Investigation of levoglucosan decay in wood smoke smog-chamber experiments: The importance of aerosol loading, temperature, and vapor wall losses in interpreting results

Changes in PM<sub>2.5</sub> peat combustion source profiles with atmospheric aging in an oxidation flow reactor

“…Figure 4 shows the presence of levoglucosan carbon for the Russian and Alaskan peats after 2 and 7 d aging, at the levels of 8 %-11 % and 2 %-9 %, respectively, in line with a chemical lifetime longer than 2 d. This is consistent with the estimated 1.2-3.9 d of levoglucosan lifetimes under different environments reported by Lai et al (2014). However, other studies (Hennigan et al, 2010;May et al, 2012;Pratap et al, 2019) found that levoglucosan experiences rapid gas-phase oxidation, resulting in ∼ 1-2 d lifetimes at ambient temperatures.…”

“…The extent of levoglucosan degradation depends on organic aerosol composition, OH exposure in the OFR, and vapor wall losses (Bertrand et al, 2018a, b;Pratap et al, 2019). Figure 4 shows the presence of levoglucosan carbon for the Russian and Alaskan peats after 2 and 7 d aging, at the levels of 8 %-11 % and 2 %-9 %, respectively, in line with a chemical lifetime longer than 2 d. This is consistent with the estimated 1.2-3.9 d of levoglucosan lifetimes under different environments reported by Lai et al (2014).…”

“…Changes in source profiles have been demonstrated in large smog chambers (Pratap et al, 2019), wherein gasparticle mixtures are illuminated with ultraviolet (UV) light for several hours and their end products are measured. Such chambers are specially constructed and limited to laboratory testing.…”

Observation of Vapor Wall Deposition in a Smog Chamber Using Size Evolution of Pure Organic Particles

“…All experiments were performed in an outdoor 6 m 3 fluorinated ethylene propylene (FEP) Teflon smog chamber (Pratap et al, 2019). The outdoor setup allows us to use ambient low temperatures in winter (<0°C) native to Potsdam, NY.…”

“…Bertrand et al (2018a, 2018b) studied the loss (and vapor wall loss) of levoglucosan and found that the loss of levoglucosan in chamber experiments is largely driven by the vapor wall loss rather than the chemical loss. Pratap et al (2019) investigated levoglucosan decay in wood smoke aerosol through chamber experiments in a subzero to low temperature range (-8 o C to +10 o C) and found the vapor wall loss of levoglucosan was negligible at temperatures < 0 o C. The chemical losses were negligible owing to the higher organic aerosol loading.…”