Investigation And Study Of Formaldehyde As Indoor Air Pollution In Newly-decorated Houses

From the related investigation results made by WHO (the World Health Organization) shows that all over the world some 30% of newly- and re-built buildings in which the polluted air does harm to human health and leads to an increase in death rate and in incidences of a disease of global population, considered as one of five environmental factors hazardous to the public health. Some experts in the field of indoor pollutions give warnings that the indoor pollution symbolizes a third pollution era coming around following preceding coal-smoke pollution and photochemical smog pollution brought about by Industry Revolution. Upon society entering information times the changes of way of life keep people stay indoors for longer time than ever before, therefore, it is considered that the air quality inside buildings of offices and homes see its importance.The indoor air pollution has such different pollution features from those outsides due to different surroundings where they occur as accumulation, long-term and diversity, and it bring about more serious harm than outdoor air pollution. Human health can be potentially damaged by gradual build-up of suspended particles in air, bacteria, virus and other harmful substance, especially it is the case if people live in closed houses over a long period of time.With deeper reform of housing and higher living level of ordinary people, especially together with swift growth of construction material-producing industries and flourishing of interior decoration, some decorative materials turn out to be main pollution sources. The quality of air indoors gradually deteriorates in the time of improvement of housing conditions. From our country's current situation one of main reasons causing indoor air pollution is due to poor decoration with which a large amount of decorative materials having different types and amount of such toxic substance as formaldehyde, ammonia gases, volatile organic substance. The indoor air pollution endangers human health by direct contact with the polluted air through respiratory system, eyes and skin. Among all these contaminations compared with other indoor organic pollutants the negative effects and sources of formaldehyde in decorated houses play an important role and draw more attention of the public.Some wood-ply veneers, sawdust-boards, medium-density fiberboards and flake-boards for interior fittings contain formaldehyde. Even to keep in touch of low dosage of formaldehyde can lead to development of chronic respiratory diseases, and higher concentration will harm nerve system and liver. The acute melancholia can be caused by long-time living such an environment with higher concentration. Institute of International Cancer Research (ICRI) has treated it as cancer-causing substance. There indicates a year-to-year rapid increase of formaldehyde emission from construction materials, particularly nowadays with a hot tendency of interior decoration, the indoor formaldehyde pollution has been drawn great attention of people concerned.Within one month after completion of decoration work, we carried out a serial of experiments for 25 newly-fit houses during a period from 2002 July to 2004 March in terms of indoor formaldehyde concentration by means of investigation, sampling, analysis and monitoring, track check especially made for tensely polluted houses and research and analysis have been done based on the results.Newly-decorated houses face serious phenomenon of formaldehyde concentration above the values as specified in standards, 19 out of 25 data groups actually measured exceed the national standards, approximately 80%. The highest group comes around 6 times the standard value, average equals to 1.3 times. We find that there exists fundamentally a relationship of formaldehyde concentration plus proportional to how much amount per unit volume of sawdust or chippings pressed boards will have been used as representative decoration materials through a top-to-toe track investigation and according to the actual results of monitoring and measurement.