Portsmouth air quality improves with only one site over limit

The council’s annual status report, which has been reviewed and accepted by the Government, sets out the latest monitoring results for Nitrogen Dioxide (NO2) gathered throughout 2024.

PCC says reducing harmful NO2 levels remains a priority, adding that cleaner air will “contribute positively to the health of our residents, employees, and visitors to the city.”

Over the last five years, the council has expanded its monitoring network using Nitrogen Dioxide Diffusion Tubes. The system grew from 27 sites before 2017 to 228 today.

The report highlights a steady fall in NO2 exceedances. In 2023, three sites breached the national limit – two on Alfred Road and one on Hope Street.

In 2024, only one site remained over the standard, again on Alfred Road. The council also reviewed whether it should expand its particulate monitoring network but concluded it would offer limited value.

Particulate matter is measured as PM10 and PM2.5 – particles 10 micrometres or smaller, and 2.5 micrometres or smaller, respectively.

Data from existing stations shows that levels of both PM10 and PM2.5 have stayed consistently low for five years, remaining below national objectives even in high-traffic areas.

Being in “substantial compliance”, officers say further improvements are likely to slow.

Richard Lee, Assistant Director of Culture, Leisure, and Regulatory Services, said: “It’s a fairly good news story in terms of the level of pollution we are picking up from our very comprehensive network of devices and it shows a downward trend.

“This is the first year in my view that we’ve had full compliance with the objective standards across the entire city.

“NO2 is the first year in all locations, with that caveat around Alfred Road, that we’ve been compliant – it’s got to be a positive position.”

He added that while his report demonstrates compliance “we’ve always had a narrative around the importance of continuous improvement”.