Ozone Fact Sheet | Facts About SCR

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What is Ozone?
When &: Where
is ozone a problem?
How does ozone
harm the body?
Who is at risk?
Ozone pollution, ozone layer
Nitrogen Oxide (NOx) Facts
Carbon Dioxide (CO2) Facts
Carbon Monoxide (CO) Facts

What is Ozone?

• Ozone (O3) is an extremely reactive gas molecule composed of three oxygen atoms.
• Ozone forms in chemical reactions in the atmosphere when nitrogen oxides (NOx) and volatile organic compounds (VOCs), also called hydrocarbons (HC), come into contact with both sunlight and heat
• VOCs and NOx form when fossil fuels like gasoline or coal are burned, or when fossil fuel-based chemicals, like paints, evaporate
• NOx is emitted from power plants, motor vehicles and other sources of high-heat combustion
• VOCs are emitted from motor vehicles, chemical plants, refineries, factories, gas stations, paint and other sources

When and where is ozone a problem?

• Ozone levels typically rise in much of the U.S. between May and October due to a combination of higher temperatures, more sunlight and stagnant air masses. However, some parts of the nation have unhealthful levels of ozone independent of the season1
• Based on current scientific understanding of health risks, unhealthful levels of ozone show up all across the nation
• Wind patterns blow ozone produced in one region into other regions

How does ozone harm the body?

• Ozone attacks lung tissue by reacting chemically with it, called “oxidizing,” and acting as a powerful irritant at the levels frequently found across the nation (some compare this to getting a “sunburn” on the lungs)
• New research has confirmed that breathing ozone over a short period can increase the risk of premature death (includes levels found in cities around the U.S. and in Europe)
• Many areas in the U.S. have enough ground-level ozone during the summer months to cause health problems that can be felt right away, including:
- • Shortness of breath
- • Chest pain when inhaling deeply
- • Wheezing and coughing
- • Increased susceptibility to respiratory infections
- • Inflammation of the lungs and airways
- • Increased risk of asthma attacks
- • Increased need for medical treatment and hospital admission for people with lung diseases like asthma or chronic obstructive pulmonary disease (COPD)
• Animal toxicology studies have shown that long-term exposure to high levels of ozone can cause structural changes to the lungs

Who is at risk?

• Anyone who has asthma or COPD (Chronic Obstructive Pulmonary Disease—emphysema or chronic bronchitis) or any other lung disease
• Children, because their airways are smaller, their respiratory defenses are not fully formed, and their higher breathing rates increase their exposure to ozone
• Senior citizens
• Anyone—even a healthy adult—who works or exercises outdoors
• Responders—otherwise healthy individuals who for unknown reasons are especially sensitive to ozone exposure

How does ozone pollution differ from the ozone layer?

• The ground-level ozone in the lower atmosphere (troposphere) should not be confused with the natural protective layer of ozone in the upper atmosphere (stratosphere). Although both are made of the same molecules (ozone), the ozone in the upper atmosphere protects us from the sun’s harmful ultraviolet (UV) rays, while the ozone in the lower atmosphere harms us.

Nitrogen Oxide (NOx) Facts

Nitrogen oxides are a major contributor to ozone production and smog.

• Diesel engines produce nearly 20% of the total NOx in outdoor air and 26% of the total NOx from on-road sources

Carbon Dioxide (CO2) Facts

• About 33% of U.S CO2 emissions come from the burning of gasoline in internal-combustion engines of cars and light-trucks (minivans, SUV’s and pick-up trucks)
• Vehicles with poor gas mileage contribute the most to global warming, according to U.S. Emissions Inventory 2006(PDF)

Carbon Monoxide (CO) Facts

• Carbon monoxide (CO) is an odorless, colorless, poisonous gas that comes from burning fossil fuels, including the exhaust from motor vehicles and other combustion exhaust
• CO interferes with the blood’s ability to carry oxygen to the brain, heart and other tissues. It is particularly dangerous for people with existing heart disease and for newborn children
• CO exposure has been associated with aggravation of angina pectoris and other aspects of coronary heart disease, decreased exercise tolerance in people with peripheral vascular disease and lung disease, impairment of central nervous system functions, and possible increased risk to fetuses
• More than 80% of the CO emissions in the larger urban areas are produced from motor vehicles

Reducing Emissions is Key to Lessening Our Impact on Global Warming

Ozone (NOx) Fact Sheet