Acid Rain Research Articles

The potentials of copper chromite nanoparticles on ammonium nitrate decomposition: Towards eco-friendly oxidizers for green solid propellants

Abstract Ammonium perchlorate (AP) is the universal oxidizer for solid propellants; AP combustion is accompanied with the release of white smoke (HCl). HCl has raised an environmental concern; it could cause acidic rain and deteriorate the fertile soil. Chlorine free and eco-friendly oxidizers are highly appreciated for green solid propellants. Ammonium nitrate (AN) could be the greener substitute for AP; yet AN expose low performance. Whereas AP demonstrated exothermic decomposition with the release of -733 J/g; AN demonstrated strong endothermic decomposition process of +1707 J/g. AN with strong endothermic decomposition process could render high burning rates. Copper chromite Nano catalyst of 45 nm was developed via hydrothermal synthesis. Copper chromite was integrated into AN matrix. Catalyzed AN demonstrated advanced exothermic decomposition enthalpy of -1492 J/g. Catalysed AN experienced diminish in activation energy by - 41.5 %, and – 40.6 % using Kissinger and Ozawa models respectively. Copper chromite NPs could secure novel catalytic effect via condensed phase reactions of chromium, and copper ions with nitrate ions (NO-3) to develop NOx gases. This catalytic effect can secure alternative pathway with low energy barrier. Consequently, catalysed AN can expose novel characteristics as a green eco-friendly oxidizer.

Experimental study on compressive behavior of compressive stress-loaded concrete at different strain rates under simulated acid rain environment

Concrete is typically under stress when exposed to acid rain corrosion. This study aimed to assess the physical and compressive behavior of compressive stress-loaded concrete (CSLC) under a simulated acid rain environment. The compressive stress states (0 %, 15 %, 20 %, 25 %, and 30 % of its compressive strength) and a simulated acid rain environment (pH = 2) were replicated in the laboratory. A compression tester was used to control loading at different strain rates (0.5 × 10−3/s, 10−3/s, 10−2/s, and 10−1/s). The results elucidate a three-stage pattern in the mass degradation of CSLC, accompanied by shallower corrosion depth compared to unstressed concrete. During the initial phases of the corrosion, compressive stresses at levels of 15 %, 20 %, and 25 % enhance the concrete's compressive strength by 2.8 %–10.1 %. However, this initial enhancement transitions to deterioration as external stress levels and corrosion time increase. SEM images validate these findings, showcasing initially denser internal structures in CSLC (15 %–25 %) compared to unstressed concrete (0 %), but severe deterioration at a 30 % stress level. Additionally, the strain-rate effect is more pronounced in unstressed concrete initially, with enhancement ranging from 12 % to 15 %, but gradually diminishes with increasing stress levels and corrosion time. It can be concluded that service stress significantly accelerates the long-term deterioration of concrete exposed to acid rain and should not be ignored in practical analysis.

Characterization of Waste Biomass Fuel Prepared from Coffee and Tea Production: Its Properties, Combustion, and Emissions

In order to reduce global warming, new energy fuels that use waste biomass to replace traditional coal are rapidly developing. The main purpose of this study is to investigate the feasibility behavior of different biomass materials such as spent coffee grounds (SCGs) and spent tea grounds (STGs) as fuel during combustion and their impact on the environment. This study involves using fuel shaping and co-firing methods to increase the fuel calorific value and reduce the emissions of pollutants, such as NOX and SO2, and greenhouse gas CO2. The produced gas content was analyzed using the HORIBA (PG-250) laboratory combustion apparatus. The results indicate that, among the measured formed particles, SCG:STG = 8:2, 6:4, and 4:6 had the lowest post-combustion pollutant gas emissions. Compared to using only waste coffee grounds as fuel, the NOx emissions were reduced from 166 ppm to 102 ppm, the CO emissions were reduced from 22 ppm to 12 ppm, and the CO2 emissions were reduced from 629 ppm to 323 ppm. In addition, the emission of SO2, the main component of acid rain, was reduced by 20 times compared to the combustion of traditional fuels. The SO2 emission of five different proportions of biomass fuels was 5 ppm, which is much lower than that of traditional coal fuels. Therefore, SCG and STG mixed fuels can replace coal as fuel while reducing harmful gasses.

