|2 Children’s Environmental Health and Countermeasures against Indoor Air Chemicals|
|Iwao Uchiyama||Graduate school of Engineering, Kyoto University|
In 1997, the Declaration of the Environment Leaders of the Eight on Children's Environmental Health was announced. Sick School Problem is one type of problem of Environmental Health for children. In this paper, child properties different from adult properties are described. Subsequently, the status of chemical pollutants at nursery schools and schools is introduced and the countermeasures and prevention methods are outlined.
1. The characteristics of a child’s inhalation of chemicals
1) The difference between children and adults in presuming the rate of inhalation
The total amount of a child’s food intake and respiratory volume is less than that of an adult. However, when considering toxicity, it needs to be compared per kilogram of body weight. As shown in Table 1, the rate of inhalation from respiration, orally, from soil, and through skin per body weight is approximately more than twice as much as that of an adult, respectively.
2) The difference in sensitivity between a child and an adult
A human child is born in an immature state, and after birth the nervous system develops actively and the blood-brain barrier is completed by around 6 years of age. In such a growth stage, a child is vulnerable to environmental insults. It is found that the influence of organophosphorus pesticide, which acts on the nervous system, and heavy metal (lead) that is easily absorbed by the gastrointestinal tract is significant in childhood.
2. The preliminary survey on the pattern of a child’s behavior in Japan (Ministry of the Environment)
The results of a questionnaire survey conducted by 654 parents (response rate 67.4%) of children between 0-6 years old indicated that the period of time when children spend outdoors on holidays is between 18 minutes and one hour. This shows that they spend most of their time at home. Also, respiratory volume fluctuates in a range of approximately 7 times by the extent of their activities. In the future the number of cases will be increased and the following examinations are planned: a researcher directly observes and records the patterns of nursery school toddlers’ behavior in a nursery school and the number of nursery school toddlers’ movements who put things into their mouths and lick their hands.
3. With respect to a measurement spot of chemicals based on child properties
Volatile organic compounds (VOCs) are a major indoor air pollutant. Each relative vapor density is larger than air relative density (=1) and easily stays in the lower atmosphere. In case of poor ventilation, the concentration difference increases indoors during use of a floor heater. Especially, when a source is from flooring materials, the concentration at 10 cm or higher above the floor is high. Attention has been drawn to a child (especially one – two years old) who often lies down, or sits on a floor for play. Measurement at 120 – 150 cm above the floor is often performed. However, when measurement at a nursery school and school is performed, considering a child body height of 100 cm, measurement at 20 – 50 cm above a floor should be also conducted in a child’s room and any space where children often play.
4. How does Sick School Problem occur?
The following factors, as the background for Sick School Problem occurrence, are considered:
1) Rebuilding of the end-of-life school buildings built in the postwar period (new buildings)
2) Extension or reconstruction of buildings by school consolidation of elementary and junior high schools owing to a decrease in students (remodeling)
3) Implementation of antiseismic reinforcement of building (remodeling)
4) Reduction in the number of air vents by using sash windows for noise prevention, air pollution control and energy conservation (poor air ventilation)
5) New educational equipment and educational material purchase for more relaxed education and information education (new purchases)
6) Possibility of the increase in children with allergic disorder and in children who are sensitive to chemical substances (Sensitivity)
As mentioned above, these situations are similar to ones which cause sick building syndrome. The actual examples indicate that high concentrations of formaldehyde and toluene after new construction and renovation were a major cause. The survey conducted in Tokyo indicates that the indoor levels of various chemicals in special classrooms, such as the music room and the computer room are higher than in standard classrooms.
Even if symptoms appear, the symptoms of most children disappear when the concentrations of chemical substances is reduced. On the other hand, there are children that develop chemical sensitivity which react to minute amounts of chemicals. In a severe case, there are children who cannot go to school. They won’t be what they were. A nursery school and school administrators should never understate when concentrations of chemical substances are beyond the standard.
5. Not to cause Sick School Problem
The countermeasures against Sick School Problem should be considered from the following three aspects: 1) High concentration chemical volatilization from building materials during construction and reconstruction; 2) How to live under poor ventilation; 3) Sensitivity of children. In 2002, by revision of “the School Environmental Health Standards” with respect to new buildings, reconstruction and repair, after checking if concentrations of formaldehyde and volatile organic compounds were below the standard value, a building must be handed over. Also, you should recognize that concentrations of indoor air chemicals rise by temperature increase in summer, poor ventilation in special classrooms, and the use of an air conditioner.
In the manual of the Saitama Prefectural Board of Education, the regulations on the response to an appeal and consultation of school children are also described in detail: First, consultation at a medical institution is recommended to those who report poor physical health. Next, check how the poor physical condition occurred. Then, receive instructions and advice from a school physician and a school pharmacist. After that, an investigation of both the cause and environmental health in the classroom is conducted.
Moreover, the flow chart in the manual shows the response when a juvenile student that reacts adversely to chemical substances enters or moves into a school. In short, everyone involved must fully understand that there is a juvenile student who reacts adversely to chemical substances. That should be the first step towards prevention and countermeasures against Sick School Problem.
Measures against indoor air pollution and health for children
1 Challenges and the Present Condition of Countermeasures against Indoor Air Chemicals
2 Children’s Environmental Health and Countermeasures against Indoor Air Chemicals
3 Measurement and Evaluation for the Determination of Indoor Air Chemicals
4 Building Materials and Furniture and Reduction Countermeasures against Indoor Air Chemical
5 Daily Life of a Patient with Multiple Chemical Sensitivity