This study was conducted to identify and assess key parameters affecting greenhouse gas emissions and odor intensity at a naturally ventilated dairy farm. Measurement data of greenhouse gases (CO2, CH4, N2O), odorants (NH3 and H2S), and meteorological data (wind speed, temperature, relative humidity, and solar radiation) were posited as the parameters influencing those emissions. Carbon dioxide and methane emissions correlated well to CO2-equivalent emissions and the contribution of carbon dioxide emissions (R2=0.9181) was greater than that of methane emissions (R2=0.8854). Hydrogen sulfide emissions were highly correlated with odor intensity (R2=0.9989), but the contribution of ammonia emissions to odor intensity was not significant (R2=0.0081). No correlation among CO2-equivalent and odor intensity emissions and meteorological parameters was observed. In this study, the relationship between emissions of greenhouse gases and odor intensity in a naturally ventilated dairy barn mainly depended upon carbon dioxide and hydrogen sulfide emissions. The results in this study will be helpful in the mitigation planning of greenhouse gases and odor in animal feeding operations (CFOs).

The correlation among gaseous air pollutants (odorous compounds, greenhouse gases) and meteorological parameters was analyzed in-depth using measurement data at a barn and ambient in a naturally ventilated dairy farm. Both concentration and emission data (loading rate and emission rate), which more accurately express the actual pollutant emissions, were used in the correlation analysis. Gaseous air pollutants (ammonia, hydrogen sulfide, carbon dioxide, nitrous oxide, methane) and meteorological factors (relative humidity, temperature, wind speed, solar strength) were measured for one week in July 2013. The upper and lower outliers of measured data by inducing 1.5 times the interquartile range (IQR) were eliminated. After eliminating the outliers and grouping according to data magnitude, the correlation analysis among gaseous compounds and meteorological factors was conducted using the average values of each group. In the correlation analysis, data for the emission rate (barn) and the loading rate (ambient) showed a better correlation than concentration data. Gaseous air pollutants except for hydrogen sulfide in the barn showed a good correlation. Hydrogen sulfide might not be produced from manure or animal origin. Rather, the compound may be produced by flushing water, which was flushed at periodical times (every six hours). Ammonia emissions increased with increasing temperature, and this increase can be affected from greater exertion of feces by frequent water drinking in a high-temperature condition. In the ambient, the correlation for all gaseous air pollutants was better than that in the barn, because those air pollutants from manure, animals, and flushing water origins were sufficiently mixed in the atmosphere. Wind speed also showed a good correlation with all gaseous air pollutants.

In this study, the loading rates (or emission rate) and concentrations of air pollutants (ammonia, hydrogen sulfide, carbon dioxide, methane, nitrous oxide, and particulate matter (PM2.5, PM10 and TSP)) emitted from a naturally ventilated dairy facility were analyzed and compared to enable a better understanding that are in close proximity to each other, air pollution status. In general, the pollution patterns should be similar in measurement sites that are in close proximity to each other, and this hypothesis was fundamental to our approach in this study. For the comparison in nearby different sites, monitoring points were located at inside (source site) and outside the dairy building (ambient site), and concentrations and wind velocity were simultaneously monitored in real time. The patterns of PM2.5 emission rate and loading rate were similar in the source site and the ambient site which was consist with the hypothesis, while the PM2.5 mass concentration were not similar in both sites. As well as PM2.5, the emission rates (source site) of gaseous carbon dioxide (CO2) and nitrous oxide (N2O) were highly correlated to their loading rates (ambient site), while the concentrations of CO2 and N2O were not similar. Therefore, wind velocity, which is included in the emission or loading rate, should be simultaneously monitored with the concentration at the same measurement points for better understanding of the air pollution status.