Increasing SO2 Concentration Research Articles

Unveiling urban air quality dynamics during COVID-19: a Sentinel-5P TROPOMI hotspot analysis

In India, the spatial coverage of air pollution data is not homogeneous due to the regionally restricted number of monitoring stations. In a such situation, utilising satellite data might greatly influence choices aimed at enhancing the environment. It is essential to estimate significant air contaminants, comprehend their health impacts, and anticipate air quality to safeguard public health from dangerous pollutants. The current study intends to investigate the spatial and temporal heterogeneity of important air pollutants, such as sulphur dioxide, nitrogen dioxide, carbon monoxide, and ozone, utilising Sentinel-5P TROPOMI satellite images. A comprehensive spatiotemporal analysis of air quality was conducted for the entire country with a special focus on five metro cities from 2019 to 2022, encompassing the pre-COVID-19, during-COVID-19, and current scenarios. Seasonal research revealed that air pollutant concentrations are highest in the winter, followed by the summer and monsoon, with the exception of ozone. Ozone had the greatest concentrations throughout the summer season. The analysis has revealed that NO2 hotspots are predominantly located in megacities, while SO2 hotspots are associated with industrial clusters. Delhi exhibits high levels of NO2 pollution, while Kolkata is highly affected by SO2 pollution compared to other major cities. Notably, there was an 11% increase in SO2 concentrations in Kolkata and a 20% increase in NO2 concentrations in Delhi from 2019 to 2022. The COVID-19 lockdown saw significant drops in NO2 concentrations in 2020; specifically, − 20% in Mumbai, − 18% in Delhi, − 14% in Kolkata, − 12% in Chennai, and − 15% in Hyderabad. This study provides valuable insights into the seasonal, monthly, and yearly behaviour of pollutants and offers a novel approach for hotspot analysis, aiding in the identification of major air pollution sources. The results offer valuable insights for developing effective strategies to tackle air pollution, safeguard public health, and improve the overall environmental quality in India. The study underscores the importance of satellite data analysis and presents a comprehensive assessment of the impact of the shutdown on air quality, laying the groundwork for evidence-based decision-making and long-term pollution mitigation efforts.

Experimental study on the flux-controlled growth of CO2-SO2 hydrates: Implications for hydrate-based CO2 sequestration

Sulfur dioxide (SO2), an impurity in flue gas, could reduce capture costs if it could be co-sealed with carbon dioxide (CO2) as hydrates. This paper investigated the one-dimensional growth process and selectivity of diffusive flux-controlled CO2-SO2 hydrates using in situ Raman spectroscopy at different temperatures (278.15 and 283.15 K), pressures (5 and 10 MPa), and feed gas concentrations (4 % and 7 % SO2). It is found that, macroscopically, separation factors (S.F.) at the hydrate-aqueous solution interface reveal that the hydrate is more selective for CO2 (S.F. < 1), with SO2 more inclined to dissolve in water. Microscopically, the less abundant SO2 in the aqueous solution would be locally depleted, providing heterogeneous nucleation sites for the surrounding dissolved CO2, promoting CO2 hydrate formation. The increase in SO2 concentration would increase the hydrate growth rate and accelerate the CO2 sequestration process. The results provide valuable insights into the synchronized sequestration of CO2-SO2 by hydrates.

Pilot-tests of the coal-fired power plant indirect coupling with multi-source organic solid waste incineration technology

The production of organic solid waste is increasing as the development of society. However, the investment of waste incineration power plant is very high and the thermal efficiency is very low. At the same time, the load of coal-fired power plant is suppressed due to the carbon neutralization policy. Therefore, using the existed coal-fired power plant to co-process the organic solid waste is a feasible method. In this paper, a coal-fired power plant indirect coupling with waste incineration technology based on flue gas circulation was proposed and studied on a 100 kW pilot-test bench. In this technology, the polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) was reduced by a three stages controlling method, which adopts the blending of multi-source organic wastes, high-temperature decomposition and selective catalytic reduction (SCR) catalyst decomposition, simultaneously. The effects of waste incineration coupling, replacement ratio of coal, and flue gas circulation on the combustion and pollutant emission characteristics of the system were studied. The experimental results indicate that the waste incineration coupling has minor influence on the temperature distribution and the toxicity of fly ash of the coal-fired furnace. The NO, HCl, and PCDD/Fs concentrations of flue gas of coal-fired furnace generally decrease as the replacement ratio of coal increases, while the SO2 concentration increases. With the help of three stages controlling method or the flue gas circulation, the PCDDFs concentration of the flue gas of coal-fired furnace can be much lower than 0.1 TEQ ng/Nm3.

