Teasing the Signal from the Noise!

Through the help of nearly 1,000 community member participants in Operation Healthy Air, we have collected hundreds of thousands of data points in various formats. After picking up the last field sensors in early October, we are now making sense of all this information. We are trying to discern the patterns and test ideas about trends in air quality and temperature over the region. We—as a project team—owe this next step of analysis to our funders, NASA, but also our institutions, partners, and community scientists.

While we are anxious to produce the definitive figures and results that increase our knowledge about air quality that can lead to action, there remain a few steps required to get there, and this is what we have been doing. In technical terms, we often call this data cleaning and curation; this often includes rolling up our sleeves and scrubbing. Using the Wikipedia definitions, data cleansing, data cleaning, or data scrubbing is the process of detecting and correcting (or removing) corrupt or inaccurate records from a record set, table, or database. Like museum curation, we need to “curate” data to ensure its value and use for analysis both today and to ensure it remains available for reuse—shared and into the future.

All data go through cleaning and curation—not just those collected by community scientist. Even data collected by expensive and highly accurate instruments need to go through this process. During the three campaigns of our Operation Healthy Air program, we have collected data from:

  • 17 ozone sensors
  • 237 iButton temperature sensors placed at community sites (e.g., homes and schools)
  • 96 iButton temperature sensors placed on street trees
  • 64 home indoor and outdoor temperature sensor data sheets
  • More than 150 habitat maps created with the help of 100+ community members

All of this data is the result of the help and participation of more than 20 local partner organizations, 150 community members, and ten schools—including 700 of their students! To view a map of where of this data was collected, visit the Operation Healthy Air Participants webpage.

One of the questions that the data will start to help us understand better is the extent to which local trees can help cool and/or alter the air quality around homes and schoolyards. To gather local-level information, many participants helped us map using the online tool, Habitat Network, which maps the kinds of habitats around the sensors. Many participants also collected information (using a tape measure) about the local tree under which the sensor was placed. While we have not completed pulling this information from all sensors together, here is an example from one home of what bringing this information together in one location looks like. A “Habitat Map,” created for a home in Riverside, is available below. The various shapes represent different kinds of habitats mapped and identified: darker grey is asphalt or concrete pavement, lighter grey is buildings, brown is soil, green is grass, etc. The round “bull’s-eye” objects are mapped trees.

Three iButton temperature sensors were placed around this home (three different colored arrows) and thanks to the help of the local community scientist, we have species identification and size of each tree where the sensors were placed. For example, sensor number CS-032 was placed in a crepe myrtle that was 15 feet tall and had an average canopy width of 13 feet (see the yellow lines).

We also plotted the average daily temperature (24 hours—zero is midnight) for each of these sensors. The black line along the bottom is the predicted temperature using a weather forecasting program, and the red line represents a separate sensor not mapped.

From this plot, we can see how different the temperature profiles are from one tree to the next. The green line for the Wilson peach is for the smallest tree heats up earlier and much hotter than the other two trees, and the elderberry (blue line) heats up earlier than the crepe myrtle.

We are planning to use the Habitat Maps to compare different homes and whether the amount of pavement predicts local temperature differences as well. While there is much more to do, we wanted to share these early results to illustrate how we are beginning to use the data so many local participants helped us collect. Thank you!

As always, please send any suggestions or ideas to me at mchandler@earthwatch.org.

Partnering with the Community: Operation Healthy Air

In May, we began Operation Healthy Air in Long Beach. There was strong support from the Aquarium of the Pacific, Long Beach City College, California State University Long Beach, Saint Anthony’s High School, the City itself and many local residents. This was our first deployment of sensors. The feedback from local participants and partners helped us figure out how to best continue the program. We learned about the subtle (and not so subtle) temperature gradients that cut across the city, and the challenges in finding suitable backyards for the ozone sensors given how compact the downtown area of Long Beach is.

From the beginning of July through the end of September, we worked with partners to train and find interested community members across the Inland Empire. Partners included: Chino Basin Water Conservation Resource District, Riverside Corona Resource Conservation District and the UC Cooperative Extension for Master Gardeners. These partners hosted training events and supported our collective efforts to plan and support the setting up of sensors in local backyards, front yards, parks, and schools. Through discussion groups, we found that there is interest from community members in understanding the effect of landscaping on local temperature, as well as the influence of seasonal winds from the foothills.

As our Operation Healthy Air participants know, opportunities to engage in the “science” were quite varied—with some ways being quite challenging. Those of you who tried the mapping know! Thank you for all of your feedback to date. It has been a huge help in shaping our efforts going forward. Many of our participants had sensors in their backyard, while others wanted to do all of the possible activities.

Based on our preliminary findings, it seems that every part was useful. Many participants who collected in-home temperature data said that they learned a lot about which parts of their houses were cooler and at what times. They were able to use that information to decide when to open or close windows to move cooler air from outside when it was hotter inside.

For those of you who wondered if we lost any iButton sensors left on street trees, the short answer is yes, but not enough to create a problem. Working with incomplete data is a challenge that we face in cities, and we have some data analysis tools that help us overcome that.

We found the mapping component to be the most challenging. We are working closely with the developers of the programs and they are thankful to have all of your feedback—even those who were frustrated. We have seen interest from teachers in mapping, as it fits well with the science curriculum they need to teach. We hope that involving students could be helpful in finishing the mapping work that remains. If you are a teacher or know one who is interested in participating (regardless of your location), please contact Mark Chandler at mchandler@earthwatch.org.

After spending time with community members, it is clear that there is an interest in figuring out how to create more livable cities.

There are several next steps planned. The first is to process all the data. Processing the data means putting it all into spreadsheets, cleaning it up (making sure it contains as few errors as possible), and then sharing it with partners and anyone who is interested in access to “raw” data.

We have much of the air temperature data from Campaigns 1 and 2 available for sharing for anyone who wants raw data. We have begun to incorporate some of the ozone data into a website where you can view the data based on which sensor it came from. We will share updates on this as they become available.

We look forward to sharing more results at upcoming workshops early in 2018. This will also be a chance to share what our plans are in 2018 for continued engagement.

We are also working with students from Claremont McKenna College who will be conducting a survey of all those who participated to better understand why you became involved and what your hopes for outcomes might be. This again will be very helpful as we think about how best to engage community members going forward. Thank you for your time on this.