At the end of 2017, the country's civilian car ownership has exceeded 200 million, and its number continues to grow, and the growth of civilian car ownership is bound to be accompanied by the increase in traffic congestion in the city, the people's commute time is also longer.
The extension of commuting time means that the time people spend in the car is also gradually increasing. According to data, people spend about 90% of their lives in semi-confined spaces, of which 5.5% is in cars. According to 80 years old to calculate, life **** has 29,200 days, and stay in the car for about 1445 days.
People stay in semi-confined space for a long time, air quality has become an important factor affecting health. In fact, the number of complaints about air quality in cars has been high for a long time, and as of December 17, 2019, the cumulative number of complaints about odor in cars is as high as 10,059, which is ranked 11th on the list of faulty issues on TrainQuality.com.
In recent years, consumers have almost come to "talk about odor", the car smell and car air quality are two different concepts. Certain pollutants will be in the form of odors for the car occupants to perceive, but many pollutants are colorless and tasteless, can be called the car "invisible killer".
What should I be concerned about when it comes to interior air quality?
Inside the car environment by the car roof, door trim, seats and other structures and interior accessories, plus the role of air-conditioning equipment, the integrated formation of a different climate with the car outside the car. In-vehicle air quality is affected by a variety of factors, currently divided into four main parts:
1, outside air pollution: the atmospheric environment of smoke, hydrogen sulfide and inhalation of particles and other pollutants will enter the car through the air vents;
2, the products of combustion of the engine: engine combustion of the gas produced by the car body gaps and connections to enter the car;
3, the car volatile Organic matter: Harmful gases released from car interior materials;
4, bacteria in the car: As the condenser part of the car air-conditioning system has a humid environment, it is easy to breed bacteria, and the internal circulation may lead to the spread of bacteria in the car.
While there are various sources of air pollution in cars, the current worldwide standards for evaluating the quality of air in cars are mainly for volatile organic compounds (VOCs) and focus on controlling eight substances: benzene, toluene, xylene, styrene, ethylbenzene, formaldehyde, acetaldehyde and acrolein.
Taking formaldehyde as an example, when its concentration is greater than 0.08 mg/m3, it will cause eye redness, throat discomfort and other symptoms; the concentration is more than 0.1 mg/m3, eyes and mucous membrane cells will be injured; the content reaches up to 30 mg/m3, it will immediately cause death. Even if the formaldehyde content in the environment is low, long-term exposure to the environment, but also cause chronic respiratory diseases, nasopharyngeal cancer, leukemia and other serious diseases. These eight substances are known as "five benzene and three aldehydes", in the car content and frequency of occurrence of higher, more toxic, and therefore become the focus of the control of the target.
What are the criteria for VOCs in cars?
At present, many countries have developed relevant standards, including KOR for the Korean national standard, JAMA for the Japanese autonomous action plan?
Chinese standards are quite demanding compared to those of Korea and Japan. For example, the vehicle inspection process, South Korea only need to close the door for 2 hours, China is 16 hours. The longer the vehicle is closed, the higher the concentration of volatile hazardous substances in the vehicle.
However, it is unfortunate that the GB/T27630-2011 "Guidelines for the Evaluation of Air Quality in Passenger Vehicles" is only instructive and suggestive, but not mandatory, and this regret also creates a dilemma for consumers.
How to do a good job of VOC protection in the car?
The main source of VOC in the car parts and interior materials, to reduce the VOC in the car, need to car companies based on GB/T?27630-2011 limit value indicators, set the VOC emission control target for the model. However, the national standard is not mandatory, so a car's VOC content is qualified, consumers have no way to know, and VOC testing equipment requirements are high, involving ion chromatography and reflectance interference spectroscopy, etc., for ordinary users, the cost is too high.
Based on the awakening of consumers' awareness of automotive health, China Automotive Research, combining research resources from the automotive industry, medical industry, and communications industry, initiated and led the ? At this stage, the China Automotive Health Index mainly focuses on volatile organic compounds (VOC), vehicle odor (VOI) and electromagnetic radiation (EMR), and will also include measurements of particulate matter (PM) and allergenic risk (VAR) at a later stage.
At present, the China Auto Health Index has evaluated 28 models. By scoring high or low, consumers can directly judge whether a model's VOC content is up to standard, whether the odor inside the car is strong, and whether the electromagnetic radiation inside the car exceeds the standard. In the future, China Auto Health Index will also actively carry out evaluation work to expand the dimension of evaluation, in order to provide consumers with a broader and more comprehensive reference.
In addition to purchasing healthier models, consumers can also reduce the amount of VOCs in their cars through a number of techniques.
Although many people will recommend products such as activated carbon, photocatalysts and negative ion purification, the effect of these black technologies often plays a very limited role. For example, activated carbon belongs to the passive physical adsorption, formaldehyde is its prey, and activated carbon is a trap without bait, can only wait for the prey to throw themselves into the net.
In fact, ventilation is a way to effectively reduce VOC in the car. Some studies have found that good ventilation helps reduce VOC levels, which are significantly lower after 30 minutes of ventilation. At the same time, there is also experimental data showing that the concentration of VOC in the car will increase with the temperature. The boiling point of formaldehyde is 19?degree Celsius, and above 29 degrees Celsius, formaldehyde volatilizes faster.
A new car can be exposed to high temperatures to accelerate the volatilization of VOC, and then use the ventilation, you can effectively remove the VOC in the car. it should be noted that the old car does not apply to the sun. Because with the passage of time, the VOC inside the car will gradually reduce, to achieve a stable state, but the sun is very likely to make the original stable material again emit harmful substances, and the car interior will accelerate the aging of the interior.
Therefore, in our daily life, we need to open the windows more often to ventilate, and at the same time, we should try to avoid entering the car in the high temperature state.
In the epidemic environment, the requirements of automotive air filtration systems are becoming more and more stringent, but the attention to the quality of the air inside the car should not stop here, the car VOC and VOI should also become the focus of attention. Nowadays, people are spending more and more time in their cars, and the issue of in-vehicle air quality cannot be ignored.
This installment of the Auto Health Clinic focuses on the dangers of VOCs in cars. If you have any concerns, you are welcome to ask questions, and we'll see you in the next installment.
This article comes from the authors of Auto Home Car Family, and does not represent the viewpoint position of Auto Home.