PM2.5 air pollutant gravimetric monitoring solution

Global air pollution is responsible for respiratory diseases and even death. Particles (PM) pose serious health risks because they can deposit in the lungs through the nose and throat. The EU sets limits for concentrations of sulfur oxides, nitrogen dioxide, nitrogen oxides, lead and particulate matter (PM) in ambient air. The main methods of particle monitoring include: gravimetric method, micro-oscillation balance method and β-ray method. At present, the determination of atmospheric particulate matter in China mainly adopts the gravimetric method.

The sample is first preset for 48 hours, and the dust-free filter paper is numbered for subsequent identification, and the weighing is performed using an electronic balance . Then take it out of the center and take it to the air test station. Samples were taken 24 hours a day at an average flow rate of 30 m3/h. After returning to the laboratory, the sample was again placed under constant temperature and relative humidity for 48 hours and then weighed using an electronic balance . The mass of the particulate matter PM is calculated based on the difference in weight. The particulate matter remains on the filter paper for a certain period of time. The concentration is calculated by differential weighing of the filter paper. Two key issues involved in this standard approach can be effectively addressed with METTLER TOLEDO's electronic balance solutions. First, because of the light weight of the filter paper and the large surface area, the pre-weighing process and the homing process time are different, and fluctuations in temperature, humidity, and air pressure cause errors. For this METTLER electronic balance LubX software automatically performs the necessary mathematical corrections for each weighing. Second, the filter paper is susceptible to electrostatic charge, resulting in incorrect readings. An anti-static assembly that can be installed next to the METTLER electronic balance can effectively neutralize the charge of the filter paper before weighing. The special filter paper weighing unit in the METTLER electronic balance XP ultra-micro electronic balance has an automatic door opening function for quick and easy loading and unloading of filter paper. The anti-static assembly can also be turned on synchronously only when the door is opened. The integration program utilizes the software's intrinsic design tool, and METTLER TOLEDO implemented Perkins' particle measurement method in lubX. In order to comply with the regulations, the measured values ​​are accepted only when the reference filter paper has a mass change between the pre-weighing and the replies procedure that is less than 10 pg. This can also be easily integrated into this method using LabX. Each sample and reference filter paper has a unique ID. To avoid clutter or erroneous work data input in the electronic balance weighing program, the barcode label on the filter paper container allows the sample to be scanned by the bar code reader. The METTLER Electronic Balance LabX software allows Perkins to specify the content of its results report. Including company logos, charts and forms are available.