「气溶胶」是什么？
据维基百科（Wikipedia），气溶胶（Aerosol），又称气溶胶、烟雾质，是指固体或液体微粒稳定地悬浮于气体介质中形成的分散体系，其中颗粒物质则被称作悬浮粒子，其粒径大小多在0.01-10微米之间，根据其生成原因可分为自然源及人为源两种。
Aerosols, explained
National Geographic
Tiny particles floating in the atmosphere have a much bigger impact on the planet than you might think, and human activity plays a role.
THE MOST VIBRANT sunsets, cloud-choked skies, and cough-inducing days all have something in common: They happen because of aerosols, tiny particles that float in the air. Aerosols can be tiny droplets, dust particles, bits of fine black carbon, and other things, and as they float through the atmosphere they change the whole energy balance of the planet.
aerosol
aerosol /ˈeərəsɒl/ 可以指“（喷油漆、头发定型剂等的）喷雾器，雾化器；气雾剂； 气溶胶”，英文解释为“a metal container in which a liquid such as paint or hairspray is kept under pressure and released as a spray”。
Aerosols have an outsized effect on the planet’s climate. Some of them, like black and brown carbon, warm the Earth’s atmosphere, while others, like sulfate droplets, cool it. Scientists think that on balance, the whole budget of aerosols ends up cooling the planet slightly. But exactly how much, and how much that effect can shift over days, years, or centuries is still not totally clear.
sulfate
sulphate的美式拼写，表示“硫酸盐；硫酸酯”，英文解释为“a chemical formed from sulphur, oxygen, and another element”。
What are aerosols?
The term aerosol is a catch-all for many kinds of little bits of stuff that end up suspended in the atmosphere, from the surface of the planet all the way to the edges of space. They can be solid or liquid, infinitesimally small or big enough to see with the naked eye.
catch-all
作名词，表示“笼统的一类（或描述）”，英文解释为“a group or description that includes different things and that does not state clearly what is included or not”；也可以作形容词，表示“宽泛的；包罗万象的；面面俱到的”，英文解释为：general and intended to include everything，举个🌰：
"South London" is a catch-all phrase/term for anywhere south of the river.
“伦敦南部”是个很宽泛的名称，适用于河以南的任何地方。
infinitesimally
infinitesimally /infini'tesiməli/ 表示“极小地”，英文解释为“to an extremely small degree”。
“Primary” aerosols, like dust, soot, or sea salt, come directly from the planet’s surface. They get lifted into the atmosphere by gusty winds, shot high into the air by exploding volcanoes, or they waft away from smokestacks or flames. “Secondary” aerosols form when different things floating in the atmosphere—like organic compounds released by plants, liquid acid droplets, or other materials—crash together, culminating in a chemical or physical reaction. Secondary aerosols, for example—make the haze that gives the U.S.’s Great Smoky Mountains their name.
organic compounds 有机化合物
soot
表示“煤烟；煤灰”，英文解释为“a black powder composed mainly of carbon, produced when coal, wood, etc. is burned”。
gusty wind
gusty wind表示“阵风，疾风”；gusty表示“一阵阵劲吹的，刮着阵风的”，英文解释为“with sudden, strong winds”，举个🌰：
The forecast was for gusty winds and rain.
天气预报说有阵风和降雨。
waft
表示“（使）（在空气中）飘荡”，英文解释为“to (cause to) move gently through the air”举个🌰：
A gentle breeze wafted the scent of roses in through the open window.
一阵微风将玫瑰的香味从敞开的窗子里送了进来。
culminate
表示“以…告终；达到…的顶点”，英文解释为“If an event or series of events culminates in something, it ends with it, having developed until it reaches this point.”举个🌰：
My arguments with the boss got worse and worse, and finally culminated in my resignation.
我和老板的争吵日益恶化，直到最终我决定换工作。
Aerosols come from both natural and human sources—and sometimes both at once. Dust, for example, is scoured from deserts, the dried-out edges of rivers, dry lakebeds, and more. Its concentrations in the atmosphere rise and fall with climate; in cold, dry, periods in the planet’s history like the last ice age, more dust filled the atmosphere than during warmer stretches of Earth’s history. But humans have affected that natural cycle, making some places dustier than they otherwise would be and keeping other areas damp.
scour
表示“冲刷成；冲刷出”，英文解释为“to make a passage, hole, or mark in the ground, rocks, etc. as the result of movement, especially over a long period”举个🌰：
The water had raced down the slope and scoured out the bed of a stream.
水顺着山坡流下来，冲刷出一条小河道。
damp
表示“潮湿的，潮乎乎的”，英文解释为“slightly wet, especially in a way that is not pleasant or comfortable”举个🌰：
The grass is still damp.
草还有些潮湿。
Sea salts provide another natural source of aerosols. They’re whipped out of the ocean by wind and sea spray and tend to fill the lower parts of the atmosphere. In contrast, some types of very explosive volcanic eruptions can shoot particles and droplets high into the upper atmosphere, where they can float for months or even years, suspended miles above Earth’s surface.
spray
表示“浪花；水花；飞沫”，英文解释为“a mass of very small drops of liquid carried in the air”举个🌰：
Can you feel the spray from the sea/waterfall?
你能感觉到海上的浪花/瀑布溅起的水雾吗？
Human activity produces many different types of aerosols. Fossil-fuel burning produces particles, as well as the well-known greenhouse gases like carbon dioxide—so cars, airplanes, power plants, and industrial processes all produce particles that can collect in the atmosphere. Agriculture produces dust, as well as other things like aerosolized nitrogen products, both of which affect air quality near and far.
Overall, humans have increased the total amount of particles floating around in the atmosphere, which is about twice as dusty now as it was in the 19th century. The amount of very fine material—generally referred to as “PM2.5”—particulate matter less than 2.5 microns across—has increased by something like 60 percent since before the Industrial Revolution. Other aerosols, like ozone, have also increased—with dramatic health impacts around the world.
Air pollution has been linked to increased risk of heart disease, stroke, lung disease, asthma, and more. By some recent estimates fine particles in the air contributed to over four million premature deaths globally in 2016, hitting children and the elderly the hardest. The health risks from fine-particle exposure are highest in China and India, particularly in urban areas.
asthma
asthma /ˈæsmə/ 表示“气喘，哮喘”，英文解释为“a medical condition that makes breathing difficult by causing the air passages to become narrow or blocked”，如：an asthma sufferer 哮喘病患者。
很好的一篇科普文，押个题，说不定不久的将来，高考/四六级/考研阅读...就出了。留个小作业，What are aerosols?请用一句话概括。
- END -