Acidic Gas Determination Using Indium Tin Oxide-Based Gas Sensors.

This work has presented gas sensors based on indium tin oxide (ITO) for the detection of SO2 and NO2. The ITO gas-sensing material was deposited by radio frequency (RF) magnetron sputtering. The properties of gas sensing could be improved by increasing the ratio of SnO2. The response characteristics of the gas sensor for detecting different concentrations of NO2 and SO2 were investigated. In the detection of NO2, the sensitivity was significantly improved by increasing the SnO2 ratio in ITO by 5%, and the response and recovery time were reduced significantly. However, the sensitivity of the sensor decreased with increasing SO2 concentration. From X-ray photoelectron spectroscopy (XPS) analysis, the gas-sensitive response mechanisms were different in the atmosphere of NO2 and SO2. The NO2 was adsorbed by ITO via physisorption but the SO2 had a chemical reaction with the ITO surface. The gas selectivity, temperature dependence, and environmental humidity of ITO-based gas sensors were systematically analyzed. The high detection sensitivity for acidic gas of the prepared sensor presented great potential for acid rain monitoring.

Evaluating the potential footprints of land use and land cover and climate dynamics on atmospheric pollution in Pakistan

Evaluating the potential impacts of land use and land cover change (LULCC) and climate change on air pollution is crucial to unravel the driving forces and mechanisms behind changes in air quality. A multi-faceted approach was adopted, including a land change model (LCM) and Mann–Kendall (MK) test, to evaluate the transition of land cover type, changes in climate, and atmospheric pollutants during 2004–2021 in Pakistan. Moreover, a multiscale geographically weighted regression (MGWR) model and a mathematical model were used to assess the potential contribution of LULCC and climate dynamics to atmospheric pollution. It was revealed that during 2004, croplands covered an area of 9.72 × 104 mile2, accounting for 38% of the total area. However, the area of the croplands increased to 10.1 × 104 mile2, accounting for 40% of the total area in 2021. The MK test showed that the north and west–south regions significantly experienced air pollution, with the increasing trend for nitrogen dioxide (NO2) and sulfur dioxide (SO2) being 0.89× 1015 molecules/cm2 per year and 0.54 DU/year, respectively. For climate variability, mean precipitation (Precp) and mean surface pressure (SP) showed a prominent increasing trend, with a maximum value of 1 mm/year and 0.01 Kpa/year, respectively. The mean temperature maximum (Tmax) showed an increasing and decreasing trend, with the highest value of 0.28°C/year and 0.08°C/year, respectively. In the context of contribution, the conversion of cropland to grasslands increased the trend for SO2 concentrations. The highest increasing trend of 1.5 DU for ozone (O3) was found due to conversion of grasslands to shrublands. Additionally, regional climate played a significant role in making air pollution stagnant across the country. Precp and wind speed (WS) contributed significantly in escalating NO2 concentrations in Pakistan, while Precp contributed most (0.004 DU) to increasing SO2 concentrations. For O3, the most influential climate factor was Precp. These results on a long-term temporal scale demonstrated how maintaining climate variability through comprehensive land use management can help improve ambient air quality in Pakistan.

