The United Nations body published its current guidelines on particulate matter, ozone, nitrogen dioxide and sulphur dioxide in 2005. But adherence to them – particularly for particulate concentrations – continues to be a subject of controversy.
Although referencing it in the Clean Air Strategy, the government has carefully avoided saying that it would adopt the WHO’s existing guideline limit for fine particulates (PM2.5). This is despite evidence of its damaging effect on health building up steadily over recent years, from causing dementia and heart disease to diabetes and kidney failure.
For the moment, it is unclear if the recommended limit for the pollutant will tighten. But the WHO has hinted that it will, stating that the new guidelines will “provide clear evidence of the damage air pollution inflicts on human health and recommend new air quality levels to protect health for all, by reducing levels of key air pollutants”.
The date of publication is just before when the Environment Bill will return for debate in the Commons, the Lords having backed an amendment this week to formally enshrine the target of reaching an annual average of 10 micrograms per cubic metre by 2030. The government favours setting a target, which it has so far not defined, in secondary legislation once the bill becomes law.
The WHO’s move will add pressure on the government to accept the Lords’ amendment. However, doing so would also imply that the bill will be out of date even before it receives royal assent.