Planning4Minerals header
  Influence of EU
 Role of central government
 Role of regional bodies
 Enviro protection/heritage
 Role of elected members
 Local communities
 Planning process
 Future aggregate sites
 Commercial interests
 Planning permission
 Enforcing planning rights
 Natural and built heritage
 Noise and vibration
 Transport and traffic
 Air quality
 Water resources
 Mineral waste
  What are aggregates?
 Resources vs Reserves
 Location of aggregates
 Quarry design/restoration
 Aggregate process
 Aggregate testing
  Aggregates use
 Supply and demand
 Value to economy
 Regional supply issues
 Local economy
 Transportation issues
 Site map
 Notes for trainers

Why are air quality issues important to councillors?

The most common cause of air quality problems is airborne dust. Once present in the open air, dust is extremely difficult to remove and the only realistic option is to allow it settle back to the surface in its own time. The location at which settling occurs may be difficult to accurately predict and impossible to control. As a consequence, dust is a major source of complaints from local communities and residents suffering dust deposition on their property. Although there is little evidence to suggest that health risks are significant, local people may also be concerned about risks to their health arising from exposure to dust. Consequently, when considering planning applications, the proposed approach to preventing dust generation will be a major factor in predicting the significance of potential impacts on the wider community.

What are the causes of air quality issues?
The main cause of air quality issues is dust, which is also one of the most common sources of complaints from local communities and residents. Exhaust fumes from fixed and mobile plant running on diesel, and odours from associated works such as bitumen plant, can theoretically cause impacts outside the site boundary, but unlike dust, other sources of air emissions are generally small or easy to control, and such impacts are rare. Dust, however, can potentially be generated on a large scale throughout the life of the operation and therefore has a higher potential for traveling beyond the site boundary and affecting surrounding areas.
Dust can be a major issue for local communities. Living with dust fallout in surrounding areas can be a source of annoyance for local people and concerns regarding the health impacts of dust may be difficult to dismiss irrespective of the likely risk. As with all environmental issues, prevention is better than cure and the operator's efforts should be focused on controlling dust generation.
Strictly speaking, dust is made up of solid particles between 1 and 75 microns in size (1000 microns are equal to 1 millimetre). However, the term is also used to describe larger particles resting on the ground or other surfaces that can become airborne to disperse in the air before returning to the surface.

Activities that can generate dust include soil and overburden stripping, drilling and blasting, stockpiling, disposal of wastes, processing operations, loading and unloading, haulage, site restorations and ancillary operations such as concrete and asphalt plant.

The relevance of each of these is influenced by duration and location (particularly whether it takes place above or below surface level), site topography and the proximity of local communities. Local weather is also extremely important an activity that is a major dust generator during hot, dry and windy weather may generate no dust when it is raining or when there is little or no wind.

Dust generation in an active quarry

Dust generated during loading of primary crusher.

It is important to recognise that there may be many sources of dust in the same area that are unrelated to aggregates production (for example, combustion products from fires, power stations and motor vehicles and dusts from other industrial activities) and aggregates production may be a major or minor contributor to existing dust creation.
  Dust generated during loading of primary crusher

Dust generated during hauling of dug material.

Why is dust significant?
Irrespective of the actual risks, the perception of health risks may still persist in the local community and need to be addressed proactively by the operator to avoid adverse publicity.
The potential significance of dust is influenced by the size of particles. Large dust particles (greater than 30 microns) make up the greatest proportion of dust and largely deposit within 100 metres of the source. Intermediate sized particles (10 to 30 microns) are likely to travel 200 to 500 metres. Smaller dust particles (less than 10 microns, also known as PM10) make up a smaller proportion of the dust and remain airborne for longer, dispersing more widely and depositing more slowly over a wider area.

Effects tend to diminish with distance from the source as larger particles rapidly settle back to the surface and the most acute impacts are likely to occur close to major sources of dust. Local communities can potentially be affected by dust up to 1 km from the source but concerns about dust are more likely within 100 metres of the source (, 2005).

Larger particles are associated with public nuisance, being particularly noticeable on clean surfaces such as cars, windows and window ledges, or surfaces that are usually expected to remain free of dust. Deposition may impact dust-sensitive locations such as schools, retirement homes, hi-tech industries and hospitals and deter the use of amenity areas by local residents. Complaints may increase when dust has a contrasting colour that is more noticeable on deposition or when deposition of dust is frequent, heavy or occurs over a large area.

Guidance relating specifically to mineral operations suggests that complaints are most likely when dust is being deposited at two or three times the background rate in the area.

There may also be a perception amongst local community residents that dust from aggregate operations is a risk to their health. However, the concentration of dust in the air decreases rapidly with distance from the source and there is no evidence that it can affect the health of local residents at the low levels seen in adjacent communities.

Irrespective of the actual risks, the perception of health risks may still persist in the local community and need to be addressed proactively by the operator to avoid adverse

However, as a precautionary measure (based on findings at coal operations) the Proposed Extended Minerals Planning Guidance Note 11 (ODPM, 2000) recommends that a survey of PM 10 be undertaken if a community is within 1 km of a site. Irrespective of the actual risks, the perception of health risks may still persist in the local community and need to be addressed proactively by the operator to avoid adverse publicity.

Although there are few studies of the effects of dust on soils and plants it is generally accepted that dust may lead to physical damage and reduced growth of plants (including crops) and possibly changes in the characteristics of soils and the plants and animals that the soil can support (, 2005).
Many of these potential impacts can be prevented or mitigated by the implementation of good practice. The acceptability of impacts that remain after good practice measures have been put in place should be considered in the context of the economic and other benefits that accrue from aggregates production.

Aerial view of typical quarry site annotated with major sources of dust

Aerial photo of ‘typical' quarry site annotated with the major sources of dust. (Click to enlarge).

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