Long-Term Dynamics of Atmospheric Sulfur Dioxide in Urban and Rural Regions of China: Urbanization and Policy Impacts

High levels of sulfur dioxide (SO2) due to human activities pose a serious air pollution issue in China, especially in urban agglomerations. However, limited research has investigated the impact of anthropogenic emissions on higher SO2 concentrations in urban regions compared to rural areas in China. Here, we analyzed the trends in SO2 concentrations from 1980 to 2021 in China using the Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2) dataset. SO2 column concentrations from the Copernicus Atmosphere Monitoring Service (CAMS) and the Ozone Monitoring Instrument (OMI) during the years 2007–2021 were also examined for validation and comparison purposes. Eight representative areas, including four urban regions (Pearl River Delta [PRD], Beijing-Tianjin-Hebei [BTH], Yangtze River Delta [YRD], and Sichuan Basin [SCB]) and four rural regions (Northeast Region [NER], Mongolian Region [MR], West Region [WR], and Tibetan Plateau Region [TR]) were selected for the analysis. Overall, a significant but fluctuating increase in SO2 concentrations over China was observed during 1980–2021. During 1980–1997 and 2000–2010, there was an increase in SO2 concentration, while during 1997–2000 and 2010–2021, a decreasing trend was observed. The average increase in SO2 concentration was approximately 16 times higher in urban regions than in the rural background. We also found that SO2 dynamics were highly associated with expansion of urban areas, population density, and gross domestic product. Nonetheless, since 2007, SO2 concentrations have exhibited a downward trend, which is mainly attributed to the air pollution policies implemented by the Chinese government. Our findings highlight the need for further studies on the impact of SO2 on regional climate change in China.

Exploring the association between atmospheric pollutants and preterm birth risk in a river valley city.

To investigate the association between exposure to atmospheric pollutants and preterm birth in a river valley-type city and its critical exposure windows. A retrospective cohort study was used to collect data from the medical records of preterm and full-term deliveries in two hospitals in urban areas of a typical river valley-type city from January 2018 to December 2019. A total of 7,288 cases were included in the study with general information such as pregnancy times, the number of cesarean sections, occupation, season of conception and regularity of the menstrual cycle. And confounding factors affecting preterm birth were inferred using the chi-square test. The effects of exposure to each pollutant, including particulate matter 2.5 (PM2.5), particulate matter 10 (PM10), nitrogen dioxide (NO2), sulfur dioxide (SO2), carbon monoxide (CO) and ozone (O3), during pregnancy on preterm birth and the main exposure windows were explored by establishing a logistic regression model with pollutants introduced as continuous variables. Maternal age, pregnancy times, number of births, number of cesarean sections, season of conception, complications diseases, comorbidities diseases, hypertension disorder of pregnancy and neonatal low birth weight of the newborn were significantly different between preterm and term pregnant women. Logistic regression analysis after adjusting for the above confounders showed that the risk of preterm birth increases by 0.9, 0.6, 2.4% in T2 and by 1.0, 0.9, 2.5% in T3 for each 10 μg/m3 increase in PM2.5, PM10, NO2 concentrations, respectively. The risk of preterm birth increases by 4.3% in T2 for each 10 μg/m3 increase in SO2 concentrations. The risk of preterm birth increases by 123.5% in T2 and increases by 188.5% in T3 for each 10 mg/m3 increase in CO concentrations. Maternal exposure to PM2.5, PM10, NO2, CO was associated with increased risk on preterm birth in mid-pregnancy (T2) and late pregnancy (T3), SO2 exposure was associated with increased risk on preterm birth in mid-pregnancy (T2).

SO3/sulfuric acid mist removal in simulated flue gas: Multi-factor study based on two-film theory mass transfer process

SO3/sulfuric acid mist is a strongly irritating pollutant presented in small quantities in flue gas, which poses a major threat to the power plants operation and atmospheric environment. In this study, SO3/sulfuric acid mist at different positions and after different spraying time of the small desulfurization tower were extracted and absorbed by isopropanol solution, and the SO42- concentration was detected by barium-thorium titration. Then the SO3/sulfuric acid mist mass transfer model in desulfurization process was constructed on the basis of two-film theory to investigate the effects of different tower structures, spraying time and operating conditions on SO3/sulfuric acid mist removal in desulfurization tower. The results showed that the tower structures had the greatest influence on SO3/sulfuric acid mist removal, and the highest SO3/sulfuric acid mist removal efficiency was achieved after the spraying time of 0–20 min and at the flue gas distribution plate. Moreover, according to the results of SO3/sulfuric acid mist mass transfer model, SO3 removing process was not controlled by solid dissolution instead of by gas–liquid film turning to gas film with flue gas residence time running in the tower. The model results also showed that SO3 removing process was controlled by gas film for a very short period then turning to gas–liquid film immediately with spraying time accumulating in a specific tower position. Besides, it showed the increase of NH3 concentration and spraying flow rate promoted the SO3/sulfuric acid mist removal, and the increase of SO2 concentration and slurry temperature inhibited the SO3/sulfuric acid mist removal.

