There are two ozone layers in Earth's atmosphere.
Understanding the Two Ozone Layers
The ozone layer isn't a single, uniform layer but exists in two distinct regions of the atmosphere:
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Stratospheric Ozone: This is the "good" ozone, located in the stratosphere (about 10-50 kilometers above the Earth's surface). This ozone layer absorbs most of the sun's harmful ultraviolet (UV) radiation, protecting life on Earth. Measurements of this layer are often taken in Dobson Units (DU) to quantify the ozone concentration. https://www.eea.europa.eu/en/topics/in-depth/climate-change-mitigation-reducing-emissions/current-state-of-the-ozone-layer Satellites constantly monitor this layer, providing up-to-date information on its status. https://ozonewatch.gsfc.nasa.gov/
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Tropospheric Ozone: This is the "bad" ozone found in the troposphere, the layer closest to the Earth's surface. Unlike stratospheric ozone, tropospheric ozone is a harmful air pollutant. It's formed when sunlight interacts with various chemicals emitted by human activities, such as vehicle emissions and industrial processes. https://scied.ucar.edu/learning-zone/air-quality/ozone
The Montreal Protocol is an international treaty designed to phase out the production and consumption of ozone-depleting substances (ODS), such as chlorofluorocarbons (CFCs), that were previously found in aerosol cans and other products. https://www.state.gov/key-topics-office-of-environmental-quality-and-transboundary-issues/the-montreal-protocol-on-substances-that-deplete-the-ozone-layer/ This has resulted in a reduction in the depletion of the stratospheric ozone layer. However, increasing space travel could present a new challenge to the ozone layer in the future. https://research.noaa.gov/projected-increase-in-space-travel-may-damage-ozone-layer/
