Emissions

This guide, part of the Foundation Course on Air Quality Management in Asia, provides a comprehensive technical framework for developing emissions inventories and implementing control measures for air pollutants. It details the methodologies for quantifying emissions from stationary, area, and mobile sources, evaluates various international software tools for inventory compilation, and describes the physical and chemical processes used to control particulate and gaseous emissions.

• Emissions inventories are essential for air quality management (AQM) as they identify key pollution sources, provide data for dispersion modelling, and help policy makers set reduction objectives. In Asia, Africa, and Latin America, these inventories are often absent or unreliable, which hinders the development of strategic plans and the monitoring of their effectiveness.
• Two primary methodologies exist for creating emissions inventories: the top-down approach and the bottom-up approach. The top-down method uses national or regional estimates allocated via surrogate parameters like population or energy use and is typically used for area sources. The bottom-up method collects source-specific data on individual processes and activities to estimate emission factors, resulting in higher accuracy but requiring more financial resources.
• Air pollution sources are categorized into four main types: stationary (point) sources like industrial sites; area (non-point) sources such as domestic heating and cooking; mobile (line) sources including motor vehicles; and biogenic (natural) sources such as volcanic eruptions and forest fires.
• The document identifies several international computer programs and systems for compiling emissions inventories. These include the EU's EMEP/CORINAIR, the USEPA's Air CHIEF (and its MOBILE 6 and NONROAD models), the Norwegian Institute for Air Research's AirQUIS, and the WHO's Rapid Inventory Assessment Technique (RIAS), which is specifically recommended for resource-limited developing countries.
• Control of particulate matter (PM) is achieved through various devices based on different collection processes: inertial dust separators (settling and baffle collectors), cyclones (centrifugal force), wet scrubbers (liquid contact), filters (fabric or bed filters), and electrostatic precipitators (electrical charging).
• Gaseous emissions are managed through six primary physical, chemical, or biological processes: combustion (including direct flame, thermal, and catalytic incineration), absorption (gas scrubbing), adsorption (binding to solid surfaces), condensation (cooling or compression), biofiltration (microbial degradation), and flaring.
• Reducing emissions from mobile sources requires a four-pronged approach: implementing strict emissions standards and vehicle technology (e.g., catalytic converters), using cleaner fuels (e.g., phasing out lead), establishing inspection and maintenance (I&M) programs, and utilizing transportation planning and demand management.
• The document emphasizes that for developing countries, the most cost-effective way to obtain a reliable emissions inventory is through rapid assessment techniques, though these carry larger uncertainties than sophisticated models.

APA

Haq, G., & Schwela, D. (2008). Emissions. Stockholm Environment Institute. https://www.sei.org/mediamanager/documents/Publications/Atmospheric/Cleanair/download/Module2-%20EMISSIONS-AirQualityManagement.pdf

Chicago

Haq, Gary, and Dieter Schwela. Emissions. Stockholm Environment Institute, 2008. https://www.sei.org/mediamanager/documents/Publications/Atmospheric/Cleanair/download/Module2-%20EMISSIONS-AirQualityManagement.pdf.

Wikipedia

{{cite report |last1=Haq |first1=Gary |last2=Schwela |first2=Dieter |title=Emissions |publisher=Stockholm Environment Institute |date=2008 |url=https://www.sei.org/mediamanager/documents/Publications/Atmospheric/Cleanair/download/Module2-%20EMISSIONS-AirQualityManagement.pdf |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{haq2008emissions, author = {Haq, Gary and Schwela, Dieter}, title = {{Emissions}}, institution = {Stockholm Environment Institute}, year = {2008}, url = {https://www.sei.org/mediamanager/documents/Publications/Atmospheric/Cleanair/download/Module2-%20EMISSIONS-AirQualityManagement.pdf}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }