Snowpack serves as a complex participant in atmospheric chemistry, acting as a reservoir, photochemical reactor, and emission source for volatile organic compounds (VOCs). We hypothesize that snow-air VOC exchange varies by snow type and is influenced by ultraviolet (UV) exposure and temperature. To test this, we constructed a two-chamber cryogenic system using a modified chest freezer that allowed us to control UV exposure and temperature across samples of clean (remote-source) and dirty (oilfield-source) snow, each isolated in custom PTFE bags. Air samples were collected post-exposure using gas canisters and DNPH cartridges. These samples were then analyzed via GCMS and HPLC to quantify selected VOCs which were then summarized as groups of hydrocarbon subclasses.

Most hydrocarbon subclasses showed negligible relationships between temperature and emission rates (R² < 0.25), except carbonyls, which exhibited a weak positive correlation (R² = 0.2756) in the clean snow samples. Alcohols showed no clear emission trends in response to temperature, UVA, or UVB (R² < 0.25). In contrast, alkenes exhibited strong positive correlations with increasing UV intensity, especially in clean snow samples: for UVA, R² = 0.8742 (clean) and 0.3301 (dirty); for UVB, R² = 0.8541 (clean) and 0.3259 (dirty). Interestingly, along with it being the only subclass to exhibit any response to temperature, carbonyls were also the only subclass to show a negative relationship with UV: for UVA, R² = 0.5589 (dirty) and 0.6351 (clean); for UVB, R² = 0.6505 (dirty) and 0.5996 (clean).

These results suggest that VOC flux at the snow-air interface is both compound and snow-type dependent. While UV exposure strongly influences alkene emission-particularly in clean snow-carbonyl emissions appear to be driven by temperature and suppressed by UV. This underscores the complexity of snowpack-atmosphere interactions and highlights the importance of environmental context in understanding atmospheric chemistry.