Health Effects of Ambient
Concentrations of Ozone
Michael Honeycutt, Ph.D.
Toxicology Division
Texas Commission on Environmental Quality
1
Independent Workshop on Ozone
NAAQS Science & Policy
April 7-9 UT Austin Conference Center
• Purpose: to engage a multi-disciplinary group of
science and policy experts to review the scientific
evidence regarding ambient ozone’s health effects
and to deliberate on the nexus between scientific
findings and implications for public health
• Goal: to provide an independent evaluation and
synthesis of key considerations for approaching the
difficult and complex ozone NAAQS decision
2
Session 1 – Context of the O3 Rule
• Seyed Sadredin – San Joaquin Valley Air pollution control district
– Air quality in California has greatly improved in the last 40 years
– Spent $40B in reducing air pollution, will barely meet the 84 ppb standard;
could eliminate all stationary sources and passenger vehicles, and still not
meet the present standard
– Need more time for implementation, less chaos when changing the
standard and better information to the public
• Henry Nickel – Special Counsel, Hunton & Williams
– NAAQS are the heart of the modern clean air act
– The program separates standard setting from implementation
– Primary standards must be requisite to protect public health with an
adequate margin of safety – level of the standard must be sufficient to
protect public health, but not lower than necessary (the Goldilocks
standard)
– Costs cannot be considered when establishing the standard
3
Session 1 – Context of the O3 Rule
• Roger McClellan – Advisor, Toxicology and Human Health Risk Analysis
– Policies and regulations should be informed by the science, but science alone
is not sufficient – judgment is also required
– It is important to look at every aspect of the standard: indicator, form, level
and averaging time
– Common sense and context should be used when setting the standard
• Tim Verslycke – Gradient
– The latest ozone proposed rule will keep the secondary (welfare-based)
standard the same as the primary (health-based) standard
– There are benefits to plants just by meeting the current ozone standard, but
little evidence for increased benefits by further lowering the level of the
standard
4
Session 2 – Selected Topics of the O3 Science
• One full day of presentations and discussion
on 4 ozone science topics:
– Ozone mode of action
– Human clinical studies
– Epidemiology studies and exposure
– Evidence integration
5
Human Clinical Studies
• These studies measure physiological effects, primarily
respiratory function (forced expiratory volume in 1
second - FEV1)
• They take into account 3 parameters, which make up O3
dose:
– O3 concentration (in ppm)
– Duration of exposure (in min)
– Ventilation rate (ie. Exercise level; in L/min)
6
Adverse Effects – FEV1
• ATS, 2000 - “reversible loss of lung function in
combination with the presence of symptoms should be
considered adverse.”
• ATS/ERS, 2005 - “two-point, short-term changes of
>12% and >0.2L in the FEV1 are usually statistically
significant and may be clinically important” (Pellegrino
2005)
• US EPA 2014b - “…a focus on the mid- to upper-end of
the range of moderate levels of functional responses
and higher (FEV1 decrements ≥ 15%) is appropriate for
estimating potentially adverse lung function
decrements in active healthy adults, while for people
with asthma or lung disease, a focus on moderate
functional responses (FEV1 decrements down to 10%)
may be appropriate”
7
O3 Dose-Response Curves
Longer Exposure (6-8 hours)
Shorter Exposure (≤ 3 hours)
8
O3 Dose-Response Curves
9
D-R Curves with Sensitive Populations
10
D-R Curves with Sensitive Populations
11
Ozone Dose Thresholds
12
O3 FEV1 Dose Thresholds
Individual Data Dose-Response Curves
Mean % Change in
FEV1
0
-5
-10
-15
-20
Short exposure
dose (ppm•L)
N/A
740.2
926.7
1467.4
N/A
Long exposure
dose (ppm•L)
608.5
953.5
1553.8
N/A
N/A
13
Exercise Ventilation Rates & Durations
Source
Population
Exercise Intensity
Ventilation Rate
(L/min)*
Duration (hours)*
US EPA 2009
Children (6 - < 11
years old)
Sedentary
4.8 (3.7-6)
13.7 (13-15)
Light
11.3 (9.2-14)
7.4 (5.5-9.6)
Moderate
21.6 (17-26.8)
2.6 (0.9-4.1)
High
41.5 (31.4-53.5)
0.3 (0.02-0.9)
Sedentary
5.3 (3.6-5.9)
12.5 (11.2-13.8)
Light
11.8 (9.2-14.9)
6.3 (3.8-9.7)
Moderate
26.1 (18.8-34.4)
5 (1.8-7.6)
High
49.8 (34.6-67.2)
0.3 (0.05-0.6)
Non-occupational
24 hr Ventilation with
8 hrs Manual labor
14
24
Occupational
Manual labor
22
8
Zuurbier 2003
Adult
Bicycle commute
23.5 (11-47.7)
2
Samet 1993
Child
Outdoor play
16 (12.1-17.4)
1.9
Child
Bicycling
27.1 (16.7-34.8)
2.1
Adult
Vigorous bicycling
65 (40.8-87.8)
0.8
Adult (21 - < 31
years old)
US EPA 1994
* Mean ventilations and times, and where available, the 10th and 90th percentiles in parentheses.
