Performance evaluation of DXC1 visual obstruction phenomenon observer and its relationship with weather conditions

LI Xinhao; LI Guohua; CHEN Zhenghong; SONG Yun; CHEN Yu; SHEN Yi

doi:10.19513/j.cnki.hyqxxb.20250618001

Abstract：Taking the hourly data of PM2.5 mass concentration monitored by the LGH-01E β-ray method atmospheric particulate matter monitor(hereinafter referred to as the atmospheric particulate matter monitor)in 2024 at Huanggang national basic meteorological station as the benchmark,combined with simultaneous meteorological data,this study systematically evaluates the accuracy and consistency of the observation data from the newly deployed DXC1 visual obstruction phenomenon observer(hereinafter referred to as the visual obstruction observer)at the same station.It also analyzes the impacts of climatic characteristics in different months and various meteorological factors on the differences between the observation data of the two devices.The results are as follows.(1)The monthly analysis reveals that the PM2.5 mass concentration from the visual obstruction observer and the atmospheric particulate matter monitor exhibits a consistent monthly variation characteristic of first decreasing and then increasing.Their difference is the smallest from May to August,and the maximum negative bias reaches-20.1 μg·m一3 from October to December.(2)In terms of meteorological factors,under high humidity conditions(relative humidity equal to or higher than 80％),the average error of PM2.5 mass concentration measured by the visual obstruction observer is reduced to±5 μg·m-3;under low temperature conditions(temperature equal to or lower than 4 ℃),the average error of concentration increases significantly,with a maximum of-17.6 μg·m-3 at-4 ℃;under calm winds or small wind speeds,the negative bias is large,and when the wind speed is equal to or higher than 1 m·s-1,the bias decreases rapidly;under high-pressure systems(pressure higher than 1 010 hPa),the maximum negative bias can reach-40.3μg·m-3.(3)The regression slope(0.86),intercept(7.8 μg·m-3)and absolute error(12.5 μg·m-3,when PM2.5 mass concentration equal to or lower than 100 μg·m-3)of PM2.5 mass concentration from the visual obstruction observer meet the requirements of the observer's performance indicators.When the mass concentration is higher than 100 μg·m-3,the relative error is 23.5％,which exceeds the requirements.(4)The annual average systematic error of PM2.5 mass concentration from the visual obstruction observer is-3.86 μg·m-3,which is slightly lower.In conclusion,the visual obstruction observer exhibits good data reliability,and the data quality is closely related to different weather conditions.