Near Real-time, Low-cost, Hand-held Sensors for Measuring Elemental Concentration of Airborne Particles for Indoor or Outdoor Air Quality Monitoring

Airborne particles can have great impact on air quality, weather, and human health. In particular, long-term inhalation of toxic particulate matter in workplaces could pose a significant health risk. NIOSH scientists have developed a new, low-cost approach based on application of atmospheric radio frequency glow discharge (rf-GD) optical emission spectroscopy for near real-time measurement of elemental concentration in aerosols. The method involves collection of aerosol particles on an electrode tip in a coaxial microelectrode system, followed by excitation of the particles using rf-GD. NIOSH scientists identified far less expensive excitation sources for the rf-GD than traditional spark and laser-based excitation sources. Additionally, these excitation sources are compact and can be miniaturized for development of sensors for personal air sampling. The scientists developed a laboratory instrument, calibrated it for various elements including carbon, cadmium, manganese, and sodium, and established analytical detection limits for these elements. They demonstrated that these limits are well below most occupational exposure limits, allowing sensitive near real-time detection. This technology provides an excellent resource for air quality monitoring and the development of low-cost, hand-held sensors for aerosol measurement.