Where to Begin

Beijing is currently experiencing a prolonged period of high temperatures and sweltering weather, coinciding with the peak summer travel season. This has led to a significant increase in railway and civil aviation passenger numbers. As the "first stop" for out-of-town visitors arriving in Beijing, can the city's "eight stations and two airports" satisfy passengers' need for a cool summer journey? Can departing passengers say goodbye to the experience of "sweating with their luggage" before they leave? What measures have these major transportation hubs taken to cope with the persistent heat? To answer these questions, we conducted a comprehensive survey of the cooling measures and their effectiveness across Beijing's "eight stations and two airports." The "eight stations and two airports" refer to the city's eight major railway hub stations, Beijing Capital International Airport, and Beijing Daxing International Airport. Among the eight railway stations, they can be clearly divided into new and old stations based on their opening dates. Beijing Tongzhou Railway Station, Beijing Chaoyang Railway Station, Beijing Fengtai Railway Station, and Qinghe Railway Station are new stations that have been built and put into operation in the last decade. In contrast, Beijing Railway Station, Beijing West Railway Station, Beijing South Railway Station, and Beijing North Railway Station are older stations that have been in service for a longer period. Our investigation found that new stations, due to their more scientific design and the use of new technologies, generally do not have significant ventilation and cooling issues, largely maintaining internal temperatures between 26°C and 27°C. On the other hand, many older stations face long-standing challenges in completely alleviating summer heat. They continue to combat the heat by running air conditioning at full capacity, adding fans and air coolers, and installing heat-reflective films and sunshades on their roofs. A similar situation is evident at the airports. We learned that in response to higher temperatures in certain areas, all air conditioning systems within the terminals of Beijing Capital International Airport are operating at full capacity. The airport has also added temporary cooling equipment in some areas and is progressing with an upgrade project for the overall air conditioning system in the terminals.

Locations: Beijing Tongzhou Railway Station and Beijing Chaoyang Railway Station

Architectural Design Cools the Stations, Providing Overall Comfort

"I just walked in from outside and immediately felt cool, but the air vents are far away from me, so there's no chilling draft from the air conditioner," said Ms. Cao, a passenger waiting at Beijing Tongzhou Railway Station. She noted that compared to other stations she has visited, Beijing Tongzhou Railway Station not only has a design that captures attention but also offers a more comfortable indoor temperature. At 10:30 AM on August 4, we arrived at Beijing Tongzhou Railway Station. At that time, the outdoor temperature in the open area was over 35°C, with a stifling, muggy feel. Upon entering the station, we immediately felt waves of cool air. The waiting area on the second basement level, the station's core area, measured approximately 26°C on a thermometer. We noticed that air supply vents are evenly distributed throughout the waiting hall, resulting in minimal temperature differences between areas. Only when standing directly under a vent does one clearly feel the cool air. Station staff explained that the air conditioning in the second basement waiting area is set to a constant 25°C, with equipment undergoing regular maintenance and inspections. On the first basement level, near the entrances and exits, the temperature readings were similar to the waiting area on the second basement level. However, due to the frequent mixing of hot and cold air near the entrances, passengers reported feeling somewhat stuffier. "But it's still acceptable; at least it's quite cool inside the station," one passenger commented. We learned that the cooling strategy for Beijing Tongzhou Railway Station is not just an operational matter; it was thoroughly considered from the initial design stage. The Beijing Sub-Center Transportation Hub features ten "Jingfan" (Beijing Sail) canopies. The upper part of the canopy is a hollow sail design, while the lower part uses a transparent ETFE membrane structure, the same type used for the Water Cube, creating a translucent "bubble skylight." This design not only brings natural light into the underground platform areas but also effectively blocks direct sunlight, balancing indoor and outdoor cooling and heating loads. Furthermore, the overall layout of the hub is key to its natural temperature regulation. The station's main structure, tracks, waiting halls, and transfer passages are all built underground, leveraging the stable temperature characteristics of the earth. Combined with a zoned central air conditioning system, it creates a constant-temperature waiting and transfer space as needed. Beijing Chaoyang Railway Station also offers a similarly good experience. At 4:00 PM on August 4, when we took temperature readings at Beijing Chaoyang Railway Station, we noticed that sunlight was entering the station through the gaps in the glass ceiling. Because the glass on the ceiling and curtain walls is not a continuous design, the sun does not continuously "heat" any single area, achieving a balance between indoor lighting and temperature control. Inside Beijing Chaoyang Railway Station, people do not feel a strong blast of cold air from the air conditioner, but the overall sensation is very comfortable. After taking temperature readings in various parts of the waiting hall, we found that the temperature control at Beijing Chaoyang Railway Station is relatively uniform, generally stable at 27.5°C. Some shaded areas near the air vents were even cooler, at temperatures below 26°C. The air conditioning temperature inside Beijing Chaoyang Railway Station is relatively balanced, with little variation across different areas, controlled between 26°C and 28°C.

