1 research outputs found
Quantifying O<sub>3</sub> Impacts in Urban Areas Due to Wildfires Using a Generalized Additive Model
Wildfires
emit O<sub>3</sub> precursors but there are large variations
in emissions, plume heights, and photochemical processing. These factors
make it challenging to model O<sub>3</sub> production from wildfires
using Eulerian models. Here we describe a statistical approach to
characterize the maximum daily 8-h average O<sub>3</sub> (MDA8) for
8 cities in the U.S. for typical, nonfire, conditions. The statistical
model represents between 35% and 81% of the variance in MDA8 for each
city. We then examine the residual from the model under conditions
with elevated particulate matter (PM) and satellite observed smoke
(“smoke days”). For these days, the residuals are elevated
by an average of 3–8 ppb (MDA8) compared to nonsmoke days.
We found that while smoke days are only 4.1% of all days (May–Sept)
they are 19% of days with an MDA8 greater than 75 ppb. We also show
that a published method that does not account for transport patterns
gives rise to large overestimates in the amount of O<sub>3</sub> from
fires, particularly for coastal cities. Finally, we apply this method
to a case study from August 2015, and show that the method gives results
that are directly applicable to the EPA guidance on excluding data
due to an uncontrollable source