The Science and Law of Air Quality
Fundamental problem:
• Science is inexact, with a continuum of limits,
errors and uncertainties
– Environmental science is more uncertain than many
other disciplines because it addresses biological
problems in both natural and human modified
situations, including human health
• Law tends to require a “bright line” demarcation
between good and bad, legal and illegal.
– Environmental law is all the more demanding
because questions of risk and safety, cost and
benefit, life and death are addressed
The Science and Law of Air Quality
• Air Quality
– Science of air quality
• gasses
• Particles
• Risk and Safety
• Historical impacts of air pollution
• European and eastern US concerns
• California problems - Example: Lead and CA freeways
• Clean Air Act – 6 (7) criteria pollutant
CO (HC), SO2, NO2,,ozone, lead, and TSP mass
– Amendments and key modified regulations
•
•
•
•
1977 (visibility in Class 1 areas), Example: Grand Canyon
1987 TSP to PM10
1991 (regional haze and eastern sulfur reduction),
1997 PM10 to PM2.5 (fine particles) Example: vf/uf, diesel, WTC
Global Perspective
• Despite using 1/5 of the world’s energy and about 1/3 of
the worlds VMT, the US has much better air quality than
most of the developed or developing countries
• Air quality in major international cities outside of Western Europe
is usually appalling!
• California leads the nation in cleaning up smog
• In 1965, Los Angeles was worse than Mexico City in 1995
• The Central Valley lags but still is not bad by global
standards
• There is no way that Fresno is really the 4th most polluted
urbanized area in the US (Sacramento is listed the 7th) since
most forms of “pollution” are not considered in the ranking.
• Blue skies and good visibility in the Sacramento Valley each Fall
(rice stubble burning suppressed); Bakersfield (oil improvement)
Health Impacts of Air Pollution
• 1890 – onward - Industrial Impacts – “black lung”, “brown
lung”, silicosis, toxics, …..
• 1930s - Meuse Valley (FR) and Donamora, PA – 100s of
excess deaths
– Essentially ignored – The Great Depression
• London “killer” smog of 1952
– First serious studies; doubled death rate
• Los Angeles becomes a national joke –
– stinging eyes, brown haze
Health Impacts of Air Pollution
• 1970s – onward – Major work of health effects of ozone
in California
– Health and welfare, including crops and forests
• 1980s – major EPA epidemiological studies – Harvard “6
cities study” over 10 years; Utah valley, others
– Soon becomes the “Gold Standard”;
– introduction of PM2.5 “fine particle” standard 1997
• 1990s – major international efforts at long term “epi”
studies aided greatly by the decline in cigarette smoking
• 1990s - some gaseous pollutants de-emphasized
• 2000 – better animal models, etc, isolate the heart as the
target of fine particles
– Very fine/ultra fine particles arise as causal factors
Health and Aerosols in the Central Valley of California
Data Relative to Shasta and Butte counties
Annual PM10
Childhhod Asthma
2.5
2
1.5
1
0.5
ha
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B
ut
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S
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P
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M s
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Fr a
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Tu
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0
S
Values Relative to Butte and Shasta
Ischemic Heart Mortality
PM10 mass and Ischemic Heart Disease
Annual Valley PM10 (ug/m3)
California Central Valley
200
r2 = 0.56
150
100
50
0
70
80
90
100
110
120
Ischemic Heart Disease (% of state average)
130
140
Ozone and Ischemic Heart Disease
Ozone Average Top 30 hrs (ppm)
California Central Valley
0.15
r2 = 0.18
0.1
0.05
0
70
80
90
100
110
120
Ischemic Heart Disease (% of state average)
130
140
Welfare Impacts of Air Pollution
• 1970s – onward – Major work in California
– Bimodal particle size distribution and visibility reduction
– Effects of gaseous pollutants (ozone, PAN) on vegetation
• 1977 – National visibility studies (viz CAA 1977)
– Airport visibility nationwide
– First aerosol measurements Class 1 areas
• 1980s – start of national effort at aerosols and visibility
(NPS, 1981; IMPROVE 1987)
– First actions under CAA 1977 “plume blight” – control of haze at
Grand Canyon NP
• 1991 Kuwaiti oil fires rekindle global climate /aerosol
connection
– Major international studies ongoing
– Aerosols now 80% of the uncertainty in global climate forcing
models
Calculation of Risk
NRC Redbook 1983
1. Hazard identification
a. Qualitative evaluation of adverse effects
2. Exposure assessment
a. “Maximally exposed individual” MEI versus
b. Population at large
3. Dose response
a. Animal models, scaled
b. Linear extrapolation to zero
4. Risk characterization
a. Reduction of lifespan
b. Tumors, leukemia cases per 100,000 people in
specific regions
Problems with Risk Assessment
• Maximally exposed individual is not realistic for
the person with maximum exposure
• Repeated use of conservative assumptions (The
EPA “Precautionary Principle”) propagates error
• No assessment of the fate of the pollutant under
transport
• Failure to validate and test assumptions
• Entire process often happens within the EPA –
science, evaluation, assessment, and standard
setting, with major political conflicts of interest
Factors in Safety Judgments
• Risk assumed voluntarily
x 1000!
