Child Health and the Environment

Abstract

In developed countries, people spend around 90% of their time indoors. Therefore, indoor air pollution could be a greater health hazard than outdoor air pollution. The possible components include tobacco smoke, the products of cooking, cleaning materials, insecticide sprays, and contaminants such as asbestos from work clothing. In the USA the Environmental Protection Agency has categorized indoor air pollution as one of the top five public health concerns. The subject receives close attention in Donald Wigle's Child Health and the Environment. Children are particularly vulnerable to indoor air pollutants because they inhale relatively high volumes of air per unit body weight and play on the floor where contaminant levels tend to be particularly high. The immaturity of organ systems and metabolic functions adds to the vulnerability of young children. Furthermore, children have little control over their own environment. The poor housing conditions of those from disadvantaged backgrounds may expose them to the pollutant hazards of dampness, degradation of building materials and lack of ventilation. Environmental tobacco smoke (ETS) is probably the best studied indoor air pollutant and represents an important preventable cause of childhood respiratory illness and death. Maternal exposure to ETS has been associated with increased risk of spontaneous abortion, preterm birth, low birthweight and intrauterine growth retardation. Childhood exposure to ETS has been associated with lung function deficits, exacerbation of asthma in preschool children and increased risk of lower respiratory tract infections. Also maternal and postnatal ETS exposure has been associated (weakly) with brain tumours, leukaemia and lymphomas. A meta-analysis of 39 studies of sudden infant death syndrome showed odds ratios of 2.1 (95% CI 1.8-2.4) for maternal smoking and 1.9 (1.6-2.4) for postnatal ETS. Carbon monoxide is another important indoor air pollutant to which children may be extra-susceptible on account of their high metabolic rates. The developing fetus is likewise at risk, not only because it has a higher oxygen demand but also because fetal haemoglobin has a high affinity for carbon monoxide. Volatile organic chemicals in the indoor environment include formaldehyde from chip-board, which can cause respiratory symptoms such as wheezing in children. Other such chemicals that may impact on child health include benzene from motor vehicles and paint solvents. In addition to chemicals, biological material from pets or house dust mites may be important. Pet allergens have been associated with asthma sensitization and house dust mites with asthma development. House dust mites and other allergens tend to be most concentrated on the floor, where children play. Child Health and the Environment, the first textbook of its kind, provides comprehensive coverage of current research areas. The early chapters give an overview of child environmental health, environmental epidemiology and risk assessment. The following nine chapters each address specific hazards including metals, polychlorinated biphenyls and dioxins, pesticides, hormonally active agents, radiation, indoor and outdoor air, and water. Each chapter is divided into health effects, exposures and risk management. The book does an excellent job at drawing together work from diverse areas and highlighting the many gaps in our knowledge.