Air quality in Bristol

What is the air quality index of Bristol?

Bristol is a city in England with a 2017 estimated population of 463,400, it is the most populous city in South West England. The city is situated between Gloucestershire to the north and Somerset to the south. South Wales lies at the other side of the Severn estuary.

In early 2021, Bristol was experiencing a period of “Good” quality air with a US AQI reading of 37. This classification is based on recommended levels by the World Health Organisation (WHO). The recorded concentrations of the pollutants were as follows: PM2.5 - 9 µg/m³, PM10 - 12.6 µg/m³ and nitrogen dioxide (NO₂) - 25.8 µg/m³. There are no real problems with the air quality with these sort of figures so windows and doors can be safely opened to let in the fresh air and all forms of outdoor activity can be enjoyed.

Does the level of air quality differ in Bristol throughout the year?

Looking back at published figures from 2019 it can be seen that for 6 months of the year, Bristol achieved the WHO target figure of less than 10 µg/m³. In January and November, it attained a “Good” level with readings between 10 and 12 µg/m³. For February, April, July and December, the air quality was not quite as good. The figures classified it as being of “Moderate” quality with figures between 12.1 and 35.4 µg/m³.

As an average for 2017, it once again attained the WHO target figure of less than 10 µg/m³ with a 9.7 µg/m³ reading. It slipped slightly in 2018 to 12 µg/m³ but then improved again in 2019 with a figure of 11.3 µg/m³.

What is the main source of air pollution in Bristol?

After intensive research from an eminent London college, it can be seen that the main source of air pollution is domestic wood and coal burning, together with industrial combustion and nitrogen dioxide (NO₂) which mainly comes from older diesel-powered vehicles.

The fine particulates of PM2.5 and PM10 and nitrogen dioxide that pollute Bristol’s air are the alleged cause of death for approximately 260 people each year. These pollutants could cause up to 36,000 deaths across the UK each year, and also contribute to several health conditions including asthma, lung cancer, heart disease, stroke and diabetes.

Bristol was found to have higher levels of PM2.5 pollution than Liverpool and Greater Manchester, but a lower death rate which is partly because it is less densely populated.

Is air pollution in Bristol getting better or worse?

With all the new rules and regulations, the air quality is improving, overall. But there will always be someone who disagrees with any new policy. For example, during lockdown, Bristol Bridge and Baldwin Street were closed to traffic to encourage more cyclists and pedestrians in those areas. The ban was welcomed by most but strongly challenged by local businessmen whose businesses were adversely affected because of the ban on traffic.

What can be done to improve the air quality in Bristol?

Towards the end of 2020, the city announced radical plans to address air pollution, including a proposal to ban diesel cars from the city centre between 7am and 3pm from 2021. The plans are subject to government approval and consultation with residents and businesses.

Bristol City Council has an extensive network of monitors spread across the city. Over 100 of these monitor the levels of nitrogen dioxide and publish the results in real-time.

Trends in nitrogen dioxide levels have remained stable over the last 20 years but have shown a slight improvement over the past five years. At some locations, the annual mean concentrations exceed 60 µg/m³ and widespread breaches of the annual mean objective for nitrogen dioxide exist.

The council also monitors levels of the unseen PM2.5 pollutant. It makes sure that it does not breach the agreed limits, but those limits are open to discussion as to what level is classed as “safe”.

Because of the lockdown brought about because of COVID-19, the figures for 2020 are unusually low and it is not reasonable to base solutions on those low figures. Throughout every month in 2020 levels of nitrogen dioxide were lower than the corresponding month in 2019. In May, the figure was almost 72 per cent less. However, as the city eases out of lockdown, the figures are seen to be creeping up again.

It is Bristol City Council’s plans to introduce a Clean Air Zone or Low Emission Zone in the city centre. Currently, they are looking at two options. One option is to charge commercial vehicles to enter the zone whilst allowing private vehicle free passage. The other option is to charge private vehicles too but to reduce the size of the affected zone. It is proving to be a controversial subject which is still under debate.

What are the effects of breathing Bristol’s poor quality air?

Air pollution is very often invisible but it can have serious implications for our health.

There is strong evidence that spending time in areas where there are high levels of air pollution can worsen asthma symptoms and increase the frequency of attacks, damage lung function and harm cardiovascular health.

Air pollution is estimated to be the cause of up to 36,000 premature deaths in the UK annually. In Bristol, a recent study into the health effects of air pollution concluded that around 300 deaths per year can be attributed to exposure to nitrogen dioxide (NO₂) and fine particulate matter (PM2.5), with roughly an equal number attributable to each one.

This represents about 8.5 per cent of deaths in Bristol being caused by air pollution.

Other effects caused by air pollution can include low birth weight for babies. Growing children may suffer from impaired lung development which could result in smaller lung capacity. Air pollution is a major contributing factor in the onset of heart disease and other vascular problems. It exacerbates pre-existing respiratory problems and can sometimes lead to premature death.

Air pollution does affect everybody, but some groups of people are more vulnerable than others. Pregnant women, children under the age of 14 years and senior citizens are more prone to problems brought on by polluted air.

Air pollution often affects the most disadvantaged people more as areas with poor air quality are also often the least affluent areas.