• Effect immediate
• No alternatives available
• Risk known with certainty
• Exposure is essential
• Encountered occupationally
• Common hazard
• Affects average people
• Will be used as intended
• Consequences reversible
Risk assumed
involuntarily
Effect delayed
Many alternatives
available
Risk not known
Exposure is a
luxury
Encountered nonoccupationally
Dread hazard
Affects especially
sensitive people
Likely to be misused
Consequences
irreversible
Protection by Criteria and Standards
Criteria and standards
Example
• Personal exposure standards
• Ambient composition standards
• Product design standards
radiation, (air?)
air, water
seat belts, cars,
gasoline
car exhaust,
flammability of
clothes
air traffic controller
hours
truth in
advertising?
Childproof pill
bottles
• Product performance standards
• Work practice standards
• Promotional claims standards
• Packaging standards
Clean Air Act 109 b.1
• National primary ambient air quality standards,
prescribed, under subsection (a) shall be ambient air
quality standards the attainment and maintenance of
which in the judgment of the Administrator, based on
such criteria and allowing an adequate margin of safety,
are requisite to protect the public health. Such primary
standards may be revised in the same manner as
promulgated.
– Question: Does “Requisite to protect public health” mean no
harm to anyone? If not, which “anyones” don’t we protect?
– Question: How does “Adequate margin of safety” handle
pollutants in which any amount produces some harm?
– Question: What should California's position be to this federal
mandate?
PM
2.5
PM
10 TSP
Particle Size versus Persent
Deposition
Particulate
Matter in the cAtmospheric
–
the Atmospheric Aerosol
• Total Suspended Particulate
mass TSP
– < 35 μm
• 10 to 2.5 μm, largely natural
• Inhalable Aerosols PM10
– < 10 μm
• 35 to 10 μm, mostly natural
– Dust, sea salt, pollen, …
0.25 μm
• Fine Aerosols PM2.5
– < 2.5 μm
• Very fine aerosols, < 0.25 μm,
ultra fine aerosols, < 0.10 μm
– Dust, sea spray, some nitrates
2.5 μm
• 2.5 to 0.25 μm, mostly man
made
– Fine dust, nitrates, sulfates,
organics, smoke
• 0.25 to circa 0.01 μm, almost
entirely man made;
– high temperature combustion,
heavy organics, soot, metals
Journal of Inhalation Research (1995).
This figure shows the relationship between particle size and
what percent is deposited in different parts of the respiratory
tract.
Particulate Matter in the Atmospheric –
the Atmospheric Aerosol
• Total Suspended Particulate
mass TSP
– < 35 μm
• Inhalable Aerosols PM10
– < 10 μm
• Fine Aerosols PM2.5
– < 2.5 μm
• Very fine aerosols, < 0.25 μm,
ultra fine aerosols, < 0.10 μm
• 35 to 10 μm, mostly natural
– Dust, sea salt, pollen, …
• 10 to 2.5 μm, largely natural
– Dust, sea spray, some nitrates
• 2.5 to 0.25 μm, mostly man
made
– Fine dust, nitrates, sulfates,
organics, smoke
• 0.25 to circa 0.01 μm, almost
entirely man made;
– high temperature combustion,
heavy organics, soot, metals
Making of the EPA Fine Particle
Standard
“Those who like law or sausage should never watch either
one being made”
• CAASAC – 8 of the scientists said no new PM2.5 annual
average standard was justified
• Of the 13 who wanted a standard, 6 said science could
not support a numerical standard
• Of the 7 who supported a numerical standard, the
choices ranged from 15 to 30 μg/m3 (average 22 μg/m3)
• The EPA staff recommended a standard in the range
from 20 μg/m3 to 12.5 μg/m3
• The EPA Administrator (in a room with 11 others, none of
whom were scientists) chose 15 μg/m3
Fine particles – age the lung and heart
Statistically, excellent connection between fine
particles and health, including mortality
Causally, most of fine particle mass is totally
harmless even in massive doses….
