Source Of HCHO Research Articles

Measurement of formaldehyde in clean air

A method for the measurement of small amounts of formaldehyde in air has been developed. The method is based on the derivatization of HCHO with 2.4‐Dinitrophenylhydrazine, forming 2.4‐Dinitrophenylhydrazone, measured with GC‐ECD‐technique. HCHO is preconcentrated using a cryogenic sampling technique. The detection limit is 0.05 ppbv for a sampling volume of 200 liter. The method has been applied for measurements in continental and marine air masses showing HCHO mixing ratios of 0.4 ‐ 5.0 ppbv and 0.2 ‐ 1.0 ppbv, respectively. HCHO mixing ratios show diurnal variations with maximum values during the early afternoon and minimum values during the early morning. In continental air, HCHO mixing ratios are positively correlated with CO and SO2, indicating anthropogenic HCHO sources which are estimated to be 6‐11 × 1012g/year−1 on a global scale.

Indoor Air Pollution as an Environmental Factor

An average person spends most of his time indoors and the quality of indoor air affects his performance and well-being. This justifies the study of indoor air pollution for the development of working and living environments which are comfortable and safe. As a part of a larger program to study traffic-generated air pollution in the vicinity of streets, a simultaneous indoor/outdoor sampling program was carried out at three sites in the city of Zurich, Switzerland. Parameters included CO, NO, NO2 and HCHO. The results show the direct relationship between indoor and outdoor concentrations of CO, NO and NO2. HCHO concentrations were found to be substantially higher indoors than ourdoors thus supporting the hypothesis that HCHO source could be in the buildings themselves. The importance of indoor air is emphasized, and the interplay of indoor and outdoor air pollution is demonstrated.