Air Quality of Work, Residential, and Traffic Areas during the COVID-19 Lockdown with Insights to Improve Air Quality.

This study investigated the concentrations of air pollutants (NO, NO, NO, SO, CO, O, PM, and PM) at three sites with different traffic loads (work, residential, and traffic sites) before, during, and after the COVID-19 lockdown. The main objective of this study was to evaluate the effects and associated potential pollution control implications of the lockdown on the quality of ambient air at three selected sites in the urban area of Riyadh City. The average concentrations of NO, NO, NO, and CO decreased during the lockdown period by 73%, 44%, 53%, and 32% at the work site; 222%, 85%, 100%, and 60% at the residential site; and 133%, 60%, 101%, and 103% at the traffic site relative to the pre-lockdown period, respectively.

Firefighter exposures to organic and inorganic gas emissions in emergency residential and industrial fires.

The gas emissions generated from fires could cause mortalities and diseases in firefighters. Gas emissions from fire contain a mixture of a wide range of organic and inorganic gases, depending on several elements that are not currently known. In this study, firefighters were equipped with portable gas detectors to measure selected organic and inorganic gases in 26 emergency fire incidents.

Assessing the response of five tree species to air pollution in Riyadh City, Saudi Arabia, for potential green belt application.

Tree species (including Eucalyptus camaldulensis, Ziziphus spina-christi, Albizia lebbeck, Prosopis juliflora, Pithecellobium dulce, and Ficus altissima) were investigated to elucidate their appropriates for green belt application. Leaf samples were collected from four different locations in Riyadh: (1) residential; (2) dense traffic; (3) industrial; and (4) reference sites located approximately 20 km away from the city of Riyadh. Leaves collected from the industrial site showed the highest leaf area reduction.

Contamination and risk levels of metals associated with urban street dust in Riyadh, Saudi Arabia.

Urban street dust was collected from 22 locations in Riyadh, Saudi Arabia, and nine metals (Pb, Cr, Zn, Co, Cu, Al, Fe, Mn, and Ni) were investigated. The concentrations of these metals were employed in several common contamination evaluation indices to examine the contamination and the health risk caused by metals. Evaluation of these indices showed that they had variable degrees of contamination sensitivity.

Metal contamination decrease with new legislation: A decade of metal risk assessment in urban dust.

New scientific discoveries for new applications of materials (e.g., metals) lead to extensive industrial use of these materials, which in turn, has significant negative health and environmental impacts.