Morphoanatomical alterations in extrafloral nectaries of Cedrela fissilis Vell. (Meliaceae), a native species of the Atlantic Forest, in response to simulated acid rain

Acid rain is one of the major contributors to the loss of tropical forest. Although the effects of acid rain in leaf anatomy have been widely studied, its impact on specialized secretory structures remains unknown. The aim of this study was to investigate the morphoanatomical changes in the extrafloral nectaries of Cedrela fissilis in response to simulated acid rain. Each seedling was sprayed with 50 ml of an acidic solution daily for 19 consecutive days. Anatomical and micromorphological changes in the nectaries were described. The treated plants exhibited plasmolysis and disruption of epidermal cells, cell collapse, hypertrophy, plasmolysis, phenolic and starch accumulation in the nectar-secreting cells, and the formation of a wound healing tissue. The results indicate that the nectaries of C. fissilis undergo alterations when exposed to acid rain, which may compromise the functioning of the entire structure and potentially impact plant-insect ecological interactions.

Assessing the interactive effects of microplastics and acid rain on cadmium toxicity in rice seedlings: Insights from physiological and transcriptomic analyses

In heavy metal-contaminated areas, the simultaneous occurrence of increasing microplastic pollution and persistent acid rain poses a serious threat to food security. However, the mechanisms of combined exposure to microplastics (MP) and acid rain (AR) on the toxicity of cadmium (Cd) in rice seedlings remain unclear. Our study investigated the combined effects of exposure to polyvinyl chloride microplastics and AR (pH 4.0) on the toxicity of Cd (0.3, 3, and 10 mg/L) in rice seedlings. The results showed that at low Cd concentrations, the combined exposure had no significant effect, but at high Cd concentrations, it alleviated the effects of Cd stress. The combined application of MP and AR alleviated the inhibitory effects of Cd on seedling growth and chlorophyll content. Under high Cd concentrations (10 mg/L), the simultaneous addition of MP and AR significantly reduced the production of reactive oxygen species (ROS), the content of malondialdehyde (MDA), and the activity of the superoxide dismutase (SOD). Compared with AR or MP alone, the combination of MP and AR reduced root cell damage and Cd accumulation in rice seedlings. Transcriptomic analysis confirmed that under high Cd concentrations, the combination of MP and AR altered the expression levels of genes related to Cd transport, uptake, MAPK kinase, GSTs, MTs, and transcription factors, producing a synergistic effect on oxidative stress and glutathione metabolism. These results indicate that co-exposure to MP and AR affected the toxicity of Cd in rice seedlings and alleviated Cd toxicity under high Cd concentrations to some extent. These findings provide a theoretical basis for evaluating the toxicological effects of microplastic and acid rain pollution on crop growth in areas contaminated with heavy metals, and are important for safe agricultural production and ecological security.

Elucidating the Ramifications of Simulated Acid Rain on Palak (Beta vulgaris L.) Cultivars: Insights from Morphological, Physiological, Biochemical and Quality Analyses

Elucidating the Ramifications of Simulated Acid Rain on Palak (Beta vulgaris L.) Cultivars: Insights from Morphological, Physiological, Biochemical and Quality Analyses

Acid rain resistance of geopolymer recycled pervious concrete featuring top-bottom interconnected pores under freeze-thaw cycles and fatigue loads

