products provided in this study can constrain regional air quality forecasting models and top-down emission inventory estimation. [ABSTRACT FROM AUTHOR]

This study evaluates formaldehyde (HCHO) over the U.S. from 2006 to 2015 by comparing ground monitor data from the Air Quality System (AQS) and a satellite retrieval from the Ozone Monitoring Instrument (OMI). Our comparison focuses on the utility of satellite data to inform patterns, trends, and processes of ground-based HCHO across the U.S. We find that cities with higher levels of biogenic volatile organic compound (BVOC) emissions, including primary HCHO, exhibit larger HCHO diurnal amplitudes in surface observations. These differences in hour-to-hour variability in surface HCHO suggests that satellite agreement with ground-based data may depend on the distribution of emission sources. On a seasonal basis, OMI exhibits the highest correlation with AQS in summer and the lowest correlation in winter. The ratios of HCHO in summer versus other seasons show pronounced seasonal variability in OMI, likely due to seasonal changes in the vertical HCHO distribution. The seasonal variability in HCHO from satellite is more pronounced than at the surface, with seasonal variability 20–100% larger in satellite than surface observations. The seasonal variability also has a latitude dependency, with more variability in higher latitude regions. OMI agrees with AQS on the interannual variability in certain periods, whereas AQS and OMI do not show a consistent decadal trend. This is possibly due to a rather large interannual variability in HCHO, which makes the small decadal drift less significant. Temperature also explains part of the interannual variabilities. Small temperature variations in the western U.S. are reflected with more quiescent HCHO interannual variability in that region. The decrease in summertime HCHO in the southeast U.S. could also be partially explained by a small and negative trend in local temperatures. [ABSTRACT FROM AUTHOR]

Biogenic volatile organic compounds (BVOCs), primarily emitted by terrestrial vegetation, are highly reactive and have large effects on the oxidizing potential of the troposphere, air quality and climate. In terms of global emissions, isoprene is the most important BVOC. Droughts bring about changes in the surface emission of biogenic hydrocarbons mainly because plants suffer water stress. Past studies report that the current parameterization in the state-of-the-art Model of Emissions of Gases and Aerosols from Nature (MEGAN) v2.1, which is a function of the soil water content and the permanent wilting point, fails at representing the strong reduction in isoprene emissions observed in field measurements conducted during a severe drought. Since the current algorithm was originally developed based on potted plants, in this study, we update the parameterization in the light of recent ecosystem-scale measurements of isoprene conducted during natural droughts in the central U.S. at the Missouri Ozarks AmeriFlux (MOFLUX) site. The updated parameterization results in stronger reductions in isoprene emissions. Evaluation using satellite formaldehyde (HCHO), a proxy for BVOC emissions, and a chemical-transport model, shows that the adjusted parameterization provides a better agreement between the modelled and observed HCHO temporal variability at local and regional scales in 2011–2012, even if it worsens the model agreement in a global, long-term evaluation. We discuss the limitations of the current parameterization, a function of highly uncertain soil properties such as porosity. [ABSTRACT FROM AUTHOR]

Mass suspension of anthropogenic activities is extremely rare, the quarantine due to the coronavirus disease 2019 (COVID-19) represents a natural experiment to investigate the impact of anthropogenic activities on air quality. The mitigation of air pollution during the COVID-19 lockdown has been reported from a global perspective; however, the air pollution levels vary in different regions. This study initiated a novel synthesis of multiple-year satellite observations, national ground measurements towards SO2, NO2 and O3 and meteorological conditions to evaluate the impact of the COVID-19 lockdown in Beihai, a specific city in a less developed area in southwest China, to reveal the potential implications of control strategies for air pollution. The levels of the major air pollutants during the COVID-19 lockdown (LP) and during the same period of previous years (SP) were compared and a series of statistical tools were applied to analyze the sources of air pollution in Beihai. The results show that air pollutant levels decreased with substantial diversity during the LP. Satellite-retrieved NO2 and SO2 levels during the LP decreased by 5.26% and 22.06%, while NO2, SO2, PM2.5 and PM10 from ground measurements during the LP were 25.6%, 2.7%, 22.2% and 22.2% lower than during SP, respectively. Ground measured SO2 concentrations during the LP were only 2.7% lower than during the SP, which may be attributed to uninterrupted essential industrial activities, such as power plants. Polar plots analysis shows that NO2 concentrations were strongly associated with local emission sources, such as automobiles and local industry. Additionally, the much lower levels of NO2 concentrations during the LP and the absence of an evening peak may highlight the significant impact of the traffic sector on NO2. The decrease in daily mean O3 concentrations during the LP may be associated with the reduction in NO2 concentrations. Indications in this study could be beneficial for the formulation of atmospheric protection policies. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Remote Sensing is the property of Editorial Office of Journal of Remote Sensing & Science Publishing Co. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

