High-Precision Differential Optical Absorption Spectroscopy (DOAS)
Monitor trace gases and air pollutants with DOAS systems built for real-time, remote sensing across industrial and environmental settings.
Advanced DOAS Technology for Long-Range Atmospheric Gas Detection
Differential Optical Absorption Spectroscopy (DOAS) is a well-established technique for measuring trace gases in the atmosphere using ultraviolet and visible light. It enables accurate, real-time detection of pollutants such as NO₂, SO₂, O₃, HONO, and formaldehyde by analyzing their unique absorption spectra over long distances. This makes DOAS ideal for urban air quality surveillance, industrial fence-line monitoring, and environmental compliance.
Air Quality Instruments provides DOAS-based solutions engineered for dependable gas detection in complex outdoor and industrial environments. As a trusted B2B company with a growing presence across North America, we deliver robust, turnkey systems with high sensitivity and low detection limits. Designed to support continuous monitoring with minimal maintenance, our DOAS offerings empower organizations to meet strict regulatory standards, enhance operational transparency, and protect public and environmental health. Our team ensures precise system configuration, smooth deployment, and long-term support for scalable monitoring.
Core Components of Differential Optical Absorption Spectroscopy (DOAS)
In addition to offering products and systems developed by our team and trusted partners for Differential Optical Absorption Spectroscopy (DOAS), we are proud to carry top-tier technologies from Global Advanced Operations Tek Inc. (GAO Tek Inc.) and Global Advanced Operations RFID Inc. (GAO RFID Inc.). These reliable, high-quality products and systems enhance our ability to deliver comprehensive technologies, integrations, and services you can trust. Where relevant, we have provided direct links to select products and systems from GAO Tek Inc. and GAO RFID Inc.
Core Components
- UV-Vis Light Sources – Supported by Optical & Imaging Sensors for consistent spectral calibration across long optical paths.
- Receiving Optics & Spectrometer Modules – Best paired with Fiber Optic Multimeters for signal integrity testing and spectral response validation.
- Open-Path Cells or Retroreflectors – Matched with Manometers to ensure accurate pressure and flow control during open-path calibrations.
- Enclosures & Mounting Systems – Integrated with Industrial & Asset Monitoring Sensors to monitor operational conditions and enclosure stability.
- Control Units – Deployed using Industrial Tablet PCs for direct interface, diagnostics, and field-level spectral calibration management.
- Spectral Analysis Software: Performs real-time DOAS fitting and baseline corrections for accurate concentration outputs.
- Gas Library & Reference Database: Includes cross-section data for major atmospheric trace gases.
- Auto-Calibration & System Check Routines: Ensure accuracy and reliability over long-term use.
- Data Export Options: CSV, XML, or cloud API integration for third-party analysis tools and reporting systems.
- Remote Monitoring Dashboards: Access real-time gas concentration data and diagnostics from anywhere.
- Automated Reporting: Generate compliance-ready reports and custom analytics dashboards.
- Multi-Site Management: Aggregate data from multiple DOAS stations into a centralized platform.
- Alert Notifications: Trigger alerts via SMS/email for exceedance events or system faults.
Key Features and Functionalities
- Real-time detection of NO₂, SO₂, O₃, HONO, HCHO, and other trace gases
- Long-path, open-air or in-situ configurations for flexible deployment
- High spectral resolution with minimal cross-interference
- Fully automated operation with low maintenance requirements
- Integrated auto-alignment and calibration
- Remote connectivity for diagnostics, data retrieval, and software updates
Integrations & Compatibility
Our DOAS systems are designed for seamless integration with:
- Continuous Emissions Monitoring Systems (CEMS)
- Ambient Air Monitoring Networks
- Smart City and Environmental IoT Platforms
- EPA and ECCC-compliant reporting tools
- Industrial safety and environmental compliance infrastructures
Benefits of Our DOAS-Based Monitoring Solutions
- Highly Selective and Sensitive: Differentiates between gases with overlapping spectra.
- Non-Intrusive and Remote: Ideal for industrial sites, fence-line monitoring, and urban areas.
- Low Operational Cost: Minimal maintenance and reagent-free operation.
- Scalable Infrastructure: Supports expansion across facilities and regions.
- Regulatory-Grade Data: Suited for real-time compliance and early warning systems.
Applications
- Urban and roadside air quality surveillance
- Industrial perimeter and fugitive emissions monitoring
- Tunnel, traffic, and port emissions detection
- Volcanic and wildfire emissions tracking
- Academic and atmospheric research campaigns
- Safety monitoring in chemical and petrochemical facilities
Industries Served
Environmental Protection Agencies
Oil & Gas and Petrochemical Plants
Transportation and Infrastructure Projects
Public Health and Urban Planning Departments
Mining and Metallurgy Operations
Research Institutions and Universities
Relevant U.S. & Canadian Standards
U.S. EPA Clean Air Act (CAA) – Title V Compliance
U.S. EPA Method TO-11A and Method 21 (Modified for Optical Systems)
Canadian Environmental Protection Act (CEPA)
Case Studies
Industrial Fence-Line Monitoring – Houston, Texas
A petrochemical facility in Houston used open-path DOAS units along its fence line to monitor for NO₂, SO₂, and VOCs. Data enabled real-time alerts for emissions exceedance and supported EPA audit readiness, reducing environmental violation risks.
Tunnel Emissions Management – Denver, Colorado
The Department of Transportation installed DOAS systems in a major commuter tunnel to track NO₂ and O₃ levels. Real-time measurements informed ventilation operations, enhanced worker safety, and contributed to environmental compliance.
Urban Pollution Study – Toronto, Canada
Researchers deployed rooftop DOAS stations across central Toronto to study pollution transport. Data from the multi-year study influenced urban traffic policy and improved understanding of secondary pollutant formation.
Contact Us
Looking for reliable DOAS-based air monitoring solutions?
Contact Us Today to learn how Air Quality Instruments can support your environmental goals, regulatory needs, or custom integration projects.