Particulate matter emission rates from beef cattle feedlots in Kansas—Reverse dispersion modeling

Figures & data

Table 1. Description of feedlots KS1 and KS2

Parameter		Feedlot KS1	Feedlot KS2
Capacity, head		30,000	25,000
Area, ha		50	68
Dust control methods	Water sprinklersystem	≤5 mm/day	None
	Pen cleaning	2 to 3 times/year-pen	5 to 6 times/year-pen
Weather conditions	Prevailing winddirection	South-southeast	South-southeast
	Average annualprecipitation (mm)	679	757

Figure 1. Schematic diagram showing locations of PM₁₀ samplers and weather stations at feedlots (a) KS1 and (b) KS2.

Figure 2. Wind speed and wind direction distributions at the feedlots for the 2-yr period: (a) KS1 May to November; (b) KS1 December to April; (c) KS2 May to November; (d) KS2 December to April.

Table 2. Median PM₁₀ concentrations at feedlot KS1 and KS2 for 2007 and 2008

	Feedlot KS1		Feedlot KS2
	12 a.m.–4 p.m.	5 p.m.–11 p.m.(EDP)	12 a.m.–4 p.m.	5 p.m.–11 p.m.(EDP)
Number of hourly values	4376	2066	3751	1607
Downwind concentration (μg/m^3)	49	82	38	53
Upwind concentration (μg/m^3)	23	27	13	17
Net concentration (μg/m^3)	32	47	22	37
Note: For each feedlot (i.e., KS1, KS2) and location (i.e., downwind, upwind, net), median concentration values for the 12 a.m.–4 p.m. and 5 p.m.–11 p.m. periods are not significantly different at the 5% level of significance.

Figure 3. Median hourly net PM₁₀ concentrations for feedlots (a) KS1 and (b) KS2. Median values were based on days with emission data. Error bars represent upper standard deviation estimates.

Table 3. PM₁₀ emission fluxes and factors at feedlots KS1 and KS2

		Emission Flux(g/m^2-day)		Emission Factor(kg/1000 hd-day)
Year	Parameters	KS1	KS2	KS1	KS2
January to December 2007	Number of Daily Values	101	91	101	91
	Minimum	0.04	0.09	1	2
	Maximum	9.70	6.84	162	187
	Median	1.68	1.08	28	30
January to December 2008	Number of Daily Values	140	95	140	95
	Minimum	0.07	0.06	1	2
	Maximum	9.04	6.86	151	188
	Median	1.58	1.13	26	31
Overall	Minimum	0.04	0.06	1	2
	Maximum	9.70	6.86	162	188
	Median	1.60^a	1.10^b	27^c	30^c
Note: Overall median emission fluxes or emission factors followed by the same letters are not significantly different at the 5% level of significance.

Figure 4. Monthly trends of emission flux plotted with temperature at feedlots (a) KS1 and (b) KS2; with amount of rain at (c) KS1 and (d) KS2; and with amount of sprinkler water at (e) KS1.

Figure 5. Median hourly PM₁₀ emission fluxes at feedlots (a) KS1 and (b) KS2. Median values were based on days with emission data. Error bars represent upper standard deviation estimates.

Figure 6. Percentage contribution of each hour to the daily PM₁₀ emission flux for feedlots KS1 and KS2 based on mean hourly PM₁₀ emission fluxes for the 2-yr period using days with emission data.