Pay attention to breathing depth while running and adjust your pace on windy days.

　　As spring arrives and flowers bloom, many urban fitness enthusiasts begin setting their exercise plans, and jogging is one of the urban sports favored by many fitness lovers. However, faced with changeable weather and air quality, many urban joggers have concerns—whether it’s okay to run in bad weather. After this year’s Two Sessions, PM2.5 monitoring has been put on the agenda in several major cities across the country, including Beijing. Yet, many jogging enthusiasts may not understand the impact of PM2.5 on running. In fact, although running is a relatively simple sport, it has relatively high requirements for air quality.

　　Regarding air quality, many runners may be particularly interested in the recently released PM2.5 data. At the end of January this year, the official website of the Beijing Municipal Environmental Monitoring Center began publishing hourly concentration data from the comprehensive observation laboratory’s research testing on PM2.5. However, when reporters visited the Beijing Municipal Environmental Monitoring Center’s website, they found that the published PM2.5 data still only reflects real-time conditions for the day. To learn about the next day’s air quality forecast, one still has to rely on the air quality forecast data published on the homepage.

　　In the primary pollutant column of the air quality forecast, we see that in recent days, the main source of pollution has been inhalable particulate matter, i.e., PM10. Wang Yus, a researcher at the Institute of Atmospheric Physics, Chinese Academy of Sciences, said that PM2.5 and PM10 are highly correlated. Simply put, the relationship between the two can be described as roughly equal, with PM10 encompassing PM2.5. Generally speaking, during dusty weather, the proportion of PM10 is higher, whereas during hazy days, the proportion of PM2.5 is higher.

　　During foggy weather, water vapor condensates suspended close to the ground often dissolve sulfur dioxide, nitrogen oxides, and surface-bound metals and organic compounds, especially PM2.5. Therefore, the PM10 forecast has certain reference value for outdoor exercisers.

　　Wang Yus said that air quality should also take many other factors into account. Currently, in addition to PM2.5, air quality monitoring also includes nitrogen dioxide, sulfur dioxide, and PM10. When the general air pollution index approaches 150, the air quality level is Grade III. For sensitive groups such as the elderly and children, health can be affected in such air. Once the air pollution index exceeds 150, the air quality falls into the poorer category of Grade III, and most people will feel uncomfortable. It is best for citizens to postpone or cancel outdoor workouts, as deep breathing during exercise will inhale more PM2.5.

　　It is understood that in 2012, key regions as well as municipalities and provincial capital cities will take the lead in conducting monitoring of PM2.5 and ozone, and by the end of 2016, the entire country will uniformly implement the new air quality standards and publish the monitoring results to the public.

　　The new air quality standards have added three monitoring indicators: PM2.5, ozone, and carbon monoxide, and the grading has been expanded to six levels: green, yellow, orange, red, purple, and brownish-red. Judging by color, when the air quality turns red or darker, the public should reduce outdoor exercise. When the air quality index is between 151 and 200, it is classified as red. If the index exceeds 150, it is not suitable for outdoor running.

　　While running, many people notice changes in their bodies but fail to take corresponding measures to prevent them. This may lead to increased fatigue, making running feel like a burden.

　　Liu Ying, deputy chief physician of the Respiratory Department at Beijing Tiantan Hospital, said that the body’s demand for oxygen increases significantly during running, as does the demand for lung capacity. The human lungs can hold approximately 50L–100L of gas, but only about 5L is needed in a resting state—the rest of the lung capacity is reserved for strenuous physical activity or sports.

　　However, nowadays, fewer people in cities engage in strenuous physical labor, and many lack the habit of regular exercise, leading to a decline in lung exhaust capacity. A reduced ability to expel air from the lungs leads to a significant decrease in the amount of gas exchanged with each breath. Without proper air exchange, the body cannot get enough oxygen, which causes chest tightness, labored breathing, and a sharp increase in fatigue during exercise.

　　Wang Liming, a sports medicine PhD and lecturer at the Beijing Sport University, said that running itself is an exercise to strengthen the body and improve lung function. But without paying attention to breathing, it’s hard to sustain running and achieve the desired training effect.

