Atmospheric pollution assessment near potential source of natural aerosols in the South Gobi Desert region, China

Figures & data

Figure 1. Geographic location of the study site and five main deserts of the South Gobi region.

Table 1. Annual average concentrations (±standard deviation) of air pollutants (µg/m³ for PM_2.5, PM₁₀, NO₂, SO₂ and mg/m³ for CO) in the seven cities.

	Year	PM2.5	PM10	SO2	NO2	CO
Wuhai	2016	46.5 ± 29.2	109.7 ± 69.9	55.6 ± 48.7	27.8 ± 14.9	0.94 ± 0.55
	2017	44.4 ± 25	113.3 ± 87.4	51 ± 39.5	31.1 ± 14.7	1.07 ± 0.48
	2018	40.8 ± 21.7	117.8 ± 97	34.1 ± 29.3	28.7 ± 13.4	0.99 ± 0.4
	Annual	43.9 ± 25.6	113 ± 85.4	46.9 ± 41	29.2 ± 14.5	1 ± 0.48
Alashan	2016	36.1 ± 19.8	89.2 ± 100.4	10 ± 2.7	10.3 ± 4.4	0.6 ± 0.15
	2017	35.2 ± 22.7	75.8 ± 88.9	11.3 ± 5.6	11.3 ± 4.3	0.61 ± 0.17
	2018	32.4 ± 152	70.35 ± 52	11.7 ± 8.1	11.3 ± 4.6	0.57 ± 0.17
	Annual	34.2 ± 19.5	78.4 ± 83.3	11 ± 6	11 ± 4.5	0.59 ± 0.16
Wuzhong	2016	48.47 ± 29.8	100 ± 65.6	41.7 ± 38.3	27.5 ± 14.6	0.73 ± 0.41
	2017	43.8 ± 32.8	107.4 ± 85.8	29.8 ± 22.9	29 ± 13.8	0.87 ± 0.4
	2018	38.4 ± 26.1	107.31 ± 111.5	16.4 ± 11.5	23.1 ± 10.9	0.56 ± 0.3
	Annual	43.5 ± 30	104.9 ± 89.6	29.3 ± 28.5	26.8 ± 13.4	0.72 ± 0.39
Zhongwei	2016	45 ± 27.3	100.6 ± 83.9	30.3 ± 29.7	20.9 ± 10.2	0.75 ± 0.33
	2017	38.9 ± 28.5	105.9 ± 113.5	24.1 ± 20.6	26.11 ± 11	0.84 ± 0.3
	2018	38.9 ± 25.7	115.9 ± 134.1	16.5 ± 8.5	23.9 ± 10.8	0.78 ± 0.23
	Annual	41 ± 27.3	107.5 ± 112.5	23.6 ± 22.1	23.6 ± 10.8	0.79 ± 0.29
Wuwei	2016	38.7 ± 26.4	99.5 ± 83.8	23.4 ± 22.5	27.5 ± 12.3	1.26 ± 0.67
	2017	43.8 ± 36.5	112.9 ± 169.1	13.9 ± 11.9	28.4 ± 10.2	0.92 ± 0.49
	2018	41.9 ± 32.5	120.3 ± 156	7.8 ± 4.8	25.1 ± 10.2	0.79 ± 0.4
	Annual	41.4 ± 32.1	110.9 ± 141.4	15 ± 16.2	27 ± 11	0.98 ± 0.57
Jinchang	2016	31.7 ± 21.1	103 ± 84.1	34.8 ± 26.4	1.12 ± 0.47	15.7 ± 7.4
	2017	28.8 ± 25.2	100.3 ± 126.4	26.9 ± 23.8	15.5 ± 7.4	0.59 ± 0.29
	2018	25.8 ± 22.4	105.2 ± 133.3	20 ± 16.2	15.3 ± 7.2	0.47 ± 0.22
	Annual	28.8 ± 23.1	103.1 ± 116.5	27.2 ± 23.3	15.8 ± 7.4	0.73 ± 0.44
Zhangye	2016	37.8 ± 26.5	90.3 ± 71.3	25.2 ± 27.8	22.4 ± 8.7	0.77 ± 0.47
	2017	28.9 ± 24.3	80.3 ± 95.3	13.2 ± 6.8	20.8 ± 6.9	0.58 ± 0.31
	2018	36.8 ± 26	96.4 ± 110.7	10 ± 5.2	17.5 ± 8.1	0.52 ± 0.22
	Annual	34.4 ± 25.9	89 ± 94	16.1 ± 18	20.2 ± 8.2	0.62 ± 0.37

Figure 2. Seasonal mean concentrations of pollutants in the seven cities.

Figure 3. Mean ((a) and seasonal (b) – winter, (c) – spring, (d) – summer, (e) – autumn) AOD change (550 nm) in the South Gobi region for 2016–2018.

Figure 4. Frequency distribution (in %) of AOD in the region.

Figure 5. Contour density maps of the AOD (550 nm) versus AE (440–870 nm) in the period 2016–2018 for indicating major aerosol type in the South Gobi region. Figures in brackets demonstrate a percentage of each type of aerosols in the total amount for the entire study period.

Figure 6. Spatial distributions of daily average MODIS AOD during dust event days over China on 3–4 May 2017 and 2–3 December 2018. Color lines demonstrate 72-h backward trajectories of air masses arriving in the cities (3 May 2017 – Jinchang, 4 May 2017 – Wuhai and Alashan, 2–3 December 2018 – Wuwei, Zhongwei and Wuzhong) at a height of 500 m (red line), 1500 m (blue line), and 2500 m (green line).

Figure 7. Spatial distribution of OMI UV aerosol index (UVAI) during the dust storm in the territory of continental China on 3–4 May 2017.

Figure 8. Spatial distribution of OMI Aerosol Absorbing Optical Depth (AAOD) during the two dust storms in the period of 3–4 May 2017 and 2–3 December 2018.

Figure 9. Temporal variation of OMI SSA at 388 nm during dusty days and non-dusty days during 2–6 May 2017 and 1–5 December 2018 in the South Gobi.

Figure 10. The Navy Aerosol Analysis and Prediction System (NAAPS) simulated surface level dust concentration (µg/m³) on 2–3 May 2017 and 2–3 December 2018 at 6 a.m. (UTC).