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Science and Technology Branch

What does this program measure?

The GAPS program at MLO is part of a sampling network with approximately 65 sites on seven continents that was established to investigate air concentrations of persistent organic pollutants (POPs, e.g., PCBs, organochlorine pesticides). Pass

How does this program work?

Passive air samplers (PASs) are used to obtain spatial information on the distribution of POPs because of their simplicity, low cost, and electricity-free operation.

At MLO, there will be two passive air samplers which consist of a stainless steel chamber that protects a sampling medium (from precipitation and wind). The samplers will be placed approximately 1.5-2.0 meters above ground in an apen area with unobstructed airflow, far way from potential sources of contamination on the site.

At the end of each sampling year, the samples will be returned to Environment Canada for analysis. The samples are resealed in glass jars or steel tubes before being sent from the observatory.

Why is this research important?

Deployment of PASs over several seasons and years would allow temporal trends to be established, and thus the effectiveness of POPs control measures to be evaluated on a global scale.

Air sampling for POPs at the GMD facility in Mauna Loa, Hawaii would allow for greater spatial resolution, specifically around the south west Pacific.

Are there any trends in the data?

The program at Mauna Loa is upcoming. Results from MLO will be available within 6-12 months after the first samples are sent to Environment Canada (which is 1 year after the program begins). The "Comments and References" section below lists results that have been published from other GAPS sites.

How does this program fit into the big picture?

What is it's role in global climate change?

The purpose of the study is to increase the resolution of background passive air monitoring stations at oceanic sites. The results of this network will be used to assess time trends of POPs concentrations in air and to develop/test global atmospheric transport models for POPs. This information is being compiled to assess the effectiveness of recent control measures on POPs that have been established as part of the international treaties on POPs such as the Stockholm Convention of the United Nations Environment Program - ratified in 2004.

Comments and References

Results have been published form the pilot phase of the global passive sampling network. They include:

  • Harner, T.; Pozo, K.; Gouin, T. W.; Macdonald, A.M.; Hung, H.; Cainey, J.; Peters, A. Global pilot study for persistent organic pollutants (POPs) using PUF disk passive air samplers. Environ. Pollut. 2006, 144, 445-452
  • Pozo,K.; Harner, T.; Wania, F.; Muir, D.C.G.; Jones, K.C.; Barrie, L.A. Toward a global network for persistent organic pollutants in air: Results form the GAPS study. Environ. Sci. Technol. 2006, 40, 4867-4873.
  • Lee, S.C.; Harner, T.; Pozo, K.; Shoeib, M.; Wania, F.; Muir, D.C.G.; Barrie, L.A.; Jones, K.C. Polychlorinated naphthalenes in the Global Atmospheric Passive Sampling (GAPS) study. Environ. Sci. and Technol. In review.
Lead Investigator(s):

Tom Harner

MLO Contact(s):

Dr. John E. Barnes
808-933-6965 (x222)

Web Site(s)

not applicable

Date Started


Related Programs

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