Sandblasting or steel grit blasting of any object is likely to generate solid particulates, that depending upon their size, will suspend in the atmosphere. Particulates produced by sandblasting can vary in size from 1.0 micron to 200 microns. Particulate sizes of 50 microns or larger are generally visible. Those of less than 100 microns in diameter will normally remain suspended in air while larger particulates will settle out of the air under the influence of gravity in a short period of time. When this occurs, the ground or surface water on which they land becomes contaminated with lead. Therefore, the uncontrolled blasting of leaded paint is a major pollution concern due to its potential for contaminating air, water, or land and because it can cause violations of ambient air quality standards for total suspended particulates and lead.
The State of Illinois has adopted the National Ambient Air Quality Standards (NAAQS) for lead and for particulate matter, which are 10 micrometers, and smaller (PM10) in size.
|Particulate Matter - 10 micrometer (PM10)||annual arithmetic mean||50 µg/m3||50 µg/m3|
|24-hour average||150 µg/m3||150 µg/m3|
|Lead||calendar quarter arithmetic mean||1.5 µg/m3||1.5 µg/m3|
The blasting process can cause "air pollution" and also create visible dust. The specific rules which prohibit such pollution are specified below.
The demonstration of compliance with air pollution regulations is essential. One way of complying with these rules is by total enclosure of the project in a manner which will prevent the uncontrolled dispersion of particles into the environment. Such an enclosure should be maintained under negative pressure to minimize the release of airborne particles. This containment should utilize the best technology available.
Many contractors are currently using complete enclosure and such enclosures are maintained by directing the exhaust to a baghouse. Such a device, when appropriately engineered, will control the lead contaminated paint chips properly and will prevent the chips from becoming airborne. This method should be used whenever possible.
Depending on the nature and extent of the removal activity, a monitoring plan may be appropriate. This monitoring plan may include background testing for existing levels of lead in soil, water, sediment, and ambient air to provide a record of baseline lead levels.
When there is a potential for significant human and/or environmental exposure to occur outside the containment structure, ambient air monitoring should be conducted for lead and particulate matter of 10 micrometers and smaller (PM10). Such a monitoring program should start with a detailed written plan, subject to approval by the appropriate agency and should address the following elements:
Such a plan and any questions related to such a plan should be directed to the following address if the Agency is the appropriate review entity:Manager, Air Monitoring Section