Guidance

Cement, lime and mineral sector: pollution inventory reporting

Updated 21 August 2024

Applies to England

• Publication for Northern Ireland
• Publication for Scotland
• Publication for Wales

If you operate an A1 facility you must submit data to the pollution inventory. The Environment Agency will have sent you a notice explaining this when your environmental permit was issued.

The ‘general guidance’ available in the pollution inventory reporting guidance gives information that applies to all business and industries. It explains what the pollution inventory is and how to report.

In this guidance you will find information specific to the cement, lime, and minerals (CLM) products sector. The term ‘CLM sector’ includes production of cement, lime, plasterboard and glass or mineral fibre.

If you burn waste, you may need to refer to our incineration sector guidance when reporting the pollution inventory for your installation. You may also find our combustion sector guidance helpful.

This guidance was developed in consultation with the Mineral Products Association (MPA) to improve the accuracy of the pollution inventory. Any deviations from the MPA guidance are considered best practice for the purposes of calculating and reporting the pollution inventory. The changes mainly concern emissions to air from cement and lime installations.

Reporting mass releases and estimation techniques

You should report annual mass releases of specified substances to air, water, and land, as well as off-site transfers of waste. This guidance note applies to air, water, and off-site waste transfer only. We do not typically expect emissions to land from CLM activities.

Release estimation techniques (RETs) are described in our general guidance. Here is a summary of our preferred RETs for CLM activities.

First preference

Use continuous emissions monitoring systems (CEMS) data. Calculate the release based on daily CEMS average and daily average flow, integrated over the year. You should use the raw, as measured, data without subtraction of confidence intervals.

Second preference

Use periodic monitoring data. Calculate the release based on an average of periodic samples and annual flow.

Third preference

Use mass balance or emissions factors. Calculate release based on mass balance or emission factors.

Fourth preference

Use an agreed alternative technique. If you deviate from the above arrangements, you need to agree an appropriate technique with us.

Emissions to air

Monitoring emissions to air

Where wastes are used as fuels, your installation may be considered a co-incinerator and subject to Chapter IV of the Industrial Emissions Directive (IED).

Continuous monitoring is normally required for:

• carbon monoxide (CO)
• hydrogen chloride (HCl)
• hydrogen fluoride (HF)
• nitrogen oxides (NOx)
• sulfur dioxide (SO₂)
• total organic carbon (TOC)
• total particulate matter

Under certain circumstances, continuous monitoring of HF, HCl and SO₂ may not be required, and you can use periodic monitoring instead. The specific requirements for continuous or periodic monitoring are laid down in your environmental permit.

Your environmental permit may also specify frequencies for periodic monitoring for:

• dioxins and furans
• dioxin-like polychlorinated biphenyls (PCBs)
• heavy metals
• polycyclic aromatic hydrocarbons (PAHs)

The frequencies required by Chapter IV of the IED are the minimum frequencies for such periodic measurements, but your permit may specify higher frequencies.

Your environmental permit may specify additional site-specific monitoring requirements depending upon the local circumstances. These may include where SNCR (selective non-catalytic reduction) is in operation, and N₂O or NH₃ releases depending on the reductant used.

See technical details at the end of this note for currently used release estimation techniques. Check the ‘technical guidance and equations’ in our pollution inventory reporting guidance for information on calculating releases of substances to air from various sources.

Relevant pollutants

The most common air emissions from CLM production activities, and their sources, are:

