Air Quality Management
Turning data into knowledge
Zephyr has three decades of experience in helping clients to characterise, manage and control conventional air pollutants across all industry sectors.
We offer a holistic approach to air quality modelling and management.
We use the optimal air quality modelling tools to fit your application. Having previously maintained NATA-accredited methods for ambient air quality monitoring, we are skilled in designing an air quality monitoring solution that balances budget and utility.
For straightforward evaluations, we may use screening level tools such as CALINE, CAL3QHCR or the RAQST roadway assessment tools. More typically, we apply regulatory dispersion models such as the USEPA's AERMOD or the CALPUFF modelling suites. For advanced, or regional assessments we apply state-of-the-science software including WRF, WRF-CHEM, SCIPUFF or CMAQ.
See our other core areas of work
Air quality relevant projects
Major International Airport Master Plan and Environment Strategy
We delivered a specialist air quality assessment to support the development of two Master Plans and Environment Strategies for a major international airport. The work included preparing emissions inventories for multiple pollutants for a base year and two future years, covering aircraft, APUs, GSE, parking, roads and stationary sources such as boilers and generators. Detailed dispersion modelling focused on nitrogen dioxide, fine particulate matter and air toxics, completed using the Aviation Environmental Design Tool (AEDT). The whole-of airport model continues to be used to inform future expansions and modifications.
Airport Ambient Air Quality Monitoring
We managed and reported data from a regulatory‐grade ambient air quality monitoring station at a major airport, meeting requirements of the national testing authority. Additional periodic monitoring of air toxics—including benzene and formaldehyde—was undertaken using evacuated canisters. This monitoring provided robust evidence to inform long‐term environmental management and future airport expansion.
International Airport – Ambient Air Quality Monitoring
We specified, procured and oversaw the installation and maintenance of a regulatory‐grade air quality monitoring station for an international airport. Our work included site suitability assessment, parameter selection, review of proposed equipment, and ongoing data verification and reporting.
Urban Airshed Ambient Monitoring Network
To support a major program of new road infrastructure, we procured, installed and maintained a city‐wide ambient monitoring network of 12 regulatory‐grade stations. These data underpinned the air quality assessments for multiple new urban road tunnels.
Air Emissions Exposure Compliance Monitoring Papua New Guinea
We completed occupational and environmental monitoring at several oil and gas processing facilities in the PNG Southern Highlands. Occupational monitoring measured CO, NO, NOₓ and VOCs, while ambient monitoring included PM₁₀, metals and VOC sampling via evacuated canisters using USEPA Method TO‐15. Results informed compliance assessment against permit requirements.
New Road Tunnel Ventilation Optimisation in a Major Urban Centre
We assessed the air quality impacts of all major new road tunnels within a large state‐led infrastructure program. The work included iterative optimisation of tunnel ventilation design using road‐ and portal‐specific modelling software across thousands of road links. We delivered numerous presentations to regulators and stakeholders, and participated in community forums to explain the methodology and results. Our involvement also included designing, procuring and maintaining a network of regulatory‐grade ambient air quality monitoring stations.
In‐Vehicle Nitrogen Dioxide Concentrations in Tunnels
We investigated NO₂ exposure for vehicle occupants travelling
through major and minor tunnels and busy surface roads. Using
high‐resolution direct‐measurement instruments inside and
outside nine vehicle types, we evaluated how vehicle age,
design and ventilation settings influenced exposure. Findings
showed that in‐vehicle concentrations were consistently lower
than external levels in major tunnels, particularly when cabin
recirculation was enabled. Results informed future tunnel design
and user safety measures.
Public Transport Climate Risk Assessment
We completed a climate risk assessment for new major public transport infrastructure, engaging key stakeholders through workshops and consultations. The assessment followed a standard methodology involving hazard identification, vulnerability analysis, exposure assessment, impact and risk evaluation, and adaptation and mitigation planning.
Local Government Air Quality Management Toolkit
We prepared a suite of guidance notes and supporting materials to assist local government regulators in understanding and managing air quality within their jurisdictions. Commissioned by state government, the project included both the development of the toolkit and the delivery of stakeholder training sessions.
Development of a Steelworks Site‐Wide Air Emissions Model
We developed a site‐wide atmospheric dispersion model for a major steelworks to enable the client to add or remove industrial emission sources and assess alternate operating scenarios. The model incorporated more than 40 stacks, area sources and several buoyant fugitive sources, and included multiple pollutants such as particulates, gases and metals. This work now provides the client with a flexible tool to support environmental management and long‐term planning.
Quarry Air Quality Assessment
We completed an air quality assessment for a proposed sand quarry expansion involving five years of AERMOD dispersion modelling for PM₁₀, PM₂.₅ and respirable crystalline silica. Results showed that background concentrations, rather than project emissions, were the dominant driver of particulate levels. The findings supported a justified variation to the standard 500‐metre separation distance
Odour Risk Assessment for a Resource Recovery Precinct
We undertook a comprehensive odour risk assessment for a proposed 550,000‐tonne‐per‐year waste transfer and resource recovery precinct. Using field odour surveillance from a reference site and site‐specific WRF meteorological modelling, we demonstrated that best‐practice controls— including negative‐pressure enclosures, rapid‐close doors and carbon‐filtered containers—would reduce odour impacts to negligible levels at all sensitive receptors.
Adaptive Dust Management System
We delivered an innovative digital ADMS for a combined landfill and resource recovery facility. The system integrated real‐time PM₂.₅ and PM₁₀ monitoring with an automated escalation protocol covering four operational levels, triggering alerts and recommended actions when thresholds were exceeded. This transformed traditional paper‐based dust management into a responsive, real‐time operational tool that supports compliance and community protection.