•
EPA’s current thinking: health effects caused by
1.
2.
3.
4.
5.
Biological agents (fungi, bacteria, viruses, spores..)
Acidic aerosols
Fine metals such as iron in the lung
Insoluble very fine and ultra fine particles
High temperature organic matter
Visibility reduction is mostly caused by fine
particles, < 1 m; sulfates, organics
(smoke), soil, nitrates, soot, and sea salt
Typical Sacramento/San Joaquin Valley Particle Sizes
Deep lung deposition
25
Relative Concentration
Typical Haze Particles
Soils
20
15
10
Sulfates
PM
2.5
PM
10
5
0
12 to 5
Coarse
2.5 to 1.15
0.75 to 0.56
0.34 to 0.24
< 0.09
5 to 2.5
1.15 to 0.75
0.56 to 0.34
0.24 to 0.09
Fine
Particle Diameter (microns)
Soils
Sulfates
Very fine
Ultra-fin
Example #1: Lead and the
California freeways
• Data on human health effects of lead cause the
California ARB to pass a standard - < 2.5 μg/m3
– These levels were thought to be violated near
freeways in LA, many in low income areas
• Research on ozone shows ARB that radical
technology was needed to correct LA’s problem
– the catalytic converter – on all new cars
– But the catalytic converter, which makes CO into CO2
and HC into H2O and CO2, needs lead free gasoline
– However, the catalytic converter also changes SO2
from the sulfur in gasoline into sulfuric acid
Fine Particulate Profiles from Los Angeles Freeways
Micrograms/m3 per 10,000 v/hr
San Diego at Harbor, August, 1972
5
Wind
4
3
2
1
0
0
Freeway
150
300
450
550
Distance (feet) from upwind site
Lead
Bromine
Br/Pb ratio x 5000
Sulfur
Effect of roadway distance and configuration on
downwind concentrations of lead 1.
Roadway
Distance
27 m
40 m
100 m
160 m
At grade
Calculated
4.0*
3.4
1.4
0.41
0.35
*
not scaled!
At grade
Measured
4.0
3.1
1.4
Depressed
Measured
4.5
1.7
0.26
Elevated
Measured
(2 sites)
4.8
2.3
3.1
1 - per 10,000 v/hr
(3.5)
(one site)
Reduction in ozone precursors in LA roughly
tracks ozone decline
Trends of ozone Precursors in Los Angeles
NOx
ROG (reactive organoc gasses)
2500
Tons/day
2000
1500
1000
500
0
1980
1985
1990
1995
Year
2000
2005
Los Angeles 1 hr Ozone Maximum
Global
background
Los Angeles Ozone 8 hr 4th Highest 3 yr
Average
Global background
Alameda County Ozone 8 hr 4th Highest 3
yr Average
Global background
Fresno Ozone 8 hr 4th Highest 3 yr
Average
Global background
Health and Aerosols in the Central Valley of California
Data Relative to Shasta and Butte counties
Annual PM10
Childhhod Asthma
2.5
2
1.5
1
0.5
ha
st
a
B
ut
te
S
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P
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S
ac Yol
o
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S me
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Jo o
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ta uin
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M s
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Fr a
es
no
K
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Tu
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K
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0
S
Values Relative to Butte and Shasta
Ischemic Heart Mortality
Particulate Matter in the Atmospheric –
the Atmospheric Aerosol
• Total Suspended Particulate
mass TSP
– < 35 μm
• Inhalable Aerosols PM10
– < 10 μm
• Fine Aerosols PM2.5
– < 2.5 μm
• Very fine aerosols, < 0.25 μm,
ultra fine aerosols, < 0.10 μm
• 35 to 10 μm, mostly natural
– Dust, sea salt, pollen, …
• 10 to 2.5 μm, largely natural
– Dust, sea spray, some nitrates
• 2.5 to 0.25 μm, mostly man
made
– Fine dust, nitrates, sulfates,
organics, smoke
• 0.25 to circa 0.01 μm, almost
entirely man made;
– high temperature combustion,
heavy organics, soot, metals
PM 0.25 ?
PM 10
PM 2.5
Aerosols at the Fresno 1st Street Supersite
PM2.5 Mass, 2001
120
Microrgams/m3
100
EPA 24 hr
standard
80
60
40
EPA annual
standard
20
0
1
1
1
2 2 3 3 4 4 5 5 6 6 7 7 7 8 8 9 9 10 10 11 11 12 12 12
1 2 2 3 3 4 4 4 5 5 6 6 7 7 8 8 9 9 9 10 10 11 11 12 12
Month of the year, 2002
Strontium Aerosols at Fresno during the FACES Study
DRUM Impactor, S-XRF Analysis Data, 6 hr resolution
PM10
PM2.5
Nanogram/m3
30
20
10
0
10
19
27
14
23
4
31
12
8
March
20
16
29
24
7
3
15
11
April
23
19
1
27
May
9
5
17
13
25
21
June
3
29
11
7
July, 2001
DRUM Impactor, S-XRF Analysis Data, 3 hr resolution
PM10
PM2.5
35
Nanogram/m3
30
25
20
15
10
5
0
12
20
16
July
28
24
5
1
13
9
August
21
17
29
25
6
2
14
10
September
22
18
30
26
8
4
16
12
October
24
20
1
28
9
5
November
17
13
24
21
2
28
10
6
18
14
December, 2001
Very fine aerosols characteristic of
diesels/smoking cars
Aerosols at the Fresno First Street Super-site
Very fine (0.26 > Dp > 0.09 micron) elemental concentrations for FACES, CARB
S-XRF analyses via DELTA Group, UC Davis
300
Nanograms/m3
250
200
150
100
50
0
15 17 19 21 23 25 27 29 1 3 5 7 9 11 13 15 17 19 21
16 18 20 22 24 26 28 30 2 4 6 8 10 12 14 16 18 20
November
Phosphorus x 10
December
Sulfur
Potassium
Zinc x 10
So what if Fresno in winter is Impacted
by diesels and smoking cars ?
“It is important to note that the estimated health risk
from diesel particulate matter is higher than the risk
from all other toxic air contaminants combined….
“In fact, the ARB estimates that 70 percent of the
known statewide cancer risk from outdoor air toxics
is attributable to diesel particulate matter”.
“The ARB does not routinely monitor diesel
particulate matter concentrations”.
ARB Almanac 2001, pg. 346
Example #2: Yosemite NP, Navajo
Power Station and Grand Canyon NP
• CAA amendments of 1977 identified Grand
Canyon NP as a “Class 1” area in which visibility
had to be protected (to “close” to natural
background) from human impact
• If an anthropogenic plume were identified as
impacting the park, NPS could request EPA for
hearings on mandated mitigation
• Navajo Power station in Page, AZ, was a large
coal fired power plant with no SO2 controls
located 18 miles from the east end of the park.
• The NPS wanted this cleaned up! I was in
charge of the aerosol science
Visibility reduction is mostly caused by fine
particles, < 1 m; sulfates, organics
(smoke), soil, nitrates, soot, and sea salt
Typical Sacramento/San Joaquin Valley Particle Sizes
Deep lung deposition
25
Relative Concentration
Typical Haze Particles
Soils
20
Sulfates
15
10
5
0
12 to 5
Coarse
2.5 to 1.15
0.75 to 0.56
0.34 to 0.24
< 0.09
5 to 2.5
1.15 to 0.75
0.56 to 0.34
0.24 to 0.09
Fine
Particle Diameter (microns)
Soils
Sulfates
Very fine
Ultra-fin
Informational Resources for this Talk
•
San Joaquin Valley Unified Air Quality Management District
– http://www.valleyair.org
•
California Air Resources Board - Almanac of Emissions and Air Quality and
http://www.arb.ca.gov/html/aqe&m.htm
– Routine monitoring – ADAM http://www.arb.ca.gov/adam
– Special Studies - CRAPAQS, FACES, ….
•
US Environmental Protection Agency
– Routine monitoring – AIRS data base
– Special studies – Fresno Super-site,
•
US Interagency Monitoring for Protected Visual Environments (IMPROVE) –
Yosemite and Sequoia NP
– Routine monitoring – http://vista.cira.colostate.edu/improve/
– Special studies – Yosemite Study, summer, 2002
•
Research Projects –
•
– Universities – UC Davis http://delta.ucdavis.edu (I’ll post this talk) FACES, UN
Reno Desert Research Inst., CORE http://nurseweb.ucsf.edu/iha/core.htm
– Non Governmental Organizations – ALASET HETF, Valley Health Study and
Sacramento/I-5 Transect Study; HEI www.healtheffects.org
Federal resources NOAA HYSPLIT http://www.arl.noaa.gov/ready/hysplit4.html