| Due to the physical characteristics of large specific surface area,harmful substances such as viruses,bacteria,and heavy metals are easily adsorbed on the surface of PM2.5particles.When PM2.5 reaches a certain concentration,fine particles carrying harmful substances enter the lungs through the respiratory tract,causing various health problems such as respiratory system diseases,cardiovascular system diseases,and metabolic system diseases.With the continuous enrichment of material living standards,people’s requirements for indoor air quality monitoring and control are gradually increasing.The current main detection methods for indoor particulate matter include sampling and nonsampling methods.The sampling method has higher accuracy and more reliable detection results.However,due to the increase of PM2.5 real-time monitoring applications in civil buildings and the dense distribution of points,such methods have shown problems such as economy,high labor costs,and poor real-time performance.In addition,the sampling method is not conducive to access to the air conditioning control system for real-time control.The emergence of economical laser scattering method sensors provides a solution with good economy,low professional requirements,and good real-time performance,which is conducive to the combination of indoor environmental monitoring and building intelligence.At present,the application scale of indoor PM2.5 monitoring sensors in civil buildings is gradually increasing.However,in practical applications,the drift problem greatly reduces the accuracy and reliability of the sensor.The solution to the problem of long-term drift and short-term drift that is mainly influenced by temperature and humidity has become a key step in promoting the application of indoor PM2.5 monitoring technology.At present,there are three main solutions to the drift problem: hardware development,signal noise reduction preprocessing,and reference model modification.Due to the high cost of research and development and the reliance on breakthroughs in the discipline of materials,long-term scientific research planning is required.At this stage,the monitoring needs of people cannot be met in time.However,the development of methods to improve the accuracy of sensors through signal noise reduction preprocessing is still immature.The application of sensor drift remains at the level of qualitative discrimination,and quantitative judgment still lacks effective means.At this stage,the correction of drift by the reference model correction method is a more mature solution to improve the accuracy of the sensor on the basis of reducing the development and maintenance costs as much as possible.In this paper,the temperature and humidity drift of the sensor is studied by the reference model correction method.Through the weighing method,the economical laser scattering method PM2.5 sensor was tested,and orthogonal experiments were designed to explore the degree of influence of temperature,relative temperature and humidity,and PM2.5 concentration on the accuracy of the sensor,and find the corresponding law of influence And amend it.The study found that in the range of 5 ～ 33 ℃,the temperature will not cause the sensor to drift,and the PM2.5 concentration and relative humidity have a significant impact on the accuracy of the laser scattering PM2.5 sensor,and need to be corrected.Through the study of the influence of the single factor of PM2.5 concentration on the accuracy of the sensor,it is found that the ratio between the value of the economical sensor and the value of the high-precision instrument is linear with the concentration of the particulate matter.In this way,a quick correction method for the economical laser scattering particle sensor is obtained.In addition,the study found that the relationship between the ratio of the sensor value and the reference value with the relative humidity is a quadratic curve.According to this law,a relative humidity compensation model is established.It has been verified that the model can better correct the effect of relative humidity on the sensor. |
