Wet deposition and scavenging ratio of air pollutants during an extreme rainstorm in the North China Plain

Figures & data

Figure 1. Spatial distribution of the precipitation amount and scavenging ratio of fine particles during the ‘720’ rainstorm in 2016.

Figure 2. Hourly variation of precipitation, wind speed (WS), wind direction (WD) and concentrations of aerosol and gaseous pollutants during 18–22 July 2016.

Table 1. Scavenging ratio (SR) of each species due to rain events in July 2016.

Date		7/12	7/14	7/19	7/20	7/23	7/25	7/27
Precipitation (mm)		1.20	6.20	19.80	231.80	1.40	9.20	17.40
Duration (h)		6	10	11	27	1	4	4
Rain intensity (mm h^−1)		0.20	0.62	1.80	8.59	1.40	2.30	4.35
Concentration of PM2.5		51.79	36.41	67.64	57.90	95.85	53.86	38.60
SR	PM2.5	0.90	0.83	0.45	0.97	0.72	0.62	0.74
	PM1	0.84	0.41	0.42	0.93	0.60	0.63	0.64
	SO2	0.66	0.75	0.06	0.10	0.05	0.02	0.40
	NO2	0.16	0.77	0.19	0.70	0.05	0.37	0.32
	O3	0.63	0.63	0.87	0.92	0.75	0.68	0.76
	Org	0.72	0.49	0.35	0.85	0.27	0.53	0.53
	NO3	0.91	0.31	0.38	0.97	0.81	0.60	0.56
	SO4	0.91	0.44	0.45	0.93	0.73	0.58	0.41
	NH4	0.93	0.29	0.42	0.97	0.77	0.16	0.49
	Cl	0.84	0.75	0.44	0.97	0.65	0.15	0.52

Figure 3. Concentrations and wet deposition fluxes of water soluble species in rainwater collected in July 2016.

Table 2. Concentrations and fluxes of water soluble species in rainwater collected during the ‘720’ rainstorm and from December 2015 to November 2016.

Unit	Date	Rain (mm)	Na^+	NH4^+	K^+	Mg^2+	Ca^2+	Cl^−
Conc.	‘720’ rainstorm	325.6	0.06	1.66	0.00	0.61	6.10	0.10	0.83	1.08
Conc.	2015–2016 mean		3.1	4.8	0.8	2.2	17.2	9.9	28.7	29.2
Flux	‘720’ rainstorm		18.76	539.87	0.78	199.19	1987.20	31.52	270.31	351.62
Flux	2015–2016 sum	787.5	615.3	2472.1	200.9	899.5	7330.9	1692.3	7150.4	6822.1
%		41.4%	3.0%	21.8%	0.4%	22.1%	27.1%	1.9%	3.8%	5.2%