System of Air Quality and Weather Forecasting And Research
Ministry of Earth Science, Govt. of India.
Indian Institute of Tropical Meteorology, Pune


 How we maintain good data quality

Quality control and quality assurance is the major and essential step performed by the scientist of IITM before releasing the air quality data to public in the form of Air Quality Index (AQI) or UV-Index (UVI).

 Instrument calibration

The equipments are maintained and operated according to the standard specifications of supplier.  The instruments are US EPA approved and the quality system is certified ISO9001by Bureau Veritas Certification. We have adopted US EPA’s Standard Operating Procedures for instrument calibration and maintenance. For more information about calibration procedure refer to title 40 of the Code of Federal Regulations (CFR) part 50. http://www.law.cornell.edu/cfr/text/40/part-50

 Reviw and Audit

Our field engineers visit the stations daily and perform check to ensure the instruments are working properly or not.  On the basis of drift specification, instrument environment and other factors the calibration is done at definite time interval. Field engineers are responsible for reporting the daily status of instrument health to IITM’s data validation staff. On monthly basis review meeting is conducted and monthly audits are performed in which instrument health as well as documentation has been checked by internal auditors.

 Online monitoring

 We are monitoring air quality indicators and weather parameters round the clock. The data is recorded and stored at every five minutes interval at local station. This near real time online raw data is then transferred to central AQMS server at SAFAR-Control room located at IITM, Pune, through GPRS at every 15 min interval which is a central data base where data has been validated by expert scientific team. The data is subsequently averaged to one hour interval. At SAFAR control room the robust quality check system is in place which provides alert for three major conditions (1) Instrument failure at site (2) Communication failure between instrument and local server (3) Communication failure between local server & central AQMS server, this information helps to salve the problem if occurred at any specific location with minimum time lag and prevent data loss.


The validationoperator action who certifies data quality. is an essential function of Technical management. At SAFAR-Control room errors or suspicious data has been flagged by the system which is then checked and corrected by expert scientific team.  Various quality codes are set to observational values based on information relating to the state of the sensor or measurement. The invalid or out of range data is not considered for further data analysis.  

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