Students' learning and living environment has always been concerned by the society, and good resources will be given priority to the school, hoping that the school can create a healthy and comfortable learning environment for students. But there is a problem that afflicts many schools because of faculty constraints and other factors, especially in rural areas where 50 or more students have to be taught in a single classroom. This makes the school face not only the smog pollution but also the excessive carbon dioxide and other problems. In order to create a healthy class environment for the flowers of the motherland, schools with conditions in the country have installed fresh air systems.

The government has introduced policies to promote the popularization of fresh air 

systems in schools to ensure the health of teachers and students.

For the school fresh air volume also made a standard, according to the "primary and 

secondary school classroom ventilation health standards" school classroom fresh air 

volume are:

Primary school ≥20 m3/h· person,

Junior high school ≥25m3/h· person,

High school ≥32m3/h· person.

Parameters of school fresh air system:

New air volume indicators: primary and secondary school teachers, according to the 

indicator of 20 cubic meters/hour/person, middle school and high school students and

 the number of higher classrooms have higher demand for new air volume.

PM2.5 indicator: The average hourly PM2.5 is less than 75 micrograms/cubic meter

Co2 index: The average CO2 per hour during school hours is less than 1500 PPM

The school fresh air system needs to be equipped with initial effect + medium effect +

 high efficiency (H13 medical grade HEPA filter), and the PM2.5 purification effect is over

 99%. The air volume needs to meet the minimum fresh air volume requirements of each 

student, and the air volume of the fresh air system must be large enough in the room of

 dozens of students, and the noise cannot exceed 45 decibels.

In order to ensure the air quality in the classroom, CO2, formaldehyde, air volume and

 other indicators detection systems should be configured. Teachers can control the 

classroom air quality in real time, and students should also be set locks to prevent 

students from misoperating.

When the school uses the fresh air system, it also needs to consider its installation

 method:

Central fresh air system:

More suitable for the classroom has not been decorated, the equipment is installed in the

 ceiling, the host and the air duct can be hidden.

Cabinet/Wall fresh air system:

It is more suitable for installation in the decorated classroom, so the installation is easier, 

and most schools will choose to install the simplest direct air fresh air system.

Since 2015, according to market demand and feedback from enterprises, nine group standards such as the "Technical Regulations for fresh air Purification Systems for primary

 and secondary schools" led by the China Academy of Building Science and the Chinese 

Quality Inspection Association have been compiled. The nine standards, from design to 

construction and installation, from product standards to special standards, have filled the

 standard blank of fresh air purification equipment into the campus in our country, and all

 aspects of fresh air purification equipment into the campus have become based on 

evidence.

T/CAQI 9-2016 "Commercial Air Purifier"

T/CAQI 10-2016 "Fresh Air Purifier"

T/CAQI 25-2017 "Fresh Air Purification System construction quality Acceptance Code"

T/CAQI 26-2017 "Primary and Secondary School Classroom Air Quality Test Method"

T/CAQI 27-2017 "Air Quality Standards for Primary and Secondary School Classrooms"

T/CAQI 28-2017 "Guidelines for the Design of Fresh Air Purification Systems in Primary 

and Secondary Schools"

T/CAQI 29-2017 Air Quality Management Guidelines for Primary and Secondary School

 Classrooms

T/CAQI 30-2017 "Technical Regulations for Fresh Air Purification System in Primary and 

Secondary Schools"

T/CAQI 31-2017 "Indoor Air Quality Online monitoring system Technical Requirements"