Proposed Lead Monitoring Changes

On December 23, 2009 the US EPA proposed to revise the ambient monitoring requirements for measuring airborne lead. These rule amendments would improve the lead monitoring network to better assess compliance with the revised National Ambient Air Quality Standards (NAAQS) established in November 2008.  

History:  

The lead monitoring network measures concentrations of lead in the outdoor air, to assess compliance with the lead national ambient air quality standards (NAAQS). EPA substantially strengthened those standards in a rule issued October 15, 2008, revising the level of the primary (health-based) standard from 1.5 micrograms per cubic meter (ug/m3) to 0.15 micrograms per cubic meter (ug/m3), measured as total suspended particles (TSP). The agency revised the secondary (welfare-based) standard to be identical to the primary standard. 

In January 2009, EPA received a petition to reconsider the lead monitoring requirements from Missouri Coalition for the Environment Foundation, Natural Resources Defense Council, Coalition to End Childhood Lead Poisoning and Physicians for Social Responsibility.   EPA granted the petition to reconsider on July 22, 2009. This proposal represents the results of the EPA’s reconsideration of the lead monitoring requirements. The reconsideration will not change the timeline for meeting the revised lead standards or the deadline for deploying monitors around sources that emit at least 1.0 tons per year of lead.  

Current Proposal: 

The EPA is proposing revisions to the requirements for both source-oriented and non-source-oriented monitoring for lead.  

Source Based Monitoring: 

The current source based monitoring emission threshold is 1.0 tpy. EPA is proposing to change the lead emissions monitoring threshold to 0.50 tpy. Air quality monitoring agencies would use this threshold to determine if an air quality monitor is required to be place near a facility emitting lead.   The EPA projected the source-oriented portion of the network to be up to 135 monitors based on these requirements and the 2002 NEI (National Emission Inventory).

EPA proposes that these source-oriented monitors would begin operating one year after this rule is finalized. Monitors around the largest sources (those that emit 1.0 tpy or greater) are already required to be operational no later than January 1, 2010.  

Lead is emitted at airports as a result of leaded aviation fuel. As a result, EPA is proposing to treat airports identically to other sources of lead when determining if source-oriented lead monitoring is needed. The EPA identified 55 airports that may exceed the proposed 0.50 tpy emission threshold.  

Non-Source-Oriented Monitoring:  

The EPA is proposing to replace the current non-source-oriented monitoring approach with the requirement for lead monitoring at the national multi-pollutant monitoring network known as NCore. 

The NCore network is intended to be a long-term, multi-pollutant monitoring network that provides data useful for NAAQS attainment decisions, understanding of air quality conditions and pollutant interactions, evaluating air quality models, developing emission control strategies, and supporting long-term health studies. The NCore network will become fully operational no later than January 1, 2011 and will consist of approximately 80 sites – 60 sites located in urban areas and about 20 sites in rural areas.  

The purpose of these monitors is to measure neighborhood scale lead concentrations in urban areas impacted by re-suspended dust from roadways, closed industrial sources which previously were significant sources of lead, hazardous waste sites, construction and demolition projects, or other fugitive dust sources of lead.  

EPA had proposed and taken comment on a smaller non-source-oriented lead monitoring network that included 1 monitor in each CBSA with a population of 1,000,000 or more people, located to measure typical neighborhood scale lead concentrations in urban areas. The EPA noted that data from these non-source oriented monitors would be helpful in better characterizing population exposure to ambient air related lead and may assist in determining non attainment boundaries.  

During the comment period, concerns were raised that non-inventoried lead sources in urban areas, such as closed industrial sources, hazardous waste sites, and construction and demolition projects could potentially result in ambient lead concentrations in excess of the lead NAAQS. To address these concerns, the EPA modified the siting criteria to require non-source-oriented monitors to be sited to evaluate these non-inventoried lead sources.   The EPA also lowered the population threshold from requiring monitoring at CBSAs with a population of 1,000,000 people or more to requiring monitoring at CBSAs with a population of 500,000 people or more.  

Map of Proposed Monitoring Locations 

A map of the proposed monitoring location is provided at the link below. Currently there are no proposed monitoring locations in West Virginia. http://www.epa.gov/air/lead/pdfs/leademissionsmap.pdf 

Comment Period:  

EPA will accept comment on the proposal until February 16, 2010. On-line instruction for submitting comments are available at www.regulations.gov.  Use the following to identify the comments: Docket ID No. EPA-HQ-OAR-2006-0735. 

This article was excerpted from publically available information, and was authored by Joyce Gentry, Acacia Environmental Group LLC.  For more information on the author see here.