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Chapter 19:
Air Pollution and Noise
Living and Working in a Healthy Environment
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Image from www.collegesherbrooke.qc.ca/~graphycs/martinaube.html
Sources of air pollution
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Sources of air pollutionEmissions
Anthropogenic (manmade): Fossil fuel combustion, biomass burning, industrial processes, etc.
Biogenic: Emissions from vegetation, soil, wildlife, forest fires, etc.
Other natural: Volcanos, lightning, sea salt, meteors, windblown dust, etc.
Photochemical production from other compounds in atmosphere (“secondary source”)
Transport: If considering only troposphere, then transport from stratosphere is a source
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NO
NO2
HO2
OH
CO2, etc.
CO, VOC
O3
Primary & secondary pollutants
Primary(e.g., lead)
Secondary
VOC NOx O3
Primary: Emitted directly to the atmosphereSecondary: Forms in the atmosphere
Sources of the 5 major pollutants in the U.S
Note: Historically, the 6th Major Pollutant was lead.
Source and Composition of Particulates
sulfates, ash
sea salt
meteoritic material
Soot, NOx, VOCs
Soot, organic
soot
methane, ammonia
soot
Soot, sulfates, VOCs
Minerals, clays
Emission events (Nov. 18, 2008)Textruve Plant on 2001 Sheldon Road (Channelview, TX)
Picture taken at 4:00 pm from 20 miles awayPicture taken at 6:00 pm on site
Impacts: Ozone and PM2.5 Non-Attainment
Source: U.S. EPAU.S. EPA, 2006
2002 2003 2004 2005 2006 20070
50
100
150
200
250
2002 2003 2004 2005 2006 20070
10
20
30
40
50
Year
PM
2.5 a
nnua
l ave
rage
con
c. (g
/m3)
Annual average
NAAQS (15 g/m3)
Ma
xim
um
PM
2.5 c
on
cen
tra
tion
(g
/m3 )
24hour NAAQS (35 g/m3)
Very close to non-attainment
Fine PM levels in Clinton Drive (Houston, TX)
Let’s consider those compounds that the Federal Government regulates National Ambient Air Quality Standards (NAAQS)
Secondary(1300
µg/m3)0.50 ppm3-hour Average
Primary(365 µg/m3)0.14 ppm24-hour Average
Primary(80 µg/m3)0.03 ppmAnnual Arithmetic Mean
Sulfur Dioxide (SO2)
Primary & Secondary65 µg/m324-hour Average **
Primary & Secondary15 µg/m3Annual Arithmetic Mean **
Particulate (PM 2.5) Particles with diameters of 2.5 micrometers or less
Primary & Secondary150 µg/m324-hour Average
Primary & Secondary50 µg/m3Annual Arithmetic Mean
Particulate (PM 10) Particles with diameters of 10 micrometers or less
Primary & Secondary1.5 µg/m3Quarterly Average
Lead (Pb)
Primary & Secondary(157 µg/m3)0.08 ppm8-hour Average **
Primary & Secondary(235 µg/m3)0.12 ppm1-hour Average
Ozone (O3)
Primary & Secondary(100 µg/m3)0.053 ppmAnnual Arithmetic Mean
Nitrogen Dioxide (NO2)
Primary(40 mg/m3)35 ppm1-hour Average
Primary(10 mg/m3)9 ppm8-hour Average
Carbon Monoxide (CO)
STANDARDTYPE
STANDARDVALUE *
POLLUTANT
Secondary(1300
µg/m3)0.50 ppm3-hour Average
Primary(365 µg/m3)0.14 ppm24-hour Average
Primary(80 µg/m3)0.03 ppmAnnual Arithmetic Mean
Sulfur Dioxide (SO2)
Primary & Secondary65 µg/m324-hour Average **
Primary & Secondary15 µg/m3Annual Arithmetic Mean **
Particulate (PM 2.5) Particles with diameters of 2.5 micrometers or less
Primary & Secondary150 µg/m324-hour Average
Primary & Secondary50 µg/m3Annual Arithmetic Mean
Particulate (PM 10) Particles with diameters of 10 micrometers or less
Primary & Secondary1.5 µg/m3Quarterly Average
Lead (Pb)
Primary & Secondary(157 µg/m3)0.08 ppm8-hour Average **
Primary & Secondary(235 µg/m3)0.12 ppm1-hour Average
Ozone (O3)
Primary & Secondary(100 µg/m3)0.053 ppmAnnual Arithmetic Mean
Nitrogen Dioxide (NO2)
Primary(40 mg/m3)35 ppm1-hour Average
Primary(10 mg/m3)9 ppm8-hour Average
Carbon Monoxide (CO)
STANDARDTYPE
STANDARDVALUE *
POLLUTANT
Texas Air Quality
Lecture 32Texas Air Quality
http://www.airnow.gov/index.cfm?action=airnow.national
U.S. Federal Regulation of Air Pollution
Air pollution Control Act of 1955Clean Air Act of 1963Amendment to CAA - Motor Vehicle Air
pollution Control Act of 19651970 Clean Air Amendments and formation of
the EPA. 1975 catalytic converter developed.
