Jamestown Citizens’ Air Monitoring Project, year 1: Worst air days, what the numbers mean, etc.

In a report for the U.S. EPA, results from the Citizen's Air Monitoring Project over the past year reveal the average Air Quality Index (AQI) is 49.8, with peak pollution days identified. The average PM2.5 levels are close to new federal standards. The project, financed without cost to Jamestown, utilizes EPA loaned sensors.

Here’s an update on The Jamestowner‘s Community Air Monitoring Project. As described HERE, and as reported in The Jamestown News last year, the air sensors are on loan from the EPA, have been reporting our air quality in realtime on an interactive worldwide map, and have downloaded and archived that data for further analysis.

Since last November, I’ve been downloading data every other week, supplementing it with realtime readings during periods of unusual activity, high air pollution, atmospheric smoke, and for comparisons with nearby areas.

Here’s a brief summary.

We’ll start with our AQI (Air Quality Index) readings, which are shared with sites like AccuWeather, WeatherBug, Google Maps, AirNow.gov and Weather Underground. The AQI reports daily air quality using a scale of 0 to 500, calculated for pollutants such as ground-level ozone, particle matter, and carbon monoxide:

From November 2024 through the end of September 2025 (October’s monthly number won’t be reported until November 1st), the sensors as a group had an average AQI of 49.8.

The worst months were July, June, January and August, in that order. The worst days were Friday, August 8, 2025 (the index was 121); Sunday, Nov 24, 2024 (115); Friday, March 14, 2025 (103); Wed, Feb 5, 2025 (97); Wed, June 25, 2025 (93); Tues, July 8, 2025 (93); Thursday, Dec 26, 2024 (92); Wed, March 19, 2025 (91).

Here’s how the AQI monthly average for all of the sensors graphed:

The worst AQI monthly average (56) was recorded by the air sensor at RIVERDALE ROAD:

The second highest AQI monthly average was recorded by the sensor at PENNY RD near the Piedmont Environmental Center in northeast High Point – this is a privately owned sensor that also measures VOCs (volatile organic compounds):

The third highest AQI levels were recorded at the sensor in FORESTDALE EAST:

The fourth highest AQI monthly average was recorded by the sensor on Southridge near Dillon Road: :

In fifth place was the sensor in JAMESFORD MEADOWS:

The air sensor close to MAIN STREET at OAKDALE ROAD came in sixth place:

The MACKAY ROAD sensors were at two sites – one at Adams Farm, and the other at the Guilford College Road end. One of the sensors’ position in an area surrounded by trees may have provided enough canopy to skew the AQI readings down:

Here’s how the sensors (the green dots) look on the Purple Air interactive map:

VOLATILE ORGANIC COMPOUNDS

The [experimental] VOC sensor on Penny Road near the environmental center averaged daily results equal to 142.4, with many readings in the 200 to 300 range:

Here’s how PENNY RD compared to nearby VOC-enabled sensors in THOMASVILLE (the green line on the chart below), and A&T University in Greensboro:

The VOC and AQI numbers are so consistently high at A&T University (in Greensboro) that I drove over one day to see if I could find the source – it’s an old steam plant:

PARTICULATE MATTER PM2.5

In 2023, due to an extensive body of science linking air particle pollution to a range of serious and sometimes deadly diseases, the EPA set a new health-based standard for particulate air matter that measures less than 2.5 microns in diameter, written as PM2.5.

In February 2024 the EPA set the federal annual average standard for PM2.5 at 9.0 µg/m3, and the World Health Organization set the maximum health level standard at 5. The annual average PM2.5 level thus far for our Jamestown air sensors ranges from 8.5 to 8.8 (for the period November 2024 through Sept 30, 2025).

The EPA’s federal average 24-hour standard for PM2.5 is 35 µg/m3, and the World Health Organization says 24-hour average exposures should not exceed 15 µg/m3 more than four days in one year.

Here’s the one-day chart for all of the Jamestown sensors through today, October 30 2025; the average is 7.7, and there are numerous days with readings above 15: