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AbstractThis study presents an analysis of O3, NO2, and PM10 variations in Sharjah City, UAE, from 2018 to 2021. Data from monitoring stations across the city showed consistent daily, weekly, and monthly trends. Ozone and NO2 were inversely related, with O3 increasing and NO2 decreasing from noon to sunset, and vice versa afterward. Weekends exhibited a weekend effect, with high O3 and low NO2 levels. Winters had high NO2 and low O3 levels, while summers showed the opposite trend. Urban and industrial stations had higher NO2 and lower O3 levels compared to sub-urban and rural stations. PM10 levels peaked in the afternoon to late evenings and decreased during nights and early mornings. They were lowest on weekends and highest at the start of the weeks, with July as the peak and December as the lowest month for PM10. During the COVID-19 restrictions of 2020-2021, O3, NO2, and PM10 levels significantly decreased compared to 2018-2019. Higher winds correlated with higher O3 and PM10 levels and lower NO2 levels. This study provides the first documentation of Sharjah’s air quality spatiotemporal variations pre-to-post COVID-19 restrictions using ground measurements. [ABSTRACT FROM AUTHOR]

Accumulation of heavy metals in Jordanian soils irrigated with treated wastewater threatens agricultural sustainability. This study was carried out to investigate the environmental fate of Zn, Ni, and Cd in calcareous soils irrigated with treated wastewater and to elucidate the impact of hydrous ferric oxide (HFO) amendment on metal redistribution among soil fractions. Results showed that sorption capacity for Zarqa River (ZR1) soil was higher than Wadi Dhuleil (WD1) soil for all metals. The order of sorption affinity for WD1 was in the decreasing order of Ni > Zn > Cd, consistent with electrostatic attraction and indication of weak association with soil constituents. Following metal addition, Zn and Ni were distributed among the carbonate and Fe/Mn oxide fractions, while Cd was distributed among the exchangeable and carbonate fractions in both soils. Amending soils with 3% HFO did not increase the concentration of metals associated with the Fe/Mn oxide fraction or impact metal redistribution. The study suggests that carbonates control the mobility and bioavailability of Zn, Ni, and Cd in these calcareous soils, even in presence of a strong adsorbent such as HFO. Thus, it can be inferred that in situ heavy metal remediation of these highly calcareous soils using iron oxide compounds could be ineffective.