While pervious concrete with top-bottom interconnected pores enhances the performance of pervious concrete pavements, its resistance to acid rain under combined freeze-thaw cycles and fatigue loads remains unexplored. To fill this gap, this study investigated the influence of three different qualities of recycled coarse aggregates on the acid resistance, acid neutralization, and permeability of geopolymer recycled pervious concrete (GRPC) (Low-quality, middle-quality and high-quality geopolymer recycled pervious concrete (L-GRPC, M-GRPC and H-GRPC)) under the couple effects of simulated acid rain wet-dry cycle spraying, fatigue loads and freeze-thaw cycles. After experiencing the combined action of fatigue load and freeze-thaw cycle, only the compressive strength of L-GRPC increased slightly by 9.1 % after acid rain spraying, but it had a negative impact on the flexural strength. With the increase of coupling environmental factors, the neutralization depth of GRPC was less than 4 mm, and the permeability coefficient was higher than 0.5 mm/s. Furthermore, more gypsum crystals were observed in the SEM images, and new peaks corresponded to the gypsum phase (CaSO4) appeared at 2θ = 29.4° and 2θ = 21.6° in the XRD spectra. The research results provide a broader perspective for the application of GRPC in concrete pavement engineering in acid rain area.

Soil aggregate size distribution mediates microbial responses to prolonged acid deposition in a subtropical forest in south China

Extended exposure to acid rain has vastly limited soil microbial activity with the consequences for soil carbon (C) storage, but less is known about the microbial responses within soil aggregates that to some extent determine soil C stabilization. Here, we investigated the main microbial group compositions and the relevant potential enzyme activities within different soil aggregates sizes (microaggregates (<250 μm), small macroaggregates (250–2000 μm), and microaggregates (>2000 μm)) in a subtropical forest with decade-long simulated acid rain (SAR) treatments. Four SAR treatments were set by irrigating plots with water of different pH values (i.e., 3.0, 3.5, 4.0, and 4.5 as a control). Results showed that the SAR treatment significantly inhibited microbial activities, specifically decreasing both bacterial and fungal abundances, leading to declines in C-degrading potential enzyme activities. Conversely, potential enzyme activities related to phosphorus (P) and nitrogen (N) mineralization as well as the enzyme stoichiometry for P/N ratio significantly increased under the SAR treatment. The SAR treatment showed no significant differences in microbial abundance across the three soil aggregate sizes. However, it had a more pronounced effect on potential enzyme activities in their optimal aggregate sizes, such as hydrolytic enzymes like β-glucosidase in macroaggregates and oxidases like phenol oxidase and peroxidase in microaggregates. Overall, C-degrading potential enzyme activities were more strongly decreased in the microaggregates than in macroaggregates, and the distribution in aggregates was significantly altered, transforming from large to small sizes under the SAR treatment, which together may boost SOC stabilization and accumulation. Additionally, our findings indicate that prolonged acid rain also caused soil nutrient limitation and imbalance, particularly for P, in subtropical forests. This study highlights the importance of soil aggregate size in regulating microbial responses to acid rain, which should be integrated into ecosystem models to predict soil biogeochemical cycles under future climate conditions.

Integrating Hyperspectral Reflectance and Physiological Parameters to Detect Urban Tree Stress: A Study of Drought and Simulated Acid Rain

With urbanization and climate change worsening, urban trees are constantly exposed to environmental stress. To enhance the functionality and health of trees, it is crucial to rapidly and non-destructively detect and respond to tree stress. Research utilizing hyperspectral characteristics for detecting various stresses has recently been actively pursued. This study conducted comparative analysis using various leaf physiological parameters (chlorophyll content, chlorophyll fluorescence, leaf water, and gas exchange status) and hyperspectral data (VIS: visible ray; SWIR: short-wave infrared) to diagnose stress in Prunus yedoensis, commonly grown urban trees, by subjecting them simultaneously to different stresses (drought and simulated acid rain). The findings suggest that hyperspectral reflectance proved more responsive in identifying stress compared to the physiological parameters. Initially, VIS was more effective in detecting two stress responses than SWIR through a classification model (PLS-DA: partial least squares-discriminant analysis). Although SWIR initially faced challenges in simulated acid rain stress detection, spectral preprocessing (SNV: standard normal variate, + S.G 2nd: Savitzky–Golay 2nd derivative) enhanced its stress classification accuracy. Over time, the SWIR bands (1437 nm, 1667 nm, and 1949 nm) exhibited characteristics (such as moisture detection) more closely aligned with stress responses compared to VIS, as determined through PCA (principal component analysis). Hyperspectral reflectance also revealed the potential to measure chlorophyll fluorescence (Fo: minimum fluorescence). Building upon the foundational data of this study, the future potential of diagnosing urban tree stress using portable spectrometers is strong.

