Differential Health Impacts of Short-Term Particulate Matter Exposure in Arid and Semi-Arid Regions: A Scoping Review

Particulate matter (PM) exposure is a leading risk factor for cardiovascular and respiratory morbidity and mortality across the world. While arid and semi-arid regions account for more than 40% of terrestrial land, there is a paucity of research investigating the relationship between PM exposure and health outcomes or how risk varies across different populations specific to these climate regions. To address this, we performed a scoping review to assess the extent of literature in arid and semi-arid regions that consider such morbidity and mortality risks from short-term PM exposure. Our review identified 102 studies published after 2012 located within four arid climate classifications: hot arid, cold arid, semi-arid hot, and semi-arid cold. The meta-analysis found a pooled overall increased relative risk (RR) of both cardiovascular and respiratory mortality and morbidity, with an 8% higher risk of morbidity in hot arid regions (1.11, 95% confidence interval (CI): 1.05, 1.17) compared to cold semi-arid regions (1.02, 95% CI: 1.00, 1.03) for adults (18-64). Further, we assessed effect modification (age, sex, population density and season) and found weak evidence of increased risk for both males and adults. The studies included in this review highlighted compounding risks, such as dust storms, wildfire, and extreme temperature, however there was a significant lack of studies situated in highly populated arid regions, with none identified in Africa. Given the public health burden from PM exposure and the impact of climate change and anthropogenic activities which destabilize land-surfaces and increase dust emissions, additional focus is owed to demographic effect modifiers and the role of climate specific risks.