Evaluation of High-Volume Air Samplers for Ambient Air Quality Monitoring in Real Atmosphere

Quality Assurance/Quality Control techniques have been studied in order to establish an appropriate level of quality control (QC) during ambient air quality monitoring in real atmosphere. QA/QC study of four high-volume air samplers was carried out at the roof of an ambient air quality site during the Environmental Impact Assessment study. Suspended Particulate Matter (SPM), Sulphur dioxide (SO₂), Oxides of Nitrogen (NO_x) was continuously monitored for 24 hours for 8 days. The average SPM, SO₂ and NOx measured by an identical pair of samplers ranged between 79.98 to 82.62 μg/m³; 30.40 to 36.75 μg/m³and 31.63 to 36.36 μg/m³. The standard deviation and coefficient of variation for SPM, SO₂ and NO_x were between 13.59–16.69; 8.34–10.14; 7.81–10.01 and 16.45–20.66; 22.71–33.35; 24.68–30.80 respectively. The day-to-day variation and sampler-to-sampler variation was also studied and control chart was prepared for accuracy and precision of the measurements. The QA/QC data generated in the field will be used to monitor reproducibility (precision) of the sampling methods and the accuracy of measurement. Proper quality assurance and quality control (QA/QC) procedures helps in achieving reproducible and reliable results during the ambient air quality monitoring. The reproducibility of the samplers for all the parameters is found to be satisfactory.