Central Tendency Data Real-Time Acid Rain Measurement to Evaluate Tool’s Performance Using Statistical Analysis

Increased population growth has implications for increased industrial and transportation activities. This activity increased gas emissions in the form of Sulfur Dioxide (SO2) and Nitrogen Dioxide (NO2), resulting in acid rain. The measuring instrument, a rain gauge, is used to measure acid rain in Greater Bandung at Telkom University, Indonesia, but it is currently unable to measure in real-time. Therefore, this study aims to measure acid rain in real-time by measuring parameters such as pH, temperature, conductivity, and precipitation to test the acidity contained in rainwater and evaluate the tool's performance with data for March 2022. The analysis uses various statistical methods: anomaly detection, outlier detection, central tendency, person correlation analysis, Mean Absolute Percentage Error, T-test, and Analysis of Variance (ANOVA). Each parameter can be worked out in real-time based on the central tendency and rain dispersion results. If there is only daily rain, then the correlation for each parameter is the highest, namely pH if there is acid rain. The real-time average pH is 6.45; in the laboratory, it is 6.56, so the MAPE value is 5.37 (good category). Even though this tool can work well, it needs to improve the quality of the temperature control in it. Since temperature significantly affects pH, the results show a negative correlation of -0.80 between pH and temperature. In the ANOVA test, the resulting p-value, when compared with data in the laboratory, is &gt;0.05, meaning that the average daily pH does not have a significant difference from the average laboratory test.

Vachellia nilotica sawdust-derived polymeric and magnetic biocomposites for phosphate ions removal: Kinetics, isothermal, and thermodynamic studies

Phosphorus is an important element for both animals and plants, but its excess can cause eutrophication in water. Excess phosphorus is present in wastewater mainly due to acid rain, the dissolving of rocks, and agricultural waste. There are many methods for the elimination of Phosphorus from aqueous solution, but their use is finite because of the high operational cost. Adsorption is a productive and popular method for removing phosphorus from aqueous solution. In this study, Vachellia nilotica sawdust and its different composites (Ppy/SD and MG/SD) were utilized for the effective adsorption of phosphorus from the solution. Prepared sorbents were characterized via BET, SEM, FTIR and XRD for their surface area and morphological, functional and crystallinity attributes. Adsorption tests were carried out to identify the optimal working parameters such as adsorbent dose, temperature, initial phosphorus concentration, pH, and contact time. Adsorption isotherm and kinetic model were accurately explained by the Langmuir model and pseudo 2nd order kinetics. The maximal adsorption capacity for Phosphate was 4.803, 5.32, and 6.27 mg/g for Native/SD, Ppy/SD, and MG/SD, respectively. Thermodynamic characteristics confirmed that the phosphorus adsorption was endothermic and spontaneous. Thus, sawdust is an eco-friendly and inexpensive adsorbent for phosphorus removal from wastewater.

An experimental investigation on the damage mechanisms of red glutenite in the Mount Wuyi cultural and natural heritage site subject to acid rain and wet-dry cycles: a macro-to-micro approach

