‘Astonishing’: DEFRA ‘off the hook' on air quality targets after data adjustment

DEFRA has been accused of "undermining the broad purpose" of air pollution regulations, after it removed digestate as a source of ammonia pollution in a key emissions reduction plan, leaving it on track to achieve compliance with legally binding targets.

Spraying fertilizer on wheat crop. Source - GettyImages, SteveAllenPhoto

DEFRA was due to publish the outcome of its consultation on the Draft National Air Pollution Control Programme (NAPCP) on 15 September 2022, as required by regulation 9 of the National Emission Ceilings Regulations 2018. However it missed this deadline and published the updated documents on 9 February. 

The 2018 regulations set legally binding emission reduction commitments in accordance with the National Emission Reduction Commitments (ERCs) for 2020 and 2030 for five air pollutants: fine particulate matter (PM2.5); sulphur oxides (SOx); ammonia (NH3); and volatile organic compounds (VOCs). The NAPCP sets out the measures required for the UK to meet these commitments. 

For ammonia, the ERC is 8%. However, the draft programme concluded that with existing measures, the projected percentage emission reduction likely to be achieved by 2030 compared with 2005 was just 3%. 

But in the final document, this figure has changed significantly, with the projected emission reduction now 23%. 

Despite this significant change, the consultation response states that no further changes have been made to the package of measures to reduce ammonia emissions.

The change is possible due to an adjustment to the UK’s figures requested by the UK government.

The updated documents state that the UK government submitted an adjusted inventory to the United Nations Economic Commission for Europe (UNECE) Convention on Long-Range Transboundary Air Pollution (CLRTAP) for scrutiny, seeking to remove digestate from the list of sources of ammonia emissions. 

The document states that the adjustment - which has now been accepted - “takes into account new science and new sources of ammonia emissions, in particular the spreading of non-manure digestate, that was not included in inventory reporting at the time the ERCs were agreed and has increased in recent years”.

“Applying the adjustment to the 2020 inventory reduces ammonia (NH3) emissions by 12.75 kiloton (kt). Projecting this to 2030 reduces NH3 emissions in scope of the ERC by over 20kt. This reduces the risk of the UK exceeding the 2030 ERC for NH3 in both lower and upper scenarios,” the document states.

Digestate is a nutrient-rich substance produced by anaerobic digestion that can be used as a fertiliser. It consists of leftover indigestible material and dead microorganisms. 

Removing it from the inventory means that the UK can now achieve compliance with the National Emission Ceilings Regulations without introducing any further measures to tackle ammonia pollution. 

According to DEFRA’s most recent Inventory of Ammonia Emissions from UK Agriculture, in 2020 non-manure digestate was responsible for 6% of the total ammonia emissions. This figure has increased significantly in recent years, with the National Farmers Union (NFU) highlighting that using digestate as a fuel will be key to achieving net zero in the sector. 

Emily Kearsey, clean air lawyer at ClientEarth, told ENDS that this adjustment is very “problematic” because it “undermines the broad purpose of the regulations”. 

The adjustment will mean that the government will look good on the figures that project it is set to achieve its targets, but according to Kearsey this picture is “artificial” because it doesn't reflect the reality of the totality of ammonia emissions in this country. 

She highlighted that by removing digestate it basically “reduces the incentive to take tough action to tackle ammonia emissions. 

“We've got a situation where if these emissions were included in the inventory, then either the government would need to reduce these emissions from the source in order to be compliant, or they would need to take tougher action in other areas. But the fact that the UK has made this inventory adjustment application to remove this source, it really gets the government off the hook.”

Another area of concern with the plan is regarding particulate matter (PM2.5). The national emission reduction commitment for PM2.5 by 2030 is 46%, however in the updated policy paper DEFRA outlines that the projected emission reduction to be achieved is between 42 - 47% - meaning there is a high level of uncertainty over whether the limit will be met.  

Kearsey told ENDS that “there is still a persistent risk of non-compliance because the majority of this range is below 46%.

“The whole point of this plan is to provide a road map to show how these emission reduction commitments are going to be mapped and if there is this persistent uncertainty, especially given that the majority of the range that they’ve provided would be non-compliant, then I don’t really see how that’s a plan that's going to ensure that these commitments are met.” 

“Our view is that if you have this persistent uncertainty about whether the policies and measures are enough to meet the emission reduction commitment, then you need to do more to eliminate that uncertainty, whether that’s through earlier timeframes, more rigorous enforcement of the introduction of additional policy and measures that eliminate that uncertainty”.  

PM2.5 can be formed when ammonia reacts with nitrous oxides and sulphur dioxide in the air. Therefore ClientEarth told ENDS that a failure to tackle ammonia emissions "may well" threaten the UK’s ability to comply with the new PM2.5 concentration targets adopted under the Environment Act 2021. 

However, the lawyers added that it is unlikely to affect compliance with the PM2.5 emissions reduction commitment. This is because this target covers primary PM2.5 emissions, not secondary sources. 

Kearsey also explained that the wording of the regulations does not go into the level of detail to say whether its permissible for the government to provide a range of projected emissions, but she added that ClientEarth’s view is that for the NAPCP to “provide effective path to compliance this uncertainty should be minimised.” 

Simon Birkett, founder and director of Clean Air in London, also told ENDS that it is “astonishing that DEFRA’s response to so much criticism of its emissions plan is to make no changes to it. 

“The chances of the UK meeting its obligations on ammonia and fine particles in 2025 and 2030 must be close to zero now. I'm beginning to wonder whether the department is run for the benefit of farmers and the wood stove industry."

ENDS has contacted DEFRA for comment.