Air monitoring refers to the collection and analysis of physical air samples from areas of interest. Air monitoring provides the most definitive answer to the question, “What is in the air?” However, the high costs and time-consuming nature of monitoring means it’s not always the most viable solution to understanding air quality.

The air monitoring process is one of continuous improvement and refinement. Air toxics monitors are placed in areas where IDEM expects there might be higher than normal levels of air toxics (see Monitor Siting). Then samples are collected, usually on a 1-in-6 day rotation. IDEM’s Air Laboratory analyzes the samples and places the results in the appropriate databases.

Air toxics monitoring data collected by IDEM is stored internally as well as being placed on U.S. EPA’s Air Quality System (AQS). AQS is a database maintained by U.S. EPA which contains monitoring data from around the nation.

Risk Assessors then analyze the data in the databases to determine if a problem exists and whether further monitoring at that location is warranted. If it is, sampling continues; if not, new monitoring locations are found.