This map shows the data collected by each local council in 2016.
Red and dark red dots are bad news. You can also open the full map and click on the data points to find out more information.
Red and dark red are bad news.
Red and dark red dots mean that the pollution at that site is breaking the national and EU limits for air pollution – specifically, for the average measurement of nitrogen dioxide. Yellow means the site is below the limit, but the locations are at risk of breaking the rule and so should be monitored. Overall, more than five deaths a week in Bristol are linked to air pollution. This number would decrease if our air pollution levels were lower.
Each council monitors other pollutants as well and have ways to monitor hourly emissions to check for extreme pollution events. You can find out more on their websites, here is a link to Bristol’s website.
Air pollution is caused by a combination of factors. The first is how much air pollution is being emitted: how busy is the road or are there other sources nearby. However, the level of air pollution also depends on how much the air is circulated or where the wind takes polluted air. So higher, windier places will tend to have less pollution, but low-lying places like Bedminster, or valleys may have worse pollution.
The green/grey areas on the map are “Air Quality Management Areas.” This is where each council are most concerned about the level of pollution. The management area is the focus of their monitoring and action on air pollution. For Bristol, the council are particularly concerned about the levels of nitrogen dioxide (shown on the map) and the level of PM10, tiny particles that are small enough to get deep into our lungs and which is also significantly caused by diesel emissions.
The main cause of air pollution in Bristol – and most urban areas in the UK – is traffic, especially diesel engines. In recent research on Bristol specifically (see p.105 of this document) it was found that 40% of Bristol’s nitrogen dioxide emissions in the centre are from diesel cars. Buses and coaches cause 23% of emissions. Diesel LGV (light goods vehicles like delivery vans) cause 22% and HGV (big lorries) cause 11%. Even though bigger vehicles may use more fuel, their engines are required to meet tougher standards and there are fewer of them on our roads.
Each council decides where to locate the monitors. They are not evenly spread across the city or region because the councils concentrate them where two conditions apply: areas where they know we risk breaking the nitrogen dioxide limits; and near to where people are living. This means the sites are targeted at main roads and busy central areas, or where there have been concerns about hotspots.
Anywhere with a red or dark red dot on the map is a location that is failing to meet the national and EU standards for air pollution. The rule we are breaking is the “annual mean of nitrogen dioxide,” which is 40 µg/m3 (40 micrograms per cubic metre). The problem you can see is a chronic level of air pollution that is too high overall, rather than specific short-term incidents that might make it bad for a few days, but then fine the rest of the year. Air pollution is linked to heart attacks, strokes and other conditions affecting thousands of people in our city.