A new application of multi-criteria decision making in identifying critical dust sources and comparing three common receptor-based models

Unveiling Afghanistan's wind and hydrogen potential: a comparative study

Given the detrimental environmental impacts of fossil fuels, there is a gradual worldwide shift towards renewable energy sources. Wind power, renowned for its cost-effectiveness and simplicity, has been widely embraced. Despite Afghanistan facing significant challenges in its energy sector, its considerable wind energy potential offers a chance to mitigate some of these issues. This study employed a multi-criteria decision-making approach to evaluate potential wind-hydrogen project sites in Afghanistan, encompassing economic, technical, social, risk, and environmental considerations. Five criteria and sub-criteria for wind-hydrogen project implementation were analyzed using the Step-wise Weight Assessment Ratio Analysis (SWARA) method. The Weighted Aggregated Sum Product Assessment (WASPAS), Additive Ratio Assessment (ARAS), Evaluation based on Distance from Average Solution (EDAS), and Technique of Order Preference Similarity to the Ideal Solution (TOPSIS) methods were then applied to prioritize provinces for wind-hydrogen project implementation. The analysis found that the Duration of the Payback Period and Levelized Cost of Electricity (LCOE) with weight of 6.6% and 5.6% were critical sub-criteria. Farah, Herat, and Nimroz emerged as Afghanistan's most promising provinces for wind-hydrogen energy development. In Farah, utilizing 900-kW turbines, it is feasible to generate 2679.8 MWh of electricity and produce 43.4 tons of hydrogen annually, with a Levelized Cost of Electricity of 0.0690 $/kWh and Levelized Cost of Hydrogen of 1.747 $/kg.

Characteristics of atmospheric black carbon and its wet scavenging in Nanning, South China

Based on in-situ measurement of black carbon (BC) and carbon monoxide (CO), the characteristics of BC emissions and wet scavenging were comprehensively investigated in Nanning, South China. The average annual BC concentration was 1.02 ± 0.53 μg m-3 with higher pollution levels during winter. In winter, a higher net BC/CO (ΔBC/ΔCO) ratio of 3.3 ± 0.3 ng m-3 ppb-1 along with an increased absorption Ångström exponent (AAE) and BC mass from biomass burning (BCbb), indicated a significant contribution of biomass burning to BC emissions. However, emissions from the traffic sector consistently exerted a dominant influence throughout the year. Cluster analysis of backward trajectories identified three types of air masses with distinct origins. Cluster #1 originated from Guangxi province and its vicinity, intermittently influencing the sampling site throughout the year with varying effects between winter and summer. This air mass brought in clean sea breeze in summer whereas transported a higher proportion of BCbb to the site during wintertime due to local open biomass burning. Cluster #3 primarily arrived in autumn and winter (October-December) from polluted central China, resulting in substantially high BC mass at the site. Cluster #2 coincided with the period (January-March) when extensive surface open biomass burning events occurred in Southeast Asia (SEA) regions. These BC aerosols in cluster#2 initially rose to higher altitudes above SEA before being regionally transported, but were significantly scavenged by clouds and precipitation during vertical uplift. The remaining BC exhibited a notably lower BC loss rate on relative humidity (RH) of -0.01 ng m-3 ppb-1 %-1 compared to cluster #1 (-0.03) and cluster #3 (-0.06), corresponding to an average BC transport efficiency of 0.85, 0.73, and 0.53, respectively. Nonetheless, air masses in cluster #2 could still transport considerably high BC mass to Nanning due to dry conditions and less wet scavenging along trajectory pathways. These findings provide valuable insights for policymakers and government officials in regulating and mitigating BC pollution in South China.

A multi-objective framework to select numerical options in air quality prediction models: A case study on dust storm modeling

Numerical weather prediction models are very important tools in predicting severe weather phenomena such as dust storms. However, the prediction accuracy in these models depends on the options considered in the modeling. In this study, a multi-objective framework is presented to determine the optimal options of the weather research forecasting with chemistry (WRF-Chem) model. For this purpose, a severe dust storm that occurred in the center of Iran is considered and the effect of 10 options including grid (computational domain size, modeling start time, horizontal, vertical and temporal resolution), physical (initial conditions, boundary layer and land surface schemes) and chemical options (dust emission schemes and dust source functions) are investigated. In general, the results showed that the WRF-Chem model has a high ability to model dust storms, but its results depend on the options considered in the modeling. Evaluation of grid options showed that inappropriate selection of domain size and modeling start time can lead to the failure in dust storm forecasting. Also, the land surface scheme has the greatest impact on dust concentration among the physical options. In addition, chemical options have the greatest impact on the dust storm forecasting as well. Based on the proposed multi-objective framework, the optimal options for dust storm modeling were determined. The proposed approach is comprehensive and can be used for other atmospheric/air quality modeling.

Application of multi-criteria decision-making techniques to develop modify-leachate pollution index

The modify-leachate pollution index (m-LPI) was developed with the help of multi-criteria decision-making (MCDM) technique based on the landfill leachate pollution potential by considering the limitations of traditional methodologies. Across India, twenty major landfill sites (LS) were selected for which m-LPI was assessed. Twenty-five experts' opinions were taken for the determination of nine input criteria weights, such as pH, COD, TDS, Cl, Zn, Pb, Cu, annual rainfall, and landfill age with the help of a questionnaire-based survey. In this context, six MCDM techniques were investigated to develop m-LPI. Among different MCDM techniques selected, weighted aggregated sum product assessment (WASPAS) proved to be an effective one with an R² value of 0.828 and IA value of 0.813. WASPAS gave first and last rank to Kadapa, Andhra Pradesh LS (1.677) and Turbhe, Maharashtra LS (2.193), respectively. The investigation revealed that around 90% of LS considered in the present study require leachate treatment. WASPAS sensitivity analysis showed that the least sensitive criteria were pH, followed by Cl and Zn. The m-LPI can be used by researchers and scientists to investigate and evaluate various challenges involved with solid waste management in LS.

