Every day activities such as driving, burning coal for electricity, wildfires, running factories, even cooking and cleaning, release particles into the air. Besides being an irritant, small particles of 10, 2.5, 1 micrometers (PM10, PM2.5, PM1) or less are a health hazard since they can get deep into the respiratory system and damage the delicate tissues.The exposure of populations to high levels of small particles increases the risk of respiratory and cardiovascular illnesses. The World Health Organization (WHO) guidelines provide long-term and short-term exposure limits to PM10 and PM2.5:Long-term: PM10 20 µg/m³ annual mean and PM2.5 10 µg/m³Short-term: PM10 50 µg/m³ 24-hour mean and PM2.5 25 µg/m³Exposure to PM10 and PM2.5 above these limits may significantly impact human health.The source information is the OpenAQ community which reports measured concentrations (µg/m³) and particle matter count (particles/cm³) on a global scale by aggregating station data from national networks of air quality.The Recent Conditions in Air Quality layer is updated every hour using the Aggregated Live Feed (ALF) methodology. It shows the latest mass concentrations and particulate count for PM2.5, PM10, and PM1 of the stations in the OpenAQ data set with at least one value reported in the past 30 days. Additionally, a Learn ArcGIS lesson is available for implementing one version of the ALF methodology.RevisionsJul 21, 2022: Added service to Live Feed Status Page for active monitoring!Feb 8, 2022: Update of live feed routine to use OpenAQ API v2:Addition of PM10 and PM1 layers.Values of particle matter count (particles/cm³) to all layers.Update of field labels.Removal of SourceName field.Feb 5, 2020: Official release of Feature Service offering.This layer is provided for informational purposes and is not monitored 24/7 for accuracy and currency.If you would like to be alerted to potential issues or simply see when this Service will update next, please visit our Live Feed Status Page!