Unit 3: ATMOSPHERE & AIR POLLUTION

REVIEW: WEATHER VS CLIMATE

Weather

• Conditions in the atmosphere at a given place and time

​

• Includes temperature, atmospheric pressure, precipitation, cloudiness, humidity, and wind

​

• Can vary hour to hour and day to day

Climate / Biomes BIG THREE

• Weather patterns occur slowly, over hundreds or thousands of years
• Determined by
• Earth’s distance from sun;
• Latitude: its tilt relative to its rotational axis;
• Proximity to large bodies of water and landmasses
• Elevation

​

• Organisms in a given area have adapted to these factors

Coriolis Effect?

Earth.nulllschool.net: https://earth.nullschool.net/

​

The Coriolis effect:

Winds and ocean currents are deflected to the right in the Northern Hemisphere and to the left in the Southern Hemisphere

Global Wind Patterns

Ferrell, Polar, & Hadley Cells

​

​

​

Where else have you seen convection currents?

Orogenic Precipitation

Space to Atmosphere

RADIATIVE FORCING

The capacity to retain heat in the Earth’s atmosphere

Enhanced Greenhouse Effect

Ozone Depletion in the Stratosphere

Without the ozone layer, Earth would be uninhabitable

A computer-generated image of part of the Southern Hemisphere, taken in September 2012, reveals ozone thinning (the purple area over Antarctica).

The Atmosphere

• Atmosphere
• Gaseous envelope surrounding Earth
• Composed of:
• 78% nitrogen
• 21% oxygen
• 0.04% carbon dioxide
• 0.93% argon
• 0.03% other gases
• Water vapor and trace amounts of air pollutants
• The atmosphere becomes less dense as it extends outward into space

This image of the atmosphere was taken from space; the thin blue layer that separates the planet from the blackness of space is the atmosphere

Notice how temp and pressure change with elevation

AIR POLLUTION

• Air pollution
• Primary air pollutants:
• Carbon oxides
• Nitrogen oxides
• Sulfur dioxide
• Particulate matter
• Hydrocarbons
• Secondary air pollutants:
• Ozone
• Sulfur trioxide
• Some acids

Types and Sources of Air Pollution

AIR POLLUTION TYPES

​

• Primary air pollutants
• Harmful chemicals that are released directly from a source into the atmosphere
• Secondary air pollutants
• Chemicals that form in the atmosphere when primary air pollutants react chemically with one another or with natural components of the atmosphere

Nitrogen oxides (NOx)

• Gases produced when N and O interact during combustion
• Aggravate asthma
• Involved in the production of photochemical smog and acid deposition
• Associated with global warming and ozone depletion in the stratosphere
• Corrode metals

​

Sulfur oxides

• Result from chemical interaction of S and O
• Major role in acid deposition
• Damage stone, corrode metals
• Respiratory tract irritant

Major Classes of Air Pollutants

Carbon oxides

• Carbon monoxide (CO) poisonous
• Colorless, odorless, tasteless
• Reduces the blood’s ability to carry oxygen
• Carbon dioxide (CO2) associated with climate change

Hydrocarbons

• Diverse group of organic compounds
• Variety of health effects, depending on the individual chemical
• Many are respiratory tract irritants and carcinogenic
• Most contribute to photochemical smog
• Methane linked to global warming

Major Classes of Air Pollutants

Ozone

• Stratospheric ozone essential to protect Earth’s surface from high levels of UV radiation
• Ground-level (tropospheric) ozone considered a pollutant
• Photochemical smog
• Respiratory irritant
• Contributes to plant and forest decline

​

Hazardous air pollutants (HAPs) (air toxics)

• Chlorine, formaldehyde, etc.
• Health risks to people who live and work around chemical factories and incinerators

Major Classes of Air Pollutants

Particulate matter

• Dusts and mists, solid and liquid particles suspended in the atmosphere

​

• Includes soil particles, soot, lead, asbestos, microorganisms, and sulfuric acid droplets

​

• Some particulate matter has toxic or carcinogenic effects

​

• Can corrode metals and erode buildings

​

• Scatters and absorbs sunlight

​

• Microscopic particles more dangerous than larger particles since they are inhale more deeply into lungs

Major Classes of Air Pollutants

Sources of Outdoor Air Pollution

The two main human sources of primary air pollutants are:

• Transportation (mobile sources)
• Cars, trucks, construction equipment
• Power plants (stationary sources)
• Burning coal responsible for most of these emissions
• Top three industrial sources are chemical, metal, and paper industries
• Agricultural forest burning activities also significant around the world

Effects of Air Pollution

• Injures organisms
• Reduces visibility
• Harms the respiratory tract, and can worsen existing medical conditions

• Low level exposure leads to eye irritation and respiratory tract inflammation
• Suppresses the immune system
• May lead to development of chronic respiratory disease
• Emphysema
• Chronic Bronchitis

Effects of Air Pollution

• Corrodes materials
• Metals, plastics, rubber, fabrics
• Reduces crop productivity
• Involved in acid deposition, global warming, and stratospheric ozone depletion

Controlling Air Pollutants

Electrostatic precipitator. In an electrostatic precipitator, the electrode imparts a negative charge to particulates in the dirty gas. These particles are attracted to the positively charged precipitator wall and then fall off into the collector.

Uncontrolled emissions. Industrial stacks without emission control devices can release substantial amounts of particulate matter and other pollutants.

Stacks with emission controls. Effective emission control devices can reduce particulate matter and other pollutants.

The Clean Air Act

• Clean Air Act (CAA)
• First passed in 1970 and since amended in 1977 and 1990
• Enforced by the Environmental Protection Agency (EPA)
• The EPA focuses on six air pollutants
• Lead,
• Particulate matter
• Sulfur dioxide
• Carbon monoxide
• Nitrogen oxides
• Ozone

EXCELLENT VIDEO ON AIR QUALITY (9:00) https://www.youtube.com/watch?v=W6PsasnqEZg

​

Indoor Air Pollution

• In developed countries, the most common indoor air contaminants are radon, cigarette smoke, CO, NO₂, formaldehyde, pesticides, cleaning agents, ozone, and asbestos
• Viruses, bacteria, fungi, dust mites, pollen, and other organisms, are frequently found in ventilation ducts
• Sick building syndrome
• Eye irritation, nausea, headaches, respiratory infections, depression, and fatigue caused by indoor air pollution
• The Labor Department estimates that more than 20 million employees are exposed to health risks from indoor air pollution

Indoor Air Pollution

Homes may contain higher levels of air pollutants than outside air, even near polluted industrial sites.

AIR QUALITY LAB!