Air Quality Index

A measure of the quantity of harmful particles and chemicals in the air.

Note

The index is used by weather forecasters to indicate the purity of the air on a given day. The higher the index, the smoggier (see smog) and more polluted the air.
The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.