The safety of rock landscapes in Mount Wuyi is significantly impacted by acid rain and wet-dry cycles. In this paper, the decay characteristics of the physical–mechanical properties of red glutenite were investigated under acidic wet-dry cycles. A systematic approach, including cold field emission scanning electron microscopy (CFE-SEM), image processing techniques, and X-ray diffraction (XRD), was proposed to investigate the damage mechanism of red glutenite under acidic wet-dry cycles. The results indicate that with increasing solution acidity and wet-dry cycles, dry density (DD), longitudinal wave velocity (LWV), uniaxial compressive strength (UCS), and elastic modulus (EM) of red glutenite significantly decrease. Under different acidic conditions, DD, LWV, and UCS exhibit exponential decay with wet-dry cycles, while EM exhibits linear decay. A regression fitting was employed to establish a prediction model for UCS, which exhibited a better capability in predicting the correlation between UCS, pH, and the number of wet-dry cycles. Microscopic comprehensive analysis reveals that the interaction between rock dissolution and desiccation is the primary factor leading to changes in the microstructure and mineral composition of red glutenite, culminating in the decay of its physical–mechanical properties. This study holds significant guidance implications for the preservation of cultural and natural heritage in Mount Wuyi.

Influence of simulated acid rain on morphological and phytochemicals attributes of guar (Cyamopsis tetragnoloba L.)

Influence of simulated acid rain on morphological and phytochemicals attributes of guar (Cyamopsis tetragnoloba L.)

Bioplastic Compounds of Succinic Acid from Agriculture Waste; Date Palm Syrup And Date Palm Fronds

Excessive use of petrochemical-based plastics lead to severe plastic pollution by accumulation in soil, drainage system blockage, also each year trillions of plastic residues released into the ocean. In some cases, burning plastic waste releases toxic gases and may cause acid rain. Bioplastics, biodegradable, are eco-friendly alternatives to petroleum-based plastics, reduce environmental impacts and utilize non-edible waste products for decomposition by microorganisms, making them a significant topic in the twenty-first century. Succinic acid has wide medical and industrial application, in addition to being a solution to the problem of plastic pollution for use in the manufacture of bioplastics. One of the most important biomass wastes in the Iraqi environment that are candidates for biorefinery is palm waste due to its environmental friendliness and high sugar content. In this study, succinic acid was investigated in the fermentation product of poor-quality date palms Zahid and palm fronds. The residues of Zahid dates with palm fronds and the addition of soybean were used for the production of succinic through the process of batch fermentation and solid-state fermentation using a mixture of yeasts Saccharomyces cerevisiae and P. stipitis ATCC 58785 and fungi Trichoderma reesei and Aspergillus niger after pretreatment. The succinic acid was estimated using GC mass, and the quantities of acid produced from date juice from Zuhdi dates syrup were 20.6g/L, while the optimal ratio of acid produced from palm fronds with soybeans was estimated at 2.28g/L and production improved to 3.51 g/L by fed batch fermentation. Biotonic acid, oxalic acid malic acid were detected in significant amount as 10.82,23.68 and 70.40 g/L respectively from date syrup. This research opens the horizons for the use of the biomass of the dates palm in the production of bioplastics. Consolidated bioprocessing of lignocellulose to succinic acid through a microbial cocultivation system consolidated bioprocessing.

Comparative analysis of Turkey’s environmental performance with Eastern European countries according to international EPI 2022 data

In order to effectively address environmental issues, it is important for governments to identify the problems causing environmental pollution within their scope and to develop appropriate solution policies. In order to identify environmental problems and develop necessary policies, it is necessary to consider the environmental performance of countries. Therefore, measuring the environmental performance of countries is of great importance. One of the prominent indices in measuring environmental performance today is the Environmental Performance Index (EPI) developed by Yale University. The main purpose of EPI is to quantitatively measure and compare the environmental performances of countries in order to monitor their progress in environmental sustainability. As of 2022, EPI consists of three main criteria: climate change, environmental health, and ecosystem vitality. In this study, Turkey’s environmental performance was evaluated using the Entropy-based PROMETHEE method with international EPI 2022 data. Subsequently, the environmental performances of Turkey and other Eastern European countries were compared in terms of criterion superiority to determine their strengths and weaknesses. In this context, various sub-criteria were analyzed under main criteria such as climate change mitigation, air quality, sanitation and drinking water, heavy metals, waste management, biodiversity and habitat, ecosystem services, fisheries, acid rain, agriculture, and water resources. As a result of the analysis conducted as of 2022, it emerged that Turkey generally exhibited weak environmental performance among Eastern European countries and there is a need for improvement in each criterion. Giving priority to criteria such as Climate Change Mitigation, Sanitation and Drinking Water, Biodiversity and Habitat, Fisheries, and Acid Rain, in which Turkey obtained the lowest scores in the ranking, would be a more strategic approach.

