Air Quality Science
The State of Delaware has established an air monitoring network to determine the ambient levels of ground level ozone (O3), carbon monoxide (CO), sulfur dioxide (SO2), nitrogen dioxide (NO2), lead (Pb), and particulate matter less than 10 microns (PM10) and less than 2.5 microns (PM2.5). These are considered criteria pollutants according to National Ambient Air Quality Standards (NAAQS) because of their impacts on human health and the environment and all states are required to track them. To view conditions at each of Delaware's monitoring stations, visit the Delaware Air Quality Monitoring Network.
The pollutants can be produced in many ways, including by industrial facilities, gasoline vapors, vehicle exhaust, chemical solvents, open burning, and natural sources. The original focus of the monitoring network was “point sources" (large facilities with high emissions) within Delaware. With the implementation of successful air pollution control strategies, emissions from large facilities increasingly came into compliance with air quality regulations. This led to additional focus being placed on examining impacts from pollutants that originate outside Delaware and are of regional concern.
A Closer Look
PM2.5 is of particular concern because fine particles can penetrate deeper into the lungs than larger, coarse particles and therefore is more likely to contribute to health issues. Fine particles are generally emitted from combustion activities, such as industrial and residential fuel burning and motor vehicles, while coarse particles come from dust emitted during activities such as construction and agricultural tilling. PM2.5 can also form in the atmosphere from compounds such as SO2 and NO2, through various physical and chemical processes. These compounds are monitored to characterize and track trends in concentrations and to develop and evaluate emission control programs.
Real-time Fine Particulate Matter Monitoring Data
The chart below uses fine particulate matter data from the Open Data Portal, which is updated hourly, to create 24-hour averages of PM2.5 levels at monitoring locations within the state. The red dashed-line shows the standard for the 24-hour maximum. The standard is met if the monitored value is less than the 98th percentile of the 24-hour maximum averaged over the last three years.
Data represented below are real-time, directly from the monitors before quality control and assurance measures for the data have been implemented. Anomalies (unusual or incorrect points) in the data may exist and generally represent maintenance procedures or equipment malfunctions. If you have any questions regarding the data, you may Contact the Dataset Owner through the Delaware Open Data Portal.
Use the menu at the top of the chart to change the date range for the data.
Page reviewed 2/4/19