Carbon Pollutant
Carbon-based chemical substances with high vapour pressures at ordinary room temperatures evaporate easily into the atmosphere, contributing to indoor and outdoor air pollution. Many volatile organic compounds are hazardous to human health or act as precursors to ground-level ozone. Sensors must be capable of detecting these substances at parts-per-billion levels to ensure compliance with occupational hygiene and environmental standards.
Detection Method
Photoionization detectors use high-energy ultraviolet light to ionise molecules, creating a current proportional to the total concentration of volatile organic compounds in the sample. The ionization potential of each compound determines whether it can be detected by a specific lamp energy, such as ten point six electron volts. Since the detector does not identify individual species, it provides a cumulative measurement that must be calibrated against a reference gas like isobutylene.
Environmental Metrology
The sensitivity of the measuring instrument must be calibrated across the expected temperature and humidity range of the target environment. Water vapour can absorb ultraviolet light or cause current leakage, leading to measurement errors in high-humidity conditions. Technicians utilize moisture traps and temperature compensation algorithms to minimise these interferences during field measurements.
Sourcing Tolerance
Sourcing specifications for air quality monitors define the permissible limit of detection and linearity for the target compounds. This performance is verified by testing the sensor against a certified gas mixture under reference conditions.