• ammonia (NH₃)
  • in flue gas where SNCR is used
  • where NH₃ is used as a reducing agent
  • from raw materials
• carbon dioxide (CO₂)
  • in flue gas because of complete combustion of organic material
  • calcination reactions as lime is produced from calcium carbonate (limestone)
• carbon monoxide (CO)
  • in flue gas because of incomplete combustion (for example, if spontaneously evaporating or rapid-burning substances are present, or when combustion gas mixing with the supplied oxygen is poor)
• dioxins and furans
  • in flue gas as a result of a re-combination reaction between carbon, oxygen, and chlorine
  • in cement kiln dust (CKD) and bypass dust (BPD)
  • dioxin and furan releases should be reported as International Toxicity Equivalents (I-TEQ)
• hydrogen chloride (HCl)
  • in flue gas
  • from minor additional constituents in the raw materials and fuels from the burning process
• hydrogen fluoride (HF)
  • in flue gas
  • from minor additional constituents in the raw materials and fuels from the burning process
• mercury (Hg)
  • in flue gas from minor additional constituents in the raw materials and fuels from the burning process
  • in cement kiln dust (CKD) and bypass dust (BPD)
• metals
  • in flue gas as particulate matter, usually as metal oxides and chlorides
  • semi-volatile and volatile metals and compounds other than Hg, including cadmium (Cd), thallium (Tl), arsenic (As), lead (Pb), chromium (Cr), copper (Cu), nickel (Ni) and tin (Sn)
  • in cement kiln dust (CKD) and bypass dust (BPD)
• nitrogen oxides (NOx)
  • in flue gases generated by the combustion of fuel and from the production process
  • NOx refers to the total NO and NO₂ emission
• nitrous oxide (N₂O)
  • in flue gas arising principally where SNCR is used
• particulate matter (including PM10 and PM2.5)
  • in flue gas
  • as fine ash from the production process entrained in the gas flow
  • releases of dust from storage areas and grinding areas
  • Note: emissions of PM10 and PM2.5 from the stack must be established on an installation basis and agreed with us
• sulfur dioxide (SO₂)
  • in flue gas where sulphur is present in the fuel or raw materials
  • common sources of sulphur are in the shale or waste streams such as wastepaper, plaster board (calcium sulphate), and sewage sludge
• volatile organic carbon (VOCs)
  • in flue gas
  • from combustion of organic materials
  • fugitive releases from storage areas or treatment plant

Use this list as a guide only and check that there are no other pollutants emitted from your process.

Emission sources

Point source emissions

Point source emissions are exhausted via a stack or vent. That is, from a single point source into the atmosphere. Abatement equipment (for example, scrubbing units or fabric filters (bag house)) can be incorporated into the exhaust system prior to discharge to atmosphere.

Point source (main stack) emissions will normally be the most significant emission source (in terms of annual mass releases) for combustion activities taking place within kilns and clinker coolers at cement and lime production sites.

Fugitive emissions

Fugitive emissions are those emissions generated by the installation activities but are not released from a point source, such as a stack.

Some examples of fugitive emission sources are:

• external stockpiled materials
• transferring material between vessels
• uncovered conveyor systems
• pipework and ductwork systems, for example pumps, valves, flanges
• accidental loss of containment from failed plant and equipment
• packing plant
• ancillary bag filters
• oil and ammonia storage tanks
• poor building containment and extraction
• use of poorly sealed fuel or raw meal charging systems

You only need to report fugitive emissions that leave the installation boundary, such as vapour or dust emissions that may have dispersed beyond the boundary. Emissions that are likely to have stayed within the boundary, such as contained spills, do not need to be included in your calculations.

As part of your original application for a permit you will likely have undertaken some form of modelling to account for fugitive emissions, or you may have updated the model to reflect changes to your operations. Use this model to generate a site-specific value for your fugitive emissions.

Further details can be found in the guidance on air emissions risk assessment for your environmental permit.

Emission factors

When determining the emissions for your installation you should follow the RETs preference hierarchy, as set out in the introduction to this guidance. Where you need to determine a site-specific emission factor you should base your calculation on representative monitoring data. The emission factor will be the ratio of the measured or calculated pollutant emission to the process activity (for example, clinker production rate).

Site-specific emission factors should be periodically checked to ensure they remain valid. You should especially consider how the mix of fuel types you use, or the mix of raw meal varies during the year. Where different mixes of fuels, raw meal, or combinations of both are used, you should determine the emission factor for each mix separately for the relevant period, and then add the results together to calculate the total.

Emission factors and sources for emissions to air are given at the end of this guidance.

Some air emissions, particularly metals, can vary considerably from year to year. For these emissions you should compare the emission for a given year to a rolling average. For emissions which are measured annually, use a rolling average of up to three previous years. Where the emission is measured more than once per year, use a shorter rolling average period for comparison, with up to six previous results.

Emission factors are usually expressed as the mass of a substance emitted per unit of activity, multiplied by the unit mass, volume, distance, or duration of the activity emitting the substance. In the case of new or modified processes, you can obtain initial emission factors from manufacturers’ data and carry out sampling during commissioning to confirm the assumed values.

