FAQs

Report Odor Here:
Puget Sound Clean Air Agency

Understanding Local Odors:
Landfill vs. Compost Site

In our community, strong odors can sometimes be a concern. Two primary sources of noticeable smells are the Cedar Hills Regional Landfill and the Cedar Grove Composting Facility. While both can produce odors, they are distinctly different in their cause and characteristics.

Select the topic to learn more!

When filing an air quality complaint about a "compost odor" (Cedar Grove) versus a "dump odor," (Cedar Hills Landfill) it is important to know the key difference lies in the source and type of gases emitted. This will help you to properly report where the odor is coming from.
Compost odors are often associated with the decomposition of organic matter and may smell like rotting food or earth, while dump odors are more likely to include a wider range of foul smells, including those from decaying waste and landfill gases. 

    • Source of Odor:

      Primarily from the breakdown of organic materials (food scraps, yard waste, etc.) during the composting process. 

    • Types of Gases:

      • Volatile Organic Compounds (VOCs): These can include compounds like ammonia, hydrogen sulfide (which smells like rotten eggs), and other sulfur compounds. 

      • Carbon Dioxide (CO2) and Methane (CH4): These are also produced during decomposition, but in smaller quantities than VOCs. 

    • Smell Characteristics:

      • Can smell like rotting fruit, vegetables, or earth. 

      • May have a musty or slightly acidic odor. 

      • Anaerobic decomposition (lack of oxygen) can lead to a foul, sulfurous smell. 

    • Factors:

      • Moisture levels in the compost pile. 

      • Aeration (or lack thereof). 

      • The type of materials being composted. 

    • Source:

      Odor comes from a wide range of waste materials, including garbage, industrial waste, and other non-organic materials, as well as landfill gases. 

    • Types of Gases:

      • Hydrogen Sulfide (H2S): A major contributor to the foul smell of landfills. 

      • Ammonia (NH3): Another common odor-causing gas. 

      • Mercaptans: Sulfur-containing compounds that have a very strong, unpleasant odor. 

      • Methane (CH4): A major component of landfill gas, which can also be odorous. 

    • Smell Characteristics:

      • A general foul, putrid, and often very strong odor. 

      • Can smell like rotting garbage, sewage, or industrial chemicals. 

    • Factors:

      • Type and amount of waste materials in the landfill. 

      • Decomposition processes within the landfill. 

      • Landfill gas collection and management practices. 

    When Filing an Air Quality Complaint:

    • Be Specific: Clearly describe the type of odor (e.g., "rotting fruit," "sulfurous," "garbage") and its intensity.

    • Provide Location: Specify the location where you are experiencing the odor.

    • Note Duration: Indicate how long the odor has been present and when it is most noticeable.

    • Consider Meteorological Factors: Mention wind direction and speed, as this can affect the spread of odors.

    • Include Supporting Evidence: If possible, provide photos or videos of the source of the odor.