Chapter 19: Air Pollution and Noise

Living and Working in a Healthy Environment

Sources of air pollution

Image from www.collegesherbrooke.qc.ca/~graphycs/martinaube.html

2

Sources of air pollution

 Emissions  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 3

Primary & secondary pollutants

CO 2 , etc.

CO, VOC VOC HO 2 OH NO NO 2 NO x O 3 Secondary O 3 Primary (e.g., lead) Primary: Emitted directly to the atmosphere Secondary: Forms in the atmosphere 4

Sources of the 5 major pollutants in the U.S Note: Historically, the 6 th Major Pollutant was lead.

Source and Composition of Particulates

meteoritic material Soot, sulfates, VOCs soot Soot, NOx, VOCs sea salt methane, ammonia Soot, organic Minerals, clays soot sulfates, ash

Emission events (Nov. 18, 2008) Textruve Plant on 2001 Sheldon Road (Channelview, TX)

Picture taken at 6:00 pm on site Picture taken at 4:00 pm from 20 miles away

Impacts: Ozone and PM2.5 Non-Attainment

Fine PM levels in Clinton Drive (Houston, TX)

50 40 30 250 200 150 100 50 24hour NAAQS (35  g/m 3 ) 0 2002 2003 2004 2005 2006 2007 Annual average NAAQS (15  g/m 3 ) 20 10 0 2002 2007 2003 2004 2005 2006 Year Very close to non-attainment

Texas Air Quality

Let’s consider those compounds that the Federal Government regulates  Quality Standards (NAAQS) National Ambient Air

STANDARD VALUE * STANDARD TYPE

(10 mg/m 3 ) (40 mg/m 3 )

Nitrogen Dioxide (NO 2 )

(100 µg/m 3 )

Ozone (O 3 )

(235 µg/m 3 ) (157 µg/m 3 ) 1.5 µg/m 3 50 µg/m 3 150 µg/m 3 15 µg/m 3 65 µg/m 3

Sulfur Dioxide (SO 2 )

(80 µg/m 3 ) (365 µg/m 3 ) µg/m 3 )

Lecture 32

Texas Air Quality

http://www.airnow.gov/index.cfm?action=airnow.national

U.S. Federal Regulation of Air Pollution

 Air pollution Control Act of 1955  Clean Air Act of 1963  Amendment to CAA - Motor Vehicle Air pollution Control Act of 1965  1970 Clean Air Amendments and formation of the EPA.  1975 catalytic converter developed.

Signs that regulation works!

U.S. pollution trends since 1977

Stratospheric ozone—The good ozone

Types of SMOG

-

1.

Industrial London Smog

smoke and fog – combination of 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 (O 3 ), NO 2 , 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

“London Smog or Industrial Smog” Gray-air in New York City “LA Smog”: Brown-air smog in Los Angeles © 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 (O 3 ) 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) N 2 O 5 h n NO 3 H 2 O h n HNO 3 NO 2 OH VOC NO HO 2 RO 2 O 3 H 2 O 2 HONO

NOx and VOC sources in the Greater Houston Area

Ozone Non-attainment: Old standard

26

Ozone Non-attainment: New standard

27

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 NO

x

Control: Staged Combustion

 Low-NO x Burners: Precisely control combustion to reduce NO x  Natural gas reburn: Creates fuel-rich zone and radicals which destroy NO x  Over-fire air: Completes the combustion  Together, can reduce NO x 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 SO 2 – Cobenefit of reducing mercury emissions – Byproduct can be used in wallboard, cement – 3-7% energy penalty Parish Power Plant Unit 8 FGD System

Power Plant NO

x

Control: Selective Catalytic Reduction

 Ammonia is injected

(SCR)

after boiler to convert NO x  to N 2 and water Requires catalyst  Specific temperature range  ~85% NO x reduction www.de-nox.com

Automobile Emission Controls

 3-way catalytic converter  Reduces NO x , oxidizes CO and hydrocarbons  Oxygen sensor: Controls air-fuel ratio  Diesel particulate filters and oxidation catalysts  Cleaner burning fuels  Unleaded gasoline: No lead emissions; preserves catalyst  Low sulfur fuels: Preserves catalyst  Added oxygenates: Reduce CO

Catalytic Converters

 A. Reduction Catalyst:  2NO  N 2 + O 2  B. Oxidation Catalyst:   2CO + O C x H y 2  2CO 2 + (x+y/4)O 2  xCO 2 + (y/2)H 2 O  CO 2 is dominant component of exhaust, not significantly affected by controls  19.4 lb CO 2 /gal gasoline; 22.2 lb/gal diesel 37

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% efficiency ceenve3.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 recommended

110 decibels

- regular exposure of more than one minute risks permanent hearing loss without hearing protection.

www.warrencenter.org/howloud.html

Indoor Air Pollution

FIGURE 14: Radon protection