Acid Deposition and Forest EcosystemsChapter 3.11

Acid Deposition• Video to intro acid deposition

Acid Deposition• The advancement of technology in our world

benefits us in many ways. Examples are coal burning plants, cars and trucks, metal smelters, and oil refineries which provide us with energy, transport, and materials for the industrial world

• Almost all of the electricity that powers modern life comes from burning fossil fuels

• At the same time, these technologies contribute to acid deposition by producing dangerous air pollutants

The Problem with Combustion of Fossil Fuels

• When we burn fossil fuels such as coal, natural gas or oil we end up with sulfur dioxide (SO2) and nitrogen oxides (NOx) being released into the atmosphere

• In the atmosphere, these gases combine with water droplets to form acids such as sulfuric acid and nitric acid

• These water droplets return to the surface of the Earth in the form of rain or snow, and we call this ACID PRECIPITATION

• Acid Precipitation Kills:•Fish•Bacteria in the soil•Aquatic plants•Terrestrial plants

• The sulfur and nitrogen oxides released from tailpipes and smokestacks don’t always enter the water cycle in the atmosphere

• Sulfur and Nitrogen compounds may remain airborne and settle out in the dry state, we call this DRY DEPOSITION

• Dry Deposition enters the water cycle and forms acids as it combines with moisture somewhere other than up in the atmosphere

• It can be found:• In dew on lawns•On the surface of lakes• In water inside your respiratory tract

Effects of Acid Precipitation1. Direct Effects on Humans:

i. Accelerated Respiratory problems (ie Asthma, Bronchitis)

ii. Causes eyes to wateriii. Irritates skin

2. Dissolving Marble Statues3. Corroding Metal4. Dulling Car Finishes5. Damage to Buildings

Effects of Acid Precipitation on Ecosystems• Damages to leaves• Damage to the tissues of trees which then

become more susceptible to fungal or bacterial infections

• http://www.youtube.com/watch?v=MqHw1hMEkAQ&list=PL1296CAFC988AD934

What Can Society do about Acid Precipitation?

• Clean up smokestacks and exhaust pipes (ex: use of scrubbers)

• Use alternative energy sources. Instead of using fossil fuels use hydropower, wind energy, solar power, or geothermal energy

• Work to restore damaged environments (ex: Liming)

• Take action as individuals (turn off lights, use energy efficient appliances, insulate your home well to use less energy for heating etc)

pH – Potential Hydrogen• A measure of the acidity or alkalinity of a

solution (how acidic or basic a solution is)• Measured using a pH meter• This is a scale from 0 – 14 where:• 0 – 6.9 = Acidic• 7.0 = Neutral• 7.1 – 14 = Basic

• A pH of 3 is ten times more acidic than a pH of 4

Questions1. A pH of 2 is how many times more acidic

than a pH of 5? 2. A pH of 10 is how many times more basic

than a pH of 8?3. Is a pH of 14 more acidic or more basic

than a pH of 11?4. Describe a pH of 1 in relation to a pH of 3.5. Describe a pH of 13 in relation to a pH of

10.

• pH of normal rain water•pH 5.6

• pH of Acid Rain•Range from 4.5 to 5.6, average is 5.0