### Overview Over the last decade the components of the air that we breathe have been the subject of a great deal of scientific research and environmental regulation. No longer is the mass of particles in the air the primary concern, but instead it is the species or elements that make up those particles that are important to understand. In the United States, the Clean Air Act (CAA) currently requires the U.S. Environmental Protection Agency (EPA) to regulate the emissions of 188 toxic air pollutants from industrial sources referred to as “source categories.” To accomplish this, the EPA chose the Maximum Achievable Control Technology (MACT) standards for each source category. The CAA also requires that the EPA assess the residual health risks from the source categories using MACT standards.



### Problems with Conventional Monitoring Technologies Currently, the regulatory methods being used to identify air pollutants are performed manually once every three-to-six days. With these methods, air is pulled through a filter for 24 hours and then the filter is removed and shipped to a laboratory for analysis. Data is recorded and is put through a quality assurance protocol, and is then reported back to the technician where the samples were taken. This process typically takes a few weeks to complete.

There are challenges with this type of air monitoring system – challenges that are common regardless of where the regulatory stations are placed in service. The first major challenge is that the number of metals that can be monitored is limited by the cost associated to sample and analyze the filters. This typically does not allow regulators the ability to monitor all of the metals that they would like to monitor in an effort to protect public health and public welfare. A second challenge is that a sample is collected over a 24-hour period of time. This long duration for sample collection cannot provide regulators with critical and specific information on where and when the metal arrived to the monitor. Finally, the delay between the day that the sample is taken and when the metals concentration is reported is problematic in itself. This type of monitoring and reporting system does not provide regulators with near-real-time data which could be used to immediately inform the public of unhealthy air conditions.

As an alternative, a high-resolution, multi-metal monitor is recommended to provide regulatory 

## Pall Xact1 

## 625 Series Systems Provide Near-Real-Time Monitoring of Multi-Metals

1 Xact is a trademark of Cooper Environmental Services

LLC.investigators with near-real-time data to characterize complex airsheds. The ability to provide near-real-time data is essential to advance monitoring to meet today’s needs. The challenge is how to increase the frequency and diversity of the data available so that the location and time of the most dangerous metal emissions can be identified.



### Pall Xact 625 Series Monitoring Systems Pall Xact 625 Series monitoring systems are based on X-Ray Fluorescence (XRF) technology. XRF technology was selected as an analytical method for use in this application for its long-term stability and multi-metal analysis capability. When XRF technology is combinedwith a reel-to-reel tape drive sampler, multimetals can be monitored in near-real-time, with data being reported in time periods as short as 15 minutes.

Pall Xact 625 Series systems are designed to monitor ambient air near “fence lines” of industrial facilities and in complex urban environments, where particulate matter and metal concentrations may be at elevated levels.



### Features and Benefits

• Sampling, analysis, and near-real-time

reporting

• Detection limits as low as 10 pg/m 3

• Automatic quality assurance, alarms and

control features

• Identification and measurement of up to

24 elements simultaneously

• Capable of identifying hazardous “hot

spots” around the perimeter of a facility

• Highly sensitive and reliable (low pg/m 3 to

μg/m 3 range) • Non-destructive analysis allows for sample archiving


### XRF Technology Overview XRF technology has been utilized in the scientific research community for more than 50 years. Xact monitoring systems, using XRF technology, have been successfully installed for over 10 years. The same technology has been approved by the U.S. EPA for compliance on Hazardous Waste Incinerators for the past six years.



### Recent Successes
In 2007, the first XRF ambient multi-metal monitor was introduced to the U.S. EPA, which began a three-year feasibility study. In 2010, after a full evaluation of the system, the U.S. EPA purchased its first mobile, multi-metal monitoring lab. The mobile lab was first deployed in the investigation of elevated metal concentrations surrounding certain U.S. schools.

Around the same time that the U.S. EPA was testing the XRF monitor, the South Korean government began the procurement of Pall Xact systems for their Super Site project. This was a four-year project to build five Super Site labs to characterize multi-metal pollutants from long transport emissions.

Most recently, the Chinese government purchased Pall Xact 625 Series systems for the characterization of multi-metal pollutants. The systems were placed in several major cities – Chongqing, Suzhou and Beijing. Six more cities within China have been authorized to procure Pall Xact ambient systems. The systems will be used to research, identify, and better understand the current metals baseline so that appropriate regulatory limits can be established. 

## The Xact 620 can provide hourly concentration results for multiple metals with an uptime that is equal to or better than a Federal Reference Method (FRM) sampler, stability equal to that expected from laboratory XRF analysis, and one-hour detection limits up to 10 times lower than those attainable with a 24-hour FRM sampler with laboratory XRF analysis.

U.S. EPA sponsored study2

2 U.S. EPA study, Field Bias and Precision Demonstration of a Near-Real-Time Multi-Metals Ambient Fence Line Monitor, December 2009. EPA Contract EP-D-05-096.

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PGABX625EN Produced in the USA February 2012