EARTH WOULD NOT PASS THE
Smog is a mixture of noxious air
pollutants, gases, and fine liquid and solid particles. Urban smog (in
densely populated areas/cities) contains harmful levels of ground-level
ozone. Ozone in our upper atmosphere (stratospheric ozone) is a useful gas ("good"
ozone). This ozone layer keeps much of the harmful UV radiation (ultra violet
light) from reaching us at Earth's surface. But, there is "good"
ozone and "bad" ozone, depending upon where it is located. Ozone
concentrations at ground level (tropospheric ozone) are toxic and this "bad" ozone causes
harm to living things.
Smog is most visible in very high concentrations.
You can see the dense smog in the distance in the picture above of the 10-lane
freeway clogged with fossil-fuel burning cars. Millions of vehicles
operate 24 hours a day, 7 days a week in large metropolitan areas, like Los
Angeles for instance. If you look out the window of an airplane you can see the
haze from smog that covers many regions below. It mainly is concentrated
in densely populated areas, but wind currents can carry it even hundreds of
miles away and over other areas which had nothing to do with its origination.
Smog can hover over areas for days if there are no winds to disperse it and help
clean the air. Some of our national parks and ecologically important regions on
our planet are being damaged from this human-caused pollution. And
respiratory ailments among adults and children have steadily increased over the
years, with the elderly, sick and young children suffering the greatest harm to
How is the ozone produced on Earth's surface?
Mix NOx and VOCs, apply sunlight and heat and you've got ozone.
Throw in some pollutants, water vapor and particulate matter and you've got
Ozone is a product
of chemical reactions between hydrocarbons and nitrogen oxides in the presence
of sunlight. It is created when oxides of nitrogen (NOx) and volatile
organic compounds (VOCs) react in heat and sunlight. NOx is produced and
emitted by the burning of fossil fuels in vehicles, and in industrial and power
plants. The main sources of VOCs come from industrial and commercial processes
and motor vehicles. VOCs are also released from paints, solvents,
cleansers, aerosol sprays, dry-cleaned clothing, wood preservatives, automotive
products and fuels.
Layers of the Atmosphere Google has found about 536 images of the layers
of the atmosphere. If you have trouble finding them on this link, just
type in "layers of the atmosphere" in Google's search box (without the quote
Is the Ozone
Hole really a hole? What is ozone depletion?
(NASA's Global Change Master Directory
Hole and Ozone Depletion (Includes resource links at bottom
When ultraviolet radiation from the sun reaches the ozone layer in the
stratosphere, what happens?
Click on the globe for the TOMS sensor (Total Ozone Mapping Spectrometer). The
TOMS instrument is used by NASA scientists to monitor the Antarctic ozone hole,
and local and global ozone levels. Take a look at the Aerosol Hot Spots
page (wait for page load), and see how smoke and dust from desert dust storms,
forest fires and biomass burning can be carried from one continent to another.
(NASA's Global Change Master Directory)
Ozone Hole Tour - University of Cambridge, UK
Real-Time Air Pollution Data
Current maps, forecasts and real-time information about
ground-level ozone (smog) levels. Important website for children in general and for
those people who have asthma or respiratory disease.
EPA's UV Index
Type in a zip code or city and state, and find out how much UV (ultraviolet)
radiation is reaching the Earth in that area, and what precautions people should
UV Index Information
(National Weather Service Climate Prediction Center)
Learn all about ultraviolet radiation.
The Smog Test Log (EPA/Office of
Transportation and Air Quality - maintained by Colorado School of Mines)
Public resource for central source of information on testing
programs related to emissions on mobile sources.
Links to online resources such as alternative energy, clean fuels, clean
air, clean cities coalitions, electric/green vehicles, environmentalist
resources, governmental resources, and university programs.
Search their database by category/keywords for information on acid rain,
ozone, alternative fuels, toxics, regulations, particulates, pollutants,
and much more.
(Sacramento Metropolitan Air Quality Management District)
Watch how Smog City changes as you select the weather and
the pollutants by clicking on pictures. First four: temperature, heat
inversion, wind, and sunny or cloudy (the heat inversion level goes up and down, the
clouds move faster as you increase the wind). Click a level of Population and watch
houses disappear or appear. Last choices are to select emission levels - how much
pollution is coming from vehicles, industry and products. Then click Start and watch
the chart results for ozone level and health effects. Click Reset and change your
selections to see what the effects are.
Click on website links in left frame and read about ozone.