Global sensitivities of reactive N and S gas and particle concentrations and deposition to precursor emissions reductions

Abstract. The reduction of fine particles (PM2.5) and reactive N (Nr) and S (Sr) species is a key objective for air pollution control policies because of their major adverse effects on human health, ecosystem diversity, and climate. The sensitivity of global and regional Nr, Sr, and PM2.5 to 20 % and 40 % individual and collective reductions in anthropogenic emissions of NH3, NOx, and SOx (with respect to a 2015 baseline) is investigated using the EMEP MSC-W (European Monitoring and Evaluation Programme Meteorological Synthesizing Centre – West) atmospheric chemistry transport model with WRF (Weather Research and Forecasting) meteorology. Regional comparisons reveal that the individual emissions reduction has multiple co-benefits and small disbenefits on different species, and those effects are highly geographically variable. A 40 % NH3 emission reduction decreases regional average NH3 concentrations by 47 %–49 % but only decreases NH4+ by 18 % in Euro_Medi, 15 % in East Asia, 12 % in North America, and 4 % in South Asia. This order follows the regional ammonia richness. A disbenefit is the increased SO2 concentrations in these regions (10 %–16 % for 40 % reductions) because reduced NH3 levels decrease SO2 deposition through altering atmospheric acidity. A 40 % NOx emission reduction reduces NOx concentrations in East Asia by 45 %, Euro_Medi and North America by ∼ 38 %, and South Asia by 22 %, whilst the regional order is reversed for fine NO3-, which is related to enhanced O3 levels in East Asia (and also, but by less, in Euro_Medi) and decreased O3 levels in South Asia (and also, but by less, in North America). Consequently, the oxidation of NOx to NO3- and of SO2 to SO42- is enhanced in East Asia but decreased in South Asia, which causes a less effective decrease in NO3- and even an increase in SO42- in East Asia but quite the opposite in South Asia. For regional policy making, it is thus vital to reduce three precursors together to minimize such adverse effects. A 40 % SOx emission reduction is slightly more effective in reducing SO2 (42 %–45 %) than SO42- (34 %–38 %), whilst the disbenefit is that it yields a ∼ 12 % increase in total NH3 deposition in the four regions, which further threatens ecosystem diversity. This work also highlights important messages for policy makers concerning the mitigation of PM2.5. More emissions controls focusing on NH3 and NOx are necessary for regions with better air quality, such as northern Europe and eastern North America. In East Asia, the three individual reductions are equally effective, whilst in South Asia only SOx reduction is currently effective. The geographically varying non-one-to-one proportionality of chemical responses of Nr, Sr, and PM2.5 to emissions reductions revealed by this work show the importance of both prioritizing emissions strategies in different regions and combining several precursor reductions together to maximize the policy effectiveness.

Relevance and Reliability of Outdoor SO2 Monitoring in Low-Income Countries Using Low-Cost Sensors

In the Western world, the SO2 concentration in ambient air dropped to low levels, but some emission sources (e.g., merchant ships) and some regions (e.g., low-income countries) still emit substantial amounts of SO2. At those locations, SO2 monitoring is critical. However, low-income countries do not have much access to expensive reference instruments. Low-cost gas sensors might be an alternative, but it is unclear how reliable such measurements are. To evaluate the performance of the low-cost alternative, the same SO2 gas sensor has been subjected to three different calibration methods: (1) low-cost calibration performed in the tropical climate of Cuba; (2) high-end calibration performed in Belgium; (3) a field calibration at an air quality measuring station in Belgium. The first two methods showed similar trends, suggesting that the gas sensor can be calibrated with a low-cost method. The field calibration was hampered by the low SO2 concentrations. For the monitoring campaign in Cienfuegos, Cuba, the low-cost SO2 sensor calibrated by the low-cost method appeared to be sufficiently reliable. The reliability of the sensor increases with the increase in SO2 concentration, so it can be used in Cuba instead of Belgium.

