AIR pollution levels fell by nearly two-thirds in one street in Carmarthenshire during the early part of the coronavirus lockdown, but bucked the trend and increased in another.

Nitrogen dioxide levels are measured in 91 locations across the county, with many sited at three designated air quality management areas in Llandeilo, Carmarthen and Llanelli.

Roads across the county were quiet in April, like the rest of the UK, which generally resulted in a marked drop in nitrogen dioxide levels and cleaner air.

And that improves the prospect that some hotspot areas might not exceed the legal limit of 40 microgrammes per cubic metre, measured as an annual average.

Average nitrogen dioxide levels in Bridge Street, Llandeilo, in April were almost a third of those in March – and nearly a quarter of the January level – according to a report going before the council’s executive board on September 21.

But nitrogen dioxide levels in April actually increased in Station Road, Burry Port, and Ammanford’s Wind Street, compared to March.

Weather conditions play a noticeable part, with pollutants dispersed more effectively when it’s windy.

The report said: “It is however clear that we have measured significant lower levels of NO2 (nitrogen dioxide) during April and May 2020 across Carmarthenshire’s AQMAs (air quality management areas), and for the first time in over seven years all monitoring sites measured a monthly reading below 40 microgrammes per cubic metre.”

Levels have risen as lockdown measures eased – and Llanelli’s Felinfoel Road and Carmarthen’s Priory Street remain hotspots for the two towns.

The report said the data showed how much air quality could improve by reducing non-essential car journeys.

It added: “It is recommended that the council makes a commitment to expand on current policies relating to home working and agile working so not to encourage non-essential journeys when the work can be done effectively either at home or at a closer, more convenient office base.

“Air pollution is a cause of underlying health conditions that can make people more susceptible to severe health outcomes of Covid-19.

“The Covid-19 lockdown has enabled us to think about how we travel, whether we need to use our vehicles and how we can do things differently.”

The slight increase in April in Station Road, Burry Port, was attributed to people still travelling to a local shop and bank – likewise for Ammanford’s Wind Street, where a butchers’ stayed open.

Executive board members are being recommended to make a commitment to discourage non-essential journeys by council staff, and also to encourage them to use video conferencing for training and meetings where possible.

The report also said the sunny conditions can reduce nitrogen dioxide levels via a chemical reaction, but the upshot is higher ozone levels.

It also noted that the main A483 trunk road through Llandeilo, which runs from Swansea to Chester, sent a lot of long-distance traffic through the town.