Fenceline monitoring: perils and pitfalls
Kim Hampton
Lidar Technologies Ltd.
ECG Bulletin January 2007
Lidar Technologies Ltd.
ECG Bulletin January 2007
Heightened awareness of environmental issues has led to an increased urgency in tackling problem areas of pollution. Fenceline monitoring is a technique for alerting industry about these problems. Dr Kim Hampton explains.
Introduction
New and existing environmental legislation coupled with a greater sense of corporate responsibility can assist in the protection of the environment. For UK industry, the most far reaching (and relevant) legislation to date is the regulatory framework within Integrated Pollution Prevention and Control (IPPC). IPPC is aimed at protecting the environment as a whole, taking into account emissions to air, water and land. The regulators, who are either the Environment Agency or a local authority depending on the activity, set permit conditions, i.e. the amounts of chemicals that are allowed to be released into the environment. These conditions are based in part on the implementation of Best Available Techniques (BAT), where the cost to the operator is balanced against the benefits to the environment.
The aim of IPPC is to prevent emissions and waste production, or at the very least reduce them to acceptable levels. If it is not practical to eliminate all the emissions to the environment, there is a need to monitor them to ensure permit levels are not exceeded. IPPC tends to be enforced at the exit point i.e. at the stack or effluent outlet. However, there are many emissions that cannot be tracked in this way, hence the need for fenceline monitoring. When fenceline monitoring is undertaken correctly, it is invaluable in assessing the gaseous pollutant emissions of a plant to the surrounding area.
A comprehensive monitoring scheme also influences the public perception of industrial plants. A plant which is seen to be monitoring for pollutants helps to instil public confidence, as well as complying with IPPC and other legislative criteria such as local air quality regulations.
Fenceline monitoring: objectives
The primary objectives of effective fenceline monitoring are to:
How to carry out fenceline monitoring
Dispersion modelling
In order to carry out successful fenceline monitoring, a site has to be evaluated for its local climate, emission sources, and plant geometry. Any monitoring that is carried out is highly dependent on these factors and not just on the emissions themselves.
The best way of siting instrumentation is to carry out an initial dispersion modelling of a site. A recent EU funded project run by Sira Ltd., UK, evaluated different types of remote optical sensing open path instrumentation before use on industrial sites. The sites were modelled using computational fluid dynamic (CFD) modelling. The aim of the study was to compare the instruments as well as to provide data about pollutant emissions.
Instrumentation for fenceline monitoring
The instrumentation available for fenceline monitoring can be roughly divided into two types - point measurements and remote sensing open path optical instrumentation. Both have their advantages and disadvantages, and selection is based on what is to be measured, the levels that are likely to be encountered and what the site operator wants from the data. There is no “one size fits all”.
The main advantage of point measurements is that the instruments are portable and easy to calibrate. However, to obtain any spatial information, multiple point sensors are needed. An incorrectly positioned point sensor will fail to detect the pollutant. Continuous monitors are available, or time integrated samples can be taken and then subsequently analysed in the laboratory.
With remote sensing optical open path systems, if the light beam path is broken by a pollutant, it will be detected. Hence a much greater spatial area can be covered and there is less likelihood that the pollutant plume will not be detected. Commercial systems monitor continuously but these instruments tend be fixed, and they need to be carefully aligned in order to obtain valid data.
Apart from measuring pollutants, meteorological data (particularly wind speed and direction) need to be collected to check where emissions are coming from. In a highly industrialised area it is always possible that pollutants are entering a site as well as being emitted from that site.
Case study
A good example of how fenceline monitoring has been used to allay public fears and show that pollutant emissions are within limits is at the ConocoPhillips-Rodeo oil refinery, 25 miles north east of San Francisco. The monitoring system was installed as a result of releases from the refinery that impacted the surrounding community. A monitoring network was installed, made up of remote sensing equipment that can simultaneously measure and report air pollutants at the refinery’s fenceline.