As an air pollutant closely related to urban traffic and heavy industrial capacity, the variation of NO2 (nitrogen dioxide) concentration can directly reflect the strength of socioeconomic activities. Using the weekly average results of daily product synthesis of tropospheric NO2 column concentrations from OMI (Ozone Monitoring Instrument) satellite inversion, a weekly-scale variation series of standardized socioeconomic activity index during the Spring Festival period of 2019–2021 is constructed. The results show that the OMI-NO2 satellite data are in good consistency with ground-based monitoring data; the Spring Festival holiday also suppresses socioeconomic activity in normal years, but the coronavirus disease 2019 (COVID-19) epidemic leads to an extended period of 2–3 weeks of weakened socioeconomic activity in China after the holiday, while the minimum value of socioeconomic activity intensity decreases by 0.12. Although socioeconomic activity is significantly suppressed in the short term, the intensity of socioeconomic activity rises steadily with the gradual resumption of work and production everywhere from the third week after the Chinese Spring Festival and has reached 60.91% of the highest level before the holiday in the seventh week after the holiday. OMI-NO2 satellite data can be used for a rapid assessment of the intensity of air pollution emissions and the level of socioeconomic activity in different regions. [ABSTRACT FROM AUTHOR]

Ozone in the urban atmosphere can accumulate from photochemistry involving nitrogen oxides, carbon monoxide, and volatile organic compounds mainly emitted from fossil fuel combustions and volatile chemical products. Concentrated ozone near the earth's surface has a detrimental impact on the ecosystem and our health. The Los Angeles Basin is a classic example of an urban region with long‐standing ozone pollution, frequently in violation of its standard, designated by the US Environmental Protection Agency (EPA). Studies have reported substantial declines of ozone and their precursor concentrations over the past half century in this area due to extensive pollution controls. Since 2000, however, the ozone design value has remained the same and has not been able to fully reach the air quality standard set by the EPA despite decreases in its precursor concentrations. To understand this phenomenon, we utilize a chemical transport modeling approach to reproduce historical ozone trends and to conduct sensitivity runs relative to a 2010 baseline. Based on our analysis of the model simulations comparing the weekends and weekdays, rather than focusing only on the weekly averages, we diagnose that the Los Angeles Basin is actually going under a significant transition in photochemistry toward a lower ozone concentration. This reveals how air quality management strategies are slowly moving towards a pathway of reducing ozone concentrations in the future. Our study, however, suggests that further reductions of NOx emissions can lead to continued improvement of ozone pollution in this area. Key Points: Long‐term trends of ozone and its precursors concentrations in the LA Basin were simulated with the WRF‐Chem modelWeekday and weekend ozone were almost identical or weekday ozone is higher than weekend ozone in the 2010s in the observation and modelThe model indicates that further reduction of NOx emissions decreases ozone in LA [ABSTRACT FROM AUTHOR]

The ozone data obtained from the satellite (AUREA) and the sensor Ozone Monitoring Instrument (OMI) were used to study the temporary and spatial variability of the total ozone column (TOC) in 8 different cities in Mato Grosso do Sul (MS)—Brazil, during the period 2005–2020. The monthly average values of TOC show maximum values in September and minimum values in June in all seasons. Monthly spatial behavior (TOC) is greater in the south/southwest (S/SW) and SW of MS than in the central and northern (N) parts. [ABSTRACT FROM AUTHOR]

Nitrogen dioxide (NO2) is mainly affected by local emission and meteorology rather than long-range transport. Accurate acknowledge of its long-term variabilities and drivers are significant for understanding the evolutions of economic and social development, anthropogenic emission, and the effectiveness of pollution control measures on regional scale. In this study, we quantity the long-term variabilities and the underlying drivers of NO2 from 2005 to 2020 over the Yangtze River Delta (YRD), one of the most densely populated and highly industrialized city clusters in China, using OMI space borne observations and the multiple linear regression (MLR) model. We have compared the space borne tropospheric results to the surface in-situ data, yielding correlation coefficients of 0.8 to 0.9 over all megacities within the YRD. As a result, the tropospheric NO2 column measurements can be used as representatives of near-surface conditions, and we thus only use ground-level meteorological data for MLR regression. The inter-annual variabilities of tropospheric NO2 vertical column densities (VCDs) from 2005 to 2020 over the YRD can be divided into two stages. The first stage was from 2005 to 2011, which showed overall increasing trends with a wide range of (1.91 ± 1.50) to (6.70 ± 0.10) ×1014 molecules/cm²Â·yr-1 (p<0.01) over the YRD. The second stage was from 2011 to 2020, which showed over all decreasing trends of (-6.31 ± 0.71) to (-11.01 ± 0.90)×1014 molecules/cm²Â·yr-1 (p<0.01) over each of the megacities. The seasonal cycles of tropospheric NO2 VCDs over the YRD are mainly driven by meteorology (81.01% - 83.91%) except during winter when anthropogenic emission contributions are pronounced (16.09% - 18.99%). The inter annual variabilities of tropospheric NO2 VCDs are mainly driven by anthropogenic emission (69.18% - 81.34%) except for a few years such as 2018 which are partly attributed to meteorology anomalies (39.07% - 91.51%). The increasing trends in tropospheric NO2 VCDs from 2005 to 2011 over the YRD are mainly attributed to high energy consumption associated with rapid economic growth which cause significant increases in anthropogenic NO2 emissions. The decreasing trends in tropospheric NO2 VCDs from 2011 to 2020 over the YRD are mainly attributed to the stringent clean air measures which either adjust high energy industrial structure toward low energy industrial structure or directly reduce pollutant emissions from different industrial sectors. [ABSTRACT FROM AUTHOR]

