光化学烟雾的形成机制是什么？氮氧化物和挥发性有机物各自扮演什么角色？
What is the formation mechanism of photochemical smog, and what roles do NOₓ and VOCs play?
光化学烟雾是 NOₓ 与 VOCs 在强日照下发生系列自由基链反应生成的二次污染。NO₂ 光解产生氧原子启动反应，VOCs 经 OH 自由基氧化生成过氧自由基，后者把 NO 氧化回 NO₂ 并生成臭氧与过氧乙酰硝酸酯（PAN）等氧化剂。其严重程度取决于 NOₓ/VOC 比值与光照强度，是城市夏季臭氧污染的核心。
Photochemical smog is secondary pollution formed when NOₓ and VOCs undergo radical-chain reactions under intense sunlight. NO₂ photolysis yields oxygen atoms that initiate the chain; VOCs oxidized by OH radicals form peroxy radicals that convert NO back to NO₂ while generating ozone and oxidants like peroxyacetyl nitrate (PAN). Severity depends on the NOₓ/VOC ratio and sunlight intensity and underlies summer urban ozone pollution.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 2 条独立证据
来源 · Source
《环境化学》(戴树桂, 第二版) 大气光化学章；Environmental Science & Technology (ACS)
Environmental Science & Technology (ACS), atmospheric photochemistry; Nature Geoscience
独立核验依据 · Independent verification: 核验依据 2 ISBN 9787040199567（豆瓣书目条目: 环境化学）；本条出处含多部著作，此标识只担保上面点名的这部
#光化学烟雾 #氮氧化物 #VOC #臭氧
光化学烟雾是怎样形成的？为什么汽车多的城市在晴热天容易中招？
How does photochemical smog form, and why do car-heavy cities suffer it on sunny, hot days?
光化学烟雾的核心机制是：汽车尾气中的氮氧化物（NOx）和挥发性有机物（VOC）在强紫外光照射下发生一系列自由基链式反应。二氧化氮吸收阳光光解生成一氧化氮和活性极高的氧原子，氧原子与氧气结合成臭氧；挥发性有机物氧化产生过氧自由基，进一步把一氧化氮氧化回二氧化氮，并生成 PAN（过氧乙酰硝酸酯）、醛类等二次污染物。这些物质聚集形成淡蓝色的刺眼烟雾，因此形成需要污染源、强光照和高温三个条件，夏季晴热的机动车密集城市最容易发生。
The core mechanism is a free-radical chain driven by strong ultraviolet light. Nitrogen oxides (NOx) and volatile organic compounds (VOCs) from traffic react in a series: nitrogen dioxide photolyzes under sunlight into nitric oxide and a highly reactive oxygen atom, which combines with O2 to form ozone; VOCs oxidize into peroxy radicals that recycle NO back to NO2 and generate secondary pollutants such as PAN (peroxyacetyl nitrate) and aldehydes. The accumulating mixture forms the irritating, hazy-blue smog. Formation needs three ingredients - precursor emissions, intense sunlight and high temperature - which is why sunny, hot cities with heavy traffic suffer most.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#光化学烟雾 #氮氧化物 #臭氧
二氧化碳为什么能吸收红外辐射，成为主要的温室气体之一？
Why can carbon dioxide absorb infrared radiation and rank among the main greenhouse gases?
温室气体的本质是分子振动能级与红外光子能量匹配，能吸收红外辐射。二氧化碳是直线型分子，它的不对称伸缩振动和弯曲振动会改变分子偶极矩，从而与红外光子强烈耦合，产生特征吸收带，其中最强者在约15微米。地球表面发出的热红外辐射峰值约在10微米，但覆盖很宽的波长区间，相当一部分落在二氧化碳的强吸收带上；被吸收后能量再向四面八方再辐射，一部分返回地面，形成保温效应。氮气和氧气是非极性双原子分子，振动不改变偶极矩，对红外辐射基本透明，这正是二氧化碳、水蒸气和甲烷等微量气体能主导温室效应的原因。
A greenhouse gas works because its molecular vibration levels match the photon energies of infrared light, so it can absorb IR. Carbon dioxide is a linear molecule whose asymmetric stretch and bending vibrations change the dipole moment, coupling strongly to IR photons in characteristic bands, the strongest near 15 μm. Thermal IR emitted by the Earth's surface peaks around 10 μm but spans a wide range, and a substantial share falls in CO2's strong absorption; the absorbed energy is re-emitted in all directions, and part returns to the ground, trapping heat. Nitrogen and oxygen are nonpolar diatomic molecules whose vibrations do not change the dipole moment, so they are nearly transparent to IR - which is why trace gases like CO2, water vapour and CH4 dominate the greenhouse effect.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#温室效应 #红外吸收 #二氧化碳
什么是原子经济性？为什么它在绿色化学中很重要？
What is atom economy, and why does it matter in green chemistry?
