A letter to the majority of teachers and students

Harm of chalk on the majority of teachers and students

Distinguished educators, students:


Chalk teaching is an indispensable tool for teaching at present, it is used to impart knowledge, is one of the most original and traditional teaching methods, the chalk from its application to now has thousands of years of history, has made an indelible contribution to human education, along with the progress of history and social development, human understanding of the chalk teaching aids continue to improve, the chalk to the cause of human progress and make a great contribution to education at the same time, but also to the teachers and students in the education cause great harm.

According to the survey data show that in some provinces and cities, with the progress of society and the social rhythm speeding up, the teacher occupation disease rate is increasing year by year, occupation disease is the direction of diversification, which caused by dust pneumoconiosis and a variety of acute and chronic respiratory diseases are the main Chinese occupation disease harm, the most serious and one of the most widely. The prevalence rate of myopia of students also increased year by year, to a very serious degree. As experts in education, Tian Jun in 1995 of 6 primary schools in Fuzhou 30 secondary schools, 3125 primary and secondary school teachers of the survey results show that the high prevalence of chronic respiratory disease in primary and secondary school teachers, is a common chronic pharyngitis and vocal cord diseases. The male prevalence rate of chronic diseases was 58.53%, the female chronic prevalence rate was 61.06%, and increased with the age increased trend, education experts Niu Caiying in 1996 December Kaifeng urban area were investigated 240 primary school teachers, that teachers have different severity of throat diseases, the incidence rate was 60.4%. Education experts Lu Daowen to show that in 1999 the disease investigation of Qingdao 162 University Teachers: 89 cases of chronic pharyngitis, accounted for 54.94%, 69 cases of chronic laryngitis, accounted for 42.59%, there were significant occupational status. According to the city in 57, Jinshui District 2, a total of 219 teachers in the school survey results show that: the teacher pharyngitis prevalence rate was 100%, the prevalence rate is 39%, rhinitis, asthma prevalence was 43%, bronchitis pneumoconiosis prevalence rate was 8%, the prevalence rate was 11.76%, the cancer incidence rate was 2%.

In addition students as research data on long-term, black and white, and the classroom blackboard dust pollution caused by students' myopia shows: our country in 1992 1980 compared with the same data, 10 years of the country's 22 provinces (municipalities and autonomous regions) students eyesight decline rate rose by an average of 23.45% primary school students in our country, the low vision rate reached 21.91%. 55.86% middle school students, high school students was 75.79%, close to 80%, the annual rise. According to the survey of 2, Jinshui District of Zhengzhou city for my 57 middle school students from 2839: Zhengzhou city Jinshui District 2 students myopia amblyopia was 57 in middle school students of Zhengzhou in 15.76% and the prevalence rate was 30.44%, high school students myopia prevalence rate was 74.7%

The dust containing carcinogens, Chinese Center for Disease Control and prevention information, 38000000 full-time teachers in our country the incidence of cancer accounted for 20% of the total incidence of cancer, for the general population is 8 times as strong as.

A study found that the system dynamics model of the dust distribution and harm of the classroom, in front of the diameter of the 3M space, the work environment and the severity of competition of steelmaking dust hazards before workers are very similar.

Chalk from the chemical composition of speaking, the main ingredients are calcium carbonate (limestone) and calcium sulfate (gypsum), a small amount of calcium oxide and a small amount of other metal elements such as iron, cadmium, even now on the market for the original chalk improved dustless chalk, is only in the original chalk with grease or poly alcohols as binder, adding a larger proportion of the raw material, the weight and volume of chalk are increased, easy dispersion, but in the actual application is not obvious. Chemical acid-base chalk degree belongs to weak alkaline substances, from the physical properties of the chalk in the chalk writing and erasing process and its main chemical composition, concentration, dispersion, density, shape, hardness, solubility, resulting in the whole teaching process a lot of dust, long time floating in the air, the serious pollution of indoor air, endangering the health of the teachers and students, the harm with modern features of modern teaching aids as an important equipment, projectors, projector, computer, and the laboratory, affect the performance of these devices, the use of the quality and life. The physical and mental harm to the health of teachers and students of the dust is mainly reflected in the following aspects:

Damage to the teachers and students of the respiratory system

1, the lung harm: harm of dust to teachers of the body, the lung is the most common, in the teaching process, the chalk dust can easily be inhaled into the lungs, the majority is blocked in the alveolar, after a series of stimulus, chemical and immune effect can cause lung damage, including respiratory inflammation and pulmonary ventilation function decline, common lung disease: chronic, acute pneumonia, lung cancer, such as pneumoconiosis (i.e. chalk dust containing silica, inhaled into the lungs, the lungs of free silica content of pulmonary fibrosis in more than one percent of the dust, so that the alveolar fibrosis, leading to respiratory function decline).

2, the upper respiratory tract damage: chalk dust into the lungs of the way is through the upper respiratory tract includes the nose, throat, bronchial, in this process, part of the dust will stay in the upper respiratory tract, produce mechanical irritation and damage to the epithelial cells, long-term work in such an environment, will cause a series of pathological changes, including the most common effects on the nose is induced rhinitis sicca, followed by rhinitis, nasal dryness, nasal symptoms, nasal mucosa hyperemia, increased secretions and other; to swallow is the cause of chronic pharyngitis, throat dry, difficult expectoration, pharyngalgia; effect of bronchial is mainly induced by chronic bronchitis sometimes, trigger asthma, and may cause cancer, bronchial and other parts of the nasopharynx.

