Estimating exposure to hydrogen sulfide from animal husbandry operations using satellite ammonia as a proxy: Methodology demonstration.

Husbandry trace gases that have climate change implications such as carbon dioxide (CO), methane (CH) and ammonia (NH) can be quantified through remote sensing; however, many husbandry gases with health implications such as hydrogen sulfide (HS), cannot. This pilot study demonstrates an approach to derive HS concentrations by coupling in situ and remote sensing data. Using AMOG (AutoMObile trace Gas) Surveyor, a mobile air quality and meteorology laboratory, we measured in situ concentrations of CH, CO, NH, HS, and wind at a southern California university research dairy. Emissions were 0.13, 1.93, 0.022 and 0.0064 Gg yr; emission factors (E) were 422, 6333, 74, and 21 kg cow yr, respectively, for the 306 head herd. Contributing to these strong E were spillway emissions from a grate between the main cowshed and the waste lagoon identified in airborne remote sensing data acquired by the hyperspectral thermal infrared imager, Mako. NH emissions from the Chino Dairy Complex, also in southern California, were calculated from Infrared Atmospheric Sounding Interferometer (IASI) satellite data for 2008-2017 using average morning winds, yielding a flushing time of 2.7 h, and 8.9 Gg yr. The ratio of E(HS) to E(NH) for the research dairy from AMOG data were applied to IASI NH emissions to derive HS exposure concentration maps for the Chino area, which ranged to 10-30 ppb HS for many populated areas. Combining remote sensing with in situ concentrations of multiple emitted gases can allow derivation of emissions at the sub-facility, facility, and larger scales, providing spatial and temporal coverage that can translate into exposure estimates for use in epidemiology studies and regulation development. Furthermore, with high fidelity information at the sub-facility level we can identify best practices and opportunities to sustainably and holistically reduce husbandry emissions.