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Particle settling after lead-based paint abatement work and clearance waiting period.

Authors
Choe-KT; Trunov-M; Grinshpun-SA; Willeke-K; Harney-J; Trakumas-S; Mainelis-G; Bornschein-R; Clark-S; Friedman-W
Source
Am Ind Hyg Assoc J 2000 Nov/Dec; 61(6):798-807
NIOSHTIC No.
20041053
Abstract
This study investigated the evolution of airborne particle concentration and size distribution following abatement work in a controlled environment utilizing direct real-time particle monitoring and used it to project potential lead loadings as those particles settle. An 860 ft3 environmental test chamber with sophisticated ventilation and air purifying systems was built. Wooden doors with lead-based paint were dry sanded or scraped to generate the highest feasible airborne lead concentrations. Size-fractional airborne particle concentrations decreased exponentially with time in all tests, even with no air exchange, consistent with the stirred model of constantly mixed air, which predicts longer settling than for tranquil settling. Very low levels of air mixing generated by temperature gradients and initial room air turbulence affected particle settling. About 90% of airborne lead mass settled within 1 hour after active abatement, before final cleaning began. During the second waiting period of 1 hour, which followed cleaning of the floor, additional dust settled so that the additional potential lead loading from remaining airborne lead was less than 20 microg/ft2. For this worst case scenario, the underestimate of the lead loading done by the clearance sampling did not exceed about 30%. For more realistic conditions, the underestimates are projected to be much lower than the new 40 microg/ft2. Housing and Urban Development (HUD) clearance standards for floor dust lead. These results were obtained for the first waiting period (between the end of active abatement and the beginning of cleaning) of 1 hour, as recommended by HUD guidelines. Thus, this study demonstrates no need to increase either the first or second waiting period.
Keywords
Lead-compounds; Lead-dust; Paints; Paint-removers; Air-contamination; Exposure-assessment; Aerosol-particles; Laboratory-testing; Controlled-environment; Ventilation; Air-purifiers; Control-systems; Particle-aerodynamics; Airborne-particles; Standards;
CODEN
AIHAAP
CAS No.
7439-92-1
Publication Date
20001101
Document Type
Journal Article
Funding Type
Grant
Fiscal Year
2001
NTIS Accession No.
NTIS Price
Identifying No.
Grant-Number-T42-CCT-510420; Grant-Number-T42-CCT-510520
Issue of Publication
6
ISSN
0002-8894
Source Name
American Industrial Hygiene Association Journal
State
OH
Performing Organization
Department of Environmental Health, University of Cincinnati, Cincinnati, OH
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