Meteorology 1010

Air Pollution and Climate Change

Chapters 13-14

Preparation for Quiz #4 is based on the class textbook, summarized across chapters 11-15

Lutgens • TarbuckLectures by:Heather Gallacher,Cleveland State University

Copyright © 2013 Pearson Education, Inc.

Climate and Weather

Weather = short periods of time.

Climate = a long period of time.

Climate zones Defined using Koeppen System

Uses monthly average temperature and precipitation

What information is provided in a climograph?

Climographs - Annual Temperature and Precipitation

Notice that in the southern hemisphere June and July are coldest months.Notice that in the northern hemisphere

June and July are warmest months.

Notice that some places have a DRY season.

The United States exhibits all of the major world climate zones

E = Polar

D = severe continental

C = mild

B = dry

A = tropical

H = mountains

C mild Marine West Coast

C mild coastal

Mediterranean

ATropical

Allred’s climate zone summary for the United States

B cold

B hot

D cold-wet

Cwarmwet

E Polar

H mountains are mostly in the western

United States

Hawaii also has tropical “A”

Atmospheric Conditions

Permanent gases

Variable gasesGases whose proportions

CO2 is now above 400 ppm

Water is key to everything else.

Permanent Gases

Nitrogen, oxygen, and argon

About 99% of the atmosphere

Relatively unimportant to atmospheric dynamics

Permanent Gases

Nitrogen in the air is mostly inert. However, if you put energy into making nitrogen compounds, you can get that energy back later:

FertilizerRocket fuel Explosives

Oxygen is largely inert until it ‘oxidizes’ other elements and compounds, creating powerful, variable atmospheric gases.

Humans create far more variable gases than nature needs to maintain earth stability.

Oxygen is also relatively inert as an atmospheric component.

However, oxidation combines oxygen with carbon, nitrogen and many other elements to produce molecules that are complex, reactive and important.

Are combustion, fire and explosion forms of oxidation? <Yes.>

Consider the variable gases that result.Next page

Variable Gases – Carbon Dioxide (CO2)

Extremely important, but still only about 400 parts per million in the air

Released naturally by volcanic activity, plant and animal respiration, decay of organic material.

Released unnaturally by anthro (human) processes.

Don’t forget the carbon monoxide also results from combustion and is a genuine poison.

Variable Gases – Carbon Dioxide (CO2),

Anthropogenic (human) sources Burning of fossil fuels increases CO2 . Deforestation means that excess CO2 not removed.

Atmospheric levels are increasing by 2 ppm per year.

Soil and oceans may be reaching their limits in how much CO2 they can absorb.

Let’s look at variable gases – starting with water vapor

Water processes are a solar energy function

Water vapor is humidity created by evaporation

Storing energy in the atmosphere as vapor is an efficient way to move energy and provoke vast earth changes and life processes.

Storing heat as water vapor is also a source of energy for violent storms.

.

Ice contains substantial heat energy.

Water vapor contains dangerous

amounts of latent heat

Liquid water contains a lot more heat

Variable Gases – Ozone O3

Forms when atomic oxygen (O) collides with oxygen molecule (O2) – ozone is produced by collision with incoming ultraviolet solar energy.

Mostly found in stratosphere

Acts as a shield for ultraviolet light and is essential to life on earth

Chlorofluorocarbons (CFCs) partially destroyed ozone shield Increases skin cancer, cataracts, caused local crop failures

Ozone is also created by sunlight interacting with oxides of nitrogen and sulfur.

True or False?

1. If human activity can reduce the earth’s ‘ozone layer’ then doing so should help make the surface of the earth warmer.

2. A small increase in ocean temperature represents a vast increase in energy.

3. A small change in atmospheric gases can warm the atmosphere and the ocean beneath.

Consider current Salt Lake area news: The Stericycle company uses high heat to kill pathogens in medical waste.Neighbors want the waste management plant shut down.

Questions:

1. Does burning waste contribute to climate-changing greenhouse gases?

<yes>

2. Can the process simply fail at times -- releasing excess air pollution?

<yes>

3. Does high heat reduce halogens (chlorine, fluorine, bromine-based chemicals), heavy metals and other toxins, such as radio-active isotopes?

<many toxic substances are not destroyed by fire>

4. If Uv and Ozone are dangerous, then can they be used to sterilize food and kill germs.

<Yes. But in the meantime, they can also kill or sterilize humans .>

Variable Gases – Methane (CH4) Primary constituent of natural gas

Occurs naturally from bacterial decay, intestinal tracks of termites, cows, and sheep

Anthropogenic sources: coal mines, oil wells, leaking natural gas pipelines, rice cultivation, landfills, and livestock

Levels have doubled since 1700 and is a significant contributor to warming

Methane is more than 20 times per unit more powerful than CO2 as a ‘greenhouse’ gas.

Variable Gases – Oxides of Nitrogen (N2O, NO2, NO, etc.)

