Question to the Department for Environment, Food and Rural Affairs:

To ask the Secretary of State for Environment, Food and Rural Affairs, what assessment his Department has made of the wind speed required to disperse (a) PM 0.1, (b) PM 1, (c) PM2.5 and (d) PM10 particles from the source from which they are emitted.

Defra has not undertaken such assessments.

However, our annual assessment of air pollution in the UK uses models that take into consideration general characteristics of dispersion away from emissions sources in calculating annual concentrations of PM₁₀ and PM_2.5 across the UK, and details can be found here:

https://ukair.defra.gov.uk/assets/documents/reports/cat09/1709281207_AQ0650_2015_MAAQ_technical_report.pdf

In addition, Defra commissions daily air quality forecasts from the Met Office that are issued on our UK Air website: https://uk-air.defra.gov.uk/. These forecasts provide short term predictions of the impact of the weather (including wind direction and wind speed) on UK air quality. Forecasts are provided for the purposes of informing the public about the likelihood of elevated air pollution over the coming days alongside associated health advice.