Division of Air Quality Analysis
Within the South Carolina Department of Health and Environmental Control is a technical division that measures the quality of air in South Carolina to determine if the different areas of the state meet the standards set in the Clean Air Act (CAA) and the SC Pollution Control Act (SCPCA). The Division of Air Quality Analysis (DAQA) is part of the Environmental Quality Control (EQC) Laboratories. Since the passage of the CAA and SCPCA, DAQA has played the primary role in effectively gathering ambient data from throughout South Carolina.
Data collected answers the questions, "How good is the air in SC?" and "How good is the air quality where I live?" The Division of Air Quality has four sections that collect, analyze, and manage data from field and laboratory instruments. These four sections are: Analytical Laboratory, Data Management, Audit and Calibration, and Technical Support for Sites.
There are many Environmental Protection Agency (EPA) web sites that provide useful air quality information ranging from the details of how to monitor to presentation of air quality in the last few hours. Air Pollution is a link for an EPA website which includes the Air Quality System (AQS) database, summary data, and access guidance and studies related to the technology behind the monitoring provided by the EPA. Ozone Data is a link to an EPA site that leads you to near real time maps of ozone concentrations during ozone seasons, particulate concentrations throughout the year and general information that can be useful when investigating air quality and health effects. Technical Data is a link to a connection to the repository for technical information and guidance for a wide range of Air Quality data collection and application.
The Division of Air Quality Analysis is often abbreviated DAQA. This Division is divided into four sections: Analytical Laboratory, Data Management, Audit and Calibration, and Technical Support for Sites.
Analytical Laboratory
This section performs gravimetric, inorganic and organic analyses on ambient air samples collected using various types of sampling media. Each different type of media is designed for a specific parameter. Some of these parameters include: Total Suspended Particulate (TSP), Metals (Lead, Copper, Iron, Magnesium, Nickel, etc), Particulate Matter 10 microns in size or less (PM10), Particulate matter 2.5 microns in size or less(PM2.5), acid precipitation, Volatile Organic Compounds, Semi-volatile Organic Compounds, and Carbonyl compounds like formaldehyde. Normally, these samples are collected over a 24-hour period, once every six days according to a national schedule. The samples are retrieved from the field and returned to the laboratory for analysis.
The samples are analyzed using a variety of instrumentation ranging from very simple pH meters, microscopes and balances to highly complex gas chromatography/mass spectrometers and inductively coupled argon plasma atomic emission spectrophotometers.
Data Management
The primary responsibilities of the Data Management section are the recovery, quality assurance and reporting of air monitoring data. Data management includes collection of data from the sites, verification and validation of monitoring data, submission of data to the national database and extracting data for report generation. Most data produced by the Division of Air Quality Analysis will pass through this section at some point. Section staff have assigned tasks, but can perform most tasks to insure uninterrupted data recovery. The routine collection of data from the sites, in many cases every hour, has been automated.
Ambient air monitoring data is the primary 'product' of DAQA. Insuring that the data is of known quality and is available when needed is critical. Quality Assurance requires knowledge of the monitoring instruments and data acquisition systems, computer and telecommunications systems, data base management, and report generation. Customer service is an important part of data management. Rapid evaluation of the raw data assists the Technical Support and Audit and Calibration Sections respond quickly to problems to minimize data loss.
Audit and Calibration
This section is responsible for ensuring that the instruments are accurately and precisely measuring the concentrations of pollutants in the air. The purpose of this Quality Control activity is to establish a scientifically traceable foundation for the state's ambient air monitoring data and allows verification of the data. The Precision and Accuracy results are reported to the EPA to help indicate how well the instruments and the monitoring program are performing.
Calibration - This is defined in the dictionary as "To check, adjust or determine by comparison with a standard". In DAQA, a monitoring instrument is exposed to known concentrations of pollutant and the response is determined. Thus when the instrument is sampling the air, the concentration of pollutant can be accurately determined.
Audit - This is a check of the results of the calibration. DAQA challenges every instrument with known concentrations of pollutants periodically to make sure that the instrument calibration is still valid. During an audit, the instrument is exposed to a known amount of pollutant and the operator makes sure that the response is the same as it was during the calibration. If not, a new calibration is performed.
Technical Support for Sites
The Technical Support section is responsible for establishing and maintaining the monitoring sites and equipment. This can include clearing of new sites, installing monitor buildings and equipment, building wooden stands, and erecting fences, wind towers and any other needed structures. Once the sites are built, the sites are regularly visited to control the vegetation around them to ensure they continue to meet the exposure requirements to collect valid data. After a site has outlived its usefulness, the section is responsible for removing all traces and making sure the property has een restored as before and the property owner is satisfied.
The section also maintains, troubleshoots problems, and repairs the monitoring and sampling instruments. The systems needs can range from component and board level electronics to pneumatics and flow control. The continuous monitors are essentially single parameter chemical analyzers in a box, performing collection, conversion, excitation, analysis and data processing in real time. A wide range of skills and knowledge are needed to keep them operating properly, 24 hours a day.
The people in this section could be called the Minutemen of DAQA. They must be ready to dash to any part of the state on short notice to repair any problem reported by the Data Section, Audit & Calibration or the district staff. They carry a lot of tools and parts to repair the wide range of equipment and structures at the sites. This could be anything from a complex malfunctioning of a monitor, to a leaking roof or wasp infestation. Skills and abilities range from computers to lawn mowers and sometimes must be used in remote locations. Each person typically travels an average of 30,000 miles per year during the performance of his or her duties.