What is particulate matter?

Particulate Matter (referred to as Dust in the MCPD and also as PM), can be found in sizes that range from a few nanometres to around 100 micrometres (100 μm, about the thickness of a human hair).

Diesel gensets used in industrial, commercial and power generation applications are a primary source of particulate matter.

Why is it so bad?

PM can have a detrimental affect on health. Particulates have the greatest impact on people with pre-existing lung or heart conditions, the elderly and children. There is evidence that short- and long-term exposure to particulate matter causes respiratory and cardiovascular illness.

What are we doing about it?

The UK implementation of the Medium Combustion Plant Directive (MCPD) imposes different dust limits (either 10 or 20mg/Nm³) depending on the plant size and date of installation (this does not apply to engines running on gas oil i.e EN590 Diesel).

The non-road mobile machinery regulations imposes a limit of 0.025g/kWh for particulate matter.

Clean Air Zones will be particularly important for the reduction in PM. In the first 5 years of London’s Clean Air Zone, particulate matter dropped by 3.1% according to the BBC.

The Medium Combustion Plant Directive (MCPD)

The introduction of the Medium Combustion Plant Directive and Non-Road Mobile Machinery regulations means compliance is essential. The Medium Combustion Plant Directive (MCPD) is EU legislation that became law in December 2017.

The MCPD has been brought into force across the UK through 3 different regulations:

• The Environmental Permitting (England and Wales) (Amendment) Regulations 2018.
• The Pollution Prevention and Control (Industrial Emissions) (Amendment) Regulations (Northern Ireland) 2018.
• The Pollution Prevention and Control (Scotland) Amendment Regulations 2017.

The MCP Directive (Directive (EU) 2015/2193) covers diesel engines between 1 and 50 MWth capacity. These currently fall between two other directives that cover large combustion plants and small appliances. Large combustion plants over 50 MWth are covered by the Industrial Emissions Directive (IED). Boilers, heaters and smaller appliances under 1 MWth are covered by the Ecodesign Directive (CE labelling).

EU statistics estimate there are 143,000 medium-sized combustion plants in the EU. They represent an important source of emissions of sulphur dioxide (SO2), nitrogen oxides (NOx) and dust. The MCP Directive regulates emissions of all three and monitors emissions of carbon monoxide (CO) with the sole aim of reducing these harmful substances that are known to be hazardous to human health as well as the environment.

The MCP Directive is the latest instrument to ensure the EU’s implementation of the Gothenburg Protocol under the UNECE Convention on Long-Range Transboundary Air Pollution.

The MCPD was enacted by the EU on 18 December 2015. Plants that come into operation after 20 December 2018 are classified as “new plant” in the MCP Directive; its emissions limit values (ELVs) apply as soon as the plants start operating. Older plants are classified as “existing plants” by the Medium Combustion Plant Directive. They have to conform to the MCP Directive’s ELVs by 2025 or 2030, depending on their size.

Clean Air Zones

Clean Air Zones are an area where specific action is being taken to improve the air quality. A plan is put in place which aims to deliver improved health benefits and support economic growth.

Clean Air Zones aim to address sources of pollution including nitrogen dioxide (NOx) and particulate matter, with the hope of reducing public exposure to them. Different measures may be taken depending on the location.

Diesel generators have very high NOx emission rates and their use is increasing in response to initiatives within the energy market (this is referring to the capacity market and schemes such as STOR, FFR and TRIAD).

Emissions can be so high that they breach legal limits for NO2.

Within Clean Air Zones:

• Local authorities should consider the air quality impact of plants and safeguard local air quality.
• Businesses requiring back-up power supplies should use generators with low emissions levels. Testing hours should be kept to the minimum required to ensure its safe running.