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12. Ozone pollution
Daniel J. Jacob, Atmospheric Chemistry, Harvard University, Spring 2017
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The industrial revolution and air pollution
“Make great efforts to build China into a strong and prosperous industrialized
country under the leadership of the Party and chairman Mao!”
Pittsburgh in the 1940s
http://www.google.com/url?sa=i&source=images&cd=&cad=rja&uact=8&docid=mHJWZxPwk7pPXM&tbnid=TUDuokjv6uAA7M:&ved=0CAgQjRw4JQ&url=http://en.wikipedia.org/wiki/Pittsburgh_Town&ei=NF4oU_ywJ6240AG0loDYBA&psig=AFQjCNHrLrgyZDCvV22l1JmYJVGM6c3U-g&ust=1395240884716045http://www.google.com/url?sa=i&source=images&cd=&cad=rja&uact=8&docid=mHJWZxPwk7pPXM&tbnid=TUDuokjv6uAA7M:&ved=0CAgQjRw4JQ&url=http://en.wikipedia.org/wiki/Pittsburgh_Town&ei=NF4oU_ywJ6240AG0loDYBA&psig=AFQjCNHrLrgyZDCvV22l1JmYJVGM6c3U-g&ust=1395240884716045http://www.google.com/url?sa=i&source=images&cd=&cad=rja&uact=8&docid=Ep8H4aa23gJsyM&tbnid=P79G7JMCVTm-aM:&ved=0CAgQjRw4Mg&url=http://chineseposters.net/themes/mao-cult.php&ei=PDwoU-zXGY3ykQfA9IHICw&psig=AFQjCNFuYylXaJ6bXgfQRTn5r6ccHuWgcA&ust=1395232188520294http://www.google.com/url?sa=i&source=images&cd=&cad=rja&uact=8&docid=Ep8H4aa23gJsyM&tbnid=P79G7JMCVTm-aM:&ved=0CAgQjRw4Mg&url=http://chineseposters.net/themes/mao-cult.php&ei=PDwoU-zXGY3ykQfA9IHICw&psig=AFQjCNFuYylXaJ6bXgfQRTn5r6ccHuWgcA&ust=1395232188520294http://www.google.com/url?sa=i&source=images&cd=&cad=rja&uact=8&docid=6CoQBP_p3X3buM&tbnid=wMdfh7Gwb6lAWM:&ved=0CAgQjRw&url=http://www.mnn.com/health/healthy-spaces/stories/think-air-quality-doesnt-matter-look-at-pittsburgh-in-the-1940s&ei=qV0oU9zqJMb20gHb5YGQCQ&psig=AFQjCNE8YKWf_WYGfa4qnZtDv5CUb8SPSA&ust=1395240745667186http://www.google.com/url?sa=i&source=images&cd=&cad=rja&uact=8&docid=6CoQBP_p3X3buM&tbnid=wMdfh7Gwb6lAWM:&ved=0CAgQjRw&url=http://www.mnn.com/health/healthy-spaces/stories/think-air-quality-doesnt-matter-look-at-pittsburgh-in-the-1940s&ei=qV0oU9zqJMb20gHb5YGQCQ&psig=AFQjCNE8YKWf_WYGfa4qnZtDv5CUb8SPSA&ust=1395240745667186
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LONDON FOGAerosols a.k.a.particulate matter (PM) from domestic+industrial coal combustion
“Killer fog” of December 1952 resulted in 10,000 excess deaths
Coal combustionTemperature
Altitude
inversion
sulfateorganic carbonblack carbon
particles< 1km
http://www-as.harvard.edu/chemistry/trop/news.htmlhttp://www-as.harvard.edu/chemistry/trop/news.html
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Los Angeles smogRespiratory problems, vegetation damage due to high surface ozone
troposphere
stratosphere~ 10 km
temperature
inversionozone
altitude
Nitrogen oxides (NOx ≡ NO + NO2)Volatile organic compounds (VOCs)
UV radiationOzone (O3)
vehicles, industry, vegetation
produced by photolysisof oxygen (O2)
PM
~ 1 km
http://iconbazaar.com/bars/contributed/pg04.htmlhttp://iconbazaar.com/bars/contributed/pg04.htmlhttp://www-as.harvard.edu/chemistry/trop/news.htmlhttp://www-as.harvard.edu/chemistry/trop/news.htmlhttp://iconbazaar.com/cars/fiat_multipla.gifhttp://iconbazaar.com/cars/fiat_multipla.gif
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AIR POLLUTION IN THE US TODAY:Ozone and fine particulate matter (PM2.5) are the major pollutants
http://epa.gov/airtrends
US population exposed to air pollutants in excess of national ambient air quality standards (NAAQS), 2015
PM2.5
PM10
SO2
Lead
Ozone
CO
NO2
108M
31M31M
0
1M
5M
11M
0
70 ppb (8-h average)
12 µg m-3 (annual), 35 µg m-3 (24-h)
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0 20 40 60 80 100 120 ppb
Europe AQS(seasonal)
U.S. AQS(8-h avg.)
U.S. AQS(1-h avg.)
Preindustrialozone
background
Present-day ozone background at
northern mid-latitudes
Europe AQS(8-h avg.)