Nature makes some oxides of nitrogen through wildfires, ocean waves and soil building.

Human sources include fertilizers and burning fossil fuels.

Contributes to atmospheric warming.

N2O is also “laughing gas” at the dentist’s office and dragster racing fuel.

Variable Gases – Halocarbons

Include man-made CFCs

Used in industrial processes, fire fighting, and as fumigants, refrigerants, and propellants

Contribute to warming in troposphere and ozone depletion in stratosphere

Halocarbons are extremely useful, inexpensive and not particularly toxic when in appropriate use. Replacements are less competent and cost more.

Aerosols (microscopic particles including ice)

Provide surfaces that help water vapor condense back to liquid – rain/snow may not occur without a place to go.

Associated with air pollution

Natural sources: desert dust, wildfires, sea spray, and volcanoes

Human sources: burning of forests and fossil fuels

Aerosols can be dense enough to cool the earth by screening out solar energy.

Aerosols

During a drought “rain makers” might throw dust in the air to provide ‘condensation nuclei’ <a surface on which vapor can condense and form liquid drops or ice growth>

How does that process compare to what your car is doing right now in the parking lot? <a dirty car could be cooler>

On “911” when airliners were grounded, the absence of vapor contrails allowed the earth to warm-up by about one degree. <fewer clouds, more insolation, more heat>

Rain sometimes occurs after bomb blasts and fires put dust and smoke into the air.

Montreal Protocol (banned CFCs – ozone layer is slowly repairing itself)

Kyoto Protocol(tries to limit CO2 but has not been fully ratified CO2 is still increasing in the atmosphere)

Structure of Atmosphere

Stratosphere – dry, layering by temperature and gases

Troposphere – mixing region: wet, stormy, warm, windy, dusty

Upper atmosphere is almost empty – objects can become extremely hot from solar rays

Mid-latitudes have:

- the world’s most violent storms

- the most people.

The Greenhouse Effect

Earth’s temperature depends on three things:1. Amount of sunlight received – variations in

solar flow

2. Amount of sunlight reflected

3. Degree to which the atmosphere retains heat• Water vapor, carbon dioxide, methane, nitrous oxides,

and halocarbons absorb IR radiation• Gases act as “blanket” to retain heat in troposphere

Key factor: mostly shortwave solar energy gets in easily. Once converted to mostly long wave energy, it is harder to get back out. Over-heating is easy.

How solar energy enters the atmosphere and then leaves

See simplified version next page

We can simplify the earth’s “solar budget”

For each 100 incoming: 31 reflected back out 69 absorbed:

- 45 by land and water- 21 by the atmosphere- 3 by the ozone layer

How much leaves quickly by longer-wave radiation? <69>

Total for atmosphere = about 24 percent

69 total absorbed

The “Greenhouse Effect” is vital to keep the earth at a healthy temperature (average 59°F)

However, human air emissions appear to be making the earth warm enough to alter climate

and weather:

CO2, CO, CH4, Nox, Sox, O3

Carbon Dioxide and The Greenhouse Effect

Carbon dioxide accounts for most of human-caused greenhouse effect.

Air Temperature and Carbon Dioxide Notice that air temperature varies with carbon dioxide in the atmosphere – more CO2 => more heat

Atmospheric Carbon Dioxide Concentrations

Burning fossil fuels raises world CO2 concentration exponentially.

Human industrial age

Atmospheric Carbon Dioxide Concentrations, cont.

CO2 levels go down in summer when plants absorb it.

CO2 goes up in winter when plants are dormant and humans continue to drive cars and run power plants.

Why does atmospheric CO2 appear to “ratchet” upward?

1. Most land mass and plant life are in northern hemisphere.

2. In winter, plants are mostly dead or dormant, unable to absorb CO2.

3. Meanwhile, human emissions of CO2 continue or increase.

4. World-wide loss of trees leaves earth unable to keep pace with human emissions.

U.S. Air Quality

Utah urban areas often exceed 100, or even 150.

Some Chinese cities exceed 500 often, sometimes 700+.

Air quality problems rank #1 among Utah citizens, ahead of education, crime, jobs.

U.S. Air Quality

“Smokestack” industries are largely gone to the far east these days, so as consumers we are still somewhat responsbile for world air quality.

Agriculture and mining contribute to a new pattern of air pollution.

Natural sources of oxides still play a role.

.

U.S. Air Quality

Utah does not look so bad because:

1. Particulates are worse in farming and industrial areas.

2. Utah air pollution is more involved with summer ozone and winter inversions, which are episodic and concentrated where people are.

3. Utah really is an urban state when pollution is concentrated with people.

Global Temperature Change–Last 140 Years 1750, warming trend begins until 1940s. 1910 to 1998, global temperatures rise. Temperatures in past 30 years are warmest since

monitoring began.

Volcanic Forcing Ash from eruptions becomes suspended in the

atmosphere, reflects sunlight having a cooling effect.

