Introduction to Air Quality

Air pollution impacts everyone and is a greater concern for the young, elderly and those with chronic health conditions. 

There are many different types of air pollutants. The main ones we measure in Gloucestershire are nitrogen dioxide (NO₂) and particulate matter (PM_2.5 and PM₁₀). 

Nitrogen dioxide

The combustion of fossil fuel is the biggest source of NO_2. This includes diesel and petrol vehicles, gas boilers and power stations. We often see the highest levels of NO₂ are generally by busy roads. In Gloucestershire, we get our nitrogen dioxide data from diffusion tube monitoring which measure NO₂ over one month.  

Particulate matter

PM comes from both natural and man-made sources. Natural sources include sea spray, pollen and soil. However, more than half of PM found is from made sources including from activities such as building works, dust from roads, domestic burning (wood burning), diesel and petrol engines, brake and tyre wear (including electric vehicles). The PM data we receive in the county tends to be via real-time monitors, giving us a more up to date insight into PM levels and allows us to look more closely into trends in data including observing spikes during rush hour.

Did you know? Wood burning is thought to be the main source of PM_2.5 in the home. The best, cleanest and most modern single wood burning stove, burning the best wood in laboratory conditions produced the same amount of PM_2.5 every hour as 18 new diesel cars or 6 new diesel lorries.

Health Impacts

Research has shown long term exposure to outdoor air pollution contributes to respiratory illnesses including asthma, lung cancer, pneumonia, Chronic Obstructive Pulmonary Disease (COPD), bronchitis and also, heart conditions.

With regards to PM, this is one of the biggest causes of health problems caused by air pollution. Due to its fine particle size (PM2.5 is about 30x thinner than the width of a human hair) it can cross blood barriers in the body and sees impacts not just localised to the respiratory system. We are seeing increasing emerging evidence that PM plays a role in the onset of dementia, reproductive issues and strokes. 

Children who grow up in areas with high air pollution are also more likely to develop asthma. In June 2025, the Royal College of General Practitioners revealed the number of asthma attacks being treated at GPs has increased over 45% in a year.

The district and borough councils across Gloucestershire have an extensive network of diffusion tubes to help monitor air quality. These tubes measure nitrogen dioxide and allow us to identify hotspots of poor air quality and address where interventions are needed to reduce pollution. It also helps our communities understand pollution levels where they live and help them make changes to reduce their own emissions, or pollution exposure. Some districts have monitors for particulate matter also.

Please visit our Air quality monitoring dashboard | Inform Gloucestershire or the individual district and borough council websites (below) for further information.