The photolysis branching ratio of methyl ethyl ketone (MEK) was re-evaluated using light emitting diodes centered at 285 nm or 315 nm (demonstrates atmospheric relevance) to irradiate MEK in the presence of nitric oxide (NO) and oxygen (O2). This produced peroxyacetic nitric anhydride (PAN) and peroxypropanoic nitric anhydride (PPN), which were then quantitated by gas chromatography electron capture detection (GC-ECD). The MEK photolysis branching ratio at 285 nm was determined as α = (7±1)% + (1.1±0.7)10^(-4)(T-298) for 250 K < T < 300 K (±2σ). The experiment described provides a more accurate and precise MEK branching ratio due to their lower concentration which minimizes secondary chemistry effects. Measurements of peroxycarboxylic nitric anhydrides and intermediate volatile organic compounds (IVOCs) were conducted at the Oski-Ôtin field site north of Fort McKay, Alberta (AB), Canada during the SNOWDOGS field campaign. A calibrated GC-ECD was used to quantitate PAN and PPN and semi-quantitate peroxyacrylic nitric anhydride (APAN). Photochemical day-time production of PAN and PPN was observed up to 28.8±4.6 ppt and 4.6±1.9 ppt (1σ), respectively. Minor photochemical production of APAN suggests that PAN emissions were associated to petrochemical activities. Surface deposition of PAN and PPN onto snow/ice was proposed as an alternative sink in winter with estimated deposition velocities of up to 1 cm/s. The PPN:PAN ratio was found to be 23% indicating the majority of PAN originated from anthropogenic sources. Ambient IVOCs were measured by gas chromatography ion trap mass spectrometry and combined with primary emission and meteorological data. Principal component analysis was conducted to reduce the dimensionality of the dataset followed by application of the Gaussian mixture model (GMM) clustering algorithm to isolate local IVOC sources. Chemical signatures were consistent with single ring aromatics; previously assumed to constitute a small portion of IVOCs in the region during summertime studies.