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Summary of the Revised Standard
The revised standard retains the current method for monitoring as total suspended particulate (TSP) with subsequent analysis for lead (TSP-lead). It also introduces a new monitoring and analysis method using a low-volume PM10 monitor and XRFD analysis at the monitoring stations. Use of this method is limited to certain scenarios and will require conversion of the PM10-lead results to equivalent TSP-lead values. It appears EPA is introducing this alternative method as an opportunity to study its potential for replacing TSP monitoring in the future.
This was the first NAAQS reevaluation for which EPA specifically incorporated a review of: a) concentrations of lead in the environment; b) multimedia lead exposure (via air, food, water, etc.); c) characterization of lead health effects and associated exposure response relationships; and d) delineation of environmental (ecological) effects of lead. Over 6,000 scientific studies were evaluated and summarized by the Clean Air Scientific Advisory Committee. In EPA’s Rationale for Final Decisions on the Primary Lead Standard (the “Rationale” is the means used by EPA to justify its rulemaking), continually referred to the compelling evidence related this data and to a new and emerging understanding of a more significant impact from lead exposures than previously thought.
States must identify likely non-attainment areas to EPA by October 2009. EPA will then evaluate state monitoring results from 2008-2010 and will designate new non-attainment areas by October 2011. After October 2011, the States have five years to meet these new standards. Each State with a non-attainment area will need to develop a State Implementation Plan (SIP) that outlines proposed regulations and pollution controls it will implement to reduce airborne concentrations of lead to below the standard (i.e. bring the area into attainment). In this process, it is reasonable to expect new regulatory requirements to be imposed on smaller stationary sources of lead as well as fugitive, non-point sources of emission like field painting.
While the EPA does not impose NAAQS on individual painting projects, TSP-lead monitoring has often been incorporated into specifications as a way to measure the effectiveness of the containment system’s control over emissions, with the NAAQS limits used as the acceptance criteria. Most painting specifications and many industry documents, training courses and certifications refer to the NAAQS for Lead. Accordingly, the implications of the new limits on current and future painting projects that invoke TSP-lead monitoring must be considered, and addressed as well in training curricula, and industry references, guidelines and standards.Data presented in Rationale” regarding the impact of lead on children and adults, states:
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Blood lead levels (BLLs) of 10 microgram per deciliter (μg/dL) or lower can have substantial neurological, hematological, and immune effects on children, and cardiovascular and renal effects on adults.
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The scientific evidence supports an air-to-blood ratio of 1:5 to 1:10. This means that at 0.15 μg/m3 of lead air exposure, you can expect a BLL of 0.75 to1.5 μg/dL.
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The scientific evidence supports a blood-to-IQ loss ratio of 2 IQ points for 0.15μg/m3 of lead air exposure.
EPA cited the irreversible and long-term consequences of lead exposures as outlined above as well as the persistence of lead in the environment (despite dramatic reductions in leaded gasoline over the past 30 years) and the continued addition of lead into the environment through stationary and non-stationary sources as a basis for the standard revisions.
Data Evaluation (Can Our Industry Meet these Standards?)
Our industry has been performing ambient air monitoring for lead using the NAAQS monitoring methods since the late 1980’s and continues today.
The landmark Final Environmental Impact Statement (FEIS) for the NYCDOT Bridges issued in 1998 included extensive background monitoring and air modeling of expected ambient air lead levels during bridge lead paint removal projects. The FEIS established a mitigation program and project commitments to be used during bridge painting to protect public health and welfare. It established the minimum containment classes and ambient air monitoring limits that would “meet” the 1.5 μg/m3 standard.
Review of the data presented in the FEIS indicates that in all cases both the measured background values and expected ambient air values exceed the new 0.15 μg/m3 limit.
Data provided by Zamurs and Bass of NYSDOT (JPCL October 1998) indicated background TSP-lead results of 0.12 μg/m3, average daily results (24-hour average) of 0.64 μg/m3 and an average concentration during abrasive blast cleaning in an SSPC Guide 6, Class 1A containment of 1.85 μg/m3.
Table 1 below provides a brief summary of some monitoring data collected by the authors’ company in 2007 and 2008. The table presents data on 6 projects conducted in an urban environment during abrasive blast cleaning in an SSPC Guide 6, Class 1A containment. It also provides results for comparison, monitoring conducted during robotic vacuum blasting of a water tank (considered approximately equal to a Class 1A) and a hand tool cleaning and pressure washing project in an SSPC Guide 6, Class 3P/2W-3W containment system.
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