[Analysis of Atmospheric Particulate Matter Pollution Characteristics by LIDAR in Beijing During Spring Festival,...

Real-time aerosol extinction retrieved by Micro-pulse LIDAR and concentrations of PM_2.5 and PM₁₀ in Beijing were analyzed to investigate the air quality during the Spring Festival. The results showed that fireworks on the New Year's Eve resulted in a sharp increase in particulate matter concentrations in a short time. The maximum concentration of PM_2.5 at Guanyuan station was 639.3 μg·m^-3, which increased by nearly 30 times in 9 h. The maximum hourly concentration of particulate matter at Dingling and Liulihe suburban stations were significantly higher than that in Guanyuan station, the maximum values were more than 1000 μg·m^-3. The particulate matter levels were continuously high on February 10-12 and the concentration of particulate matter at Dingling and Liulihe suburban stations were higher than that at Guanyuan. LIDAR results showed no obvious changes in the extinction coefficient at Dingling on the New Year's Eve. The extinction coefficient at Liulihe was greater than 1 km^-1, but the particulate matter pollution was concentrated at altitudes less than 400 m. The extinction coefficient at Chegongzhuang was still higher than 0.4 km^-1 at 500 m; however, the duration of pollution was shorter than that of Liulihe. The extinction coefficients at 105 m at all three stations during the New Year's Eve were significantly higher than those at 405 m. There were significant differences in the vertical extinction characteristics of the three sites. The background maximum values of Dingling, Chegongzhuang, and Liulihe were 0.09 km^-1, 0.20 km^-1, and 0.19 km^-1 under 1.0 km, respectively. The maximum extinction coefficients at 00:00 (midnight) were 0.23 km^-1, 1.36 km^-1, and 1.19 km^-1, which were 2.6 times, 6.8 times, and 6.0 times higher than the background value at the same time, respectively. In summary, discharge of fireworks led to a dramatic increase in the extinction coefficient of particulate matter. Temperature inversion and lower wind speeds were the main meteorological factors that contributed to this pollution event.