The Arabian Peninsula is one of the world’s largest sources of mineral dust that includes several major population hotspots. However, until now, few studies have performed a comprehensive quantification of the long-term variability of aerosol species in this region. In this study, the speciation, variability, and distribution of aerosol optical depth over the Arabian Peninsula during 2005–2015 is analyzed by using the modern-era retrospective analysis for research and applications, Version 2 (MERRA-2) model together with satellite retrieved data and AERONET observations and focusing on nine large cities in the region (Dammam, Doha, Dubai, Jeddah, Kuwait, Manama, Muscat, Riyadh, and Sanaa). Over the past decade, the mean annual aerosol optical thickness (AOT) values were in the range of 0.3–0.5, which is attributed to both mineral dust (60–70%) and anthropogenic activities (20–30%). An increase in AOT values between 2005 and 2009 is attributed to increased dust generation from the Sahel region in Northern Africa, and the Fertile Crescent (Syria, Iraq, Jordan) due to an extended dry period. Reductions in local urban emissions are still considered to be efficient measures to improve air quality in these population centers despite the significant contribution of desert dust in the total particulate matter levels in the region.

Human exposure to healthy doses of UV radiation is required for vitamin D synthesis, but exposure to excessive UV irradiance leads to several harmful impacts ranging from premature wrinkles to dangerous skin cancer. However, for countries located in the global dust belt, accurate estimation of the UV irradiance is challenging due to a strong impact of desert dust on incoming solar radiation. In this work, a UV Index forecasting capability is presented, specifically developed for dust-rich environments, that combines the use of ground-based measurements of broadband irradiances UVA (320-400 nm) and UVB (280-315 nm), NASA OMI Aura satellite-retrieved data and the meteorology-chemistry mesoscale model WRF-Chem. The forecasting ability of the model is evaluated for clear sky days as well as during the influence of dust storms in Doha, Qatar. The contribution of UV radiation to the total incoming global horizontal irradiance (GHI) ranges between 5% and 7% for UVA and 0.1% and 0.22% for UVB. The UVI forecasting performance of the model is quite encouraging with an absolute average error of less than 6% and a correlation coefficient of 0.93. In agreement with observations, the model predicts that the UV Index at local noontime can drop from 10-11 on clear sky days to approximately 6-7 during typical dusty conditions in the Arabian Peninsula-an effect similar to the presence of extensive cloud cover.Atmosphere 2020, 11, 96 2 of 17 photokeratitis (inflammation of the cornea), and suppression of the immune system [1,[3][4][5]. Thus, it is important for people to control their exposure to UV radiation [1,6].The UV radiation on the Earth's surface is largely determined by the solar zenith angle, clouds, total ozone column, surface albedo, aerosols, earth-sun distance, and altitude [7]. Clouds poorly absorb UV radiation and in general, scatter UV radiation into the atmosphere [8,9]. Stratospheric ozone (ozone layer) predominantly absorbs UV radiation at wavelengths below 320 nm [10]. The extent of reflectivity from a surface affects UV surface irradiance with higher surface albedo enhancing the net UV surface irradiance due to multiple scattering of the reflected irradiance with the atmosphere. For example, a surface covered by snow (with albedo of 0.8) will increase UV irradiance at 320 nm by 1.5 times compared to snow-free, low albedo conditions [11]. Aerosols also affect the incoming UV irradiance. They usually decrease UV irradiance reaching the surface by scattering and absorption. A measurement campaign in Greece showed that UV irradiance decreased by 5-35% due to aerosols [12], and similar numbers of annual average aerosol attenuation of UV irradiance were obtained around the globe [13]. Desert dust intrusions also affect UV irradiance with differences larger than 30% in cloudless conditions in Santiago de Chile [14,15]. These differences in UV irradiance highlight the need for ground-based measurements to account for the attenuation of UV radiation in the troposphere which are not accounted for in satellite derived es...

Biomass has been used as a fuel source for cooking and heating for centuries. Despite the emergence of new, efficient, and clean technologies for cooking and heating, biomass is still the primary source of fuel for poor and rural communities in several low and middle income countries around the world. This review presents the chemical composition, the health effects, and the key factors that would enhance the exposure to the emissions of high concentrations of particulate matter, inorganic, and organic chemical compounds from the use of biomass for cooking and heating. It also reviews a number of intervention programs that have been implemented by governments, non-governmental organizations, and other philanthropic societies, to mitigate the possible health risks due to biomass burning. Such programs include distribution of new cook stoves, more efficient cook stoves, cook stoves with chimneys, distribution of cleaner fuel such as LPG, and electrification, among others. This paper is a narrative literature review with some critical aspects that highlights the updated works published in the past 15 years which are related to the health hazards and intervention programs to mitigate the adverse impact of biomass burning in household environment. It was found that, despite the several efforts and initiatives taken to mitigate biomass environmental pollution, not all programs have met the desired expectations for the reduction in residents' exposure to biomass burning within the World Health Organization (WHO)'s limits. Much more work is required to be done collectively around the globe to improve the efficiency of sustained adoption of such new interventions by the poor and rural communities.