SCOTLAND stayed at home

during lockdown – but the drop in traffic did not reduce the “most harmful” type of air pollution, research shows.

Vehicle numbers dropped 65% during the first month of restrictions, but there was “little change” in levels of fine particulate air pollution (PM2.5), which has been linked to a range of health problems.

Stirling University scientists now believe traffic is not a key contributor to our outdoor air pollution – and that months at home may have put some Scots at “greater risk” from this pollutant due to cooking and smoking without

proper ventilation. That, it is

said, could prove a greater

Covid-19 threat.

Dr Ruaraidh Dobson said: “It has been assumed that fewer cars on the road might have led to a decline in the level of air pollution outdoors and, in turn, reduce the number of cases of ill health linked to this pollution. However, our study – contrary to research from places such as Wuhan in China and Milan – found no evidence of fine particulate air pollution declining in Scotland because of lockdown.

“This suggests that vehicles aren’t an important cause of this very harmful type of air pollution in Scotland – and people may be at greater risk from poor air quality in their own homes, especially where cooking and smoking is taking place in enclosed and poorly ventilated spaces.”

Dobson and colleague Dr Sean Semple analysed data from 70 roadside monitoring stations around Scotland from March 24 – the day after lockdown was introduced in the UK – to April 23 and compared these to figures from previous years.

Nitrogen dioxide, which is associated with vehicle exhaust fumes, was down but concentrations of fine particulate air pollution were just 0.1 microgramme lower than in 2017. They were, however, “substantially lower” than in 2019, when high rates were likely caused by a meteorological event that blew in fine dust from the Sahara.

The results are published in the specialist journal Occupational and Environmental Medicine.

The paper says: “If the severity of Covid-19 is related to air pollution exposure – as has been suggested – increased exposure to PM2.5 could potentially increase the death toll of that disease. Careful and balanced consideration of both outdoor and indoor sources of PM2.5 is essential to tackling the health harm of air pollution effectively and equitably.”