Research on migration and transformation behavior of selenium during the dual-alkali wet flue gas deacidification process in the simulated flue gas

Selenium easily escapes from the existing air pollution control devices (APCDs) used in municipal waste solid incineration (MSWI), which poses a threat to both the ecosystem and human health. Dual-alkali wet flue gas deacidification (DAWFGD) has been recently applied in MSWI power plants to improve the purification of flue gas. This technology provides a new route for the coordinated control of selenium in the DAWFGD device, which removes acidic gas simultaneously. In this study, a laboratory-scale DAWFGD system was constructed to investigate the migration and transformation behavior of selenium during the absorption and regeneration process in the DAWFGD system. The results showed that the Na2CO3 solution could effectively absorb SeO2, and the absorption efficiency could reach up to 97.09% by increasing the Na2CO3 concentration. High-concentration CO2 has less of an absorption inhibition effect on gaseous selenium compared to low-concentration HCl and SO2. The absorption of SeO2 was adversely affected by the decrease in pH value of the absorption solution caused by an increase in SO2 concentration. However, the addition of a small amount of alkali solution (OH–) into the absorption solution could well recover its absorption performance for SeO2. During the regeneration process, the precipitation ratio of selenium from the aqueous phase to the solid phase increased with the molar ratio of Ca/S increasing. Besides, selenium was found to be in the form of selenite during both the absorption and regeneration processes. This study helps to evaluate the potential of DAWFGD in MSWI power plants for removing SeO2 from flue gas and provides a theoretical reference for the treatment of gas-phase selenium in the waste incineration process.

Bipolar membrane electrodialysis combined with ozone oxidation wet scrubbing to remove SO2 and NOx from flue gas and achieve CO2 mineralization

This study proposed a new process based on bipolar membrane electrodialysis (BMED) for the one-stop simultaneous removal of SO2 and NOx and mineralization of CO2 from flue gas. The process could be divided into two simultaneous aspects: the mineralization of CO2 into calcium carbonate using calcium ions in seawater; meanwhile, and the removal of SO2 and NOx by wet scrubbing. During this process, the OH– generated by the bipolar membrane was used as an absorbent, and ozone (O3) was used as an oxidizer for NO in the flue gas. It was found that at higher current density, the absorption rate of CO2 could be enhanced, but the calcium and magnesium were precipitated in the form of carbonate at the same time, and the product was no longer pure calcium carbonate product, thus reducing the purity and added value of the product. Enhancing the liquid flow rate could reduce the membrane surface resistance, thus effectively decreasing the energy consumption of the system. The increase of SO2 concentration and n (O3/NO) could significantly improve the NOx removal efficiency, however, higher SO2 concentration would consume more OH– and inhibit CO2 absorption. Under the optimal conditions, the average CO2 absorption rate, decalcification rate, and denitrification rate were 53. 57%, 92.56%, and 87. 61%, respectively, and the desulfurization rate was close to 100%. Given the high energy consumption in the decalcification process and the problem that the by-product was calcium carbonate with mixed crystal form, the experiment was optimized. The electrodialysis process could produce aragonite-type calcium carbonate, which was utilized as crystal seed to ensure the purity of subsequent by-products. Especially, the energy consumption was effectively reduced by utilizing the accumulation of carbonate and bicarbonate in the mother fluid of the electrodialysis process through the self-crystallization process of calcium carbonate induced by crystal seed to shorten the time of the electrodialysis process.

