Properties
When cooler air sinks, pressing on the ground and sweeping away cloudy, rainy weather. It is usually a precursor to nice, sunny days ahead. These rotate clockwise.
What is a high pressure system (or an anticyclone, shown by a blue H on a weather map). Which direction do they rotate?
High concentrations of sulfuric or nitric acid that reduces the pH of the precipitation and makes it acidic.
What is acid rain?
4 natural sources of air pollution.
What are radon, dust, smoke, ash, greenhouse gases, mold spores, pollen, etc. (4 of them)?