Frequently Asked Questions
The EPA has determined a minimum number of monitoring sites that must be established and maintained for each pollutant. DHEC annually reviews the monitoring network to make sure the minimum requirements and the needs of the air program are met. If changes are needed in the network to meet new requirements, address new questions or redirect resources, then those changes are made available for public review and EPA approval in the Annual Ambient Air Network Monitoring Plan.
South Carolina also monitors air in smaller towns and cities where EPA does not require monitoring in order to make sure the network fairly represents all of South Carolina’s air quality.
Special studies are done when there are specific questions that need to be answered for an area or type of pollutant source.
Weather patterns can change from year to year (El Nino, droughts, etc.) and operating a monitoring site for several years is needed to understand typical air quality in that area. The year-to-year changes related to the weather can make changes in pollutant concentrations hard to see unless there is a long, consistent data record. If monitors are moved often, even within the same area, it is very difficult to know if any concentration differences are caused by something at the site or a change in the weather.