Three types of open path systems are used, which measure along a 1km light path and also evaluate meteorological conditions at the site. The remote sensing systems chosen were Fourier Transform Infrared (FTIR) Spectroscopy, Ultra Violet (UV) spectroscopy and Tuneable Diode Laser (TDL) Spectroscopy which measure 30 pollutant species, delivering data at 5 minute intervals continuously. Nine of the 30 chemicals measured are reported on a website (http://www.cchealth.org/groups/hazmat/fenceline/).
Summary
Fenceline monitoring is more complicated than just putting an instrument next to a fence or a boundary. Each site is different and has different requirements. Installations must be designed with care to obtain useful information and not to just generate numbers. It is important that along with measuring pollutants, complementary meteorological data are logged simultaneously. With increasing environmental legislation and an onus on caring for the environment, sound, comprehensive, fenceline monitoring will be needed in the future.
Web links:
Integrated Pollution Prevention and Control (IPPC) http://www.defra.gov.uk/ENVIRONMENT/ppc/ippc.htm.
Sira Ltd./ROSE (Remote Optical Sensor Evaluation) EU Contract G6RD-CT2000-00434, see: http://ec.europa.eu/research/growth/pdf/measuring-and-testing_4-060902-out_ec.pdf
Dr KIM HAMPTON
Lidar Technologies Ltd.
BIOGRAPHICAL NOTE: Kim Hampton is a systems advisor for Lidar Technologies Ltd (www.lidars.co.uk). She has a strong background in gas sensors and sensing for industrial and environmental applications. In her present role at Lidar Technologies, Kim divides her time between promoting Lidar (Light Detection and Ranging) techniques and assessing new applications for commercial Lidar systems. Kim Hampton gained a BSc and PhD in chemistry at the University of Leeds in Atmospheric Chemistry and then went on to work at the Max-Planck Institute for Chemistry, Mainz, Germany and the University of Bristol. Prior to her present appointment, Kim worked for Sira Ltd. as a senior research scientist, specialising in gas sensors and sensing. Kim is a committee member of the ECG.
Introduction
New and existing environmental legislation coupled with a greater sense of corporate responsibility can assist in the protection of the environment. For UK industry, the most far reaching (and relevant) legislation to date is the regulatory framework within Integrated Pollution Prevention and Control (IPPC). IPPC is aimed at protecting the environment as a whole, taking into account emissions to air, water and land. The regulators, who are either the Environment Agency or a local authority depending on the activity, set permit conditions, i.e. the amounts of chemicals that are allowed to be released into the environment. These conditions are based in part on the implementation of Best Available Techniques (BAT), where the cost to the operator is balanced against the benefits to the environment.
The aim of IPPC is to prevent emissions and waste production, or at the very least reduce them to acceptable levels. If it is not practical to eliminate all the emissions to the environment, there is a need to monitor them to ensure permit levels are not exceeded. IPPC tends to be enforced at the exit point i.e. at the stack or effluent outlet. However, there are many emissions that cannot be tracked in this way, hence the need for fenceline monitoring. When fenceline monitoring is undertaken correctly, it is invaluable in assessing the gaseous pollutant emissions of a plant to the surrounding area.
A comprehensive monitoring scheme also influences the public perception of industrial plants. A plant which is seen to be monitoring for pollutants helps to instil public confidence, as well as complying with IPPC and other legislative criteria such as local air quality regulations.
Fenceline monitoring: objectives
The primary objectives of effective fenceline monitoring are to:
- Evaluate the effectiveness of emission controls that are in place
- Evaluate air quality at the fenceline in terms of public health
- Develop site-specific protocols to ensure the air quality objectives and consent levels are not exceeded
- Ensure the data collected are of good quality and validated
- Provide information on risk management and information to the public
- Reduce the liability of the site owner.
How to carry out fenceline monitoring
Dispersion modelling
In order to carry out successful fenceline monitoring, a site has to be evaluated for its local climate, emission sources, and plant geometry. Any monitoring that is carried out is highly dependent on these factors and not just on the emissions themselves.