Risk and economic cost of hospitalization due to atrial fibrillation caused by air pollution: a multi-city time series analysis

BackgroundAtrial fibrillation (AF) is the most common arrhythmia, resulting in serious cardiovascular diseases. Air pollution may cause heart rate disturbance, but there is no clear or consistent evidence that short-term exposure to air pollution leads to an increased risk of hospitalisation for symptomatic episodes of AF. This study aimed to assess the impact of short-term exposure to air pollution on inpatient numbers.MethodsThe inpatient records of AF cases in nine cities of the Sichuan Province, China and air pollution and meteorological data from 183 monitoring stations from 2017 to 2018 were collected. The impact of short-term exposure to air pollution on AF inpatients was evaluated using a time-stratified crossover case study design. The economic burden of AF attributable to air pollution was also estimated.ResultsA total of 5,958 patients with AF from 123 medical institutions were included in the analysis. Air pollutants had a significant impact on the number of patients with AF. The number increased by 2.5% (95% confidence interval [CI] = 1.006 to 1.044) and 1.8% (95% CI = 1.003–1.033) for every 10 µg/m3 increase in PM2.5, PM10, concentration, respectively. Moreover, the number increased by 12.7% (95% CI = 1.006 to 1.262) for every 10 µg/m3 increase of SO2 concentration. For every 0.1 μg/m3 increase in CO concentration, the number of inpatients with AF increased by 3.9% (95% CI = 1.010–1.070). People aged 65 years or older and women were more likely to be affected by air pollutants. The AF in 430 and 209 inpatients were attributable to PM2.5 and PM10, respectively. The total hospitalization expenses attributed to excessive exposure to PM2.5 and PM10 were 13.98 million CNY and 6.68 million CNY, respectively. Furthermore, the out-of-pocket expenses were 6.81 million CNY and 3.28 million CNY, respectively.ConclusionsThis study showed a strong correlation between air pollution and AF. Hence, there is a need to reduce air pollution to control health risks.

Exploration on the source of SO42− in Condensable Particulate Matter

Condensable particulate matter (CPM) attracts wide attention as an emerging pollutant that pollutes the environment and affects human health. CPM consists of organic and inorganic components, of which the SO42−, as the anion with the largest proportion of the inorganic component of CPM, is still unclear as to its source. In this paper, two schemes based on simulated flue gas (SFG) and real flue gas (RFG) experimental systems separately were adopted to explore the potential sources of SO42− in CPM. The SFG experiment was performed by configuring the SFG containing determined concentrations of various S-containing substances. Also, the interference of SO2 on CPM measurement caused by dissolution and the effect of nitrogen purging were revealed. In the RFG experiment, some S-containing substances were extra added to the combustion system individually, and the source of SO42− was judged through observing the change of SO42− detected in CPM. It was found through experiment that SO42− in CPM was mainly from SO3/H2SO4 in flue gases, and the contribution of varied sulfates was little. The positive error factor caused by the dissolution of SO2 increases with the increasing SO2 concentration and cannot be eliminated by nitrogen purging.

Association between ambient sulfur dioxide pollution and asthma mortality: Evidence from a nationwide analysis in China

There is a lack of research on the effects of acute exposure to ambient sulfur dioxide (SO2) on mortality caused by asthma, especially nationwide research in China. To explore the acute effect of exposure to ambient SO2 on asthma mortality using nationwide dataset in China from 2015 to 2020 and further evaluate the associations in subgroups with different geographical and demographic characteristics. We used data from China’s Disease Surveillance Points system with 29,553 asthma deaths in China during 2015–2020. The exposure variable was the daily mean concentrations of SO2 from the ChinaHighSO2 10 km × 10 km daily grid dataset. Bilinear interpolation was used to estimate each individual’s exposure to air pollutants and meteorological variables. We used a time-stratified case crossover design at the individual level to analyze the exposure response relationship between short-term exposure to SO2 and asthma mortality. Stratified analyses were carried out by sex, age group, marital status, warm season and cold season, urbanicity and region. Significant associations between short-term exposure to ambient SO2 and increased asthma mortality were found in this nationwide study. The excess risk (ER) for each 10 μg/m3 increase in SO2 concentrations at lag07 was 7.78 % (95 % CI, 4.16–11.52 %). Season appeared to significantly modify the association. The associations were stronger in cold season (ER 9.78 %, 95 % CI:5.82 −13.89 %). The association remained consistent using different lag periods, adjusting for other pollutants, and in the analysis during pre-Corona Virus Disease 2019 (COVID-19) period. Our study indicates increased risk of asthma mortality with acute exposures to SO2 in Chinese population. The current study lends support for greater awareness of the harmful effect of SO2 in China and other countries with high SO2 pollution.