The other organs and tissues of the harm two

1, to the eye: eye damage is one of the most sophisticated, the most easily damaged organs organ in the human body, the chalk dust main ingredients calcium carbonate, calcium oxide is a kind of water soluble substances, easy to dissolve in water, and alkaline substances, such as teachers in the teaching process, the chalk dust falling into the eyes, stimulation of tear secretion, tear the hydrolysis of calcium carbonate and alkaline substances, can cause severe irritation of the mucous membranes of the eyes, mucous membrane injury, chronic inflammation, but also may have induced myopia.

2, to the skin damage: the teacher in the teaching process, the dust will stick in the hand, dust and particles floating in the air will fall on the teachers, the hair on the face and neck, a stimulating effect on the skin, if the summer sweat hydrolysis, producing alkaline substances, the skin and mucous membrane stimulus is bigger, because the skin of human survival environment is weak acidic environment, so that destruction of basic living environment of skin in the dust under the action of alkaline dust, so that the skin becomes dry, rough, and accompanied by itching feeling, make the body discomfort, severe cases can cause acne, folliculitis,

Pyoderma, chapped skin and hair loss, affect and interfere with the normal work and life of teachers.

3, the ear damage: chalk dust into the ear canal, mixed in sebum, formation of cerumen impaction, if so, can cause inflammation of the ear.

Three cause other diseases

Currently the chalk ingredients, in addition to containing metal elements, low lead and manganese and barium content, high content of cadmium, cadmium after being inhaled, is stored in the liver, kidney, bone, obvious to the tissue damage, major disease caused by long-term exposure to cadmium compounds is emphysema and kidney damage, the condition can be a progressive development, early signs of weakness, dizziness, insomnia, lean, loss of appetite and symptoms of neurasthenia, and nasal bleeding, nasal mucosa atrophy and chronic pharyngitis, ulcer and other phenomena. Slow progress in patients with emphysema, dyspnea, activity increased, accompanied by palpitations. Cadmium is also the most easily lead to one of the metal elements of cancer.

Effects of air quality on the four

Chalk dust has a strong adsorption capacity, a lot of harmful bacteria can be adsorbed on the fine dust into the lungs and by students, which led to acute and chronic inflammation, which causes students collective infection of the respiratory tract and other epidemics. The students in the course of lectures, laboratory and the total number of bacteria and other health indicators deteriorated gradually, and the fine dust interaction, aggravate the chalk dust harm to the health of teachers and students.

Five effect of chalk for myopia

For a long time, we use the blackboard teaching appliance, metallic green board and chalk, students commonly used books put it down in black and white, because the human vision is to recognize the font and color through the light, color, and black and white contrast is too strong, extremely easy to cause visual fatigue, resulting in a large area of the incidence rate of myopia of students produce. According to the Shanghai Department of Ophthalmology experts Lu Naichi in their study, put forward "the new idea to improve the visual environment and points out that the prevention and treatment of myopia, myopia is mainly composed of the visual environment and not bad habits with the eye caused by. He pointed out that people in the eyes when reading, chrominance and luminance contrast using the font and font shape paper to feel. The purity of color and reflection of light is proportional to the brightness and the reflected light intensity is proportional to the. White light can cause the light intensity and the maximum of the weakest of color, people in the maximum brightness contrast, can lead to visual fatigue of the largest, a long time will lead to functional regulation of myopia". In order to find the beige color the most gentle, most conducive to protect the eyesight of students. According to the newspaper reprinted, Shanghai in 2002 in the popularization of education, the other yellow textbooks in Guangdong, Hunan province has begun to promote the use of beige book, Shanxi University and other units have developed Beige dust-free teaching board and put on the market, reflecting the better, the city has more than a dozen schools in the use of.

The teacher is the engineer of the human soul, is also a human noble profession, students are the future of our country, their physical and mental health has attracted the attention of government and society, environmental protection has become increasingly popular concept, how to eliminate the chalk dust pollution, and completely behind education this huge industry, protecting the health of teachers and students has become all levels of government in China and the community of common concern and solve the problem. The city has a population of 6877000 (as of the end of 2002 the total number of students), up to more than 212.4 people, of whom about 100000 are full-time teachers, improve their health level and work of the learning environment of large teachers and students from some kind of meaning directly restricts the implementation of the strategy to the well-off society of our city, directly affect the sustainable development of education industry in our city, also influence and restrict the city hard environment and improve education.

To thoroughly solve the pollution of chalk dust is that the party and the government and the whole society to make joint efforts, in accordance with the practical situation of the city's economic development, especially for the recommendations are as follows:

1, lead to the industry department in charge of education, the establishment of the classroom to solve the dust pollution leading group, formulate relevant policies to support and encourage and guide the transformation, clean the classroom blackboard chalk; limit the development of the research and development, support teaching and the classroom clean, dust-free as a hard headed off the residents of our province, and will the classroom clean as a rigid target to establish a green campus, such as full support from tax research of clean development

The production and sales, leading clean education industry of our province.

2, the government financial allocation to a certain number of special fund, as an environmental protection investment in education, support and encourage free AIDS enterprises production and circulation, and to impose a certain number of production of green board, board manufacturers circulation enterprises and units, dust pollution charges, supplementary teaching

Room clean and reconstruction funds, special funds for the transformation of the classroom clean.

3, increase the propaganda, correctly guide the transformation of the classroom clean, so that the whole community of common concern, the harm of chalk dust, so that more social forces into the new dust-free aids the development, production, sales and the transformation of classroom clean.

4, promote the liquid chalk, thoroughly eliminate the dust harm to teachers and students.

When we see this article, who also can not believe this is true! Dust hazard of teachers is too big, we should think of ways to solve the pollution of the dust of the classroom, teachers and students to a healthy and clean environment of teaching!

Promotion of teaching, teaching environment, dust-free purification for the benefit of human society is the responsibility and goal of our!


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