The best way of siting instrumentation is to carry out an initial dispersion modelling of a site. A recent EU funded project run by Sira Ltd., UK, evaluated different types of remote optical sensing open path instrumentation before use on industrial sites. The sites were modelled using computational fluid dynamic (CFD) modelling. The aim of the study was to compare the instruments as well as to provide data about pollutant emissions.
Instrumentation for fenceline monitoring
The instrumentation available for fenceline monitoring can be roughly divided into two types - point measurements and remote sensing open path optical instrumentation. Both have their advantages and disadvantages, and selection is based on what is to be measured, the levels that are likely to be encountered and what the site operator wants from the data. There is no “one size fits all”.
The main advantage of point measurements is that the instruments are portable and easy to calibrate. However, to obtain any spatial information, multiple point sensors are needed. An incorrectly positioned point sensor will fail to detect the pollutant. Continuous monitors are available, or time integrated samples can be taken and then subsequently analysed in the laboratory.
With remote sensing optical open path systems, if the light beam path is broken by a pollutant, it will be detected. Hence a much greater spatial area can be covered and there is less likelihood that the pollutant plume will not be detected. Commercial systems monitor continuously but these instruments tend be fixed, and they need to be carefully aligned in order to obtain valid data.
Apart from measuring pollutants, meteorological data (particularly wind speed and direction) need to be collected to check where emissions are coming from. In a highly industrialised area it is always possible that pollutants are entering a site as well as being emitted from that site.
Case study
A good example of how fenceline monitoring has been used to allay public fears and show that pollutant emissions are within limits is at the ConocoPhillips-Rodeo oil refinery, 25 miles north east of San Francisco. The monitoring system was installed as a result of releases from the refinery that impacted the surrounding community. A monitoring network was installed, made up of remote sensing equipment that can simultaneously measure and report air pollutants at the refinery’s fenceline.
Three types of open path systems are used, which measure along a 1km light path and also evaluate meteorological conditions at the site. The remote sensing systems chosen were Fourier Transform Infrared (FTIR) Spectroscopy, Ultra Violet (UV) spectroscopy and Tuneable Diode Laser (TDL) Spectroscopy which measure 30 pollutant species, delivering data at 5 minute intervals continuously. Nine of the 30 chemicals measured are reported on a website (http://www.cchealth.org/groups/hazmat/fenceline/).
Summary
Fenceline monitoring is more complicated than just putting an instrument next to a fence or a boundary. Each site is different and has different requirements. Installations must be designed with care to obtain useful information and not to just generate numbers. It is important that along with measuring pollutants, complementary meteorological data are logged simultaneously. With increasing environmental legislation and an onus on caring for the environment, sound, comprehensive, fenceline monitoring will be needed in the future.
Web links:
Integrated Pollution Prevention and Control (IPPC) http://www.defra.gov.uk/ENVIRONMENT/ppc/ippc.htm.
Sira Ltd./ROSE (Remote Optical Sensor Evaluation) EU Contract G6RD-CT2000-00434, see: http://ec.europa.eu/research/growth/pdf/measuring-and-testing_4-060902-out_ec.pdf
Dr KIM HAMPTON
Lidar Technologies Ltd.
BIOGRAPHICAL NOTE: Kim Hampton is a systems advisor for Lidar Technologies Ltd (www.lidars.co.uk). She has a strong background in gas sensors and sensing for industrial and environmental applications. In her present role at Lidar Technologies, Kim divides her time between promoting Lidar (Light Detection and Ranging) techniques and assessing new applications for commercial Lidar systems. Kim Hampton gained a BSc and PhD in chemistry at the University of Leeds in Atmospheric Chemistry and then went on to work at the Max-Planck Institute for Chemistry, Mainz, Germany and the University of Bristol. Prior to her present appointment, Kim worked for Sira Ltd. as a senior research scientist, specialising in gas sensors and sensing. Kim is a committee member of the ECG.
