Zhu et al.: Long-term source apportionment of PM2.5 across the contiguous United States (2000-2019) using a multilinear engine model

Qiao Zhu, Yang Liu, and Sina Hasheminassab. Long-Term Source Apportionment of PM2. 5 across the contiguous United States (2000-2019) Using a Multilinear Engine Model. Journal of Hazardous Materials (2024): 134550.

Read Online at https://www.sciencedirect.com/science/article/pii/S0304389424011294

Identifying PM2.5 sources is crucial for effective air quality management and public health. This research used the Multilinear Engine (ME-2) model to analyze PM2.5 from 515 EPA Chemical Speciation Network (CSN) and Interagency Monitoring of Protected Visual Environments (IMPROVE) sites across the U.S. from 2000 to 2019. The U.S. was divided into nine regions for detailed analysis. A total of seven source types (tracers) were resolved across the country: (1) Soil/Dust (Si, Al, Ca and Fe); (2) Vehicle emissions (EC, OC, Cu and Zn); (3) Biomass/wood burning (K); (4) Heavy oil/coal combustion (Ni, V, Cl and As); (5) Secondary sulfate (SO42-); (6) Secondary nitrate (NO3-) and (7) Sea salt (Mg, Na, Cl and SO42-). Furthermore, we extracted and calculated secondary organic aerosols (SOA) based on the secondary sulfate and nitrate factors. Notably, significant reductions in secondary sulfate, nitrate, and heavy oil/coal combustion emissions reflect recent cuts in fossil-fueled power sector emissions. A decline in SOA suggests effective mitigation of their formation conditions or precursors. Despite these improvements, vehicle emissions and biomass burning show no significant decrease, highlighting the need for focused control on these persistent pollution sources for future air quality management.

Zhu et al.: Wildfires are associated with increased emergency department visits for anxiety disorders in the western United States

Qingyang Zhu, Danlu Zhang, Wenhao Wang, Rohan Richard D’Souza, Haisu Zhang, Binyu Yang, Kyle Steenland, Noah Scovronick, Stefanie Ebelt, Howard H Chang, and Yang Liu. Wildfires are associated with increased emergency department visits for anxiety disorders in the western United States. Nature Mental Health  2 (2024), 379–387.

Read the full paper online here.

Read the press release by Emory University here.

Check out the story by American Psychiatric Association here.

As wildfires increasingly impact the global economy and public health, understanding their effects is crucial. Particularly, the relationship between wildfires and anxiety disorders remains unclear. In this study, we explore this association by analyzing 1,897,865 emergency department visits for anxiety disorders in the western United States. We examined records from 2007 to 2018, using a case-crossover design and conditional logistic regression to assess the impact of wildfire-related exposures on these visits. Here we show that exposure to wildfire smoke PM2.5 is positively linked with emergency department visits for anxiety disorders. This effect is more pronounced in women and girls and in older adults, highlighting their vulnerability. Notably, major smoke events (smoke PM2.5 contributed ≥75% of the total PM2.5) significantly amplify this risk. These findings underscore the psychological impacts of wildfires and their smoke, suggesting a need for targeted disaster risk reduction and climate risk management strategies, especially for vulnerable groups such as older adults and women. Our results call for increased climate awareness and tailored risk communication to mitigate these emerging health challenges.