What are Aerosols?
Aerosols are tiny particles suspended in the air. Some occur naturally, originating from volcanoes, dust storms, forest and grassland fires, living vegetation, and sea spray. Human activities, such as the burning of fossil fuels and the alteration of natural surface cover, also generate aerosols. Averaged over the globe, aerosols made by human activities currently account for about 10 percent of the total amount of aerosols in our atmosphere. Most of that 10 percent is concentrated in the Northern Hemisphere, especially downwind of industrial sites, slash-and-burn agricultural regions, and overgrazed grasslands. Scientists have much to learn about the way aerosols affect regional and global climate. We have yet to accurately quantify the relative impacts on climate of natural aerosols and those of human origin. Moreover, we do not know in what regions of the planet the amount of atmospheric aerosol is increasing, is diminishing, and is remaining roughly constant. Overall, we do not eve
Aerosols are cans that hold a liquid under significant pressure along with something else to keep the pressure equalized. Some sort of valve on the can allows an amount of the liquid to be released as a mist. All sorts of things are dispersed as aerosols, ranging from spray paints to insect repellents to cleaning agents. The first widely used aerosol was utilized during World War II by American soldiers as a way of easily spraying on mosquito repellent to protect themselves from the all-pervasive bugs in the Pacific arena. After the war, the mechanism was adopted by an incredible number of products, and aerosol cans quickly became a staple of the Western consumer. Until the late 1980s, some of the most common agents used to keep the liquid in a state of equilibrium inside the can belonged to a class known as chlorofluorocarbons (CFCs). Eventually, it became apparent that these CFCs, at use not only in aerosols but also in refrigerators and many cleaners, were having incredible detrimen
Aerosols are tiny particles suspended in the air. Most occur naturally, originating from volcanoes, dust storms, forest and grassland fires, living vegetation, and sea spray (Figure 1). Human activities, such as the burning of fossil fuels and the alteration of natural surface cover, also generate aerosols. Averaged over the globe, aerosols made by human activities currently account for about 10 percent of the total amount of aerosols in our atmosphere. Most of that 10 percent is concentrated in the Northern Hemisphere, especially downwind of industrial sites, slash-and-burn agricultural regions, and overgrazed grasslands. Scientists have much to learn about the way aerosols affect regional and global climate. We have yet to accurately quantify the impacts of natural aerosols on climate, relative to impacts of aerosols made by humans. Moreover, we do not know whether the total amount of atmospheric aerosol is roughly constant, is diminishing, or is increasing. Overall, we do not even k
Aerosols are solid or liquid particles that are suspended in gas; they can be either man-made or natural. Some examples of aerosols are hairspray, smog, volcanic ash, clouds, and sea mist. Aerosols reflect or absorb solar radiation, which can have cooling effects or cause global warming, respectively. Aerosols in the lower atmosphere tend to produce a cooling effect. How do Aerosols Cool and Warm the Earth? The sun emits radiation in the form of waves. When the waves hit the aerosol particles, they are either absorbed or reflected. Reflection happens best when the wavelength and the aerosol particle are the same size. Characteristics that effect the effectiveness of scattering light are altitude, number, size, and composition. • The higher the altitude is, the longer it would take to fall back to the Earth. • The more particles there are, the more solar radiation can be reflected or absorbed. • The larger the particle, the more light it absorbs. • The smaller the particle, the more ene
Even the clearest air has many tiny particles suspended in it called “aerosols”. It is not unusual for there to be 10,000 aerosols per cubic centimeter (160,000 per cubic inch) of air. These come from many sources, both natural and man-made: the soil, salt from the ocean, the burning of fossil fuels or vegetation. They can be solid, liquid, or a mixture of both. Even though this sounds like “pollution”, aerosols are very important for the formation of clouds. Virtually all cloud droplets initially form around an aerosol. The more aerosols there are, the easier it is for clouds to form. After they are produced, aerosols typically only last a few days before they are washed out of the atmosphere by rain systems.