原子经济性是化学家特罗斯特提出的概念，指目标产物中的原子质量占全部反应物原子质量的百分比。百分百的原子经济意味着所有原料原子都进入产物、几乎无废物。绿色化学因此优先设计加成、重排等原子经济的反应，减少副产物和污染。
Atom economy, introduced by chemist Barry Trost, is the fraction of reactant atoms that end up in the desired product. One hundred percent atom economy means every starting atom enters the product with essentially no waste. Green chemistry therefore favors atom-economical processes such as addition and rearrangement, cutting byproducts and pollution.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#原子经济性 #绿色化学 #合成设计
绿色化学的十二条原则是怎么来的？核心思想是什么？
Where do the twelve principles of green chemistry come from, and what is their core idea?
绿色化学十二原则由Anastas和Warner于1998年提出并系统阐述，美国化学会绿色化学研究所（GCI）长期推广这一框架。核心思想是从源头设计无毒、高效、原子经济的化学过程，而不是等废物产生后再处理。重点包括防止废物优于治理废物、设计更安全的化学品、使用可再生原料、提高原子经济性和催化效率。
The twelve principles of green chemistry were formulated by Paul Anastas and John Warner in 1998, and the ACS Green Chemistry Institute has long promoted the framework. Their core idea is to design non-toxic, efficient, atom-economical chemical processes at the source rather than treating waste after it forms. Highlights include preventing waste rather than cleaning it up, designing safer chemicals, using renewable feedstocks, and maximizing atom economy and catalysis.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#绿色化学 #原子经济 #ACS
酸雨是如何形成的？它对环境造成哪些危害？
How does acid rain form, and what harm does it cause to the environment?
化石燃料燃烧排放的二氧化硫（SO₂）与氮氧化物（NOₓ）在大气中氧化为硫酸与硝酸，随降水落到地面形成酸雨（pH 常低于 5.6）。它酸化湖泊土壤、释放铝等有毒金属、腐蚀建筑石材，并损害森林与水生生物。
Sulfur dioxide (SO₂) and nitrogen oxides (NOₓ) from fossil-fuel combustion are oxidized in the atmosphere to sulfuric and nitric acids, which fall with precipitation as acid rain (often pH below 5.6). It acidifies lakes and soils, mobilizes toxic metals like aluminum, corrodes building stone, and harms forests and aquatic life.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#酸雨 #二氧化硫 #氮氧化物 #酸化
光化学烟雾是怎么产生的？
How does photochemical smog form?
在强日照下，汽车尾气中的氮氧化物和挥发性有机物（VOCs）发生一系列光化学反应，生成臭氧、过氧乙酰硝酸酯（PAN）等二次污染物。它常见于夏季拥挤城市，刺激眼睛和呼吸道。治理依赖减少 NOₓ 与 VOC 排放。
Under strong sunlight, nitrogen oxides and volatile organic compounds (VOCs) from vehicle exhaust undergo photochemical reactions that form secondary pollutants like ozone and peroxyacetyl nitrate (PAN). Common in crowded summer cities, it irritates eyes and airways. Control relies on cutting NOₓ and VOC emissions.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#光化学烟雾 #氮氧化物 #挥发性有机物
二氧化碳等温室气体为什么会使地球变暖？
Why do greenhouse gases such as CO₂ warm the Earth?
