The solution of fog for kindergarten

    An adult ususally eat 3 times a day ,1 kg of food intake,drink water out of 10 times,about 2 kilogram of water,breath 20000 times,25 kg air.Though the childs intake very small ,but the proportion is the same.If the air is polluted,the impact on people will greater than diet.

    With the popularity of car and factory emmissions throughout the year,in addition to winter,the fog also happens in spring and summer.More and more people have recognized the harmfulness of the fog.It has a great significance for strengthen physique and reduce the incidence of lung to improve the qir quality indoors and reduce the PM2.5 index.

Will it reduce the fog if close the door and windows

    There are a largr number of experimental data show that by closing the doors and windows to reduce the fog with only a few hours .The fog is very small,it can enter the house within a few hours and get the balance with the outside.It will be useful if you can close the door before the raising of PM2.5,however it's hard to come by.It's a special environment that dozens of children in the same place,leading to a big personnel dencity.The air circulation greatly reduced after closing the door and windows.A cold virus stay indoors for a long time,such as carbon dioxide human exhale can not be let out .Then it will cause the chroma of indoor carbon dioxide and oxygen concentration reduction.Which is not conductive to students health.

The main pollutant in classroom

    1.Fog particles:which is often said to be PM2.5,mainly comes from the outside.

    2.CO2:from the interior of the human body breath.

    3.TVOC:total volatile organic compouds,mainly from the interior decoration and other pollution.

    4.virus bacteria tansmitted in the population,mainly from the interior.

The importance of ventilation

    According to the national standards GB/T18883-2002 in China,the fresh air should not be less than 30m3/h.For children,can not be less than 15m3/h.Fresh air:refers to the fresh air introduced from the outdoor into the indoor,often said to be ventilation.

    In fog day,or in order to keep warm in the winter,open air conditioning to keep cool in summer,many people often close the door and window in the room.But the classroom is the place that people concentrated,it's easy to cause the concentration of the CO2 exceed the bid.On artificial intermittent opening the window to take a breath.It's easy to cause sever changes of temperature.CO2 is also easy to exceed the bid in a certain period of time.

    The calculation formula of CO2 rising in airtight environent:rising rate of the PM2.5 in airtight room = the volume of pure CO2 an adult exhaust / per capital building area * 1000000.

Suppose that there are 20 people in a 60-square meter-room,the rising speed of CO2 in a completely sealed environent is 2000PPM per hour.the content of the CO2 in the air is 400 PPM.We often recognized the CO2 concentration of health standards is 1000 PPM,which will exceed the bid in such environent.It's no wonder that people will be sleepy in the crowed meeting room.

    For the classroom,the children's emmision of CO2 is half of the adult,if you take breath by opening the window,you will be up to the standard by exchange the air at least 1 times per hour.

    If isn't up to the standard,then it will need the calculation formula of the fresh air:the volume of CO2 an adult exhaust = 30 cubic per hour per capita,this is the origin of national standard of fresh air.

The relationship between the concentration of CO2 and human's physiological reaction

    350~1000 PPM:fresh air ,breath easier.

    1000~2000PPM:air turbidity,and began to feel drowsy.

    2000~5000PPM:feel headache,drowsiness,sluggish,unable to concentrate,the heart speed up,mild nausea.

    Greater than 5000PPM:may lead to serious lack of oxygen,resulting in permanent brain damage,coma and even death.

    Many people may have such experience:you will feel sleepy during a long-last meeting,probably is the reason of high CO2 value.

Solution:ventilation and filtration

     Fresh air system:design the ventilation rate according to the number of people.Transmitting the fresh air into the interior by the ventilator,at the same time will discharge the air with low oxygen content outdoor.

    For putification of PM2.5 filtering tecnology is relatively mature:qualified purification system can cut indoor PM2.5 at 5~8 times.  That is to say if the PM2.5 outdoors is 100μg/m3,the PM2.5 indoors will be only 20μg/m3.That is,when the PM2.5 outdoors exceed the bid to 500μg/m3,the PM2.5 indoors can still below 100μg/m3.

    For classroom without central air coditioning,the purifier and the frsh air system are commonly used .A recommended scheme is that using the purifier and the fresh air system together.Because the fresh air system belongs to the outer loop ,it can filter the air and transmmit the air into the door.Indoor purifier belongs to the inner loop,so the PM2.5 can be filtered repeatedly ,thereby reducing the fog index significantly. The classroom with built-in ventilation central air conditioning can equipment with the tuyere in the out door and inlet.

Energy saving:air heating trasfer function

    The fresh air system with heating transfer function can achieve ventilation and heating exchange,which is more energy-saving than a window ventilation.