Canadian AQS(8-h avg.)
Ozone air quality standards in the US and in the world
20082014 1997
China AQS(8-h avg.)
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4th-highest annual maximum of daily 8-h average ozone,2010-2012
EPA [2014]
Ozone production mechanism:
2
2
O2
2 2O
2 3
VOC + OH HO products
HO +
1.
2.
3.
NO OH + NO
NO NO + Ohν
→ +
→
+ →
Production can be VOC- or NOx-limited:
O3
VOC
O3
NOx
Standard: 70 ppb
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OZONE CONCENTRATIONS vs. NOx AND VOC EMISSIONSAir pollution model calculation for a typical urban airshed
NOx-saturated
NOx-limited Ridge
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1970-2003 TREND OF U.S. EMISSIONS
Focus until past decade was on VOC emission controls
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Dominant VOC is biogenic isoprene
OMI satellite observations of formaldehyde (HCHO) columns, May-Aug 2005-2014
HCHOhν , OHoxidation~ 1 hour
isoprene
~ 1 hour
Other VOCs
http://iconbazaar.com/bars/contributed/pg04.htmlhttp://iconbazaar.com/bars/contributed/pg04.html
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OMI NO2, summer 2005
Russell et al. [2012]
Post-2000 decline in US emissions of NOx (≡ NO + NO2) as seen by OMI satellite observations of NO2
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OMI NO2, summer 2005OMI NO2, summer 2011
30% decrease in NOx emissions from 2005 to 2011
Russell et al. [2012]
Post-2000 decline in US emissions of NOx (≡ NO + NO2) as seen by OMI satellite observations of NO2
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Trend in 95th percentile daytime ozone, 1990-2010
Spring
Summer
Cooper et al. [2012]
• Decrease in eastern US driven by NOx emission controls;• Increase or flat in Intermountain West
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Ozone production efficiency (OPE) per unit NOx emitted
HO2 OH
NO2NOHNO3
VOC
hv
O3Emission Deposition
xx
ozone producedOPE = = chain length of NO cycleNO emitted
OPE ↑ as NOx ↓ and VOC ↑
Thus the response of ozone to decreasing NOx emissions is much less than linear
4
57
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Intermountain West: high plateau, deep boundary layer mixing→ downwelling of ozone from the middle troposphere
EPA [2014]
Ozone over NE Pacific(INTEX-B, Apr-May 2006)
ppb
observedmodel
Downwelling of high background ozoneover the Intermountain West
4th highest annual8-h average ozone,2010-2012
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Source attribution of ozone in Intermountain West
NA background ≡ simulation with no anthropogenic sources in N America
2006Most ozone is from non US sources, including ~10 ppb intercontinental pollution
Zhang et al. [2014]
Stratosphericintrusion
using the GEOS-Chem global 3-D chemical transport model
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North American ozone background over the US
4th highest annual North American background ozone (GEOS-Chem model)
Zhang et al. [2011]
defined as the surface ozone concentrations that would be present in the absence of North American anthropogenic emissions
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Ozone trends in remote air at northern mid-latitudes
D.D. Parrish, NOAA
Cause of increase is not clear. Asian emissions? Ships? Aircraft? Wildfires? Increasing transport from stratosphere?
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A global view of air pollution enabled by satellites
http://disc.sci.gsfc.nasa.gov/giovanni
OMI NO22013
1015 molecules cm-2
Aura observations have provided unprecedented detail, coverage, precision
http://disc.sci.gsfc.nasa.gov/giovanni
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A global view of air pollution enabled by satellites
Verstraeten et al. [2014]
OMI NO22013
1015 molecules cm-2 s-1
Aura observations have provided unprecedented detail, coverage, precision
OMI NO2 trend2005-2010
fractional change
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Rising surface ozone pollution in China
D.D. Parrish, NOAA
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INTERCONTINENTAL OZONE POLLUTION INFLUENCES
Surface O3enhancements from North American anthropogenic emissions
from European anthropogenic emissions
from Asian anthropogenic emissions
Lin Zhang, Harvard
GEOS-Chem model results for 2006
12. Ozone pollutionThe industrial revolution and air pollutionLONDON FOGLos Angeles smogAIR POLLUTION IN THE US TODAY:�Ozone and fine particulate matter (PM2.5) are the major pollutantsSlide Number 64th-highest annual maximum of daily 8-h average ozone,�2010-2012OZONE CONCENTRATIONS vs. NOx AND VOC EMISSIONS�Air pollution model calculation for a typical urban airshed1970-2003 TREND OF U.S. EMISSIONSDominant VOC is biogenic isoprene Slide Number 11Slide Number 12Trend in 95th percentile daytime ozone, 1990-2010Ozone production efficiency (OPE) per unit NOx emittedIntermountain West: high plateau, deep boundary layer mixing�→ downwelling of ozone from the middle troposphereSource attribution of ozone in Intermountain WestNorth American ozone background over the USOzone trends in remote air at northern mid-latitudesA global view of air pollution enabled by satellitesA global view of air pollution enabled by satellitesRising surface ozone pollution in ChinaINTERCONTINENTAL OZONE POLLUTION INFLUENCES