温室气体（CO₂、CH₄、N₂O 等）允许太阳短波辐射透过到达地面，却强烈吸收地表向外发射的长波红外辐射。被吸收的能量以大气再辐射形式返回地表，减少热量逸散，形成类似温室的增温效应。工业化以来大气 CO₂ 浓度从约 280 ppm 升至 420 ppm 以上，是近代全球变暖的主因。
Greenhouse gases such as CO₂, CH₄, and N₂O let shortwave solar radiation reach the surface but strongly absorb the longwave infrared radiation Earth emits back. The absorbed energy is re-radiated by the atmosphere toward the surface, reducing heat loss and producing a warming effect like a greenhouse. Atmospheric CO₂ has risen from about 280 ppm to over 420 ppm since industrialization, driving recent global warming.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#温室气体 #温室效应 #红外吸收 #全球变暖
水的硬度由什么造成？暂时硬度与永久硬度有何区别？
What causes water hardness, and how do temporary and permanent hardness differ?
水的硬度主要来自钙、镁离子，由岩石风化或溶入地下水造成。暂时硬度由碳酸氢钙/镁引起，煮沸可沉淀除去；永久硬度由硫酸盐、氯化物等引起，煮沸不去除，需用离子交换或软化法。硬水易在锅炉和管道结垢。
Hardness mainly comes from calcium and magnesium ions leached from rocks into groundwater. Temporary hardness from calcium/magnesium bicarbonates is removed by boiling; permanent hardness from sulfates or chlorides is not and needs ion exchange or softening. Hard water scales boilers and pipes.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#水硬度 #钙离子 #暂时硬度
土壤被重金属污染后为什么特别难治理？
Why is soil contaminated by heavy metals especially hard to remediate?
重金属不能像有机污染物那样被微生物降解消失，它只能从一种形态转化为另一种形态或迁移位置，总量基本不变；而土壤对重金属又有很强的吸附固定能力，污染物被锁在颗粒表面和有机质里。加上土壤污染常常是几十年的历史积累，分布不均、浓度又高，修复只能靠客土替换、植物萃取或化学淋洗等成本高昂的手段。最有效的做法仍是源头控制，避免重金属进入土壤。
Heavy metals cannot be biodegraded away like organic pollutants - they can only change chemical form or move somewhere else, with the total amount basically constant. Soil also adsorbs and immobilizes heavy metals strongly, locking them onto particle surfaces and organic matter. Combined with decades of uneven, high-concentration accumulation, cleanup has to resort to expensive methods such as soil replacement, phytoremediation (plant uptake) or chemical washing. The most effective strategy is still preventing metals from entering the soil in the first place.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#土壤污染 #重金属 #修复
氟氯烃（CFC）为什么会破坏臭氧层？
Why do CFCs deplete the ozone layer?
CFC 在平流层中受紫外线光解，释放出的氯原子作为催化剂反复破坏臭氧（O₃）分子，一个氯原子可摧毁上万个臭氧分子。这造成南极上空臭氧空洞。1987 年《蒙特利尔议定书》逐步淘汰 CFC 后，臭氧层已开始缓慢恢复。
In the stratosphere, UV light photolyzes CFCs, releasing chlorine atoms that catalytically destroy ozone (O₃)—a single chlorine can ruin tens of thousands of ozone molecules. This caused the Antarctic ozone hole. After the 1987 Montreal Protocol phased out CFCs, the ozone layer has slowly begun recovering.
难度 进阶 · 适合 小学高段(9-12)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#氟氯烃 #臭氧空洞 #蒙特利尔议定书
微塑料为什么会成为环境污染物？它们的主要来源有哪些？
Why have microplastics become an environmental pollutant, and what are their main sources?
微塑料指粒径小于 5 mm 的塑料碎屑，因难降解、比表面积大而长期残留并吸附持久性污染物。主要来源包括大塑料的紫外与机械老化破碎、合成纤维洗涤脱落、个人护理品中的塑料微珠以及轮胎磨损颗粒。它们已在海洋、土壤甚至人体中被检出。
Microplastics are plastic fragments smaller than 5 mm that persist because they resist degradation and, with high surface area, adsorb persistent pollutants. Main sources are the weathering and fragmentation of larger plastics, shedding of synthetic fibers in washing, plastic microbeads in personal care products, and tire-wear particles. They have been found in oceans, soils, and even the human body.
