The noise and mental health of children: future smart cities are silent
The health impacts of environmental noise are a growing concern among European countries and the World Health Organization has carried out some important studies on this. In particular on the mental and cognitive health of children.
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The health impacts of environmental noise are a growing concern among European countries and the World Health Organization has carried out some important studies on this. In particular on the mental and cognitive health of children. In this time of coronavirus epidemic crisis (covid-19), inhabited spaces now have another sound. The roads are less frequented, vehicular traffic has dropped sharply, air traffic is practically absent. The article intends to briefly explain this topic by crossing the topic of silence in coronavirus times with mental health, especially of minors, giving an account of a significant scientific literature. Recent research from the World Health Organization, European office, has provided scientific evidence of the relationship between environmental noise and specific effects on children’s health, cognitive impairment (cognitive impairment). Wanting to estimate prudently the number of days lost due to noise outside the person it is estimated that they amount to 61,000 years for ischemic heart disease, 45,000 years for cognitive impairment of children, 903,000 years for disturbed sleep, 22,000 years for tinnitus and 587,000 years of humoral “nuisance”. The research focused in the member states of the European Union and in other western European countries. These summarize the results. Wanting to estimate prudently the number of days lost due to noise outside the person it is estimated that they amount to 61,000 years for ischemic heart disease, 45,000 years for cognitive impairment of children, 903,000 years for disturbed sleep, 22,000 years for tinnitus and 587,000 years of humoral “nuisance”. The research focused in the member states of the European Union and in other western European countries. These summarize the results. Wanting to estimate prudently the number of days lost due to noise outside the person it is estimated that they amount to 61,000 years for ischemic heart disease, 45,000 years for cognitive impairment of children, 903,000 years for disturbed sleep, 22,000 years for tinnitus and 587,000 years of humoral “nuisance”. The research focused in the member states of the European Union and in other western European countries. These summarize the results.
Increasing urbanization and vehicular transport are the main factors of exposure to environmental noise. This is defined as noise emitted from all sources except industrial workplaces. But the EU Environmental Noise Management Directive (END) includes industrial sites, instead, as sources of environmental noise. From a methodological point of view, in order to estimate the environmental burden of the disease (Environmental Burden Desease) due to environmental noise, it is advisable to use a quantitative approach to risk assessment. Risk assessment refers to the identification of hazards, the assessment of population exposure and the determination of appropriate exposure-response relationships. EBD is expressed in “life years”, conformed to the specific morbidity sought (called DALY). DALYs are the sum of potential years of life lost due to premature death and equivalent years of “healthy” life lost from being in poor health or disability. The loss of years of life is the specific risk to look for and which can signal the danger of an element, in this case the noise. In general, risks are expressed as values, i.e. fractions, that is, still as ratios between relation quantities between different elements.
In recent years, evidence has accumulated relating to the health effects of environmental noise. For example, well-designed and meaningful epidemiological studies have found that cardiovascular disease is constantly associated with exposure to environmental noise, as well as auricular tinnitus or chronic sleep disturbance. The environmental noise risk assessment process requires to know:
Over 20 studies have shown negative effects of noise on reading and memory skills in children: epidemiological studies report the effects of chronic noise exposure, while experimental studies report acute exposure to noise. The skills analyzed were processing, language, reading comprehension, memory and attention. Exposure to noise, in particular, during critical periods of learning at school could potentially compromise development and have a permanent effect on the level of education. This is one of the most significant aspects and an indicator of health policies to be adopted.
The study of the relationship between cognitive impairment and environmental noise is not the result of a clinical diagnosis; therefore, it is not yet possible to draw a relationship between exposure to the stimulus and a specific risk, in an objectively certain way. The definition of cognitive impairment derived from noise cannot be superimposed on that used in the psychiatric and biomedical field. It should be defined as: reduction of cognitive abilities in school-age children that occurs during exposure to noise that persists and will persist for some time after the exposure to noise ceases. A feature of this definition is that cognitive impairment is assumed to show up during exposure to noise and even some time after exposure is stopped.
Epidemiological designs have been used for chronic noise exposure, while experimental designs for acute disturbance. Evans and colleagues proposed a very convincing study. It is a longitudinal observational study under natural conditions that examines the effect of the Munich airport transfer on the health and cognition of children (9-10 years, N = 326). In 1992, the old Munich airport closed and was moved elsewhere. Prior to the transfer, exposure to high noise was associated with deficits in long-term memory, reading and understanding of a school text. Two years after the airport closed, these deficits disappeared. This indicates that the effects of noise on cognition may be reversible if exposure ceases.
