Tropospheric, or ground level ozone, is not emitted directly into the air, but is created by chemical reactions between oxides of nitrogen (NOx) and volatile organic compounds (VOC).
Where is ground-level ozone located?
Ground-level ozone forms just above the earth’s surface (up to about 2 miles above ground) and impacts human, animal, and plant respiration.
Where does most ground-level ozone come from?
Ground-level ozone (O 3 ) is regulated by EPA. Ground-level ozone comes from pollution emitted from cars, power plants, industrial boilers, refineries, and chemical plants. Ozone pollution can even come from paints, cleaners, solvents, and motorized lawn equipment.
How is ground-level ozone different from ozone in the stratosphere?
Unlike stratospheric ozone, which forms naturally in the upper atmosphere and protects us from the sun’s harmful ultraviolet rays, ground-level (or tropospheric) ozone is created through the interactions of man-made (and natural) emissions of volatile organic compounds and nitrogen oxides in the presence of heat and …
How is ground-level ozone measured?
An ozone analyzer measures the real-time ozone concentration in the air. Ambient air is drawn through a sampler inlet from the top of a 10-meter tipping tower by a pump.
Where are ozone levels highest?
In general, ozone levels are higher on hot, sunny summer days especially during episodes of stagnant air. Daily ozone levels can be influenced by local weather events, regional weather patterns and the presence of chemicals in the air that react to form ozone.
Why does ground level ozone form?
It forms when heat and sunlight allow the reaction of two other pollutants: nitrogen oxides and volatile organic compounds. These chemicals come from industrial plants, electric utilities, vehicle exhaust, wildfire smoke, and oil and gas extraction. High heat can accelerate this process.
How is ground level ozone measured?
Why does ground-level ozone form?
Is ground-level ozone a primary or secondary pollutant?
Ground-level ozone is a secondary pollutant. It is formed through chemical reactions of other molecules already in the air, specifically nitrogen oxides (NOx) and volatile organic compounds (VOCs).
What is ozone in the stratosphere?
Stratospheric ozone is a naturally-occurring gas that filters the sun’s ultraviolet (UV) radiation. This is typically regarded as ‘good’ ozone since it reduces the harmful effects of ultraviolet (UV-B) radiation. A diminished ozone layer allows more radiation to reach the Earth’s surface.
What is the current status of ground-level ozone?
For instance, the current eight-hour average National Ambient Air Quality Standard for ozone in the United States is 70 parts per billion, and the current World Health Organization guideline is approximately 51 parts per billion.