Experimental investigation of stress corrosion on supercritical CO2 transportation pipelines against leakage for CCUS applications

Carbon Capture, Utilization and Storage (CCUS) is one of the key technologies that will determine how humans address global climate change. For captured CO2, in order to avoid the complications associated with two-phase flow, most carbon steel pipelines are operated in the supercritical state on a large scale. A pipeline has clear Stress Corrosion Cracking (SCC) sensitivity under the action of stress and corrosion medium, which will generally cause serious consequences. In this study, X70 steel was selected to simulate an environment in the process of supercritical CO2 transportation by using high-temperature high-pressure Slow Strain Rate Tensile (SSRT) tests and high-temperature high-pressure electrochemical test devices, with different O2 and SO2 contents. Studies have shown that 200 ppm SO2 shows a clear SCC sensitivity tendency, which is obvious when the SO2 content reaches 600 ppm. The SCC sensitivity increases with the increase of SO2 concentration, but the increase amplitude decreases. With the help of advanced microscopic characterization techniques such as scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), through the analysis of fracture and side morphology, the stress corrosion mechanism of a supercritical CO2 pipeline containing SO2 and O2 impurities was obtained by hydrogen embrittlement fracture characteristics. With the increase of SO2 content, the content of Fe element decreases and the corrosion increases, demonstrating that SO2 plays a leading role in electrochemical corrosion. This study further strengthens the theoretical basis of stress corrosion of supercritical CO2 pipelines, plays an important role in preventing leakage of supercritical CO2 pipelines, and will provide guidance for the industrial application of CCUS.

Air quality affects house prices — Analysis based on RD of the Huai River policy

Based on the quasi-natural experiment of the Huai River policy in China, this research attempts to demonstrate the causal relationship between the Huai River policy, air quality and house prices, as well as the underlying logical mechanism. This paper's findings suggest that the Huai River policy leads to higher concentrations of air pollutants such as PM10, SO2and PM2.5 in cities north of the Huai River than in the south, and lower real estate prices in cities north of the Huai River than in the south. Secondly, air quality significantly affects house prices.For every 1 unit increase in PM10 concentration, house prices will decrease by 0.24%; for every 1 unit increase in PM2.5 concentration, house prices will decrease by 0.37%; and for every 1 unit increase in SO2 concentration, house prices will decrease by 0.24%. Finally, by tracing the potential mechanisms, the results SO2 show that the Huai River policy reduces the air quality in the northern region, and then has a restraining effect on the northern housing price level, and there is no alternative path for the Huai River policy to affect house prices.

Triggering of ST-elevation myocardial infarction by ultrafine particles in New York: Changes following Tier 3 vehicle introduction

BackgroundPreviously, we found increased rates of ST-elevation myocardial infarction (STEMI) associated with increased ultrafine particle (UFP; <100 nm) concentrations in the previous few hours in Rochester, New York. Relative rates were higher after air quality policies and a recession reduced pollutant concentrations (2014–2016 versus 2005–2013), suggesting PM composition had changed and the same PM mass concentration had become more toxic. Tier 3 light duty vehicles, which should produce less primary organic aerosols and oxidizable gaseous compounds, likely making PM less toxic, were introduced in 2017. Thus, we hypothesized we would observe a lower relative STEMI rate in 2017–2019 than 2014–2016. MethodsUsing STEMI events treated at the University of Rochester Medical Center (2014–2019), UFP and other pollutants measured in Rochester, a case-crossover design, and conditional logistic regression models, we estimated the rate of STEMI associated with increased UFP and other pollutants in the previous hours and days in the 2014–2016 and 2017–2019 periods. ResultsAn increased rate of STEMI was associated with each 3111 particles/cm3 increase in UFP concentration in the previous hour in 2014–2016 (lag hour 0: OR = 1.22; 95% CI = 1.06, 1.39), but not in 2017–2019 (OR = 0.94; 95% CI = 0.80, 1.10). There were similar patterns for black carbon, UFP11–50nm, and UFP51–100nm. In contrast, increased rates of STEMI were associated with each 0.6 ppb increase in SO2 concentration in the previous 120 h in both periods (2014–2016: OR = 1.26, 95% CI = 1.03, 1.55; 2017–2019: OR = 1.21, 95% CI = 0.87, 1.68). ConclusionsGreater rates of STEMI were associated with short term increases in concentrations of UFP and other motor vehicle related pollutants before Tier 3 introduction (2014–2016), but not afterwards (2017–2019). This change may be due to changes in PM composition after Tier 3 introduction, as well as to increased exposure misclassification and greater underestimation of effects from 2017 to 2019.

