人睡着的时候，呼吸得慢，吸气的 phase 特别长。每次吸进的空气，都比醒着的时候每次吸进的空气多。平常，我们从鼻孔到肺泡之间
的呼吸道 (dead space) 里的空气是潮湿的。平常，吸进来的干空气有 dead space 里足够的湿气调节，不至于让鼻窦的粘膜干燥掉
在秋、冬季天气干冷的时候，屋子里开了暖气，相对湿度就更低了。这时候睡觉，吸气的 phase 长，吸进来的特别多,特别干燥的空气
将来等著得 silicosis, granuloma, emphysema, 和其它的毛病吧。有婴儿或者老人的家庭要特别注意这个资料。
Things We Should Know
1. Humidity is very important.
The space between nostrils and the deepest trachea in the respiratory system is called “dead space”. Oxygen and
carbon dioxide exchange does not take place in dead space. Normally, the humidity in the dead space is quite high so
the mucosa in the nasal sinus and other parts of the upper airway will not dry up. A dried up mucosa will crack. Virus
and bacteria can easily invade our system through the cracked mucosa.
When we are asleep, the central inspiratory activity (CIA) in the pons becomes less. Hence, the inspiratory phase of
breathing prolongs, and more air is inhaled in each breath. If the humidity in the air is too low, then, there will
not be enough humidity between the nostrils and the nasal sinus to boost the humidity of the inhaled air. When this
situation prolongs, the sinus mucosa might crack. Pathogens such as virus and bacteria can enter our system through
the damaged mucosa to cause people sick. Usually the air humidity is low in the fall and winter. In these seasons,
when the room is heated, the relative humidity of the air becomes even lower. People get sick more easily. Infants
and children are particularly vulnerable to dry air during sleeping because the distance between their nostrils and
nasal sinus is very short.
2. How to increase the humidity in your room.
a. Do not use an aerosol humidifier.
By agitating water, an aerosol humidifier promotes the growth of aerobic slimy fungus. (If you have an aerosol
humidifier, touch the inside of the tank to proof it to yourself.) The slimy fungus will be included in the misty
aerosol in the air. It will be inhaled by everybody in the room. Nothing good can come out of it.
After the liquid aerosol is dried up, the minerals dissolved in the water turn into micro solid particulates. Solid
particulate aerosols of this size can easily reach the deepest alveoli and never come out. Emphysema, granuloma, and
silicosis are known diseases caused by the exposure of micro solid aerosols.
b. Hang wet laundry or towels in the room, put a big pot of water on the stove, keep an electric kettle in the
bedroom, , , , , can increase the humidity of your room without harming the health of your family, especially the new
3. Why to wear a facial mask?
I fold a piece of paper towel twice (The Bounce Brand), dip it into the warm water, squeeze off the excessive water,
put it inside a facial mask and wear the mask whenever I have a cold, a flu, or need to make sure my nasal sinus won’
t dry up due to the dry air.
The heat and humidity in the air I exhale will be trapped in my facial mask. The cold and dry air I inhale will be
warmed up and humidified by this mask. Thus, my nasal sinus and trachea will not dry up and crack. Furthermore, the
sensory nerve terminals in the upper airway will not be irritated by the cold and dry air to cause the discharge of
histamine, which leads to the secretion of mucus in the upper airway. The irritated upper airway sensory nerve
terminals also can cause coughing and sneezing. Coughing and sneezing further damage the mucosa of larynx and nasal
sinus. Nerve terminals in the damaged mucosa become more sensitive and aggravate coughing and sneezing. To wear a
facial mask my way can break up the pernicious cycle and give the damaged mucosa a chance to heal.
A facial mask not only blocks the liquid aerosol produced by sick people’s coughing, but also keep your upper airway
intact to ensure your health. Usually the air in the fuselage of an airplane is quite dry. Whenever I want to sleep
during a long flight, I wear my mask.
大土佬儿于 02/02/2010 写于纽约阿帕拉契山内