Part b - the effect of aerosols on weather and climate the composition of the atmosphere can vary widely from time to time, and place to place. clean, dry air is mostly comprised of nitrogen and oxygen, with only about 1% of other gases. water vapor forms clouds and transports heat. aerosols (solid and liquid particles suspended in the air) decrease the amount of sunlight reaching earth's surface. ozone (o3) can block harmful ultraviolet radiation. increases in the concentration of water vapor and aerosols increases the presence of clouds and fog. increased clouds and fog, along with an increase in the concentration of ozone, results in a lower global temperature not only because more aerosols block more sunlight, but also because aerosols provide a surface for water to condense. high moisture content results in lower temperatures. in 1991, mt. pinatubo in the philippines erupted. the accompanying photo shows the ash and debris that the volcano propelled high into the atmosphere. what meteorological impact could these aerosols have on the global weather and climate?