难度 进阶 · 适合 大众
CC BY 4.0 · 来源待核验 · Source pending review
来源 · Source
出处备注：此条未指向带版次的可引用著作（通识性内容、机构文件或未展开的英文书名），本库不提供独立书目出处；如需精确引用，需由编辑补全具体篇目与版次。
中国科学院生态环境研究中心；Environmental Science & Technology (ACS) 微塑料专刊
Environmental Science & Technology (ACS), microplastics special issues; Nature Sustainability
#微塑料 #持久性 #塑料污染 #环境残留
含氯氟烃（CFC）是如何破坏臭氧层的？
How do chlorofluorocarbons (CFCs) destroy the ozone layer?
CFC 在对流层稳定，上升至平流层后在紫外照射下释放氯原子。单个氯原子通过催化循环（Cl + O₃ → ClO + O₂，ClO + O → Cl + O₂）反复破坏臭氧分子，自身不被消耗，因而效率极高。一个氯原子可破坏数以万计的臭氧分子，这就是蒙特利尔议定书管控 CFC 的原因。
CFCs are stable in the troposphere but release chlorine atoms in the stratosphere under UV light. A single chlorine atom catalytically destroys ozone through the cycle Cl + O₃ → ClO + O₂ and ClO + O → Cl + O₂, regenerating itself and thus acting with very high efficiency. One chlorine atom can destroy tens of thousands of ozone molecules, which is why the Montreal Protocol controls CFCs.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-11-03
来源 · Source
《环境化学》(戴树桂, 第二版) 大气环境章；世界气象组织(WMO)臭氧评估报告
WMO Ozone Assessment reports; Nature, ozone depletion mechanism
独立核验依据 · Independent verification: 核验依据 1 ISBN 9787040199567（豆瓣书目条目: 环境化学）；本条出处含多部著作，此标识只担保上面点名的这部
#CFC #臭氧层 #氯原子 #蒙特利尔议定书
臭氧层为什么能阻挡紫外线？
Why can the ozone layer block ultraviolet light?
平流层的臭氧在 200–320 nm 波段强烈吸收紫外线，把高能光子转化为热，保护了地表生命。查普曼 1930 年提出臭氧生成与破坏的循环（Chapman cycle），NASA 持续监测其变化。
Stratospheric ozone strongly absorbs ultraviolet light in the 200-320 nm band, converting energetic photons into heat and shielding life below. Chapman proposed the formation-destruction cycle in 1930, and NASA keeps monitoring it.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#臭氧层 #紫外吸收 #查普曼循环
酸雨为什么能腐蚀大理石雕像和古建筑？
Why does acid rain eat away marble statues and historic buildings?
煤和石油燃烧排放的二氧化硫和氮氧化物在大气中氧化并溶于水滴，生成硫酸和硝酸，使雨水 pH 降到5.6以下形成酸雨。大理石的主要成分是碳酸钙（CaCO3），它是弱酸盐，遇到酸会发生反应：CaCO3+2H+ 生成 Ca2+、H2O 和 CO2，变成可溶的钙盐被雨水冲走。日积月累，雕像的线条、铭文和细节被溶解，建筑结构受损，所以酸雨被称为建筑的无形杀手。
Sulfur dioxide and nitrogen oxides from burning coal and oil are oxidized in the atmosphere and dissolve in raindrops to form sulfuric and nitric acid, pushing rain pH below 5.6. Marble is mostly calcium carbonate (CaCO3), a salt of a weak acid, so it reacts with the acid: CaCO3 + 2H⁺ → Ca²⁺ + H2O + CO2, dissolving into soluble calcium salts that rain washes away. Over time the fine lines, inscriptions and details of statues are melted off and structures weaken - which is why acid rain is called the invisible destroyer of architecture.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#酸雨 #碳酸钙 #腐蚀
重金属污染为什么危害大？以铅为例。
Why is heavy-metal pollution so harmful? Take lead as an example.
重金属（如铅、汞、镉）在环境中难降解、易在生物体内富集，并能与蛋白质、酶中的巯基等结合使之中毒。铅会损害儿童神经系统和智力发育，因此汽油和涂料中的铅已被严格