2.3.2 Wind erosion and particulate matter emission measurement
The collection box is placed in the middle of the wind tunnel. The
plastic film was uncovered so that the surface of the BSC flushed with
the bottom edge of the wind tunnel. Tape was used to seal the excess
space around the collection box to prevent wind speed errors. The test
subjects were divided into algal crust and moss crust. Each type of
crust contained 4 kinds of coverage (see Table 1), and there were five
wind speed gradients under each coverage (8 m/s, 10 m/s, 12 m/s, 14 m/s
and 16 m/s). Each wind speed gradient was blown and eroded for 10
minutes. It should be noted that each sample in this study only blows
once at one wind speed, and no additional experiments are carried out.
This removes the influence of different wind speed gradients on the same
sample, which causes interference to the experimental results. The
undisturbed soil collection box was weighed before each test and weighed
again afterwards. The difference in weight was used as the total wind
erosion amount of the BSC in this wind erosion test.
In order to determine the amount of particulate matter emitted during
wind erosion of different BSCs, a particulate matter concentration
observation device (Dustmate monitor, Turnkey, UK) was placed in the
rear of the wind tunnel. Observations included the concentration of
PM10, PM2.5 and PM1 (μg/m3), and the observation
frequency was set to once every 30 s.