of 40
S1
Supporting Information for:
Evolution of reactive organic compounds and their
potential health risk in wildfire smoke
Havala O. T. Pye*
1
, Lu Xu
2
, Barron H. Henderson
3
, Demetrios Pagonis
4,5
, Pedro Campuzano-
Jost
4,6
, Hongyu Guo
4,6
, Jose L. Jimenez
4,6
, Christine Allen
7
, T. Nash Skipper
1
, Hannah S.
Halliday
2
, Benjamin N. Murphy
1
, Emma L. D’Ambro
1
, Paul O. Wennberg
8
, Bryan K. Place,
1
Forwood C. Wiser
9
, V. Faye McNeill
9
, Eric C. Apel
10
, Donald R. Blake
11
, Matthew M.
Coggon
12
, John D. Crounse
8
, Jessica B. Gilman
12
, Georgios I. Gkatzelis
4,12,
, Thomas F.
Hanisco
13
, L. Gregory Huey
14
, Joseph M. Katich,
4,12,
Δ
Aaron Lamplugh
4,12
,
Jakob Lindaas
15
, Jeff
Peischl
4,12
, Jason M. St. Clair
13,16
, Carsten Warneke
12
, Glenn M. Wolfe
13
, and Caroline
Womack
12
1
Office of Research and Development, US Environmental Protection Agency, Durham, NC,
USA, 27711;
2
Energy, Environmental & Chemical Engineering, Washington University in St.
Louis, St. Louis, MO, USA, 63130;
3
Office of Air and Radiation, US Environmental Protection
Agency, Durham, NC, USA, 27711;
4
Cooperative Institute for Research in Environmental
Sciences, University of Colorado Boulder, Boulder, USA, 80309;
5
Department of Chemistry &
Biochemistry, Weber State University, Ogden, UT, USA, 84408;
6
Department of Chemistry,
University of Colorado, Boulder, CO, USA, 80309;
7
GDIT, Durham, NC, USA, 27709;
8
California Institute of Technology, Pasadena, CA, USA, 91125;
9
Columbia University, New
York, NY, USA, 10027;
10
National Center for Atmospheric Research, Boulder, CO, USA,
80301;
11
University of California Irvine, Irvine, CA, USA, 92697;
12
NOAA Chemical Sciences
Laboratory, Boulder, CO, USA, 80305;
13
NASA Goddard Space Flight Center, Greenbelt, MD,
USA, 20771;
14
Georgia Institute of Technology, Atlanta, GA, USA, 30332;
15
Department of
Atmospheric Science, Colorado State University, Fort Collins, CO, USA, 80523;
16
University of
Maryland Baltimore County, Baltimore, MD, USA, 21250;
Now at: Institute of Energy and
Climate Research, IEK-8: Troposphere, Forschungszentrum Jülich GmbH, Jülich, Germany
Δ
Now at: BAE Systems, Inc., Boulder, CO, USA, 80301
*Correspondence to:
pye.havala@epa.gov
Pages:
40
Figures:
13
Tables:
16
S2
Equations for Calculating Risk
Many terms used here are defined in the AirToxScreen Glossary of Terms
(
https://www.epa.gov/AirToxScreen/airtoxscreen-glossary-terms
).
Cancer
Cancer risk (a dimensionless probability, often expre
ssed as “N”-in-1 million) is estimated using a species-
specific unit risk estimate (URE) (Table S9) and the species annual-average concentration (
C
i
in μg species
m
-3
air) to which the individual is exposed over a lifetime:
(S1).
To determine risk from multiple species, species-specific values from Equation S1 can be summed to give
a total N-in-a million risk. If the species exposure occurs over a fraction of the year, the annual-average
concentration can be estimated as:
(S2),
where
is the exposure concentration during the
exposure window duration in days.
Noncancer
Hazard Quotients (HQ) are dimensionless values com
puted for individual species using the annual average
species exposure concentration in mass units and a species-specific reference concentration (
RfC
i
) (Table
S10):
(S3).
A Hazard Index (
HI
) is a sum of
HQ
i
across multiple species:
(S4).