odor nuisance

August 21, 2023

Odor Complaints


Industries commonly have odor complaints, especially as suburbs encroach closer to a facility’s property boundary. Even when using scrubbers and other industrial treatment methods to eliminate odors, they can still cause nuisance problems for facilities.

To address this, environmental engineers compile processed meteorological data and odor complaint information to determine the best course of action to mitigate odor issues and create positive relations with the public.

How it Works
A large beef processing facility in Southern California has received increasing odor complaints from the public over the last five years. Enough that the courts ordered the facility to take action above and beyond what it was already providing. The engineers started by tabulating the complaints, including time, date, and supplemental information such as location, any noted comments, and findings from the regulator upon their inspection. In addition, they compiled all maintenance records from the facility and meteorological data from the adjacent airport to perform a detailed analysis of the odor problem.

By assigning each complaint with its wind speed and direction based on the logged complaint time, the engineers create a map and see that most complaints originated south of the facility when the wind blew from the north, indicating a high probability that this facility was indeed the culprit despite controls in place. Additional revelations included:

• Complaints are most common in the morning.
• All complaints are within the colder months.
• Higher wind speed mitigates odor complaints.
• Processing more cattle does not lead to more complaints, but longer processing hours may correlate.
• Scrubber maintenance reduces complaints.

Resulting Factors
Many factors contribute to odor complaints, but this assessment showed the strongest correlation when the facility performed scrubber maintenance. The scrubbers are control devices on the exit vents of the building that controls pollutants and odors leaving the facility.

Using the study results, the engineers can pinpoint recommendations to control odors. Out of all the recommendations, the simplest and most cost-effective recommendation is Option 1, to increase scrubber maintenance. Employ Option 2 if production is increasing. Options 3 through 5 are less desirable since they are more expensive or could hinder production schedules. Nonetheless, we list them so you have all of your options, as follows:

1. Perform more regular maintenance on the scrubbers, especially during the winter months.
2. Even though the system currently seems to be sized appropriately, get the scrubber manufacturer to upgrade the system if the facility increases production.
3. Install a meteorological tower on site and reduce or halt operations when the winds are slow, from the north, and in the colder months.
4. Add a deodorizing system south of the plant to inject an odor neutralizer in the air into the odor plume.
5. Construct a wind barrier or heavy-duty fans south of the plant to intersect and force more dispersion of the odorous plume.

Sustainable and Proactive Approach
The beef processing facility study determined quarterly maintenance should significantly reduce odors. Moving forward, the facility can refer to its SCS study if experiencing conditions that could increase the possibility of odors and, importantly, show regulators the facility takes a proactive approach to community concerns.


Jeffrey LeadfordMeet the Author: Jeffrey Leadford has 10 years of experience in the air quality field. His specialties include air dispersion modeling, emission inventory production, GIS mapping, and air monitoring. At SCS he creates emission inventories, reports, and runs air dispersion modeling on industrial sites in the Pacific Northwest. Mr. Leadford is a Professional Engineer licensed in Oregon, and received his Bachelor’s of Science degree in Chemical Engineering from the University of Colorado. He is also a licensed FAA Remote Pilot. Contact Jeffrey or your local resource at .


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Posted by Diane Samuels at 6:00 am

November 29, 2022

Obtaining air permit applications for cannabis manufacturing and operations - SCS Engineers
Some agricultural operations require approval from the local planning commission and air permits from the local air regulatory agency for manufacturing operations. Obtaining these permits enables industry and housing to remain good neighbors.


Agricultural growing and harvesting operations are typically exempt from air planning, permitting and odor nuisance regulations. However, cannabis operations may require approval from the local Planning Commission. They may also require air permits from the local air regulatory agency for manufacturing operations (e.g., for solvents and associated combustion equipment such as boilers). Air permit applications for cannabis manufacturing operations may include the following based on project-specific conditions:

  • Emission inventories of volatile organic compounds (VOCs) and toxic air pollutants;
  • Best Available Control Technology (BACT);
  • Air Quality Impact Assessment (AQIA);
  • Health Risk Assessment (HRA);
  • Emission Reduction Credits (ERCs); and
  • Ambient air monitoring.

In addition to these permitting services, and to avoid costly nuisance complaints, cannabis growers may also need odor-related services such as:

  • Odor assessment audits;
  • Odor sampling;
  • Odor dispersion modeling;
  • Odor mitigation;
  • Specialized Total Reduced Sulfate (TRS) Monitoring (Odor Surrogate);
  • Ventilation evaluations for greenhouses and processing buildings;
  • Odor Abatement Plans (OAPs) and Odor Management Plans (OMPs); and
  • Planning Commission hearing support.

While these may seem like imposing lists for air planning they are not for engineers who work in the industry.

Developing effective plans to mitigate odors is vital in gaining Planning Commission approvals which often depend upon resolving concerns raised by the public. Comprehensive OAPs and OMPs include odor control Best Management Practices (BMPs) and adaptive management strategies for responding to odor complaints when cannabis operations are near residences and schools.


Odor Control – Odor Nuisance Mitigation Case Study

Cannabis greenhouses in the Carpinteria, California region were causing off-site odor nuisances at nearby residences. The inherent smell needed addressing, as odor-neutralizing vapors along cannabis greenhouse perimeters and ridgelines were not providing adequate odor control.

Working with Cannabis Association for Responsible Producers (CARP) Growers, Pacific Stone, Groundswell, and Envinity Group, SCS Engineers utilized its air quality and odor expertise to collect continuous measurements using our SCSent-i-PED (Pollutant and Environmental Data). SCSent-i-PED is a state-of-the-art method for measuring TRS compounds to the parts per billion (ppb) level. The system can assess concentrations in real time, and a single machine can assess multiple locations and sources within a facility. This method successfully assessed relative odor levels and spatial/temporal fluctuations in odor-causing emissions.

Data collection is vital and useful to:

  • Evaluate what is feasible conceptually versus operationally;
  • Predict when the highest odor concentrations occur within a cannabis greenhouse;
  • Develop standard operating procedures to minimize off-site odors; and
  • Optimize cannabis greenhouse scrubber performance.

SCS, through its years of experience in air quality and odors, provides cost-effective, sustainable solutions that enable greenhouses and facilities to coexist in urban and suburban environments. Our clients not only get solutions, but they also have the data and science to understand better how odors behave and vary within a cannabis greenhouse.


To learn more, watch a video about air planning and managing greenhouse odors at https://www.scsengineers.com/services/clean-air-act-services/odor-monitoring-and-control/


Paul SchaferAbout the Author: Paul Schafer is a Vice President and Project Director at SCS Engineers and the firm’s National Expert on Ambient Air Monitoring. During his technical career, Paul has assumed key roles in several nationally significant monitoring efforts. He has in-depth experience interfacing with regulatory agencies regarding the performance of monitoring systems, source emission tests, and continuous process monitors, which SCS operates for our clientele. He has had direct working experience with multiple local, state, and federal agencies regarding monitoring programs and air quality impact assessments. As with all solutions at SCS, cost control management and defensible technical performance are primary goals integral to all sustainable monitoring programs.






Posted by Diane Samuels at 6:00 am