The recent large-scale longitudinal study (called RANCH) compared the effect of road traffic and aircraft noise on the cognitive performance of children (9-10 years old, N = 2,844) in the Netherlands, Spain and the United Kingdom. A linear exposure-effect relationship was found between long-term exposure to aircraft noise and impaired understanding of reading and recognition memory. The study is interesting because the researchers processed the data excluding the confounding factors and including socioeconomic and confounding factors into consideration. This makes the data highly predictive. No association was observed between exposure to long-term road traffic noise and cognition, except for episodic memory, which has, surprisingly, showed better performance in areas with high road traffic noise. Neither airborne noise nor road traffic noise has damaged attention or working memory.
Advertising message A study on the exposure to ambient noise (mainly on road and rail) of fourth grade children living in Tyrol in Austria compared three cognitive measures for schoolchildren (average age 9–7 years, N = 123) exposed at 46 or 62 dB (A) Ldn. The LDN is the equivalent average sound level over a 24-hour period, with an added penalty for noise during the night from 22:00 to 07:00. During the night, 10 dB are added to indicate more precisely the impact of noise. These measurements are used to assess the impact that road, rail, air and industry in general have on the local population. The two socio-demographic homogeneous samples differed only in their exposure to noise with an interval (M = 46.1 Ldn vs M = 62 Ldn). Long-term noise exposure was significantly related to both explicit and accidental intentional memory. The improvement in cognitive performance in the quieter group was estimated at 0.5% (relative to the size of the recall of words in prose and literal recognition); at 1% (in the free recall) for each less dB to which they had been exposed.
Both RANCH and Tyrolean studies indicate that aircraft noise could be worse for cognition than road traffic noise. For aircraft noise, the results in the RANCH study show a more linear association between aircraft noise exposure and impaired reading comprehension. For environmental road and rail noise, the Tyrolean study suggests that the effects occur around Ldn = 60. Memory tests are performed with children in silence on bedding material in a noisy environment. Participants are randomized into exposure and control groups and children are sampled statistically correctly.
There is evidence according to the Munich study indicating that after the cessation of aircraft noise exposure, children between the ages of 9 and 11 resume the cognitive performance levels of their year-olds who are not been exposed. Therefore, it is possible that, at least for young children, the chronic effects of noise are reversible and that the disturbances diminish with increasing age.
Figure 1: exposure-response curves of the various epidemiological researches.
Notes: Rd = reading; Rcl = memory, recall; 1 = recall, children, old airport; 2 = recall, children new airport; 3 = reading, children old airport; 4 = reading, children new airport; 5 = reading, children; 6 = free recall, children
Reliable evidence indicates the negative effects of chronic noise exposure on children’s cognition. But in the literature there is still no generally accepted criterion for quantifying the degree of cognitive impairment. However, it is possible to make a conservative estimate of the loss of DALY using mathematical methods on an epidemiological basis. In 1999, WHO had already published guidelines for noise in a community. The European Parliament and the Council adopted Directive 2002/49 / EC of 25 June 2002 with the main objective of providing a common basis for tackling noise problems across the EU. In 2009, WHO published the night noise guidelines for Europe. Considering the scientific evidence on the night noise exposure threshold indicated by Lnight as defined in Directive 2002/49 / EC, a Lnight value of 40 dB should be the goal of the night noise guidelines to protect communities, including groups more vulnerable as children, the chronically ill and the elderly. A Lnight value of 55 dB is recommended as a temporary target for countries that cannot limit night noise.
There is scientific evidence that exposure to environmental noise has negative effects on population health. Recognizing the particular need to protect children from the harmful effects of noise, the 2010 Parma Declaration adopted at the 5th Ministerial Conference on Environment and Health invited all interested parties to work together to reduce children’s exposure to noise, including that of children. personal electronic devices, recreational activities and traffic (especially in residential areas), childcare centers, kindergartens and schools and public leisure facilities.
The fact that there is not much data coming from street noise and the relative exposure to traffic noise constitutes a limit to the generality of the research. But the results of the aircraft noise studies, although few, are still consistent.The cities and communities of the future will be healthy only if they are quieter. The sustainability and nature of a smart community can only be delivered by considering noise as an essential condition.