Something in the air?
September 1st 2009

In 2005 it was predicted that approximately 1,000 accelerated deaths and 1,000 extra respiratory hospital admissions occurred in London as a result of PM10 air pollution and it's not just people on an immediate site who are affected, explains Gary Noakes of Casella

Dust is defined as particulate matter of up to 75 Ėm (micron) in diameter and includes both suspended and deposited matter, but the real culprits are airborne particles with an aerodynamic diameter of 10 microns or less. Most dust particles can cause eye and throat irritation even though they are too big to be inhaled. However PM10 particles are small enough to enter the lungs and able to transport adhered carcinogenic compounds that are associated with a range of health problems. The damaging impact of PM10 is not confined to the construction site because these airborne particles can travel further than coarser dust and affect the health of people living downwind.

Emissions of particles and dust from construction can also have an impact on indoor air quality in the neighbouring area. The Committee on the Medical Effects of Air pollution (COMEAP), a Department of Health expert group, stated that it is now recognised that many pollutants generated outdoors also penetrate indoors.

Dust and other air pollution from demolition and construction, can impact considerably on the health of people working on and living close to these sites if they are badly managed. London in particular has a raft of major construction projects (estimated 10,000 active construction sites, ranging from minor house renovations to large area regeneration schemes), including many for the 2012 Olympics, and they are all now encouraged to follow London wide Best Practice Guidance which will help to reduce emissions from these activities, as part of their planning application and on going activities.

The Guidance provides a consistent approach covering all aspects of dust control and emissions from construction and demolition activities and to allow all London's local authorities to apply advice from one source in a consistent way across the capital, and is applicable to any other construction site as a good policy to adopt.

Other commercial guidance is also available to assist in the control of dust and other pollutant emissions specifically from construction, for example the following BRE Guidance offers good examples of current best practice: Control of dust from construction and demolition activity Controlling particles, vapour and noise pollution from construction sites.

Other legislation is also applicable on site: The Environmental Protection Act (EPA) 1990, (Part 3).

Here the emission of dust, fumes and other effluvia from construction sites can be identified as a statutory nuisance if prejudicial to health or a nuisance.

Under the Health and Safety at Work Act (1974) and under the Control of Substances Hazardous to Health (COSHH) Regulations (2002), developers must ensure that they take into account risks to the workforce from exposure to any harmful substances generated by work activities. The Health and Safety Executive (HSE) is the overall enforcement agency.

Many of the ordinary tasks carried out in construction are dust producing, such as masonry cutting, finishing, welding, grinding, the use of most powered hand tools and the movement of vehicles and heavy plant. Dust created or raised by these activities will include materials both benign and dangerous such as asbestos, cement dust, wood dust and crystalline silica which is a natural component of many materials including sand, sandstone, granite, clay, shale and slate.

Breathing the very fine dust of crystalline silica can lead to the development of silicosis, which scars the lung tissue and leads to breathing difficulties. Exposure to very high concentrations over a relatively short period of time can cause acute silicosis, resulting in rapidly progressive breathlessness and death within a few months of onset.

Monitoring pollutants from all demolition and construction sites is clearly vital, and the activity will range from visual assessments for low risk sites to the installation of real time automatic monitors for PM10 for major projects and high-risk operations. Many sites undertake monitoring prior to commencement of the projects to establish background air quality and determine PM10 response threshold levels and site-specific dust action levels. The frequency of monitoring should be sufficient to take weather conditions and seasonality into account and to observe the effects of remedial measures.

A wide range of technology of various levels of sophistication is available for this type of surveillance. To discuss the options in more detail, visit Casella CEL at Health & Safety '09 North in Bolton on Stand 156.