Mount Tambora, 1815 eruption contributed to cooling in North America and Europe.

Mount Pinatubo in 1991 counterbalanced global warming during 1991 and 1992.

How would a world-class volcanic eruption affect air quality?

- Oxides of sulfur and carbon- Particulate matter (ash)

Meteorological Factors Affecting Air Pollution

Wind as a factor

Effects of Climate ChangeNovember 11, 2013 New York Times article on concerns in Miami and environs. High-tide flooding.

Desertification and Drought Climate change increases human induced

conversion of land to desert

Causes soil and natural vegetation degradation

Increase in drought events

Wildfires may become more common and more violent

As the atmosphere gets warmer

Sea level should rise.

Climate FeedbackPositive feedback – the more you do – the more you get. The more you get, the more you do.

Melting polar ice leaves dark water - - absorbs more energy and melts more ice. More melting leads to more melting.

Negative feedback – shuts itself off automatically, a self-bounding process.

Evaporating water eventually saturates the air. Resulting clouds screen out solar energy, reducing evaporation.

Summary Point: Anything that alters the atmosphere to retain more heat will lead to more energy for:

- severe storms- drought- rising sea levels

Climate Change is About Atmospheric Warming

1% Variable Gases include ‘greenhouse’ gases (GHG) that keep the earth warm.

More GHG more earth warming

More warming more evaporation

more energy for storms

bigger deserts

more heat worsens smog

99% Permanent Gases – neutral (except as plant food)

Humans burn fossil fuel adds more oxides of carbon

and oxidizes nitrogen and sulfur

smog (Nox, Sox)

Sunshine and Nox, Sox ozone (more smog)

“Bottom Line”?

Burning fossil fuels returns vast amounts of ancient “stored sunshine” back into the atmosphere, promoting:

- More heat- More acidity- Air pollution

Even neutral nitrogen gets pulled into the fire and converts to more acidic oxides and more ‘smog.’

Sunshine then combines with smog oxides to produce more ozone.

What is the “Ozone” story?

Atmospheric ozoneis made naturally in the stratosphere by Uv colliding with oxygen.

That process absorbs 95% of dangerous Uv.

Man-made CFCs destroy atmospheric ozone.

Ground-level ozone is made by natural & human processes.

Nasty stuff.

Solution: Humans have banned CFCs, but we still produce vast quantities of hazardous ground-level ozone.

Excessive ozone is the #1 reason for Utah air-quality alerts.

Bicycles are the answer.

The following additional slides provide more

background for Quiz #4

Lutgens • TarbuckLectures by:Heather Gallacher,Cleveland State University

Chapters 13 and 14: Air Pollution and Climate Change

Copyright © 2013 Pearson Education, Inc.

Types of Air Pollution – particulates (PM)

Types of Air Pollution

Sulfur dioxide (SO2) SO2 is a colorless gas originating from the

combustion of sulfur-containing fuel, such as coal and oil.

Important sources are power plants, smelters, pulp and paper mills, and petroleum refineries.

SO2 is also a cause of acid rain.

Types of Air Pollution

Nitrogen oxides (Nox) Nitrogen oxides are gases that form during

the high-temperature combustion of fuel when nitrogen in the air or fuel reacts with oxygen.

Motor vehicles and power plants are the primary sources.

It is also a contributor to acid rain.

Other Types of Air Pollution

Volatile organic compounds (VOCs): VOCs are also called hydrocarbons. They encompass a wide array of solids, liquids, and

gases. Carbon monoxide (CO):

CO is a colorless, odorless, and poisonous gas produced by the incomplete burning of coal, wood, and oil.

More than three-quarters of U.S. emissions are from motor vehicles and nonroad equipment.

Lead (Pb): Lead was formerly added to gasoline to prevent

engine knock. Occasional violations still occur at lead smelters.

Trends in Air Quality

Air Quality Index (AQI): The AQI is an indicator for reporting daily air

quality to the general public. The EPA calculates the AQI for the five

pollutants regulated by the Clean Air Act. The AQI scale runs from 0–500.

Less than 100 on the scale is good. Greater than 100 is considered unhealthy.

- The Salt Lake area exceeds 100 several times each year.

- Large cities in China are exceeding 500, even 700.

Wind as a factorChinese air pollution can reach the United States.

Utah air pollution can reach the U.S. east coast.

Meteorological Factors Affecting Air Pollution

Air stability (such as an inversion or high pressure) can allow air pollution to concentrate.

Unstable air tends to mix air and move it up and out. Unstable air tends to be cleaner and more likely to be stormy as well.

Another view of “inversions”Typically occur in cold weather or high-pressure situation where air is stable or descending. Polluted air is trapped and

concentrated.

Acid Precipitation

Extent and potency of acid precipitation

Acid Precipitation

Acid Precipitation

Effects of acid precipitation It lowers the natural pH of lakes and

rivers. It reduces agriculture yields. It corrodes metals and stone structures.