| 摘要 |
Measuring the mass of particulate matter in a gas by allowing the gas to enter through an inlet 110 and removing coarse particles larger than a selected size while permitting filtered particles of less than the selected size through to a measurement chamber 170. The particles are deposited on a quartz crystal sensor (600, Fig.4) which outputs an electrical signal in response to the deposited particle mass. A second chamber 210, 250 may be included for removing particles larger than a second selected size and the particles may be deposited on the sensor by means of ions from a corona discharge. The apparatus may comprise a filter, pump 180, flow sensor and controller 190 to maintain the gas flow at a set value and may be maintained at a suitable temperature to prevent condensation forming on the sensor. The apparatus is suitable for measuring airborne particulate matter with the selected sizes corresponding to PM10, PM2.5 or PM1 pollution standards. |
