ACID DEPOSITION AND FOREST
ECOSYSTEMS
Chapter 3.11
Acid Deposition
Technology is great but it also contributes
to acid deposition.
 Coal-burning plants, cars, and trucks,
metal smelters, and oil refineries provide
energy, transport, and materials for the
industrial world, but at the same time
produce oxides of sulfur and nitrogen,
among the most dangerous of air
pollutants.

The Problem of Combustion
Sulfur dioxide (SO2) and Nitrogen oxides
(NOx) are released into the atmosphere by
burning fossil fuels.
 Sulfur and Nitrogen enter the atmosphere
they may combine with water droplets to
form acids.
 The acids return to the surface of the
Earth in the form of snow or rain, called
ACID PRECIPITATION.
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ACID PRECIPITATION KILLS:
Fish
Soil Bacteria
Aquatic Plants
Terrestrial Plants
The sulfur and nitrogen oxides released
from tailpipes and smokestacks do not
always enter the water cycle in the
atmosphere.
Sulfur and nitrogen compounds may
remain airborne and settle out in the dry
state – DRY DEPOSITION
 Dry Deposition enter the water cycle and
form acid as it combines with moisture

CAN BE FOUND:
 Dew on lawns
 Surface of lakes
 Water inside your respiratory tract
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THE EFFECTS OF ACID
PRECIPITATION

Direct effects on Humans:

Medical effects
 Accelerated

respiratory problems
Examples: Asthma, bronchitis
 Cause
eyes to water
 Irritate skin
Dissolving marble statues
 Corroding metal
 Dulling car finishes
 Damage to buildings

Effects on Ecosystems
Damage to leaves
 Damaged to tissues of trees become more
susceptible to fungal or bacterial
infections.
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EFFECTS OF ACID RAIN

Acid
Acidfalls
FallstotoSoil
Soil
Kills Bacteria
Promotes growth
of Moss
Reduces Nutrients in
Trees
Releases Aluminum
in the soil
Damage
tree Roots
pH – Potential Hydrogen
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A measure of the acidity or alkalinity (basic) in
the solution
Measured using pH meter
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pH is a scale from 0 – 14 where:
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0 – 6.9 = Acidic
7.0
= neutral
7.1-14 = Basic
More Acidic
More Basic
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

A pH of 3 is 10 times more acidic than pH of 4

pH of Normal rain water
 pH

of 5.6
pH of Acid Rain
 Range
from 4.5 to 5.6; average 5.0

pH corresponds to the
concentration of Hydrogen
Ie. Low pH = high H
HOMEWORK
Read page 116 -118
 Fill in handout
 Answer Questions #1-4 page 118
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