Integrated ambient ozone evaluation by passive samplers and clover biomonitoring mini-stations.

An ozone monitoring network was set up using passive samplers and biological mini-stations of two clones of white clover (Trifolium repens L. cv. Regal), NC-R (O(3)-resistant) and NC-S (O(3)-sensitive). This paper reports on a pilot study performed in the period June-October 1999 in the Rome municipal area by using five biomonitoring mini-stations and ozone passive samplers with a new nitrite based design. This combined methodology can be used to obtain information on the biological implications of the injury due to tropospheric ozone. The two techniques can integrate data for the short-medium period and can be placed in different urban and rural sites, proving to be a very useful tool for ozone concentration mapping.

Study of nitrogen containing compounds in the polar troposphere.

Atmospheric nitrogen compounds play a critical role in tropospheric photochemistry and are crucial to understand the chemical and physical evolution of atmospheric pollutants in polar areas. Measurements of these species in remote areas are rare, although their relevance is well established. Sampling campaigns of gaseous and particulate atmospheric trace species were performed in Arctic and in Antarctica during three consecutive years (1997-1999), using a proper combination of annular denuders and filter pack. After sampling, the ionic species were extracted with aqueous solutions and analysed by means of ion chromatography. Quality assurance on the sampling and analytical steps allowed accurate and precise measurements of all relevant compounds, which are thought to be important to nitrogen chemistry, at very low concentration levels. In addition, the measurements also included a multistage low-pressure impactor for the collection of particulate matter in different size regions (0.035-15.9 mm). Results obtained from these campaigns demonstrate that the minor components may be measured at levels as low as a few nanograms per cubic meter. The reported concentrations are to be considered among the first observations of nitrogen containing compounds in polar sites.

The measurement of atmospheric pollutants by passive sampling at the Uffizi Gallery, Florence.

Diffusive sampling can be adopted to analyse in detail the temporal and spatial trends of pollutants concentration in specific historic buildings or in museums. An application of this method is discussed in this paper and the results of a still ongoing monitoring campaign at the Uffizi Gallery in Florence, in the framework of an EU-founded Project (MIMIC), are presented. Distinct trends in the concentration of NO2, NOx, HONO, HNO3, O3 and SO2 have been observed in eight successive sampling periods from March 2001 to February 2002. Considerations are given on possible implications for the conservation of indoor artworks.