Senior Air Quality Officer at Camden Council, Tom Parkes, provides an analysis of the recent impact of lockdown on air quality in the borough and on-going actions the Council is taking.
The introduction of coronavirus lockdown measures in London has had a significant impact on air quality in the city, but there is more behind this headline than simply the reduced level of traffic on our streets.
Breathing in polluted air can have short-term and long-term impacts on our health, at any stage in our lives. Air pollution is a build-up of gases and particles in the air that are harmful to our health. Camden regularly monitors air quality in the borough, currently having four permanent monitoring stations in place. Monitors located at Russell Square Gardens, Euston Road and Swiss Cottage monitor both nitrogen dioxide (NO2) and particulate matter (PM), with the monitor located at Cooper Lane monitoring PM10. In addition to the permanent monitors we have a high number of diffusion tubes across the borough that monitor NO2. This allows us to notice patterns in pollution in accordance to seasons and events, such as COVID-19 or car free day.
Total road transport generally contributes around half of NO2 emissions in Camden, with the remainder coming predominately from commercial and domestic gas heating systems. Long-term exposure to elevated levels of NO2 is known to damage respiratory health, and short-term exposure can cause inflammation and exacerbate existing conditions such as asthma.
The situation so far
The Environmental Research Group at King’s College London noted that as a result of lockdown measures, traffic levels reduced by 53 per cent in London. This resulted in a 39 per cent reduction in the average NO2 concentration from 24 March to 10 May 2020 at Camden’s most polluted monitoring location, Euston Road, compared to the average from 1 January to 12 March 2020. At the Swiss Cottage monitoring site (next to Finchley Road), the reduction in traffic led to a 30 per cent reduction in NO2.
In contrast to the drop in NO2, levels of particulate matter (PM10 and PM2.5, also known as ‘fine particulate matter’) were significantly higher during the lockdown period compared to the average from 1 January to 12 March 2020. PM10 levels increased by 24 – 36 per cent at our roadside monitoring sites, and 59 – 65 per cent at our background (non-roadside) sites. PM2.5 levels increased by 40 per cent or more at all three monitoring locations (including Swiss Cottage, which saw a 73 per cent rise). During this period there was almost no difference between the average PM2.5 levels measured at our roadside and background monitoring sites, which suggests that the majority of the increased pollution was derived from local non-road sources and others outside of London.
New analysis from King’s College London shows that in the weeks after lockdown started, the meteorological conditions that brought us warm, sunny weather also transported pollution long distances from Continental Europe. This international source, combined with residual emissions from within the UK and London – including PM2.5 from domestic wood-burning stoves and garden bonfires – led to a number of days with moderate-level pollution warnings in London and the South East. Preliminary analysis suggests that the reduced emissions from London’s roads averted a more severe pollution episode and the formation of smog.
Actions we are taking in Camden
In 2018 Camden became the first local authority in the UK to adopt World Health Organisation (WHO) air quality guidelines, in recognition of the serious health impacts of air pollution. We will continue doing everything we can to improve air quality in Camden, including indoor air quality in our homes, schools and businesses. Meanwhile, we will push for greater action and increased ambition at the national level, as the current situation has highlighted the importance of working collaboratively to reduce pollution and protect health. To learn more about what Camden is doing to tackle air quality, please see the Camden Clean Air Action Plan.
More must be done to improve air quality than just taking cars off the road, but it is still a vital step. The lockdown has given a glimpse of a possible future for street-level travel in London, in which cars are no longer dominant. We need to make this a permanent change for the benefit of our air and our health.
Tom Parkes, Senior Air Quality Officer, Camden Council