Unequal Environmental and Health Impacts of Co-occurring Wildfires and Dust Events: Mechanisms, Spatiotemporal Distribution, and Exposure Inequality

Wildfires and dust storms are two major environmental hazards that significantly degrade air quality and pose severe risks to human health and ecosystems. These events often occur simultaneously, forming compound extreme events that can have amplified impacts compared to individual occurrences. This study aimed to investigate the mechanisms linking wildfires and dust pollution, analyze the spatiotemporal distribution and trends of their co-occurrence, and examine the global inequality in exposure to these compound events, all using a combination of satellite data, reanalysis datasets, and environmental variables.

We first explored the underlying mechanisms by which wildfires contribute to dust pollution. This included investigating how wildfires disturb vegetation and soil, and how changes in land cover interact with meteorological factors such as wind speed and direction to produce and transport dust. Using satellite-based aerosol optical depth (AOD) and dust optical depth (DOD) data (e.g., MODIS, IASI), as well as environmental variables such as soil moisture, vegetation cover, and wind data, we aimed to understand the physical and chemical processes that link wildfire activity to increased dust emissions.

The second part focused on analyzing the spatiotemporal distribution of the co-occurrence of wildfires and dust storms. We examined the geographical overlap of these events over recent decades, identifying regions where the co-occurrence of wildfires and dust storms is most frequent. By analyzing multi-year satellite and reanalysis data, we also explored interannual variations in the frequency of these compound events and assess how their co-occurrence has changed over time.

Finally, we investigated the global inequality in exposure to the combined air pollution resulting from co-occurring wildfires and dust storms. By mapping the spatial distribution of these compound events, we identified regions and populations that were disproportionately affected, particularly in areas with high vulnerability. We analyzed the exposure levels based on socioeconomic and demographic factors, highlighting how vulnerable populations in certain regions face a higher risk of respiratory and cardiovascular diseases due to these compounded pollution events. This part of the study aimed to shed light on the unequal burden of wildfire-dust compound events and provides insights into the need for targeted mitigation and health interventions.

Our study seeks to provide a comprehensive understanding of the interactions between wildfires and dust storms, and the compounded environmental and health impacts they have. The results will contribute to the development of effective mitigation strategies, improve public health outcomes, and inform policies aimed at reducing the exposure and risks associated with these extreme events.