Locations: Qinghe Railway Station and Beijing Fengtai Railway Station

Temperatures in Specific Areas Like Dining Zones are Slightly Higher; Air Coolers and Umbrellas Added

At 11:30 AM on August 4, the outdoor temperature at Qinghe Railway Station had already reached 35°C. After taking temperature readings in several areas inside the station, we found the temperatures to be quite comfortable. The waiting areas on the west side of the hall, including the seating area, charging zone, and zone for passengers with special needs, all maintained temperatures between 26°C and 27°C, feeling comfortable. Some passengers were even wearing light long-sleeved jackets. We noticed that to ensure a comfortable temperature inside the station, all air conditioning vents in the waiting hall were open. Red cloth strips tied to the vents to indicate airflow were constantly fluttering in the stream of cold air. However, the temperature in the dining area on the upper level of the waiting hall was noticeably higher. The heat generated by cooking in the restaurants, combined with fewer air conditioning vents and a large number of passengers during lunchtime, made this area feel quite stuffy. Our temperature readings showed that multiple points were close to 29°C. The dining area at Qinghe Railway Station had a relatively high temperature, nearing 29°C. We learned that the station management had previously noticed this issue and had specifically placed air coolers in front of each restaurant in the dining area. Due to the relatively higher temperature in the dining area, many passengers were eating quickly to finish their meals and return to the cooler waiting hall on the lower level. To lower the temperature in the dining area of Qinghe Railway Station, the station has added several high-power air coolers. At around 1:30 PM on August 4, at Beijing Fengtai Railway Station, we observed numerous air conditioning vents distributed on the first and second floors, and we did not feel stuffy. The first floor was particularly cool, with many air vents and a relatively small number of passengers at that time. The temperature on the second floor felt slightly higher than the first floor but was still not hot. During our nearly one-hour observation at Beijing Fengtai Railway Station, the waiting area on the second floor was almost full of passengers, but we only saw two elderly passengers using fans to cool down. We selected two seating areas slightly farther from the air vents to take temperature readings, which showed 27.5°C and 28.5°C, respectively. The air circulation was good, and the overall feeling was cool and comfortable. The hottest area inside Beijing Fengtai Railway Station is the central light atrium corridor, which has a large transparent glass roof. Sunlight shines directly through the roof, making this area feel quite stuffy. However, this corridor is a passageway, and few people linger there. Additionally, the dense arrangement of air conditioning vents in this area effectively alleviates the stuffiness. The 12306 service desk located in the central light atrium has also been specifically equipped with a sun umbrella, so that passengers coming for inquiries or assistance are not exposed to direct sunlight. Air conditioning vents are distributed on both sides of the central light atrium at Beijing Fengtai Railway Station.

