USC Environmental Health Centers

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Pacoima Beautiful PurpleAir Data Tool

Project Background

This data visualization project focuses on atmospheric PM2.5 monitoring data from low cost PurpleAir PA-II outdoor sensors made publicly available on the PurpleAir website. PurpleAir sells low cost air quality sensors that can be installed indoors or outdoors, and rely on WiFi to transmit data to the open source map hosted on the PurpleAir website.

Sensors used in this project were located near Pacoima, Los Angeles, CA. All raw data were collected from PA-II outdoor sensors that had 80% or greater accuracy between Channels A and B, and at least 30% coverage throughout 2021 were included in the analysis. A total of 14 sensors were used in the final data set. All data were combined and analyzed using R statistical software. Data cleaning and visualizations were performed using the AirSensor, ggplot2 and openair packages. All data were retrieved using SCAQMD’s AirSensor package through their PurpleAir data archive.

The 14 sensors used in this project were in and near Pacoima and San Fernando. All data were combined and analyzed using R statistical software. Visualizations for this data includes:

Particulate Matter

Particulate matter, or PM for short, is composed of solid or liquid airborne pollutants. PM can contain dust, ash, soot, metallic particles, cement, pollen, smoke and other pollutants. These pollutants are inhalable by humans and span a diameter of 10 microns or less. 

The most common types are PM2.5 (fine particulate matter), which refers to particles that are 2.5 microns or less in diameter, and PM10 (coarse particulate matter), which includes particles with diameters of 10 microns or less. Contributors to PM2.5 levels include combustion of common energy sources, including gasoline, oil, diesel fuel and wood. Because of its small size, PM2.5 is more likely than PM10 to be inhaled deep into human lungs.

The Ambient Air Quality Standard for PM2.5 concentration in California, and nationally, is 12 µg/m3 annually and 35µg/m3 daily.

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