The Dirt That Hurts: Monitoring Harmful Particulate Matter

Category: Assessing Air Quality & Water Resources
Project Team: Maricopa County Health & Air Quality
Team Location: Maricopa County Department of Public Health and Arizona State University – Tempe, Arizona

Maricopa and Pinal County AOD measurements with PM monitor locations overlaid. Image Credit: Maricopa County Health and Air Quality Team

Maricopa and Pinal County AOD measurements with PM monitor locations overlaid. Image Credit: Maricopa County Health and Air Quality Team

Jason Hodgson
Leslie Araujo
Tamara Dunbarr

Dr. David Hondula (Arizona State University)

Past/Other Contributors:
Lance Watkins (Center Lead)


One of the most prevalent issues with air quality monitoring is the lack of distribution of sampling sites that gather data regarding particulate matter (PM) concentrations in the surrounding environment. By using data from the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Aqua and Terra satellites, the project constructed a mixed model to provide a significantly high correlation between aerosol optical depth (AOD) and particulate matter of 10 micrometers in diameter and smaller (PM10) concentrations. Due to the mixed model’s use of additional periodic variables – such as meteorological and environmental factors – the model can be used in conjunction with satellite data in the absence of ground-based monitors to present a better picture of the air quality in Maricopa County, Arizona. By employing such a model, the Maricopa County Department of Public Health and Maricopa County Air Quality Department can apply the model data to future epidemiological research, policymaking, environmental justice analyses and other important processes and decisions regarding air quality and public health improvements. The products, of the Maricopa County Health & Air Quality project, are ultimately intended to benefit the Maricopa County community by contributing to the area of public health and potentially even influencing future changes and the overall development of the county.

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Daryl Ann Winstead (Mekong River Basin Agriculture) 18-08-2016, 14:41

Great video and interesting project! Were there any processing steps when using the MODIS data? I’m intrigued on how to use it for air quality monitoring. Thanks in advance for your response!

Jason Hodgson 24-08-2016, 03:06

Daryl, thank you for the kind words. A lot of hard work went into this project and is continuing to be built upon. In regards to the processing steps, I’ve included a link that will provide you with the processing information you’re asking about. If this doesn’t answer your question, please let me know and I’ll clarify in greater detail if needed.

Sara Lubkin 17-08-2016, 19:41

Interesting use of satellite data! Is climate change expected to have a big impact on the amount of particulate matter in Maricopa County?

Jason Hodgson 24-08-2016, 03:29

Sara, Thank you for the gracious compliment. Climate change will indeed affect PM concentrations in Maricopa County. If the climate in the region gets hotter, drier and windier, that will stir up more particulate matter into the atmosphere. Soil moisture content helps to prevent the dust from being blown into the air. That in and of itself poses a threat to the populace. On the other hand policies and regulations are currently being applied, by county authorities, to help mitigate sources of PM, for instance, construction sites are required to water down dirt-work (digging/transporting dirt) in order to reduce dust from being introduced into the air. With that said, we are trying to stay ahead of the changes in climate so that we can be pro-active instead of reactive.


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