NEW ANALYST~? PASSIVE SAMPLER FOR THE MONITORING OF FORMALDEHYDE IN INDOOR AND OUTDOOR AMBIENT AIR

摘要

A large variety of Oxidized Volatile Organic Compounds (OVOCs) exist in the atmosphere that originate from both natural and anthropogenic sources. Acute and/or chronic exposure to these primary pollutants may cause adverse health effects. OVOCs, as secondary pollutants, play a polyvalent role in photochemical smog generation, and are strongly linked to both air quality and aerosol properties. Thus, the determination of the presence of carbonyl compounds, such as formaldehyde, acetaldehyde and acetone, in indoor and outdoor air quality control is of great concern. The most widely used measurement method for HCHO and other lower carbonyls is that based on pumping air through acidified 2,4-dinitrophenylhydrazine (DNPH)-coated silica cartridges: this method has been adopted as the official procedure by international standardization organizations. If a more reliable approach is to be established to evaluate the adverse health effect, it is necessary to know what the exposure to this contaminant is on average over a long time period. This approach also needs a monitoring strategy characterized by low temporal frequency (several weeks) and high spatial resolution. An alternative methodology for measuring formaldehyde is based on the use of diffusive sampling mechanisms. Laboratory and field tests performed in urban, rural and indoor sites, using a modified traditional Analyst~? passive sampler, were discussed. Laboratory tests were planned using a statistical method based on the Design of Experiment methodology. The operating conditions were chosen in order to obtain the best configuration of the passive sampler by evaluating the statistical significance of the different factors, and their interaction by the analysis of variance.