Air and Air Pollution

These slides are adapted from the Glencoe

Earth Systems Textbook for CCSD use only

and the EPA’s Air pollution website

What Causes Air Pollution?

▪ Reflection: List 5 things you think

cause air pollution.

What resources are in our air?

▪ Mixture of gases

– 78% nitrogen

– 21% oxygen

– 1% argon, carbon

dioxide, water vapor

Key Problems With Air

▪ Air pollution can harm human health and the

environment

▪ It can be harmful even when it is not visible

▪ Many countries have no laws in place to

protect their air

▪ Laws do not guarantee compliance

▪ Difficult if not impossible to clean once

polluted

Sources of Air Pollution

Natural sources

▪ Sand

▪ Dust storms

▪ volcanic eruptions

▪ forest fires

▪ Solar activity

Human sources

▪ burning fossil fuels

▪ factory and car

emissions,

▪ refrigerators and

air conditioners

Map of Air Pollution (red)

History Of Human Air Pollution▪ pre-1700s – burning of wood, coal,

animal dung, or other biofuels for cooking

and heat

▪ Industrial revolution (1700’s) –

widespread burning of wood and coal for

fuel

▪ Modern times – trash incineration and

modern chemicals introduced into the air

supply

How do we categorize air

pollutants?

▪ Primary = put directly

into the air by humans

▪ Secondary = when

chemicals react with

other substances in

the air to make

pollutants

Outdoor pollutants

1. Particulates, such as ash, dust, soot, plant

pollen

2. Gases – usually oxides, that are released

when fossil fuels are burned

3. Smog – ground-level ozone (O3) and particulate matter

4. Chlorofluorocarbons (CFC’s): once used in refrigerators, ac’s, aerosol cans, and the production of foams

5. Airborne Lead – still released in the US by certain factories

What kind of pollutant is smog?

Indoor Pollutants

Dangerous because of poor air circulation and the long amounts of time people spend inside

1. Cigarette smoke – deadliest of all

2. Microorganisms – bacteria and fungi from air ducts and vents

3. Radon – radioactive gas – comes from soil when radium breaks down

4. Asbestos – minerals that form in long thin fibers – banned in US

Temperature Inversions

▪ When weather conditions

create a trap for air so that

it cannot rise or circulate

▪ Prevents pollutants from

escaping into the

atmosphere

▪ Makes people more likely

to suffer from allergies

and pollution-related

conditions

Human Health Effects

▪ Carbon monoxide replaces oxygen

in the bloodstream

▪ Ozone and oxides – irritate eyes

and respiratory tract

▪ Particulates and asbestos cause

lung diseases, such as Emphysema

and Mesothelioma, lung cancer

– Lung Cancer – 150,000 deaths per year

in US

Ecosystem Effects

▪ Ozone is hazardous to plants, cause stems to be brittle and leaves spotted

▪ Air pollution destroys crops– US loses $1 billion of crops and

plants per year (Auburn University Research)

▪ Same health problems for animals as for humans

Natural Cleaning and Regulation

of Air

▪ Precipitation sticks to pollutant particles

and fall to the ground

▪ Plants and plankton remove excess

CO2 and help keep the planet cool

▪ Electric cars, hybrid cars

– Zero Emissions Vehicles – no tailpipe emissions

▪ Legislation (EPA)– Clean Air Act 1970

▪ Set federal limits on 6 primary air pollutants: particulates, ozone, sulfur dioxide, nitrogen dioxide, carbon monoxide, and lead

Requires:▪ Pollution control devices in factories, such as

scrubbers, which remove pollutants from exhaust

▪ States to create a plan to reduce air pollution and meet these standards

▪ Motor vehicle regulation to reduce exhaust pollution

Human Solutions to Air Pollution

Acid Rain

▪ Precipitation that is more acidic than normal

(anything < pH 5.6)

– Water in the atmosphere reacts with gases

released from factories

– Falls and builds up in lakes

▪ Canada-US Air Quality Agreement in 1991

– Agreed to:

▪ Reduce SO2 and NOx emissions

▪ Collaborate on acid-rain scientific research

▪ Share new technologies that reduce human-caused

acid rain

Noise Pollution

▪ Any unwanted sound

▪ Airplanes, machinery, loud concerts, etc.

▪ Sound measured in decibels – 70-80 dB = annoyance, hearing

loss

– 120 – 130 dB = physical pain and hearing damage

▪ Noise Control Act 1972 – sets standards for maximum noise levels in workplace

Light Pollution

▪ Not a direct health

hazard but

environmental

hazard

When lights are pointed upward (billboards, buildings),

blocking the night sky

Poor quality street lights can be upgraded

Lights can be put on timers