NAEI Reference:
ED56186012
Date:
28 March 2013
By:
Nipunika Perera and Ross Hunter (Ricardo-AEA)
Primary NO2 Emissions from Non-transport Combustion and
Industry Sources
1. Introduction
Nitrogen oxides (NOX) are emitted from mobile and stationary combustion sources and
certain industrial processes. Emission inventories are able to compile fairly accurate
estimates of NOX emissions, but are less able to split emitted NOX into its components of
nitric oxide (NO) and nitrogen dioxide (NO2) while air quality models have until recently
generally assumed the vast majority of emissions are in the form of NO. However, primary
NO2 is emitted in significant quantities from some sources, especially diesel engine vehicles
and machinery. Furthermore, an increased proportion of NOX is emitted as NO2 from diesel
vehicles fitted with certain exhaust after treatment devices such as oxidation catalysts and
types of particulate filters. This has significant implications to local NO2 air quality in urban
areas. The vast majority of such sources fall within the road transport sector. To account for
this, factors representing the NO:NO2 ratio for NOX emissions have been developed by the
NAEI for the road transport sector, provided for different detailed vehicle types and weighted
by the composition of the vehicle fleet up to 20301. The factors are expressed as the volume
fraction of NOX emitted as NO2, f-NO2.
Whilst transport is the dominant source, there is the possibility that primary NO2 emissions
also occur from other sources. This note provides a summary of the findings from an
approach taken to review emission factors for primary NO2 for other combustion and industry
sources2. It builds upon and seeks to update where possible a previous briefing note on
primary NO2 completed in 2008.
2. Overview of Previously Developed f-NO2 Factors
Apart from the f-NO2 factors for road transport and other transport, previous NAEI research2
also considered f-NO2 factors from stationary sources which included:
- Nitric acid production
- Other chemical processes
- Stationary combustion
- other sources (i.e. industrial processes such as glass and metal industry)
1
http://naei.defra.gov.uk/datachunk.php?f_datachunk_id=324
Murrells, T., MacCarthy, J., Passant, N. An Emissions Inventory for Primary NO2 and Projections for Road
Transport: 2008 NAEI. Report 21 March 2010, NAEI Ref 48954007. Not published. Available on request to NAEI
helpdesk
2
Table 1 summarises the previously developed f-NO2 factors.
Table 1: Mass fraction of NOX emitted as NO2 for stationary combustion and industry
sources
Source
f-NO2 Factors
Nitric acid production
0.605
Chemical industry - nitric acid use
0.605
Stationary combustion
0.05
3. Data gathering and review
The two main objectives of this task were:
1) Contacting potential data holders. Primarily the environment agencies in the UK to
investigate the availability of NO2 emissions data from industrial installations and the
underlying processes to obtain this data.
2) Reviewing available literature to assess if information exists that can be used to
update previous findings for these sectors.
3.1 Contacting Potential Data Suppliers
The Environment Agency (EA), Northern Ireland Environment Agency (NIEA) and the
Scottish Environmental Protection Agency (SEPA) were contacted to investigate whether
they hold f-NO2 emissions data. The primary focus of contacting the Environment Agencies
was to see if it may be possible to obtain data incorporated in permits issued to industrial
installations they are responsible for under the Environmental Permitting regime.
The responses/ findings are summarised below;
-
The Environment Agency (EA) was contacted through several routes (Air Quality
Modelling and Assessment Unit (AQMAU), Pollution Inventory (PI) Team and National
Requests Centre. However, it was not possible to obtain any f-NO2 emissions data.
o
o
o
AQMAU confirmed that they do not hold any emissions data for the installations
they have previously modelled.
The PI team confirmed that they hold NO2 data but only as a metric for total
nitrogen oxides (NOX as NO2), as provided by installations.
The National Request Centre was unable to respond during the course of this
work.
-
Response from NIEA confirmed that they do not hold data or information in addition to
what is returned annually to the NAEI already using data from the Emissions-Pollutant
Release and Transfer Register (E-PRTR).
-
SEPA were contacted but we have not, at the time of writing, received a response.
Initial discussions with the Environment Agency’s National Resource Centre are to be
followed up to investigate the possibility to access data from the Environmental Permitting
regime. Permits are managed locally by site inspectors and area teams. It is not certain
whether data on direct NO2 (as opposed to total NOx) emissions will be available.
3.2 Reviewing available literature
The literature review highlighted some data on f-NO2 emission factors; however, this sought
only to corroborate existing information outlined in previous NAEI research (given in Table
1). In addition information was also uncovered that requires further investigation and may
prove useful in updating the factors in the future.
Monitoring Quick Guide Note 5: RMQG05 - Monitoring oxides of Nitrogen (Environment
Agency 2012)3
This is a guidance note issued by EA describing the techniques and standards required to
monitor oxides of nitrogen (NO and NO2). In this note EA includes specific guidance relating
measurement of NOX and two of these techniques include ways to measure primary NO2.
