PM2.5 Levels

MQT on 2019-03-21
Session date: 
March 21, 2019
Question By: 
David Kurten
Brexit Alliance Group
Asked Of: 
The Mayor


What was the average annual PM2.5 level in each of the 19 years from 2000 to 2018 in (i) Greater London (ii) Inner London (III) Outer London (iv) Central London


PM2.5 Levels

PM2.5 Levels

Answered By: 
The Mayor

The attached table shows the annual average particulate matter levels (with a diameter of less than 2.5 micrometres; PM2.5) in micrograms per cubic metre (µg/m3) between 2004 to 2018 for background and roadside levels for Greater, Inner and Outer London. Data for Central London cannot be extracted separately.

The table does not include data from before 2004 because there were very few monitoring sites between 2000 to 2003. The 2018 data has not yet been ratified as it requires a review period before certification.

The particulate matter data is based on a limited number of sites, approximately 25 sites in 2018. As a result the data is better suited for understanding the PM levels at individual sites rather than an average for the regions of London.

Furthermore, the London monitoring network initially focused on NO2 and PM10 and over the years PM2.5 monitoring has been added. As a result there is very limited PM2.5 data before 2004, and in select cases no data is shown before 2008.

This data is readily available on the London Air Quality Network (LAQN) website at and is published in the GLA’s annual report.

Whilst there have been improvements over time, it is clear we need to accelerate our efforts. London is in breach of legal limits for PM2.5 and will be for several years without the ambitious policies I am taking forward, including the world’s first Ultra Low Emission Zone.