Air pollution in Delhi, India: It's status and association with respiratory diseases.

The policymakers need research studies indicating the role of different pollutants with morbidity for polluted cities to install a strategic air quality management system. This study critically assessed the air pollution of Delhi for 2016–18 to found out the role of air pollutants in respiratory morbidity under the ICD-10, J00-J99. The critical assessment of Delhi air pollution was done using various approaches. The mean PM2.5 and PM10 concentrations during the measurement period exceeded both national and international standards by a wide margin. Time series charts indicated the interdependence of PM2.5 and PM10 and connection with hospital visits due to respiratory diseases. Violin plots showed that daily respiratory disease hospital visits increased during the winter and autumn seasons. The winter season was the worst from the city’s air pollution point of view, as revealed by frequency analyses. The single and multi-pollutant GAM models indicated that short-term exposure to PM10 and SO2 led to increased hospital visits due to respiratory diseases. Per 10 units increase in concentrations of PM10 brought the highest increase in hospital visits of 0.21% (RR: 1.00, 95% CI: 1.001, 1.002) at lag0-6 days. This study found the robust effect of SO2 persisted in Delhi from lag0 to lag4 days and lag01 to lag06 days for single and cumulative lag day effects, respectively. While every 10 μg m-3 increase of SO2 concentrations on the same day (lag0) led to 32.59% (RR: 1.33, 95% CI: 1.09, 1.61) rise of hospital visits, the cumulative concentration of lag0-1 led to 37.21% (RR: 1.37, 95% CI:1.11, 1.70) rise in hospital visits which further increased to even 83.33% (RR: 1.83, 95% CI:1.35, 2.49) rise at a lag0-6 cumulative concentration in Delhi. The role of SO2 in inducing respiratory diseases is worrying as India is now the largest anthropogenic SO2 emitter in the world.

Ambient Air Pollution and Acute Ischemic Stroke-Effect Modification by Atrial Fibrillation.

Acute ischemic strokes (AIS) are closely linked with air pollution, and there is some evidence that traditional cardiovascular risk factors may alter the relationship between air pollution and strokes. We investigated the effect of atrial fibrillation (AF) on the association of AIS with air pollutants. This was a nationwide, population-based, case-only study that included all AIS treated in public healthcare institutions in Singapore from 2009 to 2018. Using multivariable logistic regression, adjusted for time-varying meteorological effects, we examined how AF modified the association between AIS and air pollutant exposure. A total of 51,673 episodes of AIS were included, with 10,722 (20.7%) having AF. The odds of AIS in patients with AF is higher than those without AF for every 1 µg/m3 increase in O3 concentration (adjusted OR [aOR]: 1.005, 95% CI 1.003–1.007) and every 1 mg/m3 increase in CO concentration (aOR: 1.193, 95% CI 1.050–1.356). However, the odds of AIS in patients with AF is lower than those without AF for every 1 µg/m3 increase in SO2 concentration (aOR: 0.993, 95% CI 0.990–0.997). Higher odds of AIS among AF patients as O3− and CO concentrations increase are also observed in patients aged ≥65 years and non-smokers. The results suggest that AF plays an important role in exacerbating the risk of AIS as the levels of O3 and CO increase.