The problem of air quality in the car has become one of the most concentrated consumer complaints. In order to further strengthen the air quality control of passenger cars, the Science and Technology Standards Department of the Ministry of Environmental Protection has revised the "Guidelines for Air Quality Assessment in Passenger Cars" (GB/T27630-2011) and is currently in the process of soliciting comments.
The revised version is still only applicable to new production vehicles, but will be changed from a recommended national standard to a mandatory national standard, and the corresponding provisions will be modified to adjust some of the pollutant limits.
Experts said that the revised mandatory standards are more stringent, eliminating and reducing pollution in the vehicle manufacturing process, cutting off the source of air pollutants in the vehicle, effectively solving the problem of air pollution inside the vehicle, and better protecting the occupants. health.
The recommended national standard is revised to a mandatory national standard, and the limits of major hazardous substances such as benzene are tightened.
For the purpose of this standard revision, the preparation team stated that it is mainly to amend the recommended standards into mandatory standards, and to modify the corresponding clauses according to the requirements of the mandatory standards, and to adjust some of the limits. Another important task is to study the feasibility and necessity of adding polycyclic aromatic hydrocarbons limits to the standards.
The composition of air pollutants in the car is relatively complicated, and the space inside the car is narrow and the airtightness is good. The air pollution will have a major impact on the health of drivers and passengers. Relevant agencies have detected and researched that there are hundreds of volatile organic compounds in the air, including hydrocarbons, aldehydes, ketones, etc., among them, benzene, toluene, xylene, ethylbenzene, styrene, Formaldehyde, acetaldehyde, acrolein and other substances are more harmful to the human body. The new standard gives clear limits for these harmful substances, and some harmful substances are more stringent than the original standards.
Benzene is a human carcinogen recognized by the World Health Organization (WHO). It is the most harmful to human health among the eight pollutants identified by the standard. Therefore, it is also the most strictly controlled harmful substance. WHO's recommendations for benzene in ambient air are as low as possible. This revision will significantly increase the limit of benzene from 0.11 mg/m3 to 0.06 mg/m3 in order to more effectively protect the health of drivers and passengers.
The reporter noted that in this revision, the limit of toluene was adjusted to 1.00 mg/m3, which was 10% stronger than the original standard; and the limits of xylene and ethylbenzene were both adjusted to 1.00 mg/m3, both of which were reduced to the original. 2/3.
In addition, according to the measurement results of the air quality of the typical sample car, the revised standard stipulates that the limits of three pollutants of formaldehyde, styrene and acrolein remain unchanged.
The reporter found that in this revision, the acetaldehyde limit was the only one that relaxed the requirements, from the original standard of 0.05 mg / m3 to 0.20 mg / m3. Why is this?
According to the introduction of the group, in order to determine the safe exposure concentration of acetaldehyde, the research group consulted a large number of relevant foreign authoritative literature on acetaldehyde research.
Experts at home and abroad believe that there is a great uncertainty in the concentration of acetaldehyde in the air inside the car. At present, mainstream auto companies are focusing on key substances such as benzene, formaldehyde, acetaldehyde in the selection of interior materials, adhesives and sealing materials. Toluene, xylene, etc. are strictly restricted, and good control effects have been achieved, but the control effect on acetaldehyde is not good, and the concentration of acetaldehyde in the air in the vehicle changes randomly with time, and the measurement result of acetaldehyde in mass production cars is also Shows uncertainty in time.
Analysis shows that although acetaldehyde is strictly controlled from the interior, adhesives and seals, acetaldehyde can be regenerated in the car, and there are many reasons for the formation of acetaldehyde, such as oxidation of ethanol.
Based on the above analysis and international research results on the safety limits of acetaldehyde, this revision adjusts the acetaldehyde limit to 0.20 mg/m3, which is lower than the internationally recognized 0.30 mg/m3 safety threshold for humans. .
In addition, according to the introduction, in order to further demonstrate the feasibility of increasing the content of polycyclic aromatic hydrocarbons (PAHs) and total volatile organic compounds (TVOC) in the air of the vehicle, in March 2015, the Science and Technology Standards Department of the Ministry of Environmental Protection specially organized an expert discussion. Yes, the opinions and suggestions formed are: in view of the limitations of PAHs source, physical properties and measurement and analysis methods, this standard is not included; TVOC and health are not clear, and further research should be carried out.
The original standard is not binding enough. As the level of the automobile industry increases substantially, it needs to be revised and adjusted.
China's automobile industry and automobile consumption have shown a trend of sustained and rapid growth in recent years. According to data released by the Traffic Management Bureau of the Ministry of Public Security, as of the end of 2015, the number of motor vehicles in the country reached 279 million; in 2015, there were 136 million small passenger vehicles, including small passenger cars registered in the name of individuals (private cars). ) reached 124 million vehicles, accounting for 91.53% of small passenger cars. There are 31 private cars per 100 households nationwide.
In addition to homes and workplaces, vehicles have become one of the main places for humans to stay. The China Population Exposure Handbook (Adult Volume) published in 2014 shows that the average exposure time of ordinary drivers and passengers in all modes of transportation is small cars. The national average exposure time is 40 minutes/day, including Beijing, Tianjin, The average exposure time of drivers and passengers in Guangdong and other places is as high as 60 minutes/day. The cumulative usage time of Chinese per capita cars is 71 minutes/day, but traffic congestion makes the drivers and passengers spend more and more time in the car.
On the other hand, in order to meet the requirements of consumers for car comfort, manufacturers continue to improve the interior structure design, using more new technologies, new materials, new processes, especially the large number of applications of non-metallic materials and adhesives, leading to vehicles The accumulation of internal pollutants is harmful to human health.
For the interior environment, due to the lack of relevant control standards and legal basis, the air quality problem in the car has become increasingly prominent. With the continuous improvement of public environmental awareness, the environmental problems in the car have received much attention in recent years.
The complaints about automobile product defect information published by the General Administration of Quality Supervision, Inspection and Quarantine indicate that in addition to quality problems such as transmissions, airbags and tires, the smell inside the car has become one of the most concentrated complaints of car owners.
In 2011, the Ministry of Environmental Protection and the General Administration of Quality Supervision, Inspection and Quarantine jointly issued the “Guidelines for Air Quality Assessment in Passenger Vehicles†(GB/T 27630-2011), which was officially implemented on March 1, 2012. According to the type and source of volatile organic compounds in the air and the volatilization characteristics of the main interior materials of the vehicle, the guide identifies eight main control substances, namely benzene, toluene, xylene, ethylbenzene and styrene in the air of the vehicle. Formaldehyde, acetaldehyde and acrolein, and the concentration requirements are specified.
According to the actual test results, the standard has a significant effect on improving the air quality inside the car. But at the same time, there are some shortcomings in the standard.
For example, the “Guidelines for Air Quality Assessment in Passenger Cars†is the recommended standard, and the restrictions on automobile manufacturers are insufficient. The “Sampling Method for Volatile Organic Compounds and Aldehydes and Ketones in Vehicles†requires that the vehicles under test be placed at constant temperature, constant humidity, and static. In the wind, clean air environment, and completely in a static state, this is inconsistent with the state of the actual use of the vehicle, and it is difficult to fully reflect the air quality of the vehicle under the driving state.
In addition, considering the industrial level at the time of implementation of the original standard, some car interior pollutants are set to a wider limit, which is higher than the international equivalent of the same substance.
In view of the above, the National Standardization Committee recommended that the original recommendation standard be revised to a mandatory standard and the relevant mandatory standard requirements should be added.
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