Document ID: EPA-HQ-OAR-2003-0061-0473
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2004-10-07T04:00Z

New
Jersey
Department
of
Environmental
Protection
Response
to
the
USEPA's
June
29,
2004,
Modifications
to
New
Jersey's
Annual
Fine
Particulate
Matter
(
PM2.5)
Nonattainment
Area
Recommendation
Appendix
B:
Sulfur
Dioxide
to
Sulfate
Conversion
Calculations
September
29,
2004
M
E
M
O
R
A
N
D
U
M
TO:
Bob
Stern
Bureau
of
Air
Quality
Planning
FROM:
Ray
Papalski
Bureau
of
Air
Quality
Planning
SUBJECT:
Sulfate
Conversion
Attached
please
find
the
memorandum
from
Alan
Dresser
concerning
conversion
of
sulfur
dioxide
to
sulfate,
dated
July
23,
2003.
The
conclusion
of
this
memorandum
is
that
about
2
percent
of
SO2
is
converted
to
sulfate
within
100
kilometers
of
a
release
in
Mercer
County.
This
percent
conversion
is
further
supported
by
the
empirical
equation
for
sulfate
conversion
as
outlined
in
the
USEPA's
report
entitled
"
Interagency
Workgroup
on
Air
Quality
Modeling
(
IWAQM)
Phase
2
Summary
Report
and
Recommendations
for
Modeling
Long
Range
Transport
Impacts"
(
EPA­
454/
R­
98­
019,
December
1998,
page
20).

The
SO2
to
SO4
transformation
rate
in
percent
per
hour
(
Ki)
is
as
follows:

Ki
=
36
R
0.55
[
O3]
0.71
S
 
1.29
+
k1(
aq)
where:

R
=
total
solar
radiation
intensity
(
kw/
m2)
[
O3]
=
the
background
ozone
concentration
in
ppm
S
=
the
Stability
Index
from
2
to
6
(
PG
stability
A&
B
=
2,
C=
3,
etc.)
K1(
aq)
=
the
aqueous
phase
SO2
oxidation
term
where
the
value
peaks
at
3%
per
hour
at
100
percent
relative
humidity
and
only
applies
during
the
day.
At
night,
an
oxidation
rate
of
0.2%
for
SO2
is
the
suggested
default
value.

I
obtained
solar
radiation
data
from
Andy
Mikula
of
the
Bureau
of
Air
Monitoring
from
several
sites
around
the
State
and
from
PADER's
Air
Monitoring
Website.
Varying
the
factors
in
the
equation
above
gives
a
range
of
the
SO2
to
sulfate
conversion
from
3
to
5
percent
per
hour
as
shown
in
the
attached
table.
The
majority
of
this
conversion
is
in
the
aqueous
phase
where
up
to
3
%
aqueous
phase
SO2
oxidation
could
take
place
at
100%
humidity.
This
range
is
consistent
with
Alan
Dresser's
July
23,
2003
memo
where
the
Calpuff
model
without
aqueous
phase
conversion
showed
a
2
percent
conversion
at
100
kilometers.

Please
let
me
know
if
you
would
like
me
to
follow­
up
further
on
this.

C:
Tonalee
Key
SO2
to
Sulfate
Conversion
(%
per
hour)
Under
various
Conditions
Affect
of
Increasing
Solar
Radiation:

Solar
Radiation
Ozone
Conc.
Stability
Class
k1
K
(%/
hr)

0.558
0.125
2
1.5
3.94
0.615
0.125
2
1.5
4.07
0.726
0.125
2
1.5
4.32
0.8
0.125
2
1.5
4.47
0.85
0.125
2
1.5
4.58
0.9
0.125
2
1.5
4.67
0.95
0.125
2
1.5
4.77
Affects
of
Increasing
Ozone
Concentration:

Solar
Radiation
Ozone
Conc.
Stability
Class
k1
K
(%/
hr)

0.558
0.06
2
1.5
2.95
0.558
0.07
2
1.5
3.12
0.558
0.08
2
1.5
3.28
0.558
0.09
2
1.5
3.43
0.558
0.1
2
1.5
3.58
0.558
0.11
2
1.5
3.73
0.558
0.12
2
1.5
3.87
0.558
0.13
2
1.5
4.01
0.558
0.14
2
1.5
4.14
0.558
0.15
2
1.5
4.28
0.558
0.16
2
1.5
4.41
Affects
of
Increasing
Aqeuous
phase
SO2
Oxidation
Solar
Radiation
Ozone
Conc.
Stability
Class
k1
K
(%/
hr)

0.726
0.08
2
1.5
3.55
0.726
0.08
2
2
4.05
0.726
0.08
2
2.25
4.30
0.726
0.08
2
2.5
4.55
0.726
0.08
2
2.75
4.80
0.726
0.08
2
3
5.05
Affects
of
Increasing
Stability
Class
AT
S=
3
At
S=
2
Calmer
Winds
Higher
Winds
Solar
Radiation
Ozone
Conc.
Stability
Class
k1
K
(%/
hr)
K
(%/
hr)

0.558
0.06
3
1.5
2.36
2.95
0.558
0.07
3
1.5
2.46
3.12
0.558
0.08
3
1.5
2.55
3.28
0.558
0.09
3
1.5
2.65
3.43
0.558
0.1
3
1.5
2.73
3.58
0.558
0.11
3
1.5
2.82
3.73
0.558
0.12
3
1.5
2.91
3.87
0.558
0.13
3
1.5
2.99
4.01
0.558
0.14
3
1.5
3.07
4.14
0.558
0.15
3
1.5
3.15
4.28
0.558
0.16
3
1.5
3.22
4.41