Clean Air Act Services

Clean Air Act Services

National Experts: Pat Sullivan / Josh Roth;
Odor and Tracer Gas Studies & Ambient Air Monitoring Paul Schafer


The Clean Air Act (CAA or Act) touches virtually every aspect of economic activity in the United States. It requires the U.S. Environmental Protection Agency (EPA) to establish national ambient air quality standards (NAAQS) for certain pollutants in order to protect public health and welfare nationwide. The Act provides a comprehensive set of regulations to monitor air toxins and requires major sources of air pollution to obtain detailed operating permits. The CAA also requires states to adopt enforceable plans to achieve and maintain air quality standards, and to control harmful emissions that might drift across state lines.

Other key provisions of the CAA are designed to minimize pollution increases from the growing number of motor vehicles, and from new or expanded industrial plants.  The law calls for new stationary sources (e.g., power plants and factories) to use the best available technology, and allows less stringent standards for existing sources.

SCS Engineers is a leader in providing air quality services. We offer a wide variety of services to meet our clients’ air compliance and permitting needs. Our staff consists of professional engineers, chemists, scientists, and technicians experienced in understanding regulatory requirements, solving environmental problems, and providing innovative solutions. We have conducted New Source Performance Standards (NSPS)/Emission Guidelines (EG) and Title V projects at hundreds of landfills and industrial facilities, and we have strong working relationships with both industry and the regulatory community (EPA, states, and local air districts).

More about our Landfill Air Quality Services

Our professionals have years of proven experience in environmental and risk management compliance services for CAA initiatives, including:

Permitting Support

  • New Source Review (NSR) and Prevention of Significant Deterioration (PSD) applicability reviews and air permitting
  • Title V and state operating permits, including renewals and modifications
  • Reasonably Available Control Technology (RACT)/Best Available Control Technology (BACT)/Lowest Achievable Emission Rate (LAER) analyses
  • Minor source construction permitting
  • Ambient air dispersion modeling analysis
  • Air emissions inventories
  • Ambient air monitoring
  • Permit negotiations

Compliance Assistance

  • Greenhouse gas (GHG) inventories, verification services, permitting, and compliance
  • GHG Reporting Rule plan development/monitoring/reporting
  • Section 114 information request assistance
  • NSPS/National Emission Standard for Hazardous Air Pollutants (NESHAP)/Maximum Achievable Control Technology (MACT) applicability determinations and compliance
  • NSPS/NESHAP compliance reporting
  • Compliance assistance database development
  • Title V compliance reporting
  • Air compliance audits
  • National Environmental Policy Act (NEPA) and California Environmental Quality Act (CEQA) air quality and GHG assessments
  • Annual emission inventories and reporting
  • Custom emissions tracking tool development
  • Risk management planning
  • Air toxics risk assessment
  • Regulatory advocacy for air quality and landfill gas (LFG) issues
  • Litigation support and expert witness services

Performance Testing

  • Air quality monitoring
  • Indoor Air Quality (IAQ) surveys
  • Performance testing planning, preparation, oversight and reporting
  • Gas monitoring/sampling
  • Visible emissions observations
  • Atmospheric tracer studies
  • Numerical model validation
  • Fugitive odor testing and evaluation


  • LFG system engineering design and utilization studies
  • Design, permitting, operations, and construction of LFG-to-energy (LFGE) and LFG control facilities
  • Air pollution control equipment evaluation and design, including source testing and field monitoring
  • Geographic Information Systems (GIS) design and support services

Control Technology Analysis

  • Contractor and vendor prequalification
  • Performance specification and bid document preparation
  • Bid package review and recommendation

Landfill Air Quality Services

The primary air quality concern at landfills involves LFG emissions, and the main compliance tool is the Gas Collection and Control System (GCCS). The NSPS/EG rules require LFG testing and collection system installations at many sites, and they require landfill owners/operators to:

  • Estimate total LFG emissions using sophisticated gas models, laboratory analyses, and gas pump tests
  • Install comprehensive gas collection systems throughout the landfill at any site shown to have high emissions of non-methane organic compounds (NMOCs)
  • Perform long-term operation and record keeping on such LFG systems

SCS Engineers offers comprehensive LFG services to help you meet regulatory compliance requirements within budget, including engineering test services, laboratory analysis, gas system design, system installation, and operations. We find that once compliance with NSPS air quality criteria is achieved, other LFG issues (e.g., lateral migration, impacts to groundwater, odor, etc.) usually begin to resolve.

Typical CAA tasks that SCS performs for landfills include:

  • NSPS Tier 1 NMOC emission modeling
  • NSPS Tier 2 testing
  • GCCS design plans
  • GCCS design, construction, operation, and maintenance
  • Surface emission monitoring
  • Wellfield monitoring and adjustment
  • Data analysis
  • Compliance reports
  • Startup, shutdown, and malfunction (SSM) plans and reporting
  • Expert witness

Because of our extensive CAA experience, SCS is well-positioned to perform additional services that may be required as new air quality regulations are issued in the years ahead.

Air Compliance Reporting

Air Compliance Reporting SCS Engineers helps industrial, commercial, and institutional clients comply with the Clean Air Act (CAA or Act). We determine how the rules and regulations affect your operations, … Continue reading Air Compliance Reporting

Air Emissions and Permitting

Air Emissions and Permitting The Clean Air Act (CAA or Act) provides a comprehensive set of regulations to monitor criteria and toxic air pollutants, and it requires major sources of … Continue reading Air Emissions and Permitting

Ambient Air Monitoring

Ambient Air Monitoring National Expert:  Paul Schafer SCS Engineers has advanced capabilities to design, implement, and conduct ambient air quality measurement programs. We supervise and operate air quality monitoring networks … Continue reading Ambient Air Monitoring

Dispersion Modeling

Dispersion Modeling Using our modeling tools, the SCS Engineers team of modeling professionals can determine baseline pollutant concentrations, evaluate compliance with the national ambient air quality standards (NAAQS), analyze Prevention … Continue reading Dispersion Modeling

NSPS/NESHAP Compliance

NSPS/NESHAP Compliance SCS Engineers has experience and expertise across a wide range of air compliance services, and we can help you evaluate and implement regulatory compliance requirements at all levels. … Continue reading NSPS/NESHAP Compliance

Odor Monitoring and Control

Odor Monitoring and Control National Experts:  Paul Schafer and Pat Sullivan Odor pollution is a significant aspect of a region’s air quality and is often regulated as a nuisance. It … Continue reading Odor Monitoring and Control

Tracer Gas Studies

Tracer Gas Studies SCS Tracer, a specialty division of SCS Engineers, is the most experienced and versatile tracer science consulting team in the United States. Collectively, our tracer experts possess … Continue reading Tracer Gas Studies