Jiangsu-Zhejiang-Shanghai (JZH) is an important industrial area and foreign trade base in China. In recent years, due to economic development and urban expansion, the emissions of volatile organic compound (VOC) have been increasing, which exacerbated the problem of formaldehyde (HCHO) pollution. The Ozone Monitoring Instrument (OMI) remote sensing has the characteristics of high spatial coverage and strong time continuity, which can enable long-term serial and large-scale dynamic monitoring of atmospheric pollutants. Based on the inversion data of OMI, the paper analyses the temporal-spatial distribution and change trend of the HCHO in JZH from 2008 to 2019, and discusses the transmission path of HCHO in combination with the backward trajectory. In addition, the degree of contribution of anthropogenic sources and natural sources to HCHO are analysed, which is the local HCHO pollution providing reference opinions on governance and atmospheric energy saving and emission reduction. The results showed that the spatial distribution of HCHO in JZH was uneven and will continue to increase in the future. Different types of artificial sources have different degrees of contribution to the study area. In addition, vegetation, temperature, and precipitation have obvious high correlations with HCHO, indicating that natural factors have an important influence on HCHO. [ABSTRACT FROM AUTHOR]

The first ever (to our knowledge) long-term characteristics of aerosol absorption optical depth (AAOD) and then absorption Angstrom exponent (AAE) over the Tarim Basin during 2005–2018 are investigated based on the latest Ozone Monitoring Instrument (OMI) retrievals. This paper aims at evaluating the AAOD and AAE in terms of annual, seasonal, and monthly variations, and referential AAE values of dust aerosols over the Tarim Basin. Our results reveal that the AAOD increases by a factor of nearly 2 from 2015 to 2018, with yearly average values from 0.08 to 0.14 and from 0.04 to 0.07 at 388 and 500 nm, respectively, indicating that the situation of dust aerosol pollution in the Tarim Basin has become severe in recent years. The AAE based on the AAODs at wavelengths of 388 and 500 nm over the Tarim Basin exhibits large variations, with a range of 2.5–3.8. The seasonality of AAOD depicts maximum levels in spring, moderate levels in winter and autumn, and minimum levels in summer, whereas the AAE shows a distinctive pattern with high values in summer and low levels in winter. The monthly mean AAOD values vary by twofold, while monthly average AAE is in a range of 2.8–3.3, with the lowest value in February and the highest in June. The daily AAE between 388 and 500 nm for dust episodes is found to be in a range of 3.2–3.6, with a mean of 3.3, which hopefully provides typical AAE values of dust aerosols over the Tarim Basin. [ABSTRACT FROM AUTHOR]

NO2 is a reactive gas which is produced mainly due to man-made activities (burning of fossil fuels) and influences negatively people organisms and environment. Since the Earth population keeps increasing, the content of the gas in the atmosphere is expected to rise. Satellite monitoring is the most optimal method to observe the spatio-temporal distribution of NO2 in the troposphere globally which cannot be achieved by ground-based measurements. However, there are several different satellite measurement systems which provide the information on tropospheric NO2. In the current study we compared tropospheric NO2 data for the more than 10-year period retrieved from the measurements of OMI and GOME/SCIAMACHY/GOME-2 satellite measurement systems for the territories of Saint Petersburg and Leningrad region (Russia). Also, we investigated correlation between the NO2 tropospheric content by satellite measurements and near-surface NO2 concentration by ground-based measurements in Saint Petersburg. The research demonstrated that OMI and GOME/SCIAMACHY/GOME-2 data on tropospheric NO2 content possessed large discrepancies (approximately 100% relative to OMI data) for the area and period of interest. The datasets did not correlate well but some similarities in a seasonal variation of the tropospheric NO2 content for Saint Petersburg and Leningrad region were found. In addition, we registered an obvious correlation in the trend of near-surface and tropospheric NO2 content obtained by ground-based and OMI satellite measurements respectively. [ABSTRACT FROM AUTHOR]