Landfill, Biogas & Odor

Hydrogen sulfide, with its rotten-egg smell, and ammonia are the compounds most often behind odor complaints, sometimes joined by a range of VOCs from the waste or feedstock. Methane itself is odorless, so an odor program centers on H₂S and ammonia rather than on the methane that dominates the gas by volume.

Odor complaints hinge on attribution: showing that a smell detected at a receptor originated on the site rather than elsewhere. Pairing each gas reading with wind speed and direction lets you trace the compound back to its source and forward to the affected neighbors, which is what makes the monitoring defensible.

An Aethair PRO covers methane, hydrogen sulfide, and carbon dioxide from its cartridges in a single node. Ammonia needs a dedicated sensor connected through a Thiamis gateway, so a full landfill and odor setup usually combines the multi-gas node with a Thiamis-connected ammonia sensor and a weather station.

In the US, 40 CFR 258.23 holds a municipal solid waste landfill to methane below 25 % of the lower explosive limit (1.25 % by volume) inside facility structures and below the lower explosive limit (5 % by volume) at the property boundary, checked at least quarterly; the landfill air rules add a surface-emission check at 500 ppm above background (EPA Method 21). For odor, H₂S can be smelled at a few parts per billion, far below the workplace limits on this page, so community programs compare against ambient benchmarks such as California's 1-hour standard of 30 ppb.

An Aethair PRO node for methane, H₂S, and CO₂, a Thiamis-connected ammonia sensor for odor, and a Thiamis weather station for wind-based attribution, placed along the boundary and at surface emission points. Use the configurator to add VOCs or surface-scanning instruments for your site.