Carbon dioxide factors

Most CLM industries are currently required to use UK ETS (emissions trading scheme) reporting requirements. The total CO₂ produced by the installation will include CO₂ from the combustion of fuel as well as CO₂ produced by the chemical changes brought about by the onsite processes. For example, you would include emissions from calcination of limestone. The threshold for reporting CO₂ applies to the overall CO₂ emission from the installation.

Particulate emission factors

You need to report the total particulate emissions from your installation, along with the fractions PM10 and PM2.5. The particulate fractions PM10 and PM2.5 should be calculated as a percentage of the total particulate emissions by periodic monitoring measurements. Calculate your annual emissions for PM10 and PM2.5 by multiplying the measured annual total emission by the respective calculated factors; these will be specific to your installation.

For cement kiln emissions, PM10 and PM2.5 fractions should be measured every year. You can do this either by extractive testing filter paper analysis or by a cascade impactor spot sample.

For all point sources listed in the permit (other than the main kiln stack), you should obtain a representative sample of the PM10 and PM2.5 fractions every three years. You can do this either by extractive testing filter paper analysis or by a cascade impactor spot sample.

Other, smaller sources not listed in the permit, such as local exhaust vents required mainly for occupational health reasons, do not need to be included in your calculations.

Normalisation of reporting units

Take care in all calculations to ensure that the emission concentration and flow rate are compatible. For example, normalised emission concentrations should be multiplied by normalised volumetric flow rates. Actual, measured emission concentrations should be multiplied by actual, measured volumetric flow rates.

Normalised emission rates are quoted in terms of a standard oxygen concentration, and are usually dry gas, at a temperature of 273K and a pressure of 101.3kPa.

Check our ‘technical guidance and equations’ in our pollution inventory reporting guidance for further information. This includes unit conversions and worked examples.

Emissions to water

Emissions of substances to water can be either direct to controlled waters (including groundwater), or indirect following transfer to off-site effluent treatment plant. Under normal conditions, there is usually no process water discharge from cement or lime manufacture. In some instances, discharges may result from storm water run-off, cooling water, accidental emissions of raw materials, products, or waste, or from firefighting. In these instances, the quantity discharged would normally be the same quantity abstracted or supplied.

Check our general pollution inventory guidance document for information on what we mean by emissions and transfers. You should consider all emission sources to controlled waters and characterise the flows and emission concentrations from each source, where applicable. There may be process water discharge from other activities on your site.

Relevant pollutants and emission sources

Water discharges from cement and lime processes may arise from storm water, cooling water, accidental emissions of raw materials, products, or waste materials, and from firefighting.

The main water pollutant generated by CLM activities is suspended solids derived from raw material preparation, and storage and handling. Suspended solids alone do not need to be reported to the pollution inventory, however you must consider whether other substances are emitted by your processes, including those associated with suspended particulates.

Discharges of substances depend on the ‘in process’ preventative measures (for example, good housekeeping and re-use), and the presence and technical standards of wastewater treatment facilities.

Off-site waste transfers

You must classify wastes using the European Waste Catalogue 6-digit codes and the relevant Waste Framework Directive disposal or recovery codes. Check the ‘reporting codes list’ in the pollution inventory reporting: guidance notes.

Relevant wastes

The most common wastes we expect to see from CLM facilities are:

• cement and lime kiln dust collected in particulate abatement devices
• materials arising from process clean outs
• spent kiln liner and refractory bricks
• waste oils and lubricants
• chemical containers and general inert industrial waste
• by-pass dust (cement works)

CLM source factors and common pollutants

Total releases (including notifiable releases)

You must report your total annual mass releases or transfers for each specified substance and each medium in the ‘Total releases’ column. Include point source, fugitive, and any notifiable releases in this figure. Enter a release value, ‘n/a’ or ‘brt’ in the ‘total releases’ column as appropriate:

• release – when the annual release exceeds the reporting threshold enter the total annual mass released or transferred
• n/a (not applicable) – no release or transfer of the substance occurred in the reporting year to that medium
• brt (below reporting threshold) – the annual releases or transfers have been determined and found to be below the reporting threshold
• note: we encourage you to report the actual value if available, even if it is ‘brt’

Limit of detection (LOD)

If the best available information indicates that a substance is not released from your process, report ‘n/a’ for that substance. Where a substance may be released but at a release concentration that is below the limit of detection, you also need to report ‘n/a’ unless an alternative release estimation technique, such as mass balance, produces an applicable result.

