--- title: "Landfill Gas, Biogas & Odor Monitoring | Aethair" description: "Landfill gas, biogas plant, and wastewater odor monitoring: surface and perimeter methane, hydrogen sulfide, and ammonia for odor complaint investigation,…" url: https://aethair.io/solutions/landfill-biogas/ --- Aethair solutions # Landfill, Biogas & Odor Methane, H₂S, and odor complaint response Landfill gas, biogas plant, and wastewater odor monitoring: surface and perimeter methane, hydrogen sulfide and ammonia for odor complaint investigation, CO₂, and wind direction to trace odor episodes back to their source. [Schedule a call](https://calendly.com/d/ctdd-mkr-v9v/aethair-demo-website) [Build a Configuration](https://aethair.io/build/?params=ch4,h2s,co2,wind_speed,wind_direction\&solution=landfill-biogas) At a glance 3 core parameters [Methane (CH₄)](https://aethair.io/parameters/ch4/) [Hydrogen Sulfide (H₂S)](https://aethair.io/parameters/h2s/) [Carbon Dioxide (CO₂)](https://aethair.io/parameters/co2/) 3 devices cover it - **Aethair PRO** Aethair CO₂ (dual NDIR) · Aethair CH₄ · Custom MultiSense - **Thiamis** R.M. Young Weather Stations 3 standards set limits - [OSHA OSHA Permissible Exposure Limits (PEL)](https://aethair.io/resources/osha-air-quality-standards-compliance/) - [OSHA Confined-Space Atmospheric Limits](https://aethair.io/standards/confined_space/) - [EPA EPA Landfill Explosive Gases Control (40 CFR 258.23)](https://aethair.io/standards/epa_landfill_methane/) Why it matters ## Why Landfill, Biogas, and Odor Sites Monitor Air Landfills and biogas facilities generate large volumes of gas as organic material breaks down, and managing that gas is both a safety obligation and a duty to neighbors. Methane is flammable and a powerful greenhouse gas, so uncontrolled surface emissions represent a hazard, a lost energy resource, and a climate liability. At the same time, the hydrogen sulfide and ammonia in landfill and digester gas are the compounds behind the odor complaints that can define a site's relationship with its community. Monitoring exists to find leaks and surface emissions, to control odor at the boundary, and to provide the evidence that answers a complaint or a regulator. Odor disputes in particular turn on being able to show what was in the air and where it came from, which makes continuous, wind-referenced monitoring the difference between managing a complaint and merely absorbing it. What to measure ## What to Measure and the Limits That Apply The core panel covers the main program. Other parameters are added for a specific site or requirement. Every limit below is the published value from the standard that sets it. **Methane (CH₄)** is the primary target for both safety and emissions, measured across the surface and around the perimeter to find leaks and cap failures. **Hydrogen sulfide (H₂S)** and **ammonia (NH₃)** are the principal odor compounds, the ones neighbors actually smell, so they anchor any odor program. **Carbon dioxide (CO₂)** accompanies methane as a marker of active decomposition and gas migration. **Wind speed and direction** are essential for odor work: they trace a detected compound back toward its source on the site and forward toward the receptors likely to be affected. **VOCs** may be added where the waste stream or digester feedstock warrants. Methane (CH₄) Gases & VOCs [**25 %LEL** *In facility structures* · EPA 258.23](https://aethair.io/standards/epa_landfill_methane/ "excluding gas control or recovery components") [**100 %LEL** *At the property boundary* · EPA 258.23](https://aethair.io/standards/epa_landfill_methane/ "the lower explosive limit itself") Methane is the energy product and the primary hazard of landfill gas and anaerobic digestion, flammable in confined build-ups and a potent greenhouse gas when it escapes. Continuous methane monitoring at the surface, perimeter, and gas-collection system manages explosion risk, verifies capture efficiency, and supports the emissions obligations landfill and biogas operators carry. - **EPA 258.23** 25 %LEL: excluding gas control or recovery components - **EPA 258.23** 100 %LEL: the lower explosive limit itself [Methane (CH₄): sensors, units, and every standard](https://aethair.io/parameters/ch4/) Hydrogen Sulfide (H₂S) Gases & VOCs [**20 ppm** *Ceiling* · OSHA PEL](https://aethair.io/resources/osha-air-quality-standards-compliance/) [**10 ppm** *Common alarm setpoint* · OSHA confined space](https://aethair.io/standards/confined_space/ "not set by 1910.146, which defers to the OSHA limit (a 20 ppm ceiling); 10 ppm is a common gas-detector alarm setpoint") Landfills and anaerobic digesters generate hydrogen sulfide as organic matter decays, making H₂S both a toxic-gas safety hazard and the primary driver of odor complaints around these sites. Continuous H₂S monitoring, in the breathing zone for worker safety and at the boundary with wind data for odor, is central to landfill-gas and biogas management. - **OSHA confined space** 10 ppm: not set by 1910.146, which defers to the OSHA limit (a 20 ppm ceiling); 10 ppm is a common gas-detector alarm setpoint [Hydrogen Sulfide (H₂S): sensors, units, and every standard](https://aethair.io/parameters/h2s/) Carbon Dioxide (CO₂) Gases & VOCs [**5000 ppm** *8-hour TWA* · OSHA PEL](https://aethair.io/resources/osha-air-quality-standards-compliance/) Landfill and biogas sites generate carbon dioxide alongside methane as organic matter decomposes, and the CO₂ fraction is a useful indicator of the decomposition and gas-collection process. Monitoring CO₂ at landfill and anaerobic-digestion facilities supports gas-management, safety, and emissions work, usually paired with methane and hydrogen sulfide for a full landfill-gas picture. [Carbon Dioxide (CO₂): sensors, units, and every standard](https://aethair.io/parameters/co2/) Ammonia (NH₃) Often added · Gases & VOCs [**50 ppm** *8-hour TWA* · OSHA PEL](https://aethair.io/resources/osha-air-quality-standards-compliance/) Ammonia; a toxic, pungent gas from agriculture, refrigeration, and wastewater. [Ammonia (NH₃): sensors, units, and every standard](https://aethair.io/parameters/nh3/) VOC (Total) Often added · Gases & VOCs Total volatile organic compounds: a broadband, PID-based indicator of solvent and fuel vapors. [VOC (Total): sensors, units, and every standard](https://aethair.io/parameters/voc/) Sulfur Dioxide (SO₂) Often added · Gases & VOCs [**5 ppm** *8-hour TWA* · OSHA PEL](https://aethair.io/resources/osha-air-quality-standards-compliance/) Sulfur dioxide: a criteria pollutant from fossil-fuel combustion that irritates the respiratory system. [Sulfur Dioxide (SO₂): sensors, units, and every standard](https://aethair.io/parameters/so2/) Wind Direction Often added · Meteorology Horizontal wind direction (0–360°). [Wind Direction: sensors, units, and every standard](https://aethair.io/parameters/wind_direction/) Wind Speed Often added · Meteorology Horizontal wind speed. [Wind Speed: sensors, units, and every standard](https://aethair.io/parameters/wind_speed/) ![Aethair PRO under its solar panel on a metal pole by a chain-link fence, running off-grid.](https://aethair.io/images/solutions/catalog/aethair-pro-solar-fence.webp) The setup ## How a Monitoring Setup Works An Aethair PRO measures methane, hydrogen sulfide, and carbon dioxide with its gas sensor cartridges, which makes it a strong perimeter and surface-monitoring node for the core landfill gases that logs continuously and alerts on a rise. Ammonia sits outside that cartridge set, so a Thiamis gateway connects an instrument that measures it, such as a RAE Systems multi-gas detector with an ammonia sensor (and, where needed, a professional surface-emission or specialist gas analyzer) into the same dashboards. Wind data, from a weather station on a Thiamis, is what makes odor attribution possible: it pairs every H₂S or ammonia reading with the direction it came from. Nodes are sited along the boundary facing the nearest homes and at known emission points across the cap. The recommended configuration below pairs that landfill-gas node (one Aethair PRO for the core gases) with a weather station on a Thiamis for wind. The second tab is the gas node alone. Use the configurator to add ammonia, VOCs, or surface-scanning instruments as the site needs them. [Customize this configuration](https://aethair.io/build/?params=ch4,h2s,co2,wind_speed,wind_direction\&solution=landfill-biogas) Which monitor ## The Monitors in This Configuration The configuration above is built from these monitors. Every reading lands in the same Environet account, with the same alerts and reports. ### [Aethair PRO](https://aethair.io/products/pro/) [Industrial monitor for indoor and outdoor sites. Built-in sensors cover the essentials, and hot-swappable gas sensor cartridges and a differential-pressure option add more.](https://aethair.io/products/pro/) [19 swappable cartridges (H₂S, SO₂, NO₂, CO, O₃, CH₄ and more) in 2 gas sockets, 1 MultiSense socket, and 1 expansion socket](https://aethair.io/products/pro/) [See Aethair PRO](https://aethair.io/products/pro/) ### [Thiamis](https://aethair.io/products/thiamis/) [A gateway that connects the third-party instruments you choose to the Aethair Platform.](https://aethair.io/products/thiamis/) [RS-232, RS-485, SDI-12, and USB · 224 device models from 35 integrations](https://aethair.io/products/thiamis/) [See Thiamis](https://aethair.io/products/thiamis/) What you get ## Readings, Alerts, and the Report That Proves It Every reading goes to the Aethair platform. Here is what a monitoring program gets from it. ### [Live data and alerts](https://aethair.io/platform/environet/) Every reading in Environet as it happens, with alerts by email, SMS, or webhook at the thresholds you set. ### [Compliance reports](https://aethair.io/platform/reports/) Scheduled or on-demand reports against the standards above or your own limits, as PDF or a secure link. ### [Dashboards and AI analysis](https://aethair.io/platform/dashboards/) Live displays for a site or the public, and Noesis answering questions about the data in plain language. ### [Your data, through the API](https://docs.environet.io/) Live and historical readings as JSON or CSV through the Environet API (OpenAPI 3.2), for a building management system, an ERP, or your own applications. The data is yours. [See a sample report](https://aethair.io/docs/aethair-hq-first-floor-report-example.pdf) Article Library ## Reading for Landfill, Biogas & Odor ### [OSHA Air Quality Standards 2026: PELs & 29 CFR 1910.1000](https://aethair.io/resources/osha-air-quality-standards-compliance/) OSHA air quality standards for indoor and outdoor work: permissible exposure limits, Table Z-1, 29 CFR 1910.1000, and the heat and wildfire smoke triggers. ### [Fenceline Air Quality Monitoring: Equipment and Approaches](https://aethair.io/resources/fenceline-air-quality-monitoring/) Compare fenceline air quality monitoring approaches: standalone stations, pelican-case kits, and connected 4G sensor networks. [All articles](https://aethair.io/resources/) Related solutions ## Related Solutions ### [Oil & Gas / Petrochemical](https://aethair.io/solutions/oil-gas/) Fence-line VOC, H₂S, and methane leak detection ### [Occupational Safety & Industrial Hygiene](https://aethair.io/solutions/occupational-safety/) Worker exposure, confined space, and heat stress ### [Outdoor Monitoring](https://aethair.io/solutions/outdoor-monitoring/) Continuous outdoor air quality networks that sit alongside reference monitors [All solutions](https://aethair.io/solutions/) Questions ## Landfill, Biogas & Odor FAQ Which gases cause landfill and 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. Why is wind direction critical for odor monitoring? 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. Can one device measure methane and odor gases together? 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. What methane and H₂S levels apply to a landfill? 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. What is the best monitoring setup for landfill and biogas? 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.