The primary pollutants in concrete batching are particulate matter, consisting primarily of cement and pozzolan dust but including some aggregate and sand dust emissions. In addition, there are emissions of metals that are associated with this particulate matter.
It only takes a very small amount of the very fine respirable silica dust to create a health hazard. Recognizing that very small, respirable silica particles are hazardous, OSHA regulations requires construction employers to keep worker exposures at or below a Permissible Exposure Level (PEL) of 0.1 mg/m3. The National Institute for Occupational Safety and Health has an even lower Recommended Exposure Level of 0.05 mg/m3.
A critical factor in evaluating the impact of emissions of the environment in wind. The Olympic Park Area is a very windy urban zone; prevailing winds are from the south west so there will be areas around the plant that will more affected than others; also low level edges like the Greenway will not be able to stop these pollutants to fly around.
Around the batching plant and less than 300ft away are university campuses, athletes training grounds, primary and secondary schools, visitor promenades and dense residential areas.
The planning applications and impact assessment do not include detailed maps of the site, and its microclimatic conditions, including wind patterns or any map of simulated distribution of pollutants due to wind. What’s more, there is no description in the application of any of the design measures meant to reduce the fugitive particles at any one of this points.
Some more facts about silica dust as contained in cement and pozzolanic dust: