Major ionic compositions of fine particulate matter in an animal feeding operation facility and its vicinity

Figures & data

Figure 1. The layer farm layout and the locations of PM sampling stations (not to scale). ST1 = PM sampling station 1; ST2 = PM sampling station 2; ST3 = PM sampling station 3; ST4 = PM sampling station 4; ST5 = PM sampling station 5. The distance marked at each station is relative to ST1 (Wang-Li et al., 2013a).

Figure 2. Comparison of NH₄⁺ concentration: with outliers vs. validated. The bottom and the top of the box are the 25th and 75th percentiles, the line near the middle of the box is the 50th percentile (median), and the circle is the mean. The whiskers represent the lowest datum with 1.5 interquartile ranges (IQR) of the lower quartile, and the highest datum with 1.5 IQR of the upper quartile. The small circle data points that are not included between the whiskers are potential outliers.

Table 1. Annual average concentrations of ions (NH₄⁺, Na⁺, K⁺, SO₄²⁻, Cl⁻, and NO₃⁻) at ST1–ST5

Ions	Station	n	Mean (μg/m^3)	SD	Median	Min	Max	Tukey grouping*
	ST1	59	0.20	0.11	0.19	0.02	0.45	C
	ST2	58	0.71	0.25	0.67	0.34	1.32	B
NH4^+	ST3	58	0.78	0.25	0.73	0.38	1.33	A/B
	ST4	60	0.83	0.30	0.77	0.40	1.53	A
	ST5	56	0.71	0.21	0.67	0.34	1.24	B
Na^+	ST1	58	0.62	0.55	0.41	0.00	1.95	A
	ST2	55	0.04	0.03	0.04	0.00	0.14	B
	ST3	55	0.04	0.03	0.03	0.00	0.13	B
	ST4	58	0.05	0.03	0.04	0.00	0.13	B
	ST5	54	0.04	0.03	0.03	0.00	0.11	B
K^+	ST1	60	1.29	1.17	1.15	0.00	3.91	A
	ST2	59	0.03	0.03	0.02	0.00	0.10	B
	ST3	60	0.03	0.03	0.02	0.00	0.10	B
	ST4	60	0.02	0.03	0.01	0.00	0.09	B
	ST5	60	0.03	0.03	0.01	0.00	0.11	B
SO4^2−	ST1	59	2.52	0.91	2.49	0.98	4.50	A
	ST2	57	2.03	0.78	1.94	0.80	4.07	B
	ST3	57	1.98	0.72	1.94	0.80	3.51	B
	ST4	59	2.04	0.80	1.91	0.77	4.09	B
	ST5	57	1.93	0.72	1.86	0.76	3.50	B
NO3^−	ST1	62	0.65	0.33	0.57	0.07	1.36	A
	ST2	56	0.27	0.17	0.26	0.02	0.67	B
	ST3	57	0.33	0.18	0.30	0.04	0.74	B
	ST4	61	0.39	0.26	0.30	0.06	0.99	B
	ST5	59	0.30	0.21	0.24	−0.02	0.73	B
Cl^−	ST1	58	1.11	0.96	0.75	0.02	3.29	A
	ST2	57	0.03	0.01	0.03	0.01	0.06	B
	ST3	58	0.03	0.01	0.02	0.01	0.05	B
	ST4	58	0.02	0.01	0.02	0.01	0.04	B
	ST5	55	0.03	0.01	0.02	0.01	0.05	B

Note: *Means with the same letter are not significantly different.

Figure 3. Seasonal variations of ions (NH₄⁺, Na⁺, K⁺, SO₄²⁻, NO₃⁻, and Cl⁻) of PM_2.5 samples taken at ST1 (the layer house) and at ambient stations surrounding the farm. (Plot description is the same as in Figure 2.)

2. Pearson correlation coefficients between anions and cations of PM_2.5 taken at in-house station (ST1) and all ambient stations (ST2–ST5)

	NH4^+	Na^+	K^+	SO4^2−	Cl^−	NO3^−
In house (ST1)
NH4^+	1
Na^+	NS*	1
K^+	NS*	0.97	1
SO4^2−	0.29	0.26	0.28	1
Cl^−	NS*	0.86	0.83	NS*	1
NO3^−	0.28	NS*	NS*	0.35	NS*	1
Ambient (ST2–ST5)
NH4^+	1
Na^+	NS*	1
K^+	NS*	NS*	1
SO4^2−	0.84	NS*	NS*	1
Cl^−	0.26	0.45	NS*	0.31	1
NO3^−	0.46	NS*	0.16	0.17	NS*	1

Note: *NS: correlation coefficients are not significantly different from zero under 95% confidence level.

Figure 4. The distribution of the ambient (NH₄⁺)_s/SO₄²⁻ molar ratio: (NH₄⁺)_s = NH₄⁺ – NO₃⁻ – Cl⁻. The superimposed curve is normal simulation.

3. Spearman correlation coefficients among ions and meteorological parameters

	NH4^+	Na^+	K^+	SO4^2−	Cl^−	NO3^−
RH	NS*	NS*	−0.31	NS*	0.28	−0.16
Temperature	0.27	0.32	−0.33	0.40	0.50	−0.14
U component of wind	0.16	0.44	NS*	0.20	0.36	NS*
V component of wind	NS*	NS*	NS*	NS*	0.16	NS*
Solar radiation	0.30	NS*	0.30	0.34	NS*	0.20

Note: *NS: correlation coefficients are not significantly different from zero under 95% confidence level.

Wang-Li, L., Q.-F. Li, K. Wang, B.W. Bogan, J.-Q. Ni, E.L. Cortus, and A.J. Heber. 2013a. National Air Emissions Monitoring Study’s Southeast Layer Site: Part I. Site characteristics and monitoring methodology. Trans. ASABE 56(3): 1157–71.

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