> For the complete documentation index, see [llms.txt](https://3dpaws.comet.ucar.edu/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://3dpaws.comet.ucar.edu/building-3d-paws/adding-additional-instruments/air-quality.md). # Air Quality The **PMSA003I** is a high-precision laser-based particulate matter (PM) sensor designed for real-time air quality monitoring in the 3D-PAWS system. This sensor continuously measures and reports the concentration and number of airborne particles of various sizes, providing detailed insight into local air pollution. ### How the Sensor Works * **Laser Scattering Principle:** The PMSA003I uses a laser and a fan to draw air into its detection chamber. As particles pass through the laser beam, scattered light is detected and analyzed to determine particle size and count. * **Particle Output:** The sensor outputs both the **number and mass concentration** of particles in several size bins (e.g., PM1.0, PM2.5, PM10); however, estimates of PM1.0 and PM10 are considered to be less reliable. We only recommend using the sensor for PM2.5 measurements. * **Number concentration** is reported as particles per 0.1 L of air. * **Mass concentration** is reported in micrograms per cubic meter (μg/m³). * **Adaptive Sampling Modes:** * **Stable Mode:** When air quality is steady, the sensor samples at a real interval of 2.3 seconds. * **Fast Mode:** If particle concentrations change rapidly, the sensor automatically switches to fast mode, sampling every 200–800 ms. The higher the concentration, the faster the sampling. * **3D-PAWS Integration:** The 3D-PAWS system samples the PMSA003I every second, recording the average 1-minute value observed during each measurement interval for robust air quality tracking. ### **Power Considerations & Recommendation** > **Note:**\ > The PMSA003I is a **power-hungry sensor** because it runs a fan continuously to ensure accurate, real-time sampling. This significantly increases the station’s energy requirements. > > **For reliable operation, we strongly recommend using a Voltaic V75 battery and a 10 W, 6 V solar panel** for air quality stations equipped with this sensor. ### Instruction Slides for Assembling the Air Quality Sensor {% embed url="" %} --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://3dpaws.comet.ucar.edu/building-3d-paws/adding-additional-instruments/air-quality.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.