Case Study: Using PurpleAir to Conduct Localized Air Quality Research

Air Quality in LA Case Study

How Academics in Los Angeles Forecast Local Air Quality Using Low-Cost Air Quality Monitors

  • Topic: Air Quality Research
  • Author: Adrian Dybwad
  • Website:
  • Industry: Technology, Universities


There is no single source of all air pollution. That’s because poor air quality can come from multiple sources, and it differs from location to location. While scientists work to better understand the sources of air pollution, they’re limited by the data gaps in the government-issued air quality monitors. This was the challenge researchers in Los Angeles (LA) faced when studying air pollution in busy city streets.

In Los Angeles, air quality monitors are too few to cover all 801 square miles of the city. They were also sparsely distributed, preventing researchers from collecting localized data. However, they found a solution in high-quality, commercial air quality monitors. Beyond providing an affordable alternative, PurpleAir air quality monitors supplied researchers with hyper-local and real-time air quality data.

In this case study, we'll discuss how PurpleAir air quality monitors empower local researchers and academics with highly precise and hyper-local air quality data.

Current State of Air Quality Monitoring in Los Angeles

According to the South Coast Air Quality Management District (AQMD), there are 17 active air quality monitor stations in LA. They're located in the following:

  • Santa Clarita-Placerita
  • Reseda
  • North Hollywood
  • Pasadena
  • Glendora Laurel
  • Los Angeles – VA Hospital
  • Los Angeles – North Main Street
  • Closet World (Quemetco)
  • Pico Rivera #2
  • Rehrig (Exide)
  • ATSF (Exide Rail)
  • LAX
  • Compton
  • Long Beach – Route 710 (Near Road)
  • North Long Beach (Long Beach)
  • South Long Beach
  • Long Beach – Signal Hill

Although this list is extensive compared to other local governments, there are still significant data gaps. This becomes clear when you plot them on an air quality Los Angeles map, where you can observe that many of the air quality monitors show as clustered in specific areas:

Air Quality in LA

As such, air quality data from these stations can be delayed, inaccurate, and not localized. This, in return, can adversely affect research findings as air quality differs from community to community.

Why Localized Air Quality Monitors are Crucial for Research

A study by the University of California Riverside reported a total of 13,000 individual facilities in California that are stationary sources of air pollution. But that’s only part of the picture. It doesn’t account for sources like vehicular traffic, household emissions, and wildfires.

Common Sources of Air Pollution - Natural Events, Traffic, Household, and Industrial emissions

Source: American Journal of Respiratory and Critical Care Medicine 

This is what makes studying air quality so complex; there are thousands of sources of air pollution. However, each district, region, and home tell a different story.

For example, 40% of US imports pass through Los Angeles docks, shipping and logistics are the primary source of air pollution along the Port of Los Angeles and Long Beach. Meanwhile, the air pollution in Wilmington comes from its oilfield, which is the third largest in the country.

This is also why it’s crucial to have air quality monitors that report localized data, so that researchers can have a more accurate picture of the air quality in each location. In doing so, communities and governments can better understand air pollution and take effective measures to eliminate it.

However, obtaining additional government-issued air quality monitors isn’t as easy.

One Federal Reference Method/Federal Equivalent Methods (FRM/FEM) air quality monitor can cost $15,000-$40,000. Plus, as a researcher, you need to hire a technical expert or highly train your staff to maintain and operate it. All of these go beyond the resources of a local government and researchers’ capabilities.

But thanks to developments in air quality technology, researchers can now leverage low-cost, commercial air quality monitors to enhance air quality data from government air quality monitors.

How PurpleAir Air Quality Monitors Help Close the Data Gap

Commercial air quality monitors present an affordable alternative for researchers to gain accessible data. PurpleAir’s air quality monitors cost $199-299. But academic researchers Yougeng Lu, Genevieve Giuliano, and Rima Habre warn that not all air quality monitors are the same quality.

In other studies, they observed that cheaper air quality monitors frequently report data anomalies and show higher rates of data loss. Worse, these display false readings caused by dust and humidity. However, when they tested PurpleAir air quality monitors, they recorded high air quality data accuracy. This is because PurpleAir air quality monitors undergo intensive internal testing before being shipped.

They are also evaluated by Air Quality Sensor Performance Evaluation Center (AQ-SPEC) to ensure our devices are of the highest quality. Because of all this, Lu and his team have access to hyper-local, real-time data that can complement their current research on the air quality of Los Angeles.

What Researchers Can Accomplish with Localized Air Quality Data

With the data collected from both FRM/FEM air quality monitors complemented by PurpleAir air quality monitors, Lu and his team built a machine-learning model. This model can predict hourly fine particulate matter (PM2.5) concentrations in a localized manner. More importantly, their model can forecast PM2.5 patterns during high-polluting events like wildfires.

By creating this, governments and local organizations can issue advanced poor air quality warnings before the air pollution reaches them. In return, citizens can take proactive measures to protect themselves and their loved ones from the adverse health effects of PM2.5.

The study by Lu and his team is just one instance of how academics and researchers benefit from PurpleAir air quality monitors. Hundreds of published papers show how air quality monitors can help air quality scientists improve their research and understanding.

As Lu and his team conclude in their paper, the accessibility and precision of PurpleAir air quality monitors are empowering community scientists to further air quality science around the world. We’re thrilled to see more research like this going forward.

About PurpleAir

Since it was founded, PurpleAir has dedicated itself to providing highly precise air quality monitors that track hyper-local air quality levels in real time. In doing this, PurpleAir is empowering community scientists and helping to facilitate social change through accessible air quality data for all. By working together, everyone is more informed and able to make changes in their local communities to improve air quality.