Evaluation of wind power generation projects to reduce air pollution using multi-criteria decision-making methods in Saudi Arabia

Currently, Saudi Arabia has very limited renewable energy generation capacity, as most of the country's electricity sector is dependent on cheap fossil fuels. However, in recent years, the Saudi government has announced a national development program called "the Saudi Vision 2030," whereby the country intends to increase the share of renewable energies in its total power generation to 20% by 2030. This research is aimed on the possibility of developing wind farms in Saudi Arabia's Al-Jawf area, which is known to be rich in wind sources. The potential of wind energy in the region was examined in the first phase of the research, which focused at the environmental, economic, and technical aspects. For this goal, the two-parameter Weibull function was used to model wind energy in the area. The economic assessment was performed in terms of the Levelized Cost of Energy and payback period. Multi-criteria decision-making approaches were employed in the second phase of the study to determine the most proper sites for harvesting wind energy in the study region based on eight factors including technical, economic, environmental, and social aspects. The most proper site for wind farms was identified by the combined use of Stepwise Weight Assessment Ratio Analysis and Weighted Aggregated Sum Product Assessment. The results showed that the most proper site for locating wind farms in the study area is the city of Al-Qurrayyat, where, using 1 MW turbines, it will be possible to produce 2357 MWh/year of electricity at a cost of 0.092 $/kWh, resulting in a payback period of 8.1 years. From the environmental perspective, wind power generation in Al-Qurrayyat will result in 1124.15 ton/year of CO₂ emissions reduction.

Spatial origin analysis on atmospheric bulk deposition of polycyclic aromatic hydrocarbons in Shanghai

Atmospheric deposition of polycyclic aromatic hydrocarbons (PAHs) onto soil threatens terrestrial ecosystem. To locate potential source areas geographically, a total of 139 atmospheric bulk deposition samples were collected during 2012-2019 at eight sites in Shanghai and its surrounding areas. A multisite joint location method was developed for the first time to locate potential source areas of atmospheric PAHs based on an enhanced three dimensional concentration weighted trajectory model. The method considered spatial and temporal variations of atmospheric boundary layer height and homogenized all results over the eight sites via geometric mean. Regional transport was an important contributor of PAH atmospheric deposition while massive local emissions may disturb the identification of potential source areas. Northwesterly winds were associated with elevated deposition fluxes. Potential source areas were identified by the multisite joint location method and included Hebei, Tianjin, Shandong and Jiangsu to the north, and Anhui to the west of Shanghai. PM and SO₂ data from the national ground monitoring stations confirmed the identified source areas of deposited PAHs in Shanghai.

Pollution Characteristics and Health Risk Assessment of VOCs in Jinghong

In order to investigate the seasonal variation in chemical characteristics of VOCs in the urban and suburban areas of southwest China, we used SUMMA canister sampling in Jinghong city from October 2016 to June 2017. Forty-eight VOC species concentrations were analyzed using atmospheric preconcentration gas chromatography–mass spectrometry (GC–MS), Then, regional VOC pollution characteristics, ozone formation potentials (OFP), source identity, and health risk assessments were studied. The results showed that the average concentration of total mass was 144.34 μg·m−3 in the urban area and 47.81 μg·m−3 in the suburban area. Alkanes accounted for the highest proportion of VOC groups at 38.11%, followed by olefins (36.60%) and aromatic hydrocarbons (25.28%). Propane and isoprene were the species with the highest mass concentrations in urban and suburban sampling sites. The calculation of OFP showed that the contributions of olefins and aromatic hydrocarbons were higher than those of alkanes. Through the ratio of specific species, the VOCs were mainly affected by motor vehicle exhaust emissions, fuel volatilization, vegetation emissions, and biomass combustion. Combined with the analysis of the backward trajectory model, biomass burning activities in Myanmar influenced the concentration of VOCs in Jinghong. Health risk assessments have shown that the noncarcinogenic risk and hazard index of atmospheric VOCs in Jinghong were low (less than 1). However, the value of the benzene cancer risk to the human body was higher than the safety threshold of 1 × 10−6, showing that benzene has carcinogenic risk. This study provides effective support for local governments formulating air pollution control policies.

A Thorough Economic Evaluation by Implementing Solar/Wind Energies for Hydrogen Production: A Case Study

A technical–economic assessment was carried out in this study to determine the possibilities for wind and solar power generation in Afghanistan’s Helmand province. The results showed that most of the province has a solar irradiance of over 400 W/m2, and also showed that wind and solar power generated in the province can be up to twice as cheap as the official price of renewable power in Afghanistan. The most suitable site for solar and hydrogen production was found to be Laškar Gāh, where solar and hydrogen can be produced at a cost of 0.066 $/kWh and 2.1496 $/kg-H2, respectively. In terms of wind power production and hydrogen production from wind, the most suitable site was Sangīn, where wind power and hydrogen could be produced at costs of 0.057 $/kWh and 1.4527 $/kg-H2, respectively. Despite the high potential of wind and solar energy in the Helmand province, the most suitable place in this region to produce hydrogen from wind/solar energy was evaluated from technical, economic, and environmental perspectives with the Multi-Criteria Decision-Making (MCDM) method. The Stepwise Weight Assessment Ratio Analysis (SWARA) method was used for weighting criteria and the Weighted Aggregated Sum Product Assessment (WASPAS) method was used to prioritize locations. The results show that Sangīn is the most suitable place for the construction of a wind hydrogen power plant and Laškar Gāh is the most suitable place for the construction of a solar hydrogen power plant.