Air Quality Awareness Week Day 5: Participatory Science

From May 1-5, the Nevada Division of Environmental Protection (NDEP) is helping celebrate National Air Quality Awareness Week 2023! Throughout the week, NDEP is taking steps to inform all Nevadans about how air quality affects their lives. This includes sharing information and resources about air monitoring, impacts to public health, and ways to support air quality science. This is the last blog in this series. Read Part 1, Part 2, Part 3, and Part 4.

For people in urban areas of Nevada, there are a number of resources available for information about air quality. For people in rural areas of Nevada, there are less options, and the information available doesn’t always match up. To help build a more robust monitoring network, NDEP encourages Nevadans to invest in portable air sensors, to help monitor air quality in real-time.

Federal, state, and local air agencies must follow strict rules about where to set up their regulatory monitors. While these monitors provide accurate scientific data, they’re too big and expensive to put everywhere. Portable air sensors, such as PurpleAir, are a low-cost alternative, allowing the public to monitor air quality in more remote places. Thanks to portable sensors, air quality around the world can be measured in real time by anybody with internet access.

Though they are smaller and more convenient, portable sensors simply aren’t as accurate as NDEP’s large, regulatory monitors. EPA scientists have found that sensors often overestimate or underestimate pollutant concentrations when compared to the regulatory-grade instruments operating in the same location.  

Regulatory monitors are designed to provide information about air quality over a large area – like a city or county – while portable air sensors can provide insight into air quality at the neighborhood level. To make data from smaller sensors more accurate, EPA scientists have developed a “correction factor” that’s applied to the data from PurpleAir sensors. This brings the data back in line with what a regulatory-grade monitor would read under the same circumstances. You can check out the corrected data on EPA’s Fire and Smoke Map.

Don’t see many sensors near you? If you want to stay informed about air pollution during wildfires and other large pollution events, we can help. NDEP has PurpleAir sensors available to loan out to federal, state, and local organizations, including schools and community groups. You can request a sensor by filling out the form here.

How do I use a portable sensor?

NDEP, EPA, and other public agencies are constantly working to better understand how to use portable sensors.

Based on what we’ve learned so far, here are a few suggestions and tips to keep in mind when using a portable air sensor:

• Be mindful of the weather. Portable sensors are influenced by temperature and relative humidity. A large change in your air quality reading may have more to do with an incoming thunderstorm than actual pollution concentrations. Keep track of weather conditions and pollutant concentrations to account for biases or measurement errors.

• Get a backup! If possible, always use two or more sensors in the same location. This may provide hints on their reliability.

• Compare your monitor. Try to compare the hourly measurements of your sensor with a nearby state, federal or local regulatory air quality monitor. NDEP can help with this – send us your sensor, and we’ll pair it with one of ours for a week or two so you can see how the data compares. We’ll send it back, we promise!

• Observe the area. Are there landscape features (walls, high buildings, or trees) that could block the free flow of air? This might make the air stagnate, inflate pollution concentrations, and block the sensor from measuring the pollutants. Is your sensor near a BBQ or fireplace? If possible, mount the sensor in a shady spot out of direct sunlight. Keep it away from vents or other local sources of pollution – even that delicious hickory smoke from your BBQ grill!

• Watch for seasonal changes. Expose your sensor to air pollution during all seasons: to wildfires in the summer; to woodstoves in the fall and winter; to the relatively “clean” air in spring. When doing this, ask yourself if your sensor is responding as you would expect it to.

You can also help NASA track dust storms through the GLOBE Observer app. If you see a dust storm, submit photos through the app so NASA scientists can check if their models have done a good job at predicting dust storms.