A closer look at the effects of aerosol particles
Today’s Video of the Day shows an in-depth look at what aerosol particles are and how they affect the planet. Aerosol particles are present in the Earth’s atmosphere in all different types of ecosystems. They range in size from just a few nanometers to tens of micrometers.
About 90% of aerosol particles are naturally occurring. When volcanoes erupt, they spew large heaps of ash into the air containing sulfur dioxide and yielding sulfates. Sea salt and dust are two other common aerosols that get swept up into the atmosphere by strong winds.
The other 10% of aerosol particles are human-made and can accumulate quickly in densely populated areas like major cities. The burning of fossil fuels produces large amounts of sulfur dioxides, which mix with water vapor to become sulfate aerosols. Car exhaust, power plants, and incinerators also contribute a number of artificial aerosols.
While brightly-colored or clear aerosol particles reflect sunlight, darker aerosols like black carbon absorb the light and warm the atmosphere. As such, aerosols are seen to interact with the atmosphere both directly and indirectly. A direct effect would be when aerosols reflect sunlight back into space, which has a cooling effect on the atmosphere. An indirect effect, however, refers to when aerosols interfere with cloud formation by changing the size of cloud particles.
The cooling effect of aerosols does not simply counteract the warming effect of greenhouse gases due the unequal global distribution of each. Aerosols also have a complicated effect on clouds and precipitation, though they are generally seen to suppress precipitation. Aerosol particles decrease the size of water droplets in clouds, but under certain conditions, can cause taller clouds that are more likely to produce heavy rains.
They may be tiny in size, but aerosol particles can be very powerful. As such, NASA tracks aerosol distribution using satellites and specialize aircraft devices.
Video: NASA’s Earth Minute