Overview of the national precision database for ozone
One of the most important ambient air monitoring quality assurance indicators is the precision test. Code of Federal Regulation Title 40, Section 58 (40 CFR 58) Appendix A1 states that all automated analyzers must have precision tests performed at least once every two weeks. Precision tests can be the best indicator of quality of data for the following reasons: Precision tests are performed once every two weeks. There are approximately 24 to 26 tests per year per instrument. Accuracy tests (audits) usually occur only 1--2 times per year. Precision tests and the subsequent statistical tests can be used to calculate the bias in a set of data. Precision test are used to calculate 95% confidence (probability) limits for the data set. This is important because the confidence of any data point can be determined. If the authors examine any exceedances or near exceedances of the ozone NAAQS, the confidence limits must be examined as well. Precision tests are performed by the monitoring staff and the precision standards are certified against the internal agency primary standards. Precision data are submitted by all state and local agencies that are required to submit criteria pollutant data to the Aerometric and Information Retrieval System (AIRS) database. This subset of the AIRS database is named Precision and Accuracy Retrieval Systems (PARS). In essence, the precision test is an internally performed test performed by the agency collecting and reporting the data.
- Research Organization:
- Environmental Protection Agency, Atlanta, GA (US)
- OSTI ID:
- 20002091
- Report Number(s):
- CONF-990608--
- Country of Publication:
- United States
- Language:
- English
Similar Records
Ambient air precision and accuracy program. 1995 annual report
Summary of ambient air quality monitoring precision and accuracy data