U.S. pollution trends since 1977
Signs that regulation works!
Stratospheric ozone—The good ozone
Types of SMOG
1.Industrial London Smog – combination of smoke and fog
- At the end of the 1800’s, 40% less sunlight in London than surrounding towns
- Health effects- Vitamin D deficiency, Rickets, Tubercolosis
2. Photochemical Smog
Consists mainly of secondary pollutants: Ozone (O3), NO2, VOCs
Forms when sunlight induces chemical changes in gases and aerosols
Causes poor visibility, burning eyes, sore lungs, worsen conditions of the heart and lungs, possible mortality.
Photochemical and Industrial Smog
“LA Smog”:Brown-air smog in Los Angeles
“London Smog or Industrial Smog”Gray-air in New York City
© Dean D. Fetterolf/ShutterStock, Inc. © Chad Littlejohn/ShutterStock, Inc.
Houston Case
• Which kind of smog do you think Houston has?
• Why is Houston different from London or LA case?
• How much do you think pollution from Houston will influence College Station?
Photochemical Smog Ozone (O3) in the Troposphere
Most problematic air pollutant in many areas of the U.S.
Ozone is not directly emitted into the atmosphere, but instead forms through a complex series of reactions.
It is largely because of this complexity that ozone is so difficult to control.
Ozone chemistry(gas-phase only)
NO2 NO
O3
HO2
RO2OH
N2O5
NO3
HNO3
VOC
HONO
hn
H2Ohn H2O2
NOx and VOC sources in the Greater Houston Area
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Ozone Non-attainment: Old standard
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Ozone Non-attainment: New standard
19.2 The Effects of Climate and Topography on Air Pollution
Air pollution levels in a region are affected by a number of factors, among them:
Temperature Sunlight Wind Other climate factors
They are also affected by the topography.
FIGURE 05a: Temperature profiles: normal pattern
FIGURE 05b: Temperature profiles: temperature inversion
The Health Effects of Air Pollution
FIGURE 6: Urban air pollution and incidence of emphysema in Winnipeg and St. Louis
Effects on Plants and Nonhuman Animals
FIGURE 7:Trees killed by acid deposition in
Pisgah Nation Forest, North Carolina
© Jerry Whaley/age fotostock
Power Plant NOx Control:Staged Combustion
Low-NOx Burners: Precisely control combustion to reduce NOx
Natural gas reburn: Creates fuel-rich zone and radicals which destroy NOx
Over-fire air: Completes the combustion
Together, can reduce NOx by ~50-75% US DOE NETL
Power Plant Sulfur Dioxide Control• Initially dispersed by
tall chimneys– “Solution to pollution is
dilution”• Low sulfur coal
– Some coals (e.g., Western U.S.) contain less sulfur
• Flue Gas Desulfurization– Sorbent such as
limestone or lime is injected to remove 80-98% of SO2
– Cobenefit of reducing mercury emissions
– Byproduct can be used in wallboard, cement
– 3-7% energy penalty
Parish Power PlantUnit 8 FGD System
Power Plant NOx Control:Selective Catalytic Reduction
(SCR)Ammonia is injected after boiler to convert NOx to N2 and water Requires catalyst Specific temperature
range
~85% NOx reduction
www.de-nox.com
Automobile Emission Controls
3-way catalytic converter Reduces NOx, oxidizes CO and hydrocarbons
Oxygen sensor: Controls air-fuel ratioDiesel particulate filters and oxidation catalystsCleaner burning fuels
Unleaded gasoline: No lead emissions; preserves catalyst
Low sulfur fuels: Preserves catalyst Added oxygenates: Reduce CO
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Catalytic ConvertersA. Reduction Catalyst:
2NO N2 + O2
B. Oxidation Catalyst: 2CO + O2 2CO2
CxHy + (x+y/4)O2 xCO2 + (y/2)H2O
CO2 is dominant component of exhaust, not significantly affected by controls 19.4 lb CO2/gal gasoline; 22.2 lb/gal diesel
Diesel Particulate Filter
Volkswagen
Electrostatic Precipitator (ESP)
Suspended particles are charged by electron field
Particles travel to collection plate
Plates are rapped to make PM fall to hoppers
~99% efficiencyceenve3.civeng.calpoly.edu/cota/ENVE411-ESP.html
19.5 Noise: The Forgotten Pollutant
Sound is characterized by loudness (measured in decibels) and pitch (how high or low it is).
How Loud is Too Loud?
Prolonged exposure to any noise above 85 decibels (dB) can cause gradual hearing loss.At higher decibel levels, hearing protection is strongly recommended.100 decibels - no more than 15 minutes prolonged exposure recommended110 decibels - regular exposure of more than one minute risks permanent hearing loss without hearing protection. www.warrencenter.org/howloud.html
www.warrencenter.org/howloud.html www.warrencenter.org/howloud.html
Indoor Air Pollution
FIGURE 14: Radon protection