NON-VOLATILE, SEMI-VOLATILE, OR
VOLATILE:
REDEFINING VOLATILE FOR VOLATILE
ORGANIC COMPOUNDS
June 21, 2012
South Coast Air Quality Management District
Purpose of Study
…
Validate Low Vapor Pressure (LVP-VOC)
exemption criteria
† Consumer
products will be largest source of VOC
in SCAQMD by 2020
† LVP-VOC used to exclude solvents used in
consumer products
…
…
…
Study evaporation rate under ambient settings
Review VOC reference materials
Investigate semi-volatiles
How is Volatility Currently Defined?
…
Test methods define volatility via procedures
and parameters
†
†
†
…
Time
Temperature
Reference
material
†
†
Column Polarity
Others
Definition differences lead to varying results
Potential alternatives can be excluded
Anticipated environmental benefits
may not be realized
Reference Methods
EPA Method 24
‰ Gas Chromatography (GC)
‰
‰
‰
Thermogravimetric Analysis (TGA)
‰
‰
SCAQMD Method 313
ASTM E 1868-10
Ambient Evaporation
Ambient Evaporation Study
Parameters
Sample Size:
Approx 1 g
Pan Configuration: Petri Dish
Temperature:
High ± 30ƒC
Low ± 20ƒC
Avg. ± 24ƒC
Humidity:
High ± 52%
Low ± 16%
Avg. ± 42%
Air Flow:
Negligible
Overall Ambient Evaporation Results
135
125
Nonvolatile
115
105
% Non-Volatile
95
85
75
65
Semivolatile
55
45
35
25
15
5
Volatile
-5
0
7
14
21
28
35
42
49
56
63
70
77
84
91
98
105 112 119 126 133 140 147 154 161 168 175 182
Time (Days)
Ambient Evaporation Results ±
Non-Volatile
135
125
115
105
% Non-Volatile
95
85
75
65
55
45
35
25
15
5
-5
0
7
14 21 28 35 42 49 56 63 70 77 84 91 98 105 112 119 126 133 140 147 154 161 168 175 182
Time (Days)
Methyl Palmitate
Soy Oil
Glycerol
Ambient Evaporation Results ±
Semi-Volatile
100
90
% Non-Volatile
80
70
60
50
40
30
20
10
0
0
7
14
21
28
35
42
49
56
63
70
77
84
91
98
105
112
119
126
133
140
147
154
161
168
175
182
Time (Days)
C15
Dipropylene Glycol
2-Methyl Hexadecane
C16
Hynap N60HT
C17
% Non-Volatile
Ambient Evaporation Results ±
Volatiles
135
125
115
105
95
85
75
65
55
45
35
25
15
5
-5
0
7
14 21 28 35 42 49 56 63 70 77 84 91 98 105 112 119 126 133 140 147 154 161 168 175 182
Time (Days)
IPA
Light Distillate
Ethyl Lactate
NMP
Benzyl Alcohol
C12
Propylene Glycol
Ethylene Glycol
2,2,4-Trimethylpentanediol Diisobutyrate
2,2,4-Trimethyl-1,3-Pentanediol Monoisobutyrate
% Non-Volatile
Comparison of Pure Analyte
Volatility
120
110
100
90
80
70
60
50
40
30
20
10
0
GC (M313)
TGA (E 1868)
M24 (D 2369)
Ambient Evap @ 6 Months
Regulatory Standards
Boiling points used to exclude solvents
deemed non-volatile
Agency
CARB, EPA & OTC*
EU & Canada
Green Seal
Boiling Point
216ºC
250ºC
280ºC
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0.1 mm Hg or 12 or more carbon atoms
Correlation of Boiling Point and
Ambient Evaporation Results
140
120
% Non-Volatile
100
80
60
40
20
0
50
100
150
200
Boiling Point (ƒC)
250
300
350
Correlation of Number of Carbons
and Ambient Evaporation Results
140
% Non-Volatile
120
100
80
60
40
20
0
0
2
4
6
8
10
12
Number of Carbons
14
16
18
20
Volatility by Test Method and
Regulatory Standard
IPA
Ambient Evap
@ 6 Months
V
Light Distillate
V
Analyte
V
E
1868
V
M24
(D 2369)
V
CARB, EPA
& OTC
V
EU &
Canada
V
Green
Seal
V
V
V
V
NV
V
V
M313
Ethyl Lactate
V
V
V
V
V
V
V
NMP
Benzyl Alcohol
C12
Propylene Glycol
Ethylene Glycol
2,2,4-Trimethylpentanediol
Diisobutyrate
2,2,4-Trimethyl-1,3-Pentanediol
Monoisobutyrate
C15
Dipropylene Glycol
2-Methyl Hexadecane
C16
Hynap N60HT
C17
Methyl Palmitate
Soy Oil
Glycerol
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
NV
NV
NV
NV
V
V
V
V
V
V
V
V
V
V
V
V
SV
V
NV
NV
NV
V
V
V
V
NV
NV
V
SV
SV
SV
SV
SV
SV
NV
NV
NV
V
V
V
V
V
V
NV
NV
V
SV
SV
SV
SV
SV
SV
SV
NV
NV
V
V
SV
SV
SV
SV
SV
NV
SV
NV
NV
NV
NV
NV
NV
NV
NV
NV
NV
V
NV
NV
NV
NV
NV
NV
NV
V
V
NV
NV
V
NV
NV
V
NV
Ambient Evaporation Results ±
IPA, Light Distillate and Ethyl Lactate
105
95
…
Light Distillate is CARB
³FRPSOLDQW´LVP-VOC
replacement for paint
thinners and multipurpose
solvents
…
CARB Consumer Products
Regulation claims more
than 13 tons per day
emission reduction
statewide (not including
SCAQMD) from these two
categories
…
LVP-VOC does not provide
emission benefits
85
% Non-Volatile
75
65
55
45
35
25
15
5
-5
0
1
2
Time (Days)
IPA
Light Distillate
Ethyl Lactate
Findings
…
Some non-volatile solvents calculated as VOCs
despite negligible evaporation rate
†
†
…
Semi-volatile compounds challenge GC
methods
†
…
…
Glycerol
Methyl palmitate
Possible need to acknowledge partial contribution
Some LVP-VOC solvents evaporate as quickly
as the solvents they are meant to replace
LVP-VOC exemption parameters currently
used to exclude volatile solvents should be
reconsidered
Future Work
Validate methyl palmitate GC endpoint
‰ Establish appropriate LVP exemption
parameters
‰ Address semi-volatiles in GC methods
‰ Refine TGA parameters to better reflect
ambient evaporation results
‰ Expand study beyond pure analytes
‰
Questions? Comments?
Uyên-Uyên T. Võ
Mike Morris
Air Quality Chemist
Air Quality Specialist
SCAQMD
(909) 396-2238
[email protected]
SCAQMD
(909) 396-3282
[email protected]