The document outlines a range of recommendations that focus on reducing exposure to particulate matter (PM), the very smallest of which cause the most damage.

Notable mentions include confirmation that the National Institute of Health and Care Excellence (NICE) is currently working on forthcoming guidance on IAQ; news that the government wants to raise public awareness of the potential impacts of indoor air pollution; and confirmation that the Ministry of Housing Communities and Local Government will consult in spring 2019 on changes to standards in Part F of the Building Regulations, which relates to ventilation in homes and other buildings.

Mark Taylor from Camfil said: “Reducing outside air pollution from traffic jams and exhaust fumes is, of course, a priority. What’s clear, however, is that the Clean Air Strategy recognises that this is only one part of the story, with a programme of work across government, industry and society to reduce emissions from a wide range of sources. These include agriculture, solid fuel burning and the products and materials we use to furnish, clean and decorate our buildings.”

Simon Birkett from Clean Air London (CAL), who works with Camfil to improve air quality in the capital, said: “It is marvellous to find more than 20 mentions of IAQ in Defra’s new Clean Air Strategy. The strategy helpfully identifies the sources of many different indoor air pollutants and says that plans will be forthcoming to reduce them.

“The Clean Air Strategy makes an encouraging start on IAQ but must be followed through quickly with meaningful action. For example, Building Bulletin 101 (BB101), which sought to improve IAQ in schools, was published with out of date standards for air filtration. Producing corrected guidance in 2019 must be a priority.

“Within healthcare, the Change in Air Filter Test and Classification standards, issued by SVHSoc in November 2018, is an important step but CAL considers that HTM 03-01; Specialised Ventilation for Healthcare Premises; Part A also needs to be updated for the latest ISO and British standards for air filtration.”

Mr Taylor added: “With air filtration a key step in improving IAQ, another important standard that will help contribute to improvements in this area is the Eurovent Energy Rating 2019, which came into force on January 1. Under the new Eurovent classification, the demands on energy efficiencies have increased, improving the performance of their filters through more stringent test standards.”

The UK is the first major economy to adopt air quality goals based on WHO recommendations, going far beyond EU requirements.