Something in the air?
June 1st 2008 There are many powerful reasons why developers must confront the gritty issue of dust control early in their project planning. The Health and Safety at Work Act of 1974 is the big one, but a clutch of other regulations such as the Building Regulations and the Building Act of 1984, the Environmental Protection Act (EPA) 1990, Local Air Pollution Prevention and Control (LAPPC) regulations and even the COSHH Regulations 1991 are watching for construction emissions and their impact on the environment, site workers and local residents, explains Gary Noakes, Product Manager for Casella
It can be a problem in almost any industry and region, but construction projects are usually located in urban areas where local residents are sensitive to dust and noise nuisance, and where air quality issues may already exist.
In London alone there are an estimated 10,000 active construction sites, ranging from minor house renovations to large area regeneration schemes that will run for many years. Like other major cities the capital already suffers from poor air quality, and it was predicted that in 2005 approximately 1,000 accelerated deaths and 1,000 extra respiratory hospital admissions occurred as a result of air pollution.
Dust is defined as particulate matter of up to 75 Ìm (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, but the PM10 particles are small enough to enter the lungs, are able to transport adhered carcinogenic compounds and 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.
What produces dust?
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. At the Heathrow terminal 5 site, for example, there were seven automatic air quality monitoring stations, and monitoring began 18 months prior to the commencement of the project to establish background air quality and determine PM10 response threshold levels and site-specific dust action levels.
A wide range of technologies of various levels of sophistication is available for this type of surveillance, and Casella CEL has responded with the launch of a dust monitoring tool designed for use as a static area monitor for dusts and fumes. Its ideal role is as a survey tool for workplace and medium term boundary monitoring applications where both gravimetric and historic dust profiles are required to identify trends and hot spots.
Dust detection
The Dust Detective comprises a Casella Microdust Pro real time dust monitor and Apex Lite air sampling pump. Both gravimetric and real time dust data can be obtained, and foam inserts can be used which allow pre selection of PM10, PM2.5, and respirable fractions to be taken.
Instruments are powered by internal alkaline cells offering excellent run times and no downtime for re charging.
Internal instruments can be removed and used individually to give increased versatility over previous models and the enclosure is also available separately for existing users of Apex sampling pumps and Microdust monitors.
Short term dust monitoring is used to quantify a newly arising problem and is useful in identifying hot spot areas or specific machinery that is responsible for dust generation. Ideally, baseline conditions should be established by testing before the start of operations as at T5, and continue throughout the project to ensure compliance with planning conditions. Frequency of monitoring should be sufficient to take weather conditions and seasonality into account and to observe the effects of remedial measures. More articles from Casella Measurement Ltd: | 
