AIR

• According to a study conducted at The Center for Ecology and Hydrology in Great Britain, living in a major city places people at a higher risk of having a heart ailment than living in the radioactive zone in Chernobyl.

• We breathe about 2 gallons of air every minute. Thus, a typical human lifespan can be reduced by 1-2 years from inhaling polluted air.

Air Pollution• Intro video• The Asian Brown Cloud-lots of particulates from cars, coal burning and dust, smoke and ash from drought and the clearing and burning of forests from planting crops-the cloud travels-about 25% of particulates, 77% of black carbon and 33% of toxic mercury in skies above LA can be traced to China.

Did You Know….??

• Air pollution caused by human activities, including industrial and energy production, the burning of fossil fuels and increased use of certain types of transport, causes serious health problems for hundreds of thousands of people every year.

• Environmental damage such as acidification, eutrophication, tropospheric (ground-level) ozone and reduced air quality, especially in urban areas, can be a local as well as a transboundary problem as air pollutants are transported in the atmosphere and harm human health and the environment elsewhere.

What about air pollution?

• What is in air?• How are pollutants classified?• What are the pollutants we are most

concerned about?• How do pollutants get in our air?• How can we reduce pollution?• What is indoor pollution?• how can we reduce indoor pollution?

What is in Air?

Clean air Polluted air• Harmful substances

can be solids, liquids or gases.

• Can be brown or grey.

• Breathing can be difficult

• Nitrogen gas• Oxygen gas• Small amounts of

argon, CO2 and water vapor

• Air is clear• Breathing is easy

POLLUTANTS• Can come from natural sources such as volcanoes and

dust/pollen from wind• But, most are the result of human activities

(anthropogenic).• Primary pollutants- a pollutant that is put directly into

the air by human activity such as soot from smoke.• Secondary pollutants are formed when primary

pollutants come in contact with other primary pollutants or water vapor and a chemical reaction takes place. An example is ozone that is created when emissions from cars react with UV rays from the sun and then stay in the atmosphere.

Pollutants mix in the air to form industrial smog, mostly the result of burning coal, and photochemical smog, caused by motor vehicle, industrial, and power plant emissions.

What Are the Major Outdoor Air Pollutants?

1. Carbon monoxide (CO)

2. Nitrogen oxides (NO) and nitric acid (HNO3)

3. Sulfur dioxide (SO2) and sulfuric acid (H2SO4)

4. Particulate matter - Suspended particulate matter (SPM)

5. VOCs (volatile organic compounds)- organic chemicals that vaporize easily to produce toxic fumes

6. Lead

• Most air pollution in urban areas comes from motor vehicles and industry.

Some natural pollution particulates come from volcanoes, sea spray, and flower pollen

Over 1/3 of our air pollution comes from …

• CARS! Auto emissions have effects on our air.

• The main emissions of a car engine are:• Nitrogen gas (N2) - Air is 78-percent nitrogen

gas, and most of this passes right through the car engine.

• Carbon dioxide (CO2) - This is one product of combustion. The carbon in the fuel bonds with the oxygen in the air.

• Water vapor (H2O) - This is another product of combustion. The hydrogen in the fuel bonds with the oxygen in the air.

• These emissions are mostly harmless, although carbon dioxide emissions are believed to contribute to global warming.

• Because the combustion process is never perfect, some smaller amounts of more harmful emissions are also produced in car engines.

• Catalytic converters are designed to reduce all three:

• Carbon monoxide (CO) is a poisonous gas that is colorless and odorless.

• Hydrocarbons or volatile organic compounds (VOCs) are a major component of smog produced mostly from evaporated, unburned fuel.

• Nitrogen oxides (NO and NO2, together called NOx) are a contributor to smog and acid rain, which also causes irritation to human mucus membranes.

The Clean Air Act - 1970

• Gave the EPA the authority to regulate automobile emissions.

• Required the gradual elimination of lead in gasoline and a decrease in auto emissions

• Catalytic converters help reduce auto emissions

The Catalytic Converter• Works by causing a chemical reaction that

turns exhaust emissions into less harmful substances

• 2NO → N2 + O2

• 2CO + O2 → 2CO2

How Can We Reduce Harmful Car Emissions

• Drive less• Drive vehicles that use alternative energy

sources such as EV, hybrids, ethanol …

Industrial Air Pollution

• Most industries and power plants use fossil fuels for energy. This burning releases large amounts of oxides into the air such as CO2, SO2 and NOx

• Manufacturers of electronic products contribute to VOCs from solvents used to clean circuit boards and other parts.

• The Clean Air Act requires industries to use scrubbers or other air pollution devices.

How do scrubbers work?

• Moves gases through a spray of water that dissolves many pollutants.

