How is the British Government Tackling Nitrogen Oxides in Air?

At our annual Air Quality and Emissions event, Dr. Justine Bejta, Head of Science at the Joint Air Quality Unit (JAQU), presented data on the outcomes of recent government interventions in areas with high levels of NO2 pollution – our reporter went along to find out more.

If you would like to view this presentation on the efficacy of Clean Air Zones, just follow the link. If you find it useful, consider attending our next Air Quality and Emissions event.

Between 1970 and 2019, the concentration of all pollutants (with the important exception of ammonia) in British air has been drastically reduced. But according to the national government, poor air quality is still the largest environmental health risk to the population of the UK. Official estimates put the annual death-toll somewhere between 28,000 and 36,000; the costs, in terms of healthcare rendered and productivity lost, of PM2.5 and NOx pollution alone are set to exceed £5.3 billion by 2035. So, with the clock ticking and the nation’s health on the line, what is the British government doing to curb air pollution?

Noxious Conduct

Well, recently, the focus has been almost solely on diluting the concentration of nitrogen oxides. For one thing, nitrogen oxides are especially nasty. A menace to the human respiratory system, short-term exposure promotes asthma and long-term exposure risks contracting chronic lung disease.

But there is another reason for the British government’s tunnel-vision. You see, significant swathes of Britain are currently in contravention of both national and international standards for the pollutant. Whilst the nation was under the Union’s jurisdiction, such an abundance of nitrogen oxides constituted an infraction of EU guidelines. And in 2018, a judicial review conducted by the British High Court reiterated for the third time that such exceedances of national air pollution limits be redressed “in the shortest possible time.”

In order to remedy these infractions, the Department of Transport and the Department of Environment, Food and Rural Affairs came together to bring JAQU into the world. The Joint Air Quality Unit, or JAQU, is charged with monitoring and reducing the concentration of nitrogen oxides in ambient air – and they’re leading a revolution.

Model Villages

Up and down the country, in the oddest of places, you’ll be able to find small, squat boxes sporting caged analytical instruments. Since 1998, 274 of these units have been built, from the banks of Loch Vaich in northern Scotland to the public gardens around Plymouth harbour. Together, they constitute the Automatic Urban and Rural Network, which keeps tabs on road-side air pollution across the UK in order to ensure statutory adherence, model long-term trends and assess the impact of policies. It is the lifeblood of the Joint Air Quality Unit.

According to JAQU, around 70% of the nitrogen oxides in ambient air are coming from diesel vehicles on British roads. Reducing the concentration of these pollutant thus requires the sort of comprehensive modelling of road-side emissions provided by the AURN, which the Unit supplements with its own mapping. The resulting compliance reports have unveiled a startling set of facts: of the 43 zones into which the nation is divided for the purpose of reporting NOx emissions, 33 were in exceedance of the statutory limit on nitrogen oxides (40mg/m3) in 2019. And with the aid of the AURN, the Joint Air Quality Unit were able to whittle it down to the exact 6.1% of British roadways responsible for these infractions.

As a result, JAQU has been working closely with Local Authorities to develop tailored solutions for their NOx problem. For the Unit, each area has its own difficulties, capacities and needs, so there are no one-size-fits-all measures. As a rule, though, JAQU’s solutions offer immediate implementation and tend not to exert a punitive strain on budgets, solutions like reduced speed limits to prevent the increased emissions resulting from higher revs or traffic signal optimisation to reduce idling. Even the pricier options, like retrofitting local bus fleets with selective catalytic converters, are firmly within the realm of possibility for all but the most cash-strapped Local Authorities.

As has been said, the Joint Air Quality Unit doesn’t traffic in absolutes. But there is one absolute condition which Local Authorities need to fulfil in accepting the Unit’s help, and it’s a programme that has been garnering both praise and scorn.

Roadside Picnic?

I think it would be fair to predict that, in the years to come, the Clean Air Zone will become synonymous with the Joint Air Quality Unit. For the moment, though, you will have seen, or passed through, a CAZ even if you’ve never heard about JAQU.

In principle, a Clean Air Zone attempts to reduce the emission of nitrogen oxides by levying charges on polluting vehicles, in the hope that these extra costs will incentivise motorists to switch to a less offensive mode of transport. For each area, there are different culprits, so if you were charged at the Birmingham CAZ, you might well pass through the Zone in Bath unharmed. As with any of the measures that the Joint Air Quality Unit proposes, the Clean Air Zones are, individually, having only a small effect on the local concentration of nitrogen oxides, but they are working.

For a few outspoken locals, though, the positives simply do not outweigh the negatives. Whenever a new Clean Air Zone is proposed, Twitter ignites with furious clashes between supporters and detractors. For the former, a CAZ is a necessary inconvenience that brings inestimable benefits to the quality of living in and sustainability for the area. The latter, however, are frustrated by the prospect of yet another tax and an attendant curtailment of their personal choices. For them, the proposed improvement of air quality is just an excuse. Out of the online debate come more direct forms of contest, of course. Petitions and demonstrations have been used to seal the deal in favour of either side. In all cases, though, the Clean Air Zone gets up and running, and opposition to the scheme dwindles to grumbling acceptance, to a miffed clicking of the button to pay the charge.

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