Answers about air quality, readings, and the network

The AQI is a number from 0 to 500 that summarizes how clean or polluted the air is. Higher values mean greater health concern. Delectis uses the US EPA scale, which is based primarily on PM2.5 — fine particles that can penetrate deep into the lungs.

Green (0–50) is Good, yellow (51–100) is Moderate, orange (101–150) is Unhealthy for Sensitive Groups, red (151–200) is Unhealthy, purple (201–300) is Very Unhealthy, and maroon (301–500) is Hazardous. Map pins and rankings use the same colors.

Both are particulate matter, but PM2.5 refers to particles 2.5 micrometres or smaller — small enough to enter the bloodstream. PM10 includes larger coarse particles that mainly affect the upper airways. PM2.5 is the primary driver of AQI on this platform because it poses the greatest long-term health risk.

Yes. During Harmattan season, Saharan dust raises PM levels across West Africa. You may see elevated AQI even when local emissions are unchanged. Combine regional readings with visibility and weather reports when planning outdoor activity.

We aggregate PM2.5 readings from active sensors in each town, district, or region, then convert the average concentration to AQI using EPA breakpoints. When multiple sensors cover an area, their latest readings are combined before the index is computed.

Sensor readings stream in continuously. Town and regional summaries on the home page refresh every few minutes. Rankings reflect the latest available averages across the network, not a fixed daily snapshot.

PM2.5 is the most widely measured pollutant in our network and the standard basis for public AQI reporting in many countries. It responds quickly to local sources such as traffic, biomass burning, and dust, making it a practical indicator for day-to-day decisions.

Gaps can occur during maintenance, power outages, connectivity loss, or calibration. A grey or absent pin on the map usually means no recent valid reading. Historical data may still be available on the sensor detail page.

Children, older adults, pregnant people, and anyone with asthma, heart disease, or other respiratory conditions should limit prolonged outdoor exertion when AQI exceeds 100. At 151+, everyone should reduce heavy outdoor activity.

Not exactly. Outdoor readings describe ambient air at the sensor location. Indoor air can be better or worse depending on cooking, ventilation, smoking, and building materials. Use outdoor data as a starting point — when outside AQI is high, keep windows closed and avoid bringing pollution indoors.

When outdoor AQI is in the Good or Moderate range, ventilation helps dilute indoor pollutants. When AQI is Unhealthy or worse — or during widespread dust or smoke — close windows and rely on filtered indoor air if available. Check readings for your town before ventilating.

At AQI 0–50, outdoor exercise is generally fine for most people. From 51–100, sensitive groups should consider shorter sessions. Above 100, shift vigorous activity indoors or to cleaner times of day (often early morning before traffic builds). Above 150, everyone should limit strenuous outdoor exertion.

Stations in the network use calibrated instruments maintained by deployment partners. Readings pass quality checks before publication. Low-cost sensors may drift over time; operators recalibrate or replace units according to their maintenance schedule.

The network includes reference-grade and commercial monitors deployed by universities, municipalities, and partner organisations across Ghana. Each sensor page lists its location, status, and the parameters it reports.

Yes. Visit the Provide data page to learn how partners submit measurements to the network. Contributed data helps expand coverage and improves public visibility of air quality across Ghana.

Use the map to find the closest active station, or check rankings for your district or region. Coverage is expanding — towns without sensors are omitted from live rankings until readings are available.

Rankings sort towns by current average AQI derived from active sensors in each town. “Most polluted” lists highest AQI first; “Cleanest” lists lowest. Towns without sensors or valid readings are excluded from live rankings.

Researchers and analysts can request exports through the Request data page. Specify the geography, time range, sensors, and purpose for your request. Usage should follow the terms stated on that page and credit the Delectis network where appropriate.