• Electrostatic precipitators – remove particulates by creating an electric charge which attracts these larger particles

Thermal Inversion

Thermal Inversions• When warmer air ends up above a layer of cold air. The warm

air traps the cold air below from rising.• They occur most often when a warm, less dense air mass moves

over a dense, cold air mass. • This can happen when the air near the ground rapidly loses its

heat on a clear night. In this situation, the ground becomes cooled quickly while the air above it retains the heat the ground was holding during the day.

• Temperature inversions also occur in some coastal areas because upwelling of cold water can decrease surface air temperature and the cold air mass stays under warmer ones.

• Topography can also play a role in creating a temperature inversion when cold air flows from mountain peaks into valleys. This cold air then pushes under the warmer air rising from the valley, creating the inversion.

SMOG (brown air smog)

• When smoke and fog reduce visibility• Smog results from chemical reactions

involving sunlight, NOx and hydrocarbons• Automobiles and industries are the main

causes• Cities that experience the most smog have

dense traffic and are in dry, sunny areas, such as LA, Denver and Mexico City

WHAT DO YOU REMEMBER???

• Name the major air pollutants.• What is the difference between primary and

secondary pollutants?• Name 2 examples of natural pollution and 2

examples of man made. (anthropogenic)• What are the different sources of industrial

pollution and photochemical smog?

Air Pollution Effects on Human Health

• Chronic Bronchitis and Asthma (worsened)• Emphysema and Lung Cancer• Air pollutants aggravate respiratory diseases.• Heart attacks and strokes• The young and old are most affected.

• The London Smog in 1952- 4000 people died in only a few days.

Indoor Air Pollution

• Many people spend as much as 90% of their days indoors.

• Buildings with very poor air quality are said to have sick-building syndrome.

Some Important Indoor Air Pollutants

The most threatening indoor air pollutants are smoke and soot from wood and coal cooking fires (a hazard found mostly in developing countries) and chemicals used in building materials and products.

Common indoor air pollutants include: • second-hand tobacco smoke; • airborne mold and mildew; • pet dander; • lead-impregnated dust from old paint and some vinyl mini blinds; • cockroach shedding; • Dust mite particles; • combustion gases released by stoves, heaters, candles and fireplaces; and • chemicals released by

– dry cleaned clothes; – cleaning products; – room deodorizers; – office supplies; – carpets; – paints and sealers; – new furniture and pressed wood; – personal care products; and – pesticides

To reduce the levels of indoor air pollution you can: • never allow smoking indoors; • use less toxic cleaning products; • make certain that the indoor space is properly ventilated; • reduce levels of cockroach and dust mite particles; • reduce pet dander; • avoid or minimize use of pesticides indoors; • use low toxicity paints, sealers and caulks; • reduce the use of solvent-based dry cleaning and/or air out

dry-cleaned clothes thoroughly before bringing into one's home;

• avoid idling an internal combustion engine, such as a car, lawn mower or fork lift, in an enclosed space or near the entrance to one's home or workplace; and

• change air filters frequently.• OPEN WINDOWS

To reduce the levels of indoor air pollution you can: • never allow smoking indoors; • use less toxic cleaning products; • make certain that the indoor space is properly ventilated; • reduce levels of cockroach and dust mite particles; • reduce pet dander; • avoid or minimize use of pesticides indoors; • use low toxicity paints, sealers and caulks; • reduce the use of solvent-based dry cleaning and/or air out

dry-cleaned clothes thoroughly before bringing into one's home;

• avoid idling an internal combustion engine, such as a car, lawn mower or fork lift, in an enclosed space or near the entrance to one's home or workplace; and

• change air filters frequently.• OPEN WINDOWS

Radon Gas

• An invisible, odorless, tasteless gas that is radioactive• Radon is one of the elements produced when

uranium decays. Uranium is found naturally in the earth and is most concentrated in porous soils overlying rocks that contain uranium.

• Radon gas can enter homes and stick to dust particles which can then be breathed in.

• The radon decay releases alpha particles which can lead to cancer

ASBESTOS

• Fibers containing silica are used to reinforce cement, to make brake linings, residential siding, garments to protect fire fighters, and in insulation.

• Used because the silica is strong and is heat resistant.• If these fibers get in the lungs, they can cut and scar

them causing asbestosis. Victims have a hard time breathing and often die of heart failure. Mesothelioma is an aggressive cancer of the cells that surround organs such as the heart and lungs.

• Name 3 indoor pollutants.• Name the source and effects of asbestos and

radon?• Name 5 indoor pollutants• Name 5 ways to reduce indoor pollutants

Coming next….• ACID RAIN• GREENHOUSE GASES, GLOBAL

WARMING• THE OZONE SHIELD