Causes and Effects of Sand and Dust Storms: What Has Past Research Taught Us? A Survey

Global-scale water security and desertification management amidst climate change

Deserts and semi-arid environments are habitats to rare species, rich cultural heritage, and essential ecological processes. Approximately 46% of the world's surface area is covered by drylands (arid, semi-arid, and dry sub-humid areas), where 3 billion people live and unfortunately witness water insecurity and desertification implications. In this context, the present study argued that reduced dryland ecosystem services and decreased ecosystem health have resulted from the individual and compounding impacts of desertification, water scarcity, and climate change. At 1.5 °C, 2 °C, and 3 °C of global warming, under the shared socio-economic pathway SSP2, the number of people living in drylands who will be affected by various effects on water, energy, and land sectors is projected to reach 951 million, 1152 million, and 1285 million, respectively. Due to combinations of land use change, rainfall variations, fire suppression, and CO2 fertilization, as well as unsustainable management, widespread woody encroachment has occurred in many shrublands and savannas in Africa, Australia, North America, and South America. This has altered biodiversity and reduces ecosystem services, such as water availability and grazing potential. The north side of the Mediterranean, southern Africa, and North and South America are projected to have the most semiarid expansion. Contrarily, drylands are expected to shrink in India, northern China, eastern equatorial Africa, and the southern Sahara. Growing research evidence highlights the adoption of policy frameworks deriving the solutions from soil land management (SLM), indigenous and local knowledge (ILK), early warning systems coupled with adaptation and mitigation responses, and targets of sustainable development goals (SDGs).

Environmental transport and sorting of glass retroreflective microbeads and their potential as proxies for road marking paints

Road marking paints are a potentially important contributor to the global microplastic pool but very little reliable information is available on their erosion or environmental distributions. As potential carriers of or proxies for road paints, we determine the concentrations and sorting of retroreflective glass microbeads in marking materials and in fractionated (< 5 mm) local dusts, soils and sediments. As an aid to our investigation, we also determine the concentrations of metals of geochemical significance or components of road paint pigments in markings and geosolids. Concentrations of beads up to 92,800 kg-1 were observed in street dusts, with a median diameter (350 μm) greater than that in road marking samples (270 μm). Few beads were found in adjacent (< 5 m) or more remote soils (six beads in ten 50-g samples) and none were detected in replicates of a sample of roof dust, suggesting that aeolian transport is limited. Concentrations up to 3700 kg-1 were found in estuarine sediments close to bridges or stormwater runoff effluents, and with increasing sediment depth concentrations and median diameter decreased; beads were not, however, detected in sediments 400 m away from any significant roads or runoff effluents. These observations suggest that bead accumulation is constrained locally but that the precise distance travelled and extent of burial in sediments are inversely related to size. Road marking paints sampled from urban streets readily fragmented into pieces smaller than glass microbeads, suggesting that while beads might carry small quantities of paint, transport and dispersion of the two particle types may not be directly coupled. Environmental ratios of V to Bi and Cr to Pb, as markers for BiVO4- and PbCrO4-pigmented yellow paints, respectively, did not correlate with bead distribution, presumably because these metals have a multitude of additional anthropogenic sources. However, an inverse relationship between bead concentrations and K:Ca suggests that this ratio might be a useful proxy of road marking paint in regions that are geologically similar.

Effect of air pollution on disease burden, mortality, and life expectancy in North Africa and the Middle East: a systematic analysis for the Global Burden of Disease Study 2019

BACKGROUND

Air pollution is the sixth highest risk factor for attributable disability-adjusted life-years (DALYs) in North Africa and the Middle East, but the relative importance of different subtypes of air pollution and any potential differences in their health effects by population demographics or country-level socioeconomic factors have not been fully explored. The objective of this study was to investigate the effect of high ambient particulate matter less than 2·5 μm in size (PM) and ambient ozone air pollution on disease burden, mortality, and life expectancy in 21 countries in the North Africa and the Middle East super-region from 1990 to 2019 using the Global Burden of Diseases, Injuries, and Risk Factors (GBD) Study estimates.

METHODS

The study data were derived from GBD 2019, examining data from 1999 to 2019 in North Africa and the Middle East. In this study, the types of air pollution investigated included PM pollution and ambient ozone pollution. PM pollution itself was categorised as household air pollution from solid fuels and ambient PM pollution. The burden attributable to each risk factor, directly or indirectly, was incorporated in the population attributable fraction to estimate the total attributable deaths and DALYs. The summary exposure value (SEV) as the relative risk-weighted prevalence of exposure was extracted to compare the distribution of excess risk times the exposure level in a population where everyone is at maximum risk and ranges from zero (no excess risk exists in a population) to 100 (highest risk). The effect of air pollution on life expectancy was estimated via a cause-deleted life table analysis.

FINDINGS

The age-standardised DALYs rate attributable to air pollution declined by 44·5%, from 4884·2 (95% uncertainty interval 4381·5-5555·4) to 2710·4 (2317·3-3125·6) per 100 000 from 1990 to 2019. Afghanistan (6992·3, 5627·7-8482·7), Yemen (4212·4, 3241·3-5418·1), and Egypt (4034·8, 3027·7-5138·6) had the highest age-standardised DALYs rates attributable to air pollution in 2019 per 100 000, whereas Türkiye (1329·2, 1033·7-1654·7), Jordan (1447·3, 1154·2-1758·5), and Iran (1603·0, 1404·7-1813·8) had the lowest rates. During the study period, the age-standardised SEV of air pollution (PM and ambient ozone in total) decreased by 10·9% (5·8-17·7%) in the super-region, whereas the SEV of ambient ozone pollution alone increased by 7·7% (0·7-14·3%). Among the components of PM pollution, the SEV of ambient PM pollution increased by 40·1% (25·2-63·7%); however, the SEV of household air pollution from solid fuels decreased by 70·6% (64·1-77·0%). Among the investigated types of air pollution, 98·9% of the DALYs from air pollution in the super-region were attributable to PM pollution. If air pollution had been lowered to the theoretical minimum risk exposure levels for 2019, then the average life expectancy would have been 1·6 years higher.

INTERPRETATION

The burden attributable to air pollution substantially decreased in the study period across the super-region as a whole. Most of the burden from air pollution is attributed to PM pollution, the exposure to which has substantially increased in the past three decades. Interventions and policies that reduce population exposure to PM pollution could potentially increase the average life expectancy in the super-region. This finding calls for concerted efforts from governments and public health authorities in the super-region to tackle air pollution as an important threat to population health.

FUNDING

Bill & Melinda Gates Foundation.