Locations: Beijing West Railway Station and Beijing South Railway Station

Older Stations Face Pressure to Cool Down; Air Conditioning Runs at Full Capacity, Electric Sunshades Installed

Compared to the four newly built stations mentioned above, the four older stations — Beijing Railway Station, Beijing West Railway Station, Beijing South Railway Station, and Beijing North Railway Station — have been in operation for longer, handle significantly higher passenger volumes than the new stations, and some were not designed with comprehensive consideration for temperature control and lighting. This leads to persistent issues with stuffiness during the hot summer months that are difficult to completely resolve. At 12:30 PM on August 4, we took temperature readings in waiting rooms 5 and 8 at Beijing West Railway Station. The temperature inside these waiting rooms was roughly between 27°C and 28°C. The perceived temperature also varied depending on the density of passengers in a given area. It felt slightly stuffier when passengers were gathered in queues, but as the crowds dispersed and air circulation improved, it became cooler. We found that in addition to the air conditioning running at full capacity, high-power electric fans were placed in areas where passengers congregated or where sunlight was directly shining, providing a cooling effect. A high-power fan was operating in waiting room 5 of Beijing West Railway Station. Although Beijing West Railway Station is an older station with air conditioning equipment that is somewhat outdated compared to newer stations, the station has been continuously strengthening its cooling service guarantees in recent years. During this summer's travel season, Beijing West Railway Station has three core chiller units in the basement-level air conditioning plant room on the south side, dedicated to controlling the temperature of the waiting areas. Additionally, 22 air conditioning units serving the various waiting rooms are distributed in the air conditioning equipment layer above the east-west corridor, operating round-the-clock for cooling services. At the same time, station staff use environmental thermometers to take temperature readings three times daily in each waiting room and public area. Based on changes in outdoor temperature, site-specific temperature data, and passenger flow fluctuations, they dynamically adjust the operating frequency of the units and control the chilled water outlet temperature, keeping the temperature consistently between 26°C and 28°C. Beijing West Railway Station has also installed 47 electric fans in the waiting rooms as a supplementary measure to prevent heatstroke. During high temperatures, these fans are turned on to provide supplementary airflow, ensuring a comfortable temperature in the waiting rooms. The hottest area in Beijing West Railway Station is the central corridor. Although it feels quite stuffy, the temperature was still measured at around 28°C. Another older station making efforts to cope with the heat challenge is Beijing South Railway Station. As the busiest station in Beijing in terms of passenger volume, Beijing South Railway Station dispatches approximately 170,000 passengers daily during the summer travel season. On the afternoon of August 4, we used a handheld thermometer to measure temperatures in different areas of the waiting hall at Beijing South Railway Station. The central area of the hall, exposed to direct sunlight, was noticeably hotter than other areas, with temperature readings close to 30°C. We saw many passengers constantly fanning themselves and wiping away sweat. The thermometer showed nearly 30°C in the second-floor waiting hall of Beijing South Railway Station. "It's indeed a bit hot, but it seems to be the same every year. I've heard there's no great solution," said Mr. Wang, a frequent traveler from Beijing South Railway Station. He noted that during the hottest periods of summer, the temperature in the waiting hall is always relatively high. "I've heard they put a sun-protective film on the roof before, and they also had sun umbrellas in the waiting area." Compared to the central area exposed to direct sunlight, the temperatures in some peripheral areas were noticeably lower and felt more comfortable. Additionally, the areas in front of the boarding gates were relatively cool, with multiple groups of air conditioning vents delivering a steady stream of cold air in front of each gate. We learned that to address the heat challenge, Beijing South Railway Station has implemented several cooling measures. Building on the previous installation of heat-reflective film on the roof, the station has further installed 304 electric sunshades on the roof this year, effectively reducing the indoor temperature in the waiting areas. At the same time, high-power air coolers have been placed around the boarding gates for passengers to cool down nearby. Station staff explained that all air conditioning units are operating at full capacity. Due to the combined effect of the greenhouse effect from the large transparent roof and the high passenger volume during the summer travel season, there is pressure to control the temperature in the central area of the hall. Staff guide passengers to the air vents near the boarding gates and the locations of the air coolers to escape the heat. Beijing South Railway Station has installed 304 electric sunshades on its roof this year to alleviate the temperature rise caused by direct sunlight.