Phosphonic Acids as Corrosion Inhibitors and Adhesion Promoters for Organic Coatings and Bronze.

Currently used organic coatings for the protection of bronze sculptures have a relatively short lifespan as a consequence of strict requirements of conservation ethics, which limit the selection of coatings. For that reason, enhancement of the corrosion protection level and durability of appropriate coatings is needed. The aim of this work was to examine if corrosion protection of bronze by selected acrylic and polyurethane coatings could be improved by using two phosphonic acids, 16-phosphonohexadecanoic acid (COOH-PA) and 12-aminododecylphosphonic acid (NH2-PA). Electrochemical measurements (linear polarization and electrochemical impedance spectroscopy, EIS) were performed to gain an insight into the influence of these phosphonic acids on the performance of the coatings during a two-week exposure to artificial acid rain and a three-month outdoor exposure. Besides the influence on the corrosion protection level, the influence on the coating adhesion was examined as well. A pull-off test clearly confirmed that the studied phosphonic acids act as adhesion promoters of both polyurethane and acrylic coatings, while electrochemical studies revealed improvements in corrosion protection levels, especially in the case of the acrylic coating Paraloid B72.

Characterization of the Dominant Stages at Which Gas Flaring Is Introduced: Impacts and Policy Options to Ameliorate Them

Information on associated gas flaring in the Niger Delta is analyzed to characterize the various stages in the lifecycle of an oil exploration and production facility through which gas flaring is introduced into an area, leading to ecological, health, and economic impacts, and possible policies and implementation strategies for the reduction of the flared gas are offered. Gas flaring is currently occurring at a rate of 5318 million m3 per year in the Niger Delta region. The impacts of gas flaring on the ecological, human, and economic systems include poor air quality, acid rain, and soil degradation. Other impacts include decreased crop yield, increased incidences of respiratory diseases amongst inhabitants in the area, and losses of billions of USD yearly in economic costs. Three dominant stages in the introduction of gas flaring are characterized in this study, using the concept of the management of the invasion of non-native species into an ecosystem and it is determined that the cheapest method of minimizing gas flaring is to incorporate mitigation measures during the design stage of the oil exploration/production facility, rather than after flaring has commenced, as is the common emphasis. During the early periods of oil production, gas flaring is largely localized, and the gas utilization measures can still be implemented to good effect. However, once the facility is established, gas flaring becomes pervasive, stretching kilometers beyond the flare points. Current policies like the imposition of flare-out years on the oil producers have helped, but they have been insufficient as the intensity of gas flaring in the region continues at double the average global levels. Working with relevant stakeholders, a realistic flare-out deadline should be agreed upon, clear and specific gas flaring legislation should be drawn up that includes measures to mitigate gas flaring for each proposed oil facility, and proper data collection and management services would enable the implementation of the policies to be based on robust evidence. These policies would shift the costs of gas flaring away from the inhabitants of the region back to the operators of the facilities that are the sources of the flares.

Long-term change in winter aerosol composition and sources in Guiyang Southwest China (2003–2020)

