Currently, the most common method of atmospheric mercury monitoring in the world is to use automated mercury analyzers. These instruments have good accuracy and time resolution; however, it is not easy to monitor many sites, due to their requirements (cost, power source, shelter etc.). On the other hand, monitoring method using passive sampler has advantage for its ease of installation on sampling site, but its monitoring data are still not many.

In Japan, atmospheric mercury monitoring has been conducted by manual active sampling method. In this method, mercury in the atmosphere is trapped in a small gold-coated amalgamation cartridge. The sampling equipment for this method is simple. It consists of a gold cartridge, a portable air pump, and their tubing. Therefore, it is very easily carried and installed at sites of various situation. In normal case, sampling time required is 24 hours to avoid diurnal variation. This method can detect atmospheric mercury at area of background level (1-2ng/m3) within approximately 3 hours of sample collection. Most types of air pump can be driven by batteries, which therefore enables this equipment to be located in remote sites.

Collected gold amalgamation cartridge is carried into laboratory and measured by using Atomic Absorption Spectrometer (AAS) or Atomic Fluorescent Spectrometer (AFS). Mercury collected in a gold cartridge is heated to be desorbed and introduced into the absorption cell of AAS or AFS. After the measurement, the gold cartridge can be reused for next survey or monitoring. Gold amalgamation trap method has advantages in its cost, availability, and handling. It is a complementary method to other methods of atmospheric mercury survey and monitoring such as automated analyzer method and passive sampling, to fulfill the global monitoring gaps.

Gold amalgamation trap method is an official ambient air monitoring method in Japan. There are over 200 monitoring sites, and monthly atmospheric mercury monitoring is conducted at each site. In the official method, quality assurance processes such as operation blank, travel blank (filed blank), and duplicate analysis are required. in order to ensure the comparability of these monitoring data.

In this presentation, an overview of this methodology and collected data will be introduced.