air quality regulations

December 20, 2023

Early holiday gift at Meet the Regulators!

Nicole Vogelpohl and Eva Luu attended the “Meet the Regulators” event hosted by A&WMA’s Golden West Chapter at the law firm Holland & Knight in San Francisco. It was an informative event where panelists Dr. Meredith Bauer, Hy Hinojosa, and Lisa Fasano, in for Viet Tran, from the Bay Area Air Quality Management District (BAAQMD), spoke about upcoming priorities, new organizational changes, current organizational issues, and project accomplishments. The three have recently been appointed new deputy executive officer positions at BAAQMD. They are open to taking things in a new direction regarding the permit process, communications with the public, and implementing new and upcoming methodologies for emerging analytical measurement technologies.

Environmental Justice and Air Quality

The panel discussed how, as we’ve learned and made continuous progress in air quality and local emissions reductions over the years, ozone (O3) is now less of a concern (for the Bay Area) compared to PM2.5, which now takes higher precedence as a pollutant of concern. Dr. Bauer and Lisa Fasano mentioned that in the grand scheme of things, we live in a region of great air quality; however, they acknowledge that while the greater San Francisco Bay Area has good air quality as a whole, there are always pockets of localized air pollution that need addressing. Areas specifically pointed out were marginalized communities, such as Bayview/Hunter’s Point and West Oakland. Coincidentally, SCS is currently involved in a project related to the SF Fire Department’s Training Facility moving from Treasure Island to Hunter’s Point. The goal is to ensure the air quality during their training burns will not have long-term downwind effects on the community.

Thorough Discussion Amongst the Panelists and Attendees —  Permitting Backlog Issue

The current permitting system needs to be faster, and the backlog of processed permit applications poses challenges for new clients. Attendees expressed frustration and shared testimonies about their clients moving to different states due to the extensive permitting backlog and timely process, which has ultimately halted the emersion of some new regulatory technology and projects in the state. The regulators understand the current system needs reworking and prioritizing to ease and reduce the turnover time of the permit process.

Enlightening and Enjoyable

Hearing the regulators speak passionately about their roles, goals, and investment in the organization was truly pleasing. Thanks to Pat Sullivan for knowing and having worked with everyone we talked to; everyone said hi and spoke highly of you! At “Meet the Regulators,” we connected with stakeholders from local consulting firms, attendees from the petroleum, tech, and waste management industries, and regulators – or, as Dr. Bauer renamed the group, the communicators, to help bridge the gap between the governing board and the general public.


Additional Resources




Posted by Diane Samuels at 6:00 am

September 18, 2023

Preparing for USEPA NAAQS from the Air Experts at SCS Engineers.


The other night, I woke up in a bit of a panic and thought that I must have missed an announcement by the USEPA regarding the PM2.5 NAAQS reconsideration! Did I?

The answer, thankfully, is no! However, that is not any reason to relax and take no action.

By way of background, the Clean Air Act requires that the USEPA set National Ambient Air Quality Standards (NAAQS) for each of the criteria air pollutants, including particulate matter (PM). These NAAQS are based on the best available science and aim to protect human health and welfare. In June of 2021, the USEPA announced that they would reconsider the 2020 PM NAAQS final action under the prior administration that did not lower any standards. Then, in January 2023, the USEPA published the proposed rule to revise the PM2.5 primary annual standard down from 12 micrograms per cubic meter (µg/m3) to within a range of 9-10 µg/m3. In that proposal, the agency retained the 24-hour standard of 35 µg/m3.

The comment period for this proposed rule has since closed, and the agency is now working through over 5,000 submitted comments. It is unclear when the USEPA will issue the final rule (it could be any day now) and if the new annual standard will be set at 9 or 10 or something in between.


What does this mean for me as a regulated source? What should you do? SCS Engineers recommends the following actions:

  • If you have any air quality modeling analyses in progress for PM2.5, review the annual PM2.5 analysis and ensure the results are at or below 10, or ideally 9 µg/m3.
    • NOTE: Once the proposed rule becomes final, required air dispersion modeling assessments must demonstrate compliance with the new standard before issuing a permit, even when submitting the application before the new NAAQS standard.
  • Review and understand local ambient air monitoring data and trends to develop permitting strategies depending on whether your airshed will become a non-attainment area, or if the background values will be very close to the new standard, leaving little room for regulated source emissions.
  • Review current emission inventories and calculation methodology to determine if there is room to modify conservative assumptions to reduce PM2.5 emissions.
  • Investigate potential emission reduction projects. The investigation is especially important if your area will become a non-attainment area so that you can generate offsets for future permitting needs or emission reduction banking.


Additional Resources:


About the Author: Rafe Christopherson, PE, is a project director and SCS’s industrial Clean Air Act leader. He is an air quality professional with a wide variety of experience over his 25-year career. His expertise includes consulting, working at an air quality regulatory agency and with industry. His expertise includes semiconductors, biofuels, pulp and paper, hardwoods, power generation, refineries, and general manufacturing. If you are interested in more information on this PM2.5 NAAQS reconsideration process and what it might mean for your business, you may reach Rafe at or via LinkedIn.






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


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

March 2, 2021

landfill regulatory changes


On March 1, 2021, the New Jersey Department of Environmental Protection (NJDEP) proposed several amendments to air quality regulations pertaining to the regulation of New Jersey Hazardous Air Pollutants (NJHAPs) as well as fumigation operations.  The NJHAP regulations changes could significantly impact MSW landfills because they include proposed changes to hydrogen sulfide regulation as a NJHAP.

Key changes are summarized as follows:

  • The NJDEP is proposing to regulate hydrogen sulfide as a NJHAP;
  • Proposing a reporting threshold for H2S of 90 lbs/yr,
  • Proposing a State of the Art (SOTA) threshold for H2S of 10,000 lbs/yr (5 tons/year).

Several potential implications could result from these proposed changes, including:

  • Facilities with existing Title V Operating permits would be required to calculate the potential to emit (PTE) emissions of H2S for existing sources. If H2S emissions are above the very low reporting threshold of 90 lbs/yr, the H2S PTE emission rate would need to be added to the Title V Operating permit during the next permit renewal or the next permit modification.
  • Facilities subject to Emission Statement reporting and emitting H2S in an amount greater than or equal to 90 lbs/yr would have to include H2S emissions in their annual emissions statements.
  • For sources with potential H2S emissions of 90 lbs/yr or more, risk screening would be needed as part of (1) an initial operating permit for a new major facility or (2) for a minor or significant modification to an existing operating permit.
  • For sources with potential H2S emissions of 10,000 lbs/yr (5 tons per year) or more, a SOTA analysis would be required with certain permit applications. A SOTA analysis involves evaluating and potentially implementing available control technologies to reduce emissions and considers both technical feasibility and economic impact.  The proposed changes could lead to the need to implement additional landfill gas collection, control, and potentially treatment systems at some landfills.


A virtual public hearing regarding the proposed changes is scheduled for April 8, 2021, at 4:00 PM (ET).  A link to the virtual public hearing will be posted at

Written comments are due no later than April 30, 2021, to

View the proposed changes may be viewed at


Please direct questions to your SCS Project Manager or one of our local professionals:










Posted by Diane Samuels at 5:41 pm