　　While running, the body’s oxygen demand increases with speed. To address this, one needs to increase both breathing frequency and depth. However, there is a limit to how fast you can breathe. For example, the maximum rate might reach 60 breaths per minute, averaging one breath (inhale and exhale) per second, which inevitably leads to shallow breathing, reduced air exchange, impaired oxygen intake, and increased carbon dioxide output, raising blood carbon dioxide concentration and lowering oxygen levels. Moreover, some parts of the respiratory tract, known as "dead space," allow airflow but don’t facilitate gas exchange in the lungs. Frequent rapid breathing circulates air within this dead space without allowing it to reach the lungs, thus providing no benefit in increasing oxygen intake.

　　While running, attention should be paid to breathing depth. Some people focus on inhaling deeply but often neglect exhaling deeply. In fact, during long runs, increasing exhalation depth is essential to fully meet the body’s oxygen needs. Greater exhalation depth helps expel more waste gases, increase negative pressure in the lungs, and make inhalation easier.

　　Wang Yus said that during hazy days, water vapor condensates near the ground often dissolve sulfur dioxide, nitrogen oxides, and surface-attached metals and organic compounds, especially PM2.5. The peak periods for PM2.5 concentration are generally fixed at two times: around 8–9 AM and 8 PM. The times when the concentration is relatively low are from 12 PM to 2 PM. If you want to go out for exercise, these two midday hours are most suitable. For those who work during the day and can’t exercise at noon, you could choose to go out later in the evening, for example, after 10 PM.

　　Wang Liming said that running, especially against the wind, increases the burden on the respiratory system. Windy days may also come with sand and dust, meaning the inhaled air contains dust and bacteria. These factors can cause coughing, digestive issues, or side stitches. Breathing through the nose can help reduce the inhalation of airborne dust, but windy-day running demands more oxygen. Therefore, it’s important to adjust your running pace accordingly—slowing down your speed is often more helpful than altering your breathing method. Moderately slowing your pace and adjusting your breathing, mainly through nasal inhalation, is key. When your breathing muscles feel fatigued, you can slightly open your mouth to assist breathing, letting air pass through your lips and teeth to maintain breathing depth. Using these methods will help you adjust your running rhythm even in windy conditions.

　　Around us, we often see runners equipped with various running gear, including windproof face masks. These masks are typically made of fleece material and come with ventilation holes. They cover the mouth and nose while leaving the eyes exposed. With such protection, many runners may pay less attention to the weather conditions.

　　Wang Yus said that fleece face masks can only block wind and sand and provide some warmth. Some studies have shown that even medical-grade multi-layer non-woven fabric masks cannot effectively filter certain inhalable particulate matter, so such face masks also fall short of the required standard.

　　There are some mask products on the market specifically developed for urban cycling enthusiasts, and some running enthusiasts have also introduced these products to the urban running scene, where they have become widely popular. These masks feature a detachable graphite filter mesh beneath a hard plastic outer shell.

　　Wang Yusī stated that graphite can absorb certain harmful gases in the air, such as carbon monoxide, sulfur dioxide, nitrogen oxides, and so on. The immediate sensation of wearing such a mask may be that unpleasant odors in the air are slightly reduced, and car exhaust fumes on the road may feel a bit less intense. In this regard, this protective measure does have some effect. However, there are also some issues—graphite’s filtration of the air is more sensory in nature, and the reduction of unpleasant smells may give the impression that the quality of inhaled air has improved. But there are still some suspended particles in the air that cannot be filtered. Additionally, attention should be paid to the quality of the mask and understanding the purchase channels. The quality of the graphite used, and whether the graphite production process strictly adheres to standards, are very important. If the graphite material is not specifically produced for industrial protection but instead uses other types of graphite, it may inherently contain many fine particles.

　　In addition, the graphite content is also an issue to consider. A mask that is too thin will not provide effective filtration, while one that is too thick may increase breathing resistance. Although some products incorporate exhalation valves, filtering the air that flows in through the valve is a rather difficult problem to solve, so consumers should not rely too heavily on these products.