O3 Concentration Matrix
>4 hour Dose = 1619 ppm L
FEV1 Decrement = 10%
Source
EPA
EPA
EPA
EPA
TCEQ
Samet
EPA
TCEQ
Zuurbier
EPA
Samet
EPA
EPA
Samet
Population & Exercise
Sedentary Child
Sedentary Adult
Light Int Child
Light Int Adult
General Pop (24 hr)
Child Outdoor Play
Med Int Child
Adult Worker (8 hr)
Adult Bicycle Commute
Med Int Adult
Child Bicycling
High Int Child
High Int Adult
Adult Male Bicycling
VE (L/min)
5
5
11
12
14
16
22
22
24
26
27
42
50
65
1
2
3
2917
2642
1273
1167
1000
875
636
636
596
538
519
333
280
215
1458
1321
636
583
500
438
318
318
298
269
259
167
140
108
972
881
424
389
333
292
212
212
199
179
173
111
93
72
<=4 hour Dose = 840 ppm L
Ozone Concentration (ppb)
Time (hrs)
4
5
6
7
729
660
318
292
250
219
159
159
149
135
130
83
70
54
1124
1018
491
450
385
337
245
245
230
208
200
128
108
83
937
849
409
375
321
281
204
204
191
173
167
107
90
69
803
727
350
321
275
241
175
175
164
148
143
92
77
59
8
12
24
703
636
307
281
241
211
153
153
144
130
125
80
67
52
468
424
204
187
161
141
102
102
96
86
83
54
45
35
234
212
102
94
80
70
51
51
48
43
42
27
22
17
15
Short Exposure Scenarios
Threshold O3 dose for 15%
FEV1 mean decrement
Threshold O3 dose for 10%
FEV1 mean decrement
Threshold O3 dose for 5% FEV1
mean decrement
16
Longer Exposure Scenarios
Threshold O3 dose for 10%
FEV1 mean decrement
Threshold O3 dose for 5%
FEV1 mean decrement
17
Science Panel Thoughts on TCEQ Work
• Interesting; Looks at the data differently
• Valid
• Suggested additional analyses to expand our
analysis
• Wanted to know how it compared to EPA’s
analysis
• Strongly encouraged publication
18
Session 3 – Socioeconomic Costs
• Daniel Millimet – Southern Methodist University
– Historical evidence of economic impacts of environmental regulation
– NAAQS regulatory costs have historically impacted businesses, but only the subset
of businesses that have high air pollution regulatory costs
• John Morrall – Mercatus Center at George Mason University
– Health effects of regulatory costs – changing economic conditions can have negative
impacts on health
– Health-health analysis – considers both the intended health consequences of a
regulation (the health benefits) and the unintended health consequences of a
regulation (the health dis-benefits)
– Example calculation (based on published literature) – using 1 life lost for every $25
million increase in costs:
• By the EPA’s calculations, 900 lives are saved from decreasing ozone, with a
standard at 60 ppb
• But using the above calculation (1 life lost/$25 mill in costs), 2000 lives would
be lost from the economic cost to attain 60 ppb – uses EPA’s cost estimate
19
Compliance Costs Can Have Economic Impacts Far
Beyond the Sectors and Regions That Face Those
Costs
• Businesses facing higher costs may be able to pass costs through into their
product prices  more effect on customers in other sectors that cannot
pass the costs through, or on the final consumer (“households”)
• Business that cannot pass higher costs into their product prices will pass
costs to their shareholders  reduces household income from savings
• Capital spending to purchase/construct emissions reducing equipment or
alter production processes diverts capital budgets away from productive
investments  reduces labor productivity  reduces household income
from working
• Rebate programs to incentivize owners of relatively old vehicles or other
mobile equipment to scrap them  reductions in other government
services &/or increased taxes  reduces households’ benefits &/or
spending power
NERA’s Analysis Used the NewERA Computable General
Equilibrium Model of the U.S. Economy
Total estimated compliance spending, by state, by sector, by year
+ coal-fired electricity plant closures (by unit)
“NewERAModel”
Note:
The model finds
the lowest-cost
replacement
power to meet
electricity
demands
Macroeconomic
• Consumption
• GDP
• Output by sector
Primary Fuels
• Demand
• Prices
Electricity
• Prices
• Capacity
• Load and dispatch
EPA compliance costs estimate for 65 ppb ozone
standard level
23
NERA compliance costs estimate for 65 ppb
ozone standard level
24
Main Reasons for Cost Discrepancies
• Location of NOx Reductions
– EPA spread NOx reductions evenly across Texas
– NERA concentrated them in East Texas
• Cost of unknown controls
– EPA = flat $15K/ton
– NERA = extrapolated linearly from $15k/ton to
~$235k/ton
• Timing of Controls
– EPA = 2025
– NERA = 2023 (no bump ups)
25
NERA Economic Impact Analysis: GDP
Potential Reduction in Worker Income Is 1% Nationally,
and Over 3% in Texas
Potential Impacts of 65 ppb Ozone Standard on Employment
(Average, 2017-2040)
Real Wage Rate
(% Change from Baseline)
Change in Labor Income
(% Change from Baseline)
Labor Income Change in Job-Equivalents
(Change from Baseline)
NATIONAL
TEXAS
(Preliminary)
-0.6%
-1.4%
-0.9%
-3.2%
-1.4 million
-0.4 million
Notes: Baseline annual job-equivalents is 156 million nationally, and 12 million in Texas.
