Air emissions risk assessment for your environmental permit

GOV.UK Home Business and industry Business and the environment Guidance Air emissions risk assessment for your environmental permit How to complete an air emissions risk assessment, including how to calculate the impact of your emissions and the standards you must meet. From: Environment Agency (/government/organisations/environment-agency) and Department for Environment, Food & Rural Affairs (/government/organisations/department-for- environment-food-rural-affairs) Published 1 February 2016 Last updated 21 December 2023 — Applies to England Related content Guidance for Northern Ireland (https://www.daera- Environmental ni.gov.uk/articles/ippc-guidance-and-application- permitting:

air forms) dispersion modelling Guidance for Scotland reports (https://www.sepa.org.uk/regulations/air/) (/guidance/environmental- Guidance for Wales permitting-air-dispersion- (https://naturalresources.wales/permits-and- permissions/?lang=en) modelling-reports) Contents

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Contents Medium combustion plant: apply for an — Before you start this risk assessment environmental permit — How this risk assessment works (/guidance/medium- — Steps to complete this risk assessment combustion-plant-apply- for-an-environmental- — Risk assessment tool permit) — Calculate PC to air Medium combustion — PC: dispersion factor plant and specified — PC:

release rate generator regulations — Calculating averaging periods (/government/collections/ medium-combustion-plant- — Calculate PC for substance deposition and-specified-generator- — Screen out insignificant PCs regulations) — Calculate PEC Assess the impact of air — Screen out PECs from detailed modelling emissions on global warming — Screening for protected conservation areas (/guidance/assess-the- — Detailed modelling impact-of-air-emissions- — Compare and summarise your results on-global-warming) — Check if you need to take further action Specified generator:

— Check if you need to do other risk apply for an assessments environmental permit — Environmental standards for air emissions (/guidance/specified- — Contact generator-apply-for-an- environmental-permit) Before you start this risk assessment Collection Read the following guides before you start this risk assessment: Risk assessments for specific activities:

the risk assessment overview environmental (https://www.gov.uk/guidance/risk-assessments-for- permits your-environmental-permit) – this explains the other (/government/collections steps to take in risk assessment and whether you /risk-assessments-for- need to do an air emissions risk assessment specific-activities- best available techniques (BAT) environmental-permits) (https://www.gov.uk/guidance/best-available- techniques-environmental-permits) from the European Commission – you may need to apply, Contents or in some cases exceed, BAT depending on how

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harmful your emissions could be to the environment How this risk assessment works You need to compare the impact of your emissions to air to the following environment standards: Air Quality Standards Regulations 2010 Limit Values and Target Values UK Air Quality Strategy Objectives Environmental Assessment Levels Find the environmental standards. Steps to complete this risk assessment To complete an air emissions risk assessment you need to follow these steps. 1 Calculate the environmental concentration of each substance you release into the air – known as the process contribution (PC).

Identify PCs with insignificant environmental 2 impact so that they can be ‘screened out’ – this means that you do not have to assess them any further. For substances not screened out in step 2, 3 calculate the predicted environmental concentration (PEC) for each substance you release to air – the PEC is the PC plus the concentration of the substance already present in the environment. 4 Identify emissions that have insignificant environmental impact – these can be screened out. Contents

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5 Get ‘detailed modelling’ (also known as detailed assessment or computer modelling) done for the emissions you cannot screen out. For each substance you’ve released to air, 6 compare the PC and PEC with the relevant environmental standard and summarise your results. Check if you need to take further action. 7 8 Check if you need to do any other risk assessments. The Environment Agency sometimes refers to the following stages of air emissions risk assessment:

‘stage 1’ – this is steps 1 and 2 ‘stage 2’ – this is steps 3 and 4 Risk assessment tool You should use the Environment Agency’s risk assessment tool (https://www.gov.uk/government/collections/risk- assessments-for-specific-activities-environmental- permits#H1-software-tool) to complete your risk assessment. The only stage you cannot use it for is to screen out PCs or PECs of substances in protected conservation areas. The figures the tool gives you are ‘worst case’ estimates. So the figures you get may be higher than if you calculate PCs or PECs using other methods, for example dispersion modelling software (which analyses how air pollutants disperse in the atmosphere).

This guide explains the steps to complete if you’re not using the risk assessment tool. Calculate PC to air Contents

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