Nitrogen's Big Role in Atmospheric Absorption

Nitrogen is a big player in how atmospheric organic aerosols (OAs) absorb sunlight. These tiny particles in the air affect Earth's climate. But, the way they change and absorb light is still a mystery. Scientists have found that brown nitrogen (BrN), a nitrogen-rich part of OAs, is the main absorber of light. Researchers used a global model to figure out how much BrN is out there. They also tracked how it changes over time and how much light it absorbs. BrN is responsible for 76% of the light absorption by OAs over the US. Globally, it accounts for 61% of their absorptive optical depth. This means that BrN is a major factor in how much light OAs absorb.The amount of light OAs can absorb changes based on where BrN comes from and how it ages. Biomass burning, like wildfires, is the biggest source of BrN. This makes up 18% of the global absorptive direct radiative effect of carbonaceous aerosols. This is a big deal because it shows that nitrogen is key to understanding how OAs impact climate. Scientists are now looking at nitrogen as a central factor in studying the climate effects of OAs. This new approach could help us better understand and predict how these aerosols influence our planet's climate.