NERA economic impact analysis by sector
Not Every State Will Need to Make
Reductions
% NOx Reduction Needed
Relative to Base Case Emissions
0%
1% - 25%
26% - 50%
51% - 67%
29
Even States That Have No Compliance Spending Face
Macroeconomic Impacts
Potential Impacts of a 65 ppb Ozone Standard on Annual Consumption per
Household by State (Average, 2017-2040, 2014$)
State
AL
AZ
AR
CA
CO
CT
DE
FL
GA
ID
IL
IN
IA
KS
KY
LA
-$400
-$660
-$680
-$790
-$390
-$1,520
-$2,260
-$250
-$280
-$290
-$640
-$540
-$350
-$1,990
-$470
-$710
State
ME
MD
MA
MI
MN
MS
MO
MT
NE
NV
NH
NJ
NM
NY
NC
ND
-$1,100
-$1,340
-$2,190
-$430
-$430
-$770
-$700
-$690
-$470
-$920
-$1,180
-$1,470
-$630
-$1,390
-$250
-$830
State
OH
OK
OR
PA
RI
SC
SD
TN
TX (*)
UT
VT
VA
WA
WV
WI
WY
(*): Texas results shown are the preliminary, refined estimates from April 2015 TCEQ analysis.
-440
-$900
-$280
-$1,240
-$1,050
-$300
-$310
-$960
-$1,850
-$410
-$1,200
-$1,440
-$330
-$980
-$580
-$4,380
Session 4 – Policy Panel Discussion
Considerations of the legal framework:
• In terms of litigating the decisions of the Administrator, the EPA is given the
highest level of deference on matters of technical or scientific expertise, and
the course give absolute deference to the agency for the scientific conclusions
• Supreme Court Justice Breyer, in Whitman v American Trucking Association,
stated:
– The statue also permits the Administrator to take account of comparative
health risks. That is to say, she may consider whether a proposed rule
promotes safety overall. A rule likely to cause more harm to health than it
prevents is not a rule that is “requisite to protect public health”.
• This suggests that the health dis-benefits should be considered in making this
decision
• The policy panelists were concerned that the way the decision is currently
being made (no guidance or evidence of consistent decision making, behindthe-curtain considerations of costs) will lead to cynicism in how people view
the law and the government
31
Session 4 – Policy Panel Discussion
Context of the decision
• This decision is being made in a very different environment from
that when the Clean Air Act (CAA) was written:
– In 1970 there had been some terrible air pollutions events, and now
we have had 45 years of improving air quality
– In 1970 there was a lot of pollution control “low hanging fruit”
available to clean the air, and now the low and middle hanging fruit
are gone, and we have to go for the fruit at the top of the tree
– In 1970 the country was 25 years into its best 50-60 years of economic
growth, and now we are coming off of the worst economic downturn
since the Great Depression, and economic analysts say that growth
will be slower
– In 1970 the benefits of economic growth were more widely shared,
and now even if the average wealth increases, the largest share of
those gains goes to those at the very top
– Now the CAA would likely be written to take into account cost,
background concentrations, security of the energy infrastructure, in
addition to protecting public health and welfare
32
Session 4 – Policy Panel Discussion
The EPA Administrator’s decision:
• The EPA produced many large, comprehensive documents in it’s reevaluation of the ozone NAAQS. We have had the luxury of looking at and
criticizing these documents, and of discussing the uncertainties – it is
amazing that we have so much data available to criticize (ie. there is a
wealth of data in the ozone literature)
• The Administrator has to draw a bright line across all of the uncertainties,
and she has to make a decision despite uncertainties
• Setting the NAAQS is the quintessential decision based on the
Administrator’s discretion – no criteria for making the decisions
reproducible, doesn’t have to follow CASAC’s advise
• The discussion really comes down to certainty and uncertainty – what data
are we sure of, what are we less sure of? How sure do you have to be to
set a national standard at a certain level?
• Costs are considered “behind-the-curtain”, and then the science and
uncertainty are used to justify the decision
33
Session 4 – Policy Panel Discussion
Take-home messages:
• The panel considered this workshop to be unique: bringing
together experts in science, economics, policy and law to
discuss the complex and multi-faceted NAAQS decision
• The concerns raised in the workshop (about
implementation, the ozone science, and the cost of the
rule) are valid
• For the Administrator to consider comments and
arguments, they must be part of the record (ie. comments
made in the docket), and once the comment period is over,
there is still opportunity for further discussion with
different groups in the federal government (EPA, OMB)
34