The two techniques are:
1) Measuring NO alone and then applying a conversion factor to account for NO 2 in the
stack gases, i.e. inferring the NO2 concentrations.
2) Measuring NO and NO2 separately and combining the measurements.
These monitoring methods may therefore be in use at certain installations. Further
investigative work is required to identify these installations and investigate if any permitted
data on NO2 emissions can be obtained.
European IPPC Bureau: BREF notes
Best Available Techniques (BAT) reference documents (BREF) generally give information on
best practice techniques for minimising and monitoring emissions from industrial
installations. BREF’s are usually specific to certain industrial or agricultural sectors. The
BREF note covering emissions of NOX from stationary combustion sources4 does not refer to
the NO:NO2 ratio in NOX emissions. However BREF notes for the cement, lime and
magnesium oxide manufacturing and glass manufacturing do give values for f-NO2 during
stationary combustion, as outlined in Table 2. These align with the f-NO2 emission factor for
stationary combustion of 0.05 detailed in previous NAEI research.
Table 2: Overview of f-NO2 emission factors outlined in BREF notes for stationary
combustion
Source
f-NO2 Factors
Cement, Lime and Magnesium Oxide Manufacturing 0.05 (in the exhaust gas of
Industries (2012)5
rotary kiln plants)
6
Glass Manufacturing
0.05 (in glass furnace)
3
Environment Agency (2012), Monitoring Quick Guide 5: Monitoring oxides of Nitrogen, Environment Agency,
2012
http://cdn.environment-agency.gov.uk/geho0112bwas-e-e.pdf
4 Scarlet et al. (2013) SCALET Bianca Maria,GARCIA MUÑOZ Marcos,SISSA Aivi Querol,ROUDIER Serge and
DELGADO SANCHO Luis. Best Available Techniques (BAT) Reference Document for the Manufacture of Glass
Industrial Emissions Directive 2010/75/EU Integrated Pollution Prevention and Control.
5 NO emissions from a cement kilns are normally related to the airborne nitrogen rather than by the fuel fire.
X
Nitrogen monoxide (NO) accounts for about 95 % and nitrogen dioxide (NO 2) for about 5 % of nitrogen oxides
present in the exhaust gas of rotary kiln plants. (Scarlet et al. 2013)
6 Due to the high temperatures in glass furnaces (up to 1650 °C and up to 2500 °C in the flame), the major
source of NOX is thermally generated NOX, arising from the oxidation of nitrogen in the combustion atmosphere
at temperatures above 1300 °C. The predominant species is NO (90 – 95 %) formed by the overall reaction N2 +
O2 2NO. Levels of NO2 are very low, and most NO2 detected in the emissions results from atmospheric
oxidation of NO. (IPPC 2012)
4. Conclusions
Responses received from the environment agencies indicate that current monitoring of NO2
emissions is generally only as part of total NOX or in some instances NO with uplift for NO2.
The EA’s specific monitoring guidance note does point to the possibility that some
installations may be monitoring f-NO2.
As part of wider work the next steps should be:
-
-
Investigating from EA the installations which measure only NO as a surrogate for
NOX – as these are required to validate any uplift they apply to estimate the NO 2
component and any installation using a more sophisticated separate measurement of
NO and NO2.
Establish a process for the NAEI team to access permits issued under the
Environmental Permitting regime from environment agencies – and particularly the
EA – for potential evidence on primary NO2 emissions.
A wider review of the literature, including that of EU BREF notes, has not suggested the
default factors for f-NO2 outlined in previous NAEI research should be changed. This has
confirmed that at least for stationary combustion, the proposed f-NO2 emission factors
remain valid.
References
Environment Agency (2012), Monitoring Quick Guide 5: Monitoring oxides of Nitrogen,
Environment Agency, 2012
http://cdn.environment-agency.gov.uk/geho0112bwas-e-e.pdf
IPPC (2012), Best Available Techniques (BAT) Reference Document for the
Production of Cement, Lime and Magnesium Oxide
http://eippcb.jrc.es/reference/cl.html
Murrells, T., MacCarthy, J., Passant, N. An Emissions Inventory for Primary NO 2 and
Projections for Road Transport: 2008 NAEI. Report 21 March 2010, NAEI Ref 48954007.
Not published
Scarlet et al. (2013) SCALET Bianca Maria,GARCIA MUÑOZ Marcos,SISSA Aivi
Querol,ROUDIER Serge and DELGADO SANCHO Luis. Best Available Techniques (BAT)
Reference Document for the Manufacture of Glass Industrial Emissions Directive
2010/75/EU Integrated Pollution Prevention and Control.
http://eippcb.jrc.es/reference/gls.html