Use this form to retrieve hourly data collected at IDEM monitoring stations. For air monitoring stations, we continuously sample the atmosphere (one sample per second), and every five minutes an average of all the one-second samples collected is calculated for each parameter monitored. Hourly averages are then calculated from these five-minute averages. For water monitoring stations, we take a sample once every 15 minutes. Hourly averages are then calculated from these samples. Although this is our most current data, it is not considered official until it has been certified by our technical staff. This information is updated hourly.
This web page provides the most current hourly averaged data available. Our convention for time-tagging data is the beginning of each hour. For example, values shown for the noon hour are based on measurements taken from noon to 1:00 p.m. The noon average will not be calculated until after 1:00 p.m. The noon average will then be available on our external server from 1:15 p.m. to 1:30 p.m. This results in an apparent one-hour time lag in the data. We also present our data in Local Standard Time for each measuring site. For most of Indiana this is Eastern Standard Time. During Daylight Savings, this introduces another apparent one-hour time lag in the data.
PLEASE NOTE: This data has not been verified by the IDEM and may change. This is the most current data, but it is not official until it has been certified by our technical staff. Data is collected from IDEM ambient monitoring sites and may include data collected by other outside agencies. This data is updated hourly. All times shown are in local standard time unless otherwise indicated.