How Wildfires Boost Sulfate Production

Brown carbon, a key component of biomass-burning organic aerosols (BBOA), plays a significant role in absorbing sunlight and potentially speeding up global warming. However, the chemical processes that happen within these particles after they absorb light are not yet fully understood. Scientists have been struggling to measure the exact amounts of oxidants and how quickly they react within these particles. A recent study delved into how BBOA particles react when exposed to light, focusing on the formation of sulfate. The research found that the primary driver of sulfate formation in these particles is not iron, nitrate, or S(IV) photochemistry, but rather the triplet excited states (^3BBOA*) that are produced when the particles absorb light. These reactions happen incredibly fast, about three times quicker than similar processes in liquid solutions. This discovery underscores the importance of understanding the chemistry of ^3BBOA* in particles, as it significantly contributes to the creation of sulfate, a common secondary pollutant. As wildfires become more frequent and intense globally, the role of BBOA in sulfate production is likely to become even more significant.