This study presents a comprehensive analysis of air quality in China, Southwest China, over four winter seasons: 2003–2004, 2004–2005, 2017–2018 and 2019–2020. We initially collected Total Suspended Particles (TSP) samples during the earlier periods and PM2.5 samples during the later periods. Our goal was to illustrate the changes in sources of atmospheric pollutants over time. By focusing on the chemical composition of water-soluble inorganic ions (WSIIs), we highlighted significant long-term changes in air quality and pollution sources in Guiyang alongside the effectiveness of recent pollution treatment strategies. Historically affected by acid rain and acid pollution, Guiyang has shown notable improvements in air quality. Notably, sulfate pollution, primarily from coal combustion, has significantly decreased, with the sulfates concentration declining from an estimated 19.04 μg m−3 to 30.46 μg m−3 during the winter of 2003–2004, to just 7.37 μg m−3 in PM2.5 during the winter of 2019–2020. Additionally, the mean mass concentration of PM2.5 dropped by 18% between the 2017–2018 and 2019–2020 winters. An increasing ratio of nitrate to sulfate in the aerosols indicates a shift in pollution sources, with secondary nitrate pollution, largely from vehicle emissions, becoming increasingly prevalent. Positive Matrix Factorization (PMF) model analysis identified five major pollution sources, highlighting a transition from secondary sulfate to secondary nitrate as the primary contributors to air pollution in Guiyang, and secondary nitrate pollution mainly from vehicles emission was increasingly severe meanwhile the significance of ammonium should not be overlooked. The results stress the importance of local pollution sources and suggest a need for revised pollution control policies that address the evolving characteristics of aerosols and prioritize the major pollutants in Guiyang, especially during winter months.

POLICY FORMULATION FOR ANTICIPATING THE IMPACT OF ACID RAIN ON PADDY PLANTS USING NORMATIVE JURIDICAL ANALYSIS

Law Number 32 of 2009 Article 57, paragraph 4C that one of the preservations of atmosphere functions regulate efforts to protect against acid rain. One of the effects of acid rain is soil damage to plants, such as what happened to paddy plants. In Indonesia, paddy is one of the priority food sources, but every year, it decreases in several regions. Aims: This study aimed at acid rain's anticipated impact on paddy plants in this case study Bandung Regency. Methodology and results: The approach method in this study is a normative juridical approach, using primary data sources obtained through interviews and journal literature. Then, secondary data from legal literature were analyzed descriptively and qualitatively. The study results show that the Bandung Regency Environmental Service has enforced the law. However, violations still occur by industry and society through vehicle emissions, coupled with the increase in population. One of the efforts to formulate policies to anticipate acid rain in paddy plants is to establish sanctions for violators who still pollute the environment, apply catalytic converters to vehicle exhausts that have the potential to remove NOx, carry out measurements at groundwater measurement stations, water quality information systems (manual or real-time). In addition, the irrigation policy for river water flowing on agricultural land with existing laws is being improved. Conclusion, significance, and impact study: Anticipating the impact of acid rain on rice requires various approaches, both technical and non-technical, as well as further analysis from various policy sectors.

Effect of NO2 on SO2–SO42- conversion in atmosphere: Evidence from long-term precipitation

Sulfate aerosol (SO42−) is an important factor leading to acid rain and aggravating atmospheric particulate pollution. SO42− is mainly converted from gaseous SO2, in which the oxidant gas NO2 may play a key role. In real atmosphere with complexity and nonlinearity, the impact of NO2 on SO2–SO42- conversion exhibits scale dependence due to the combined effect of meteorology, atmospheric chemistry, and pollution emission. Here, based on the long-term atmospheric precipitation data from 2014 to 2021 of Nanchong City in the Sichuan Basin, the Extended Ensemble Empirical Mode Decomposition (EEMD) and Multifractal Detrended Cross-Correlation Analysis (MF-DCCA) methods have been employed to analyze the nonlinear correlations between gaseous SO2 and SO42− in rainwater at different time scales. A multifractal parameter Δh has been described as the scaling features of SO2–SO42- conversion efficiency in the real atmosphere. Then, the impact of NO2 on SO2–SO42- conversion in cold and warm seasons has been quantified, using sliding window analysis and Pearson correlation analysis. The results show that NO2 significantly promoted SO2–SO42- conversion in the cold season, but had little effect on it in the warm season. As direct evidence from atmospheric precipitation analysis, this finding has provided a new theoretical basis for evaluating the impact of NO2 on secondary aerosol generation.