Chicago Air Quality Sensor Readings for PM2.5 and NO2

277 Clarity Node-S sensors deployed across Chicago collect individual measurements of fine particulate matter (PM2.5) and nitrogen dioxide (NO2). The project was founded by the Chicago Department of Public Health and the University of Illinois at Chicago School of Public Health, with sensor deployment starting in Summer 2025. Data includes raw and cloud-calibrated values for pollutants, along with weather metrics like temperature and wind speed.

Use Cases

• Modeling PM2.5 concentration (pm2_5ConcMassIndividual.value) against wind speed (windSpeedIndividual.raw) and direction (windDirectionIndividual.value) to map pollution dispersion.
• Analyzing spatial disparities in NO2 levels (pm2_5ConcNumIndividual.value) across Chicago's Community Areas and Census Tracts.
• Correlating ambient temperature (temperatureAmbientIndividual.value) and relative humidity (relHumidAmbientIndividual.value) with sensor-specific pollutant readings.
• Investigating temporal patterns of air quality by aggregating individual sensor readings from the time column into daily trends.

Strengths

• Data from 277 distinct sensor locations provides dense spatial coverage across a major city.
• Includes both raw sensor readings and cloud-calibrated values for key pollutants like PM2.5 and NO2.
• Individual measurements are timestamped to the second, enabling high-resolution time-series analysis.

Limitations

• Black carbon metrics (e.g., bcSpectralIRIndividual.value) are noted as offline and unavailable, creating data gaps.
• Sample size and temporal range of available measurements are unspecified.
• Sensor-based data is explicitly not for regulatory purposes and may have different accuracy standards than reference monitors.

Provenance

Source

Chicago Department of Public Health (CDPH) and University of Illinois at Chicago School of Public Health (UIC SPH).

Collection Method

Measurements collected by a network of 277 Clarity Node-S air quality sensors, with automated data quality control checks applied.

Time Range

Sensors deployed in Summer 2025; specific measurement period not provided.

Freshness

Dataset was last updated on 2026-04-03.

Geography

City of Chicago, with data tagged by Zip Codes, Census Tracts, Community Areas, and latitude.