In order to conduct real-time quantitative monitoring of dust storms, Ka-band millimeter wave radar (MMWR) was utilized for the consecutive detection of dust storms over the Taklimakan Desert from April to June 2018. The retrievals of the reflectivity factor, dust spectrum distribution and dust mass concentration were carried out with the power spectrum data detected by MMWR for three dust storm processes. The analysis shows that: The probability density distribution of dust conforms to the lognormal distribution. During the dust storm processes, the effective detection height of the reflectivity factor was within 2000 m and the range of the reflectivity factors was between $-25\mathrm{dBZ}$ and $25\mathrm{dBZ}$ . During the floating dust period, the effective height of the dust spectrum distribution was lower than 300 m and the values of dust mass concentration were less than 31.62 $\mathsf{\mu }\mathrm{g}·{\mathrm{m}}^{-3}$ , at a height of 200 m. Furthermore, during the blowing sand stage, the effective height of the dust spectrum distribution was normally lower than 600 m and the values of dust mass concentration were mainly less than $316.23\mathsf{\mu }\mathrm{g}·{\mathrm{m}}^{-3}$ , at a height of 200 m. During the dust storm period, the effective height of the dust spectrum distribution exceeded 1000 m; when the height was 100 m, the values of dust mass concentration were between $1220\mathsf{\mu }\mathrm{g}·{\mathrm{m}}^{-3}\mathrm{and}\mathrm{42,146}\mathsf{\mu }\mathrm{g}·{\mathrm{m}}^{-3}$ and the average mass concentration was $9287\mathsf{\mu }\mathrm{g}·{\mathrm{m}}^{-3}$ ; whereas, the values of dust mass concentration were between $2\mathsf{\mu }\mathrm{g}·{\mathrm{m}}^{-3}\mathrm{and}820\mathsf{\mu }\mathrm{g}·{\mathrm{m}}^{-3}$ when the height was 1200 m and the average mass concentration was $24\mathsf{\mu }\mathrm{g}·{\mathrm{m}}^{-3}$ . The relationship between the reflectivity factor Z and the dust mass concentration M is defined as $Z=651.6M^{0.796}$ . Compared with the observational data from Grimm180 particle detector, the data of the retrieved dust mass concentration are basically accurate and this retrieved method proves to be feasible. Thus, the MMWR cans be used as a new device for quantitative monitoring of dust storms.

To reveal the high-resolution atmospheric and statistical characteristics of haze events within the boundary layer (BL) in different months, this study conducted a combined detection experiment using a wind-profiling radar, a microwave radiometer, and an ambient particulate monitor on 1230 haze events occurring at Xianyang Airport from 2016 to 2021. First, the boundary layer heights (BLHs) of the haze events were calculated using the atmospheric refractive index structure constant, wind direction and speed, and these were verified against reanalysis data from ERA-Interim. Spatial–temporal evolution and statistical characteristics of temperature, and relative humidity and horizontal wind during haze events, were then analyzed. Finally, the relationships between the BLH and AQI (air quality index) and ${\mathrm{PM}}_{2.5}$ during the haze events were analyzed. The results indicate that the average BLHs during haze events at Xianyang Airport were generally lower than 1000 m. Moreover, the average BLHs in December and January were distributed in the range of 200–600 m, and lower than that in June and July, in a range of 500–1100 m. Furthermore, the maximum value of the average BLH appears at 13:00–15:00. When the temperature was low in the morning, the stratification difference was small and the sensible heat flux between ground and air was still weak, leading to a low BLH value. Meanwhile, when the air quality was poor, the relative humidity was relatively large, and the corresponding AQI and ${\mathrm{PM}}_{2.5}$ were very large. Subsequently, when the temperature gradually increased with time, the heat flux and the average BLH also gradually increased. Moreover, the relative humidity within the BL decreased, and the corresponding AQI and ${\mathrm{PM}}_{2.5}$ also gradually decreased, with the corresponding air quality improving accordingly. The results obtained herein provide a key reference for the preparedness of haze events.

To reveal the temporal–spatial characteristics of air pollution during winter haze events on the north slope of the Tianshan mountains, a combined detection experiment was conducted in this study using a tethered airship, Lidar, and ground monitors from December 2019 to January 2020 in Shihezi. First, the boundary layer height (BLH) was calculated using the temperature, relative humidity, wind speed, and atmospheric pressure detected by the tethered airship; the BLHs were mainly distributed from 200 m to 450 m, with the visibility (V) mainly less than 3000 m. Subsequently, the temporal–spatial characteristics of the atmospheric pollutants were analyzed. The results show that during winter haze events, the temperature was mainly between −5 °C and −15 °C, and the relative humidity was between 60% and 75%, with a wind speed of less than 2 m/s. Moreover, the temperature difference ($\Delta$T) within the BLH was basically greater than 0, except from 14:00 to 18:00, and a larger $\Delta$T corresponded to a lower V and more severe pollution, which indicates that the sensible heat flux is very weak, and the atmospheric structure is very stable. Meanwhile, the PM_2.5 and PM₁₀ were mainly concentrated between 130 and 180 $\mathsf{\mu }\mathrm{g}·{\mathrm{m}}^{-3}$ and between 160 and 230 $\mathsf{\mu }\mathrm{g}·{\mathrm{m}}^{-3}$, respectively; the maximum PM_2.5 and PM₁₀ appeared at 11:00–13:00. Furthermore, the black carbon was distributed at 6–8 $\mathsf{\mu }\mathrm{g}·{\mathrm{m}}^{-3}$ and decreased significantly around the BLH. Moreover, the extinction coefficient (EC) had a negative correlation with the V, and the maximum of the EC was 9 km⁻¹ when V was the minimum (less than 1500 m) from 10:00 to 11:00. Finally, the relationship between V and the air quality index (AQI) is constructed as $AQI=456e^{-0.00061V}$. The conclusions obtained provide a reference for haze elimination and environmental governance of the locale.