Hydrogen Sulfide Monitoring Data at Maine Landfills


The Bureau of Remediation and Waste Management compiles hydrogen sulfide monitoring data from solid waste landfills required to perform the monitoring. Currently, each facility required to conduct monitoring, maintains monitoring equipment and reports data to the department for evaluation.

The data presented in the spreadsheets and charts was obtained from stationary Honeywell Analytics MDA Single Point Monitors. The monitors are placed at locations around the landfill sites to record continuous ambient air quality data. The locations for these monitors were chosen taking into consideration odor complaints, prevailing wind directions, and accessibility. The monitors collect data for hydrogen sulfide gas only. Based on risk assessment work done at a facility in Maine, hydrogen sulfide is the primary issue of concern in the ambient air related to potential public health impacts and is most likely the primary cause of off-site odor impacts around the landfill.

The data is presented in units of parts per billion (ppb). The monitors are able to quantify hydrogen sulfide levels between 4 ppb and 100 ppb, with an accuracy of +/- 25 percent. The Chemcassette® tapes are capable of detecting hydrogen sulfide levels down to 2 ppb. Therefore, in the attached data, there is a column labeled “Qualifier” beside the column listing the hydrogen sulfide results from the monitor. A “Qualifier” labeled “U” means that hydrogen sulfide was not detected above the 1 or 2 ppb detection limit as applicable. A “Qualifier” labeled “J” means that hydrogen sulfide was detected above the 1 or 2 ppb detection limit, but below the 4 ppb quantitation limit. The quantitation limit is the lowest numerical value that can be determined with suitable precision and accuracy. Therefore, a listed result between 1 or 2 ppb and 4 ppb is an estimated value. Results above 4 ppb are listed without any qualifiers since the result is within the specified range of the monitors.

Each facility performs routine maintenance and checks on the monitors to ensure that they are operating properly. The proper operation of these monitors requires verification of the system’s response. These “system response checks” can be seen in the data and on the attached charts resulting in a peak value around 40 ppb. Please note that these points are labeled as such on the charts, and are not hydrogen sulfide results attributable to the landfill.

We have also included the weather data collected from the onsite weather station in the current data report. This data is used to aid in data validation. The readings obtained from the monitors, during any given time period, are compared to the corresponding wind speed, wind direction, and ambient temperature in order to determine whether the landfill is the likely source of the reading. Other sources, such as diesel fuel exhaust, can also cause elevated readings.

Hydrogen sulfide monitoring data is available to the public via Google Earth at the Department's GIS Interactive Maps and Data website. The links for this are provided below:

Contact information

For more information about Pine Tree Landfill, please contact the Project Engineer Steve Farrar at 207-287-4863. For more information about Juniper Ridge, please contact the Project Engineer Amanda Wade at 207-287-2133.

Maps and Data

Hydrogen Sulfide Data

DEP Interactive Maps and Data

General Information

Standard Operating Procedure for Hydrogen Sulfide Monitoring (pdf format)

Hydrogen Sulfide Frequently Asked Questions (pdf format)

Maine's Ambient Air Guidelines for Hydrogen Sulfide (pdf format)