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The Middle East frontal sand and dust storms (SDS) occur in non-summer seasons, and represent an important phenomenon of this region's climate. Among the mentioned type, spring SDS are the most common. Trend analysis was used in the current study to investigate the spatial-temporal variability of springtime dust events in the Middle East using synoptic station observation from 2011 to 2022. The plausible changes in some controlling factors of dust activity at selected important dust sources in the Middle East were also studied during this time period. Our results showed a statistically significant spike in springtime dust events across the Middle East, particularly in May 2022. To evaluate the relative importance of controlling factors, the applied feature of importance analysis using random forest (RF) showed the higher relative importance of topsoil layer wetness, surface soil temperature, and surface wind speed in dust activity over the Middle East between 2011 and 2022. Long-term trend analysis of topsoil moisture and temperature, using the Mann-Kendall trend test, showed a decrease in soil moisture and an increase in soil temperature in some selected important dust sources in the Middle East. Moreover, our predictions using ARIMA models showed a high tendency to dust activities in selected major dust origins (domain 2 and domain 5) with a statistically significant increase (p-value < 0.05) between 2023 and 2029. Observed spatial and temporal changes within SDS hotspots can act as the first step to build up for the first time an SDS precise intensity scale, as well as establishing an SDS early warning system in future. [ABSTRACT FROM AUTHOR]

Air pollution, particularly in urban areas, puts human health in danger and has adverse impacts on the built environment. It can accelerate the natural corrosion rate of cultural heritages and monuments, leading to premature aging and lowering their aesthetic value. Globally, at the beginning of 2020, to tackle the spread of novel COVID-19, the lockdown was enforced in the most hard-hit countries. Therefore, this study assesses, as a first time, the plausible benefits of traffic and urban mobility reductions on the natural process of deterioration of materials during COVID-19 lockdown in twenty-four major cities on five continents. The potential risk is estimated based on exceeding the tolerable degradation limits for each material. The notable impact of COVID-19 mobility restrictions on air quality was evidenced in 2020 compared to 2019. The introduced mobility restrictions in 2020 could decrease the surface recession rate of materials. Extremely randomized trees analysis showed that PM10 was the main influencing factor for corrosion of portland, copper, cast bronze, and carbon steel with a relative importance of 0.60, 0.32, 0.90, and 0.64, respectively, while SO2 and HNO3 were mainly responsible for corrosion of sandstone and zinc with a relative importance of 0.60 and 0.40, respectively. The globally adverse governed meteorological conditions in 2020 could not positively influence the movement restrictions around the world in air quality improvements. Our findings can highlight the need for additional policies and measures for reducing ambient pollution in cities and the proximity of sensitive cultural heritage to avoid further damage. [ABSTRACT FROM AUTHOR]

On 4th August 2020, drastic explosions occurred at the port of Beirut, Lebanon. These explosions released an extensive amount of toxic gases and caused atmospheric damages along with terrestrial and marine disturbances. In the current study, the impact of the incident on both local and regional air quality was assessed by ALOHA and HYSPLIT models. The ALOHA results estimated the concentrations of NO2 and NO and their exposure times for two specific densely populated locations in the high-risk zone. The concentrations of outdoor NO2 exceeded the AEGL-3 tier in Borj Hammoud, and Jdeideh after 8, and 10 min of the explosion, respectively. The HYSPLIT results showed the movement of NOx cloud eastwards, reaching Syria, and turned southwards, affecting Iraq, Jordon, Saudi Arabia, Kuwait, Iran, and then moved to central Asia through Turkmenistan. The air quality station at Khorramabad, Iran, could observe a small peak during the NOx toxic cloud arrival time on 6th August 2020 at 13:00 UTC. Besides the Mediterranean Sea, the Caspian Sea, the Persian Gulf, and the Gulf of Oman were also affected by the toxic clouds. Damascus is in the high impacted zone with around 105 kg NO2 deposition. Fragile marine environments are also disturbed. The Persian Gulf, with more than 80% of its area, under low impacted zone was receiving 10 µgm−2. Results drag the attention to the associated risk of old factories to the environment. Therefore, it is necessary to have regular safety monitoring in industrial zones and neighboring to eliminate future incidents. [ABSTRACT FROM AUTHOR]

Several different divergences are tested in the several internal wavelength locker schemes for 10 Gbps electro-absorption modulated laser (EML) module. A 10 Gbps EML module with a simple and robust internal wavelength locker for metro dense WDM application is successfully demonstrated. The wavelength aging over 2000 h is done at elevated temperature of 70°C. The average wavelength drift of 10 modules is measured to be ± 5 pm. These modules can be successfully applied to the 10 Gbps DWDM systems with 50 GHz channel spacing. [ABSTRACT FROM AUTHOR]