Air Quality
Exceptional Events
South Carolina Department of Health and Environmental Control (Department) operates
an ambient monitoring network that measures concentrations of various air pollutants.
Other environmental agencies operate similar networks throughout the United States.
When an event outside human control causes an exceedance of an ambient standard,
the event may be excluded from compliance calculations. There is a specific process
for excluding an event, which includes public notice of each request. This notice
provides an opportunity for public review and comment on the supporting documentation.
Following the opportunity for public comment, the Department submits this information
to the United States Environmental Protection Agency (EPA) for their review and
approval. If the EPA concurs that the appropriate flagged data were affected by
an Exceptional Event, data generated by the state’s monitors affected by the
Exceptional Event are not used to determine compliance with the National Ambient Air Quality Standards (NAAQS).
Contact information is provided below for questions about this process or about
a specific Exceptional Event proposal. Public comments on this web page are also
welcome.
What is an Exceptional Event?
According to
federal regulations, an exceptional event is
defined as:
“An exceptional event is defined as an event that affects air quality, an event
that is not reasonably controllable or preventable, is an event caused by human
activity that is unlikely to recur at a particular location or a is a natural event,
and is determined by the EPA to be an exceptional event.”
Exceptional Events may include, but are not limited to, prescribed burnings, wildfires,
and large firework displays.
Exceptional Events do not include stagnation of air masses or meteorological inversions, meteorological
events involving high temperature or a lack of precipitation, or air pollution relating
to source noncompliance.
To summarize, an Exceptional Event is one that:
- Affects air quality.
- Is not reasonably controllable or preventable.
- Is an event that is caused by human activity that is unlikely to recur at a particular location, or is a natural event; and
- Is determined by the Administrator of the EPA through the process established in the rule to be an exceptional event.
What Event Documents are available for Public Review and Comment?
This area contains information on events that the Department proposes to submit
to EPA for approval. Public comments are welcome on the information in this section.
Prior Event Documentation
This area contains information on past events that the Department has submitted
to the EPA.
Additional Resources
Health Effects of Pollutants
For additional information, contact:
Clay Lawson
- (803) 898-7410
DHEC
2600 Bull Street
Columbia, SC 29201
