Portsmouth's air quality improves but traffic hotspots remain a concern

Monitoring air quality

The government set limits for pollutants to protect public health. Nitrogen dioxide (NO₂) levels should not exceed an annual average of 40 micrograms per cubic metre (µg/m³), while particulate matter (PM10) has the same threshold. For fine particulate matter (PM2.5), the guideline is 25 µg/m³.

In 2023, Portsmouth recorded three instances where NO₂ levels breached the 40 µg/m³ limit using “low tech” equipment. Two of these were in Alfred Road, and one in Hope Street. However, these locations do not have sensitive receptors such as homes, schools, or hospitals. Encouragingly, monitoring showed no exceedances for PM10 or PM2.5.

Richard Lee, Portsmouth City Council's assistant director of culture, leisure, and regulatory services, noted that “high tech” continuous monitoring indicated compliance with standards for nitrogen dioxide, PM10, and PM2.5 levels.

He added that if air quality continues to improve next year “there may be a conversation around the Clean Air Zone (CAZ) and how well it’s performing".

Traffic management and behaviour change

Councillor Charlotte Gerada highlighted the challenges of managing traffic in Portsmouth, emphasising the unique difficulties posed by its status as an island city and the heavy congestion on the three main roads linking Portsea Island to the mainland.

Cllr Kimberly Barrett highlighted that "transport teams are looking at anything they can do—there have been a number of people looking into a traffic light system, even by changing it for a few seconds that can make a difference".

Efforts to reduce short car journeys have also seen some success. A 20 per cent increase in bus usage over the past year and the introduction of VOI e-scooters have provided alternative transport options. However, there is room for improvement.

Councillor Russell Simpson emphasised the need for affordable public transport to encourage behavioural change: "It would help if buses and trains were cheaper. It’s so expensive—even to go from Cosham to Portsmouth Harbour or Hilsea to Fratton, it’s £3 or £4. It’s just way too much money for something that’s supposed to be more energy-efficient. That cost definitely makes people take their cars."