It’s Air Quality Awareness Week and the DEQ Laboratory and Environmental Assessment Division (You may know us as “The Lab”) thought it a great time to address one of the most common questions we receive: What is the difference between air quality data collected by DEQ and that collected by people with low-cost sensors? As scientists, we might frame the question as so: How do I collect data of known quality?
To determine “known quality,” DEQ follows methods and procedures established by the U.S. Environmental Protection Agency that ensure the accuracy of our measurements. In addition, we frequently maintain, repair and calibrate our more than 60 monitors across Oregon. The information shows up on our Air Quality Index.
The AQI records consistent data across the state so we can examine trends in smoke, ozone, nitrogen dioxide and more. We use it when working with other agencies to determine if we should call an air quality advisory, which warns people when the air is so bad they need to take precautions to protect themselves. Many homes, schools and businesses use the AQI to understand what the air quality will be so they can decide for themselves about participating in sports or other outdoor activities that day. This may be particularly important for those who are sensitive to poor air quality, such as people with asthma, emphysema, lung disease or other respiratory illnesses. Finally, the data provides important information about wildfire smoke and pollution we use to inform policy proposals.
The network of commercial, low-cost air quality sensors continues to grow, with more than a thousand in Oregon. They can provide useful information on local conditions, but their pollutant level estimates are of unknown quality. For that reason, DEQ cannot guarantee their levels will match what our monitors indicate.
For individual and community projects, you can adopt practices to establish more confidence in your estimates. The key is to answer the important questions about the process: Who? What? Where? How? When? Why? You can find some great resources at the following:
- U.S. EPA Air Sensor Toolbox
- U.S. EPA Quality Assurance Handbook and Guidance Documents for Citizen Science Projects
- South Coast Air Quality Management District Air Quality Sensor Performance Evaluation Center
- Association of Public Health Laboratories: “Make Your Data Count: Citizen Science Quality Assurance Video Series”
- South Coast AQMD: “Air Sensor Training: Understanding Air Quality and Monitoring Video Series”
Understanding the monitoring process can help your project deliver data that counts. For more information, contact DEQ’s Air Quality Monitoring Team at Questions.AQM@deq.oregon.gov.
— Dan Johnson, air monitoring specialist, DEQ LEAD