Locations: Beijing Railway Station and Beijing North Railway Station

Indoor Perceived Temperature is Positively Correlated with Passenger Density

Among these four older stations, Beijing Railway Station and Beijing North Railway Station handle relatively smaller passenger flows. We noticed that the perceived temperature inside the stations was positively correlated with the density of passengers. At noon on August 4, we found that Beijing Railway Station was not very crowded, and the overall waiting environment was cool and comfortable. The measured temperature in the central area of the first-floor hall was stable at 25°C to 26°C. Waiting Room No. 4 on the second floor is adjacent to large glass windows. Although there was direct sunlight, there were plenty of air supply vents in the waiting room. The dense airflow from the air conditioning effectively neutralized the heat from the sunlight, with the on-site temperature measuring 26°C. Several waiting passengers reported feeling comfortable. Waiting Room No. 8 is a commercial leisure area with a glass dome ceiling. Under direct sunlight, the temperature was slightly higher, maintaining between 26°C and 27°C. The continuous supply of cold air from the surrounding shops also effectively alleviated the stuffiness. The thermometer showed 26°C in the central waiting hall on the second floor of Beijing Railway Station. In contrast, Beijing North Railway Station, due to its smaller size and higher passenger density, felt noticeably stuffier in the waiting area. At around 3:30 PM on August 4, the waiting area on the first floor of Beijing North Railway Station was very crowded. All seats were occupied, and some passengers were sitting on the floor. The airflow from the air conditioning was not very strong, and combined with the fact that passengers were standing and sitting closely packed together, it inevitably felt stuffy. We randomly selected a spot in the rest area to measure the temperature, which showed 29.5°C. We noticed that the stuffy feeling at Beijing North Railway Station is also related to its design. The station is relatively small. Passengers entering from outdoors go through the security check area, which is only separated from the outdoors by plastic curtains. With people constantly coming and going, hot air continuously enters the building. The security check area is very close to the waiting area, contributing to the higher temperature in the waiting area. At around 3:30 PM, the waiting area of Beijing North Railway Station felt quite stuffy, with the temperature near 29°C.

Locations: Beijing Capital International Airport and Beijing Daxing International Airport

Beijing Capital International Airport Plans to Optimize the Air Conditioning System; Beijing Daxing International Airport Uses Zoned Temperature Control

On July 30, we visited Terminal 3 of Beijing Capital International Airport. The security check area, located on the 3rd floor, is the main area where passengers complain about the heat. Among the crowd, some passengers were using their paper boarding passes to fan themselves, while others were waving their hands back and forth to create a breeze. The dining area on the 5th floor of the terminal was also relatively hot. A staff member from the Terminal Building Management Department's building engineering division at Beijing Capital International Airport explained that all 8 chiller units in the energy center that supplies cooling to the terminals are operating 24 hours a day at full capacity. The central air conditioning system within the terminals has 375 air handling units, which run continuously 24 hours a day during hot and humid weather to cool and dehumidify the buildings. Despite the air conditioning system working "hard," passengers still feel hot in some areas. This is partly related to the special architectural structure of Terminal 3. The terminal building uses a glass curtain wall structure, and areas near the glass curtain wall tend to be hotter. Additionally, Beijing Capital International Airport handles a large number of passengers, and the frequent opening and closing of doors at boarding gates, entrances, and exits can easily lead to the loss of cool air inside the building. To address the issue of higher perceived temperatures in some parts of the terminal, while ensuring passenger safety, Beijing Capital International Airport has implemented some temporary cooling measures. Temporary cooling equipment has been put in place in the dining areas. Furthermore, a project to upgrade the terminal's air conditioning system is underway, which includes the optimization and enhancement of the air conditioning system. Beijing Daxing International Airport, on the other hand, felt generally comfortable overall. At around 11:00 AM on August 4, the outdoor temperature around the Beijing Daxing International Airport terminal was about 32.5°C. After entering the terminal, we took temperature readings at multiple points on floors 1 through 5, including the arrival area, security check area, check-in counters, indoor bus waiting area, and dining area. Except for one point in the dining area on the 5th floor, which registered 26.4°C, the temperatures at all other points were between 24.9°C and 25.9°C. A point in the dining area on the 5th floor of the Beijing Daxing International Airport terminal registered 26.4°C. Zhou Tuo, the business manager of the Terminal Building Management Department at Beijing Daxing International Airport, explained that the entire terminal is divided into 74 independent temperature control zones, equipped with 691 air handling units, and has a total of 17,000 air supply vents throughout the building. Relying on the building automation system, the terminal achieves zoned temperature control. For example, during hot and humid summer weather, in areas with high passenger traffic, the air handling units operate at full capacity. In areas with lower passenger traffic, the unit load can be reduced to decrease power consumption during low-traffic periods. For areas that might have higher temperatures, such as the dining area on the 5th floor, in addition to the air conditioning vents, the floor is equipped with a radiant floor cooling system as an auxiliary cooling device. If the temperature in the dining area becomes too high, the radiant floor cooling can be activated. Zhou Tuo explained, "When this mode is activated, staff will adjust and optimize the operation parameters to prevent condensation on the floor." Furthermore, in areas like the security check zone, there are radiant ceiling cooling panels installed above the ceiling to provide auxiliary cooling for the terminal. Zhou Tuo mentioned that Beijing Daxing International Airport also fully utilizes the peak load shifting capability of its ice storage system. By taking advantage of the lower nighttime temperatures and lower passenger traffic, the airport pre-cools the terminal building overnight. This off-peak cold storage helps reduce the cooling load during the peak daytime hours. Additionally, through various channels including the 96158 service hotline, the airport actively collects passenger feedback to continuously optimize its various services.

Reporter's Notes

The Temperature Difference Between New and Old Hubs Highlights the Significance of Green Buildings

During our temperature measurement survey of Beijing's "eight stations and two airports," the different numbers on our thermometers reflected the different "expressions" of new and old transportation hubs in the face of extreme heat. At the new stations, a cool 26°C was readily available, while at some older stations, even with air conditioning running at full capacity, the stuffiness in areas exposed to direct sunlight was difficult to completely dispel. This direct temperature difference allows us to see the significance of green buildings. Addressing the summer heat challenges at some of Beijing's transportation hubs, green buildings demonstrate a consideration of the "full life cycle" and the use of realistic simulations based on scientific data. The "Jingfan" canopy of Beijing Tongzhou Railway Station and the ice storage system of Beijing Daxing International Airport were designed from the very beginning, taking into account Beijing's climate characteristics and future passenger flow growth. The design reduces reliance on mechanical cooling. This wisdom of "treating the disease before it occurs" is far more efficient and economical than later "patching up" problems. While innovative experiences are worth promoting, existing problems must not be ignored. New stations have achieved a balance between aesthetics, lighting, and temperature control through scientific design, but we must not forget the need to renovate the existing older stations. It is commendable that both the railway stations and the airports are actively trying to solve problems. The railway authorities are installing sunshades and heat-reflective films in older stations and adding air coolers. The civil aviation authorities are advancing the air conditioning system upgrade project at Beijing Capital International Airport and adding temporary cooling equipment in some areas. These efforts reflect the responsibility of public service providers. Facing the potential test of more frequent extreme weather events like heatwaves in the future, transportation hubs, as the "city's living rooms," need to consider not only construction costs and aesthetic design during their initial construction but also anticipate the operational maintenance pressure under the frequent occurrence of extreme weather. With the rapid progress of technology, these are not difficult problems. Through technology, future possible climate scenarios and passenger flow densities can be simulated, thereby avoiding the "greenhouse effect" predicament that older stations face today, while they are still on the drawing board. Of course, architectural iteration has its objective laws. For the older stations currently in use, the timeline and cost of a complete renovation are incalculable, which also means that some of the heat-related problems at these older stations are difficult to eradicate in the short term. Under these circumstances, we hope that the station operators can innovate their service measures to create a more comfortable and pleasant travel environment for passengers. For the public, while enjoying the comfortable experience brought by new buildings, they should also offer some tolerance and understanding towards the older stations. Understand the slight stuffiness caused by historical design limitations, and see the dedicated efforts of the staff working hard in the hot weather. After all, whether it is the scientifically designed new hubs or the old station buildings that carry the memories of generations, they are all the beating pulse of this city, worthy of our collective care.