Bath’s illegal levels of NOX from traffic fumes

nox in bath


40 µg/m3 (EU[1], limit value for human health, annual mean)


Nitrogen dioxide 5

One of the chief pollutants from vehicle emissions is nitric oxide, which through oxidation creates nitrogen dioxide (NO2). It plays a major role in atmospheric reactions that produce ground-level ozone or ‘smog’. This is the main pollutant by which air quality is assessed. 6

In 2009 the highest concentration of NO2 was recorded at Lambridge (just east of the junction with the old Gloucester Road) with an annual mean of in excess of 80μg/m3. 7

Results from automatic monitoring of nitrogen dioxide in 2012 show that all sites except at Saltford exceeded the annual average objective (two diffusion tube monitoring locations on the A4 in Saltford did exceed the annual average objective). All these sites are within Air Quality Management Areas. 8

The London Road, Guildhall and Windsor Bridge sites exceeded the hourly objective for NO2, but they were less than the 18 times allowed by the objective in 2012. 9


The trend data shows that 2012 was not a peak year for NO2, with monitoring results being similar to previous years, 2 sites were lower than 2011 and 3 sites higher. 10

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