By limit of detection, we mean the lowest concentration which can be measured by the analytical method prescribed in the permit, or such other method as we approve.

We recognise that there may be circumstances where some analyses in a series do not detect a substance, but others do. Provided that no more than 5% of the readings show a positive value, and the values obtained are not more that 20% above the accepted limit of detection, you can treat them as if they were also reported as below the limit of detection.

In any other case, use the values obtained and assume that where the substance is reported as not detected it is present at 50% of the LOD. In these cases, you need to multiply each concentration (that is, those measured at above the LOD as measured and those measured at below the LOD as half of the LOD) by the total flow during the period the measurement relates to, to determine the mass emission.

In some cases, we may have agreed a different methodology with you for a particular substance or process. If so, use this in place of the procedure above. If, because of this methodology, you get a positive result that is below the reporting threshold, you should report it as ‘brt’ (below reporting threshold), or give the calculated value, rather than ‘n/a’.

Emission factors

We have provided lists of the pollutants potentially emitted from various typical CLM processes. Where available, we have also provided a literature reference for further information, and an emissions factor.

Beside each substance name, we have suggested the most suitable method to determine the release quantity:

• M = measurement
• C = calculation
• E = estimation (engineering judgement)

For pollutants not named in these lists, a return of ‘n/a’ is expected in most cases. This would indicate that this pollutant is not knowingly discharged by the site. Use this list as a guide only and ensure that all pollutants discharged from your site are reported on your return.

Combustion sources

• ammonia (NH₃) – M or C – use MCERTS certified equipment (continuous or periodic monitoring may be required depending upon BAT assessment), refer to US EPA Method 26
• antimony (Sb) – M – use BS EN14385 for extractive monitoring (see section on emission factors for details)
• arsenic (As) – M – use BS EN14385 for extractive monitoring (see section on emission factors for details)
• cadmium (Cd) – M – use BS EN14385 for extractive monitoring (see section on emission factors for details)
• carbon dioxide (CO₂) – C – use site combustion and process sources, reporting should be consistent with UK ETS
  • the pollution inventory Schedule requires separate reporting of ‘thermal’ and ‘chemical’ CO₂, to note emissions from your combustion and non-combustion activities respectively
  • the reporting threshold for CO₂ applies to the overall CO₂ emission (thermal and chemical combined), we encourage you to provide an actual value even if your total emission is below the reporting threshold
  • note that CO₂ from all sources, including biomass, needs to be reported for pollution inventory purposes
• carbon monoxide (CO) – M – use CEN, ISO, or MCERTS, for continuous and periodic monitoring carried out for all co-incinerators, refer to IED Chapter IV, for CEMS refer to BS EN14181
• chromium (Cr) – M – use BS EN14385 for extractive monitoring (see section on emission factors for details)
• copper (Cu) – M – use BS EN14385 for extractive monitoring (see section on emission factors for details)
• dioxins and furans – M or C – only ITEQ to be reported, use BS EN1948, periodic monitoring is required for Chapter IV IED
• fluorine and inorganic compounds – M or C – use ISO or USEPA, refer to BS EN14181 for CEMS and USEPA Method 26A for periodic monitoring (not all installations are required to monitor HF continuously)
• hydrochloric acid (HCl) – M or C – use a site-specific emission factor agreed with us, refer to BS EN14181 for CEMS and BS EN1911 (or demonstrated equivalent) for periodic monitoring carried out for all co-incinerators covered by Chapter IV IED
• lead (Pb) – M – use BS EN14385 for extractive monitoring (see section on emission factors for details)
• manganese (Mn) – M – use BS EN14385 for extractive monitoring (see section on emission factors for details)
• mercury (Hg) – M – use BS EN14385 for extractive monitoring (see section on emission factors for details)
• methane (CH4) – C – use a site-specific emission factor agreed with us
• nickel (Ni) – M – use BS EN14385 for extractive monitoring (see section on emission factors for details)
• nitrogen oxides (NOx), total NO and NO₂ – M – extractive monitoring is required for Chapter IV IED (ASTM D634803, ISO 10849, VDI2469-1)
• nitrous oxide (N₂O) – M or C – extractive monitoring is required for Chapter IV IED (ASTM D634803, ISO 10849, VDI2469-1)
• NMVOCs – M – use MCERTS or BS EN 12619, both CEM and extractive monitoring required
• total particulate matter – M – use continuous monitoring carried out for all co-incinerators covered by Chapter IV IED, refer to BS EN13284-2 for CEMs and BS EN13284-1 for SRM
• vanadium (V) – M – use BS EN14385 for extractive monitoring (see section on emission factors for details)
• zinc (Zn) – M – although not specifically validated for zinc, BS EN14385 will be applicable in most cases

SNCR nitrogen oxide abatement

• ammonia (NH₃) – M or C – use MCERTS certified equipment (continuous or periodic monitoring may be required depending upon BAT assessment), refer to US EPA Method 26

Process sources

• carbon dioxide (CO₂) – C – use site combustion and process sources, reporting should be consistent with UK ETS
  • the pollution inventory Schedule requires separate reporting of ‘thermal’ and ‘chemical’ CO₂, to note emissions from your combustion and non-combustion activities respectively
  • the reporting threshold for CO₂ applies to the overall CO₂ emission (thermal and chemical combined), we encourage you to provide an actual value even if your total emission is below the reporting threshold
  • note that CO₂ from all sources, including biomass, needs to be reported for pollution inventory purposes

Fugitive VOC releases

• NMVOCs – C – see section on fugitive emissions for further details

Dioxins and furans

This family of compounds is known chemically as:

• polychlorinated dibenzodioxins (PCDDs)
• polychlorinated dibenzofurans (PCDFs)

Each compound is made up of two benzene rings interconnected by oxygen atoms. Each individual PCDD or PCDF is termed a congener (there are 210 congeners in total).

When reporting dioxin and furan releases, only the mass of PCDD and PCDF with chlorine atoms in the 2, 3, 7 and 8 positions should be included. These are releases of the most environmental concern.

We want you to report the toxicity of dioxin releases using I-TEQs. Each dioxin congener is assigned a toxic equivalency factor (I-TEF for the international scheme). The 2,3,7,8-TCDD isomer is the most toxic, and is assigned a TEF of 1.0. The remaining 2,3,7,8-positional congeners are then assigned lower relative TEFs.

The toxicity mass of a particular substance relative to 2,3,7,8-TCDD can then be expressed by multiplying the mass of those 2,3,7,8-positional congeners present in the mixture by their respective TEFs. The resulting toxic equivalents (TEQs) are expressed as masses in the same way that the individual congeners are expressed.

You must give the total quantity of dioxins and furans in terms of their I-TEQs. TEFs for each of the 17 relevant 2,3,7,8-positional congeners of PCDDs and PCDFs are given, along with their toxic equivalency factors for the international scheme (I-TEF). All other congeners that may be present in a sample are not reportable.

PCDD (congener and I-TEF):

• 2,3,7,8-TCDD – 1
• 1,2,3,7,8-PeCDD – 0.5
• 1,2,3,4,7,8-HxCDD – 0.1
• 1,2,3,7,8,9-HxCDD – 0.1
• 1,2,3,6,7,8-HxCDD – 0.1
• 1,2,3,4,6,7,8-HpCDD – 0.1
• OCDD – 0.001

PCDF (congener and I-TEF):

• 2,3,7,8-TCDF – 0.1
• 2,3,4,7,8-PeCDF – 0.5
• 1,2,3,7,8-PeCDF – 0.05
• 1,2,3,4,7,8-HxCDF – 0.1
• 1,2,3,7,8,9-HxCDF – 0.1
• 1,2,3,6,7,8-HxCDF – 0.1
• 2,3,4,6,7,8-HxCDF – 0.1
• 1,2,3,4,6,7,8-HpCDF – 0.01
• 1,2,3,4,7,8,9-HpCDF – 0.01
• OCDF – 0.001

Worked example – calculating dioxin and furan releases

If monitoring data representative of annual releases are available, you can get the TEQ of the mixture by summing the individual TEQs as follows:

Step 1: Calculate the TEQ for each congener released. Multiply the concentration (per m³) of each released congener by its TEF and then by the total volume released in that year (in m³) to provide the TEQ.

Step 2: Calculate the total TEQ released. Add together the TEQs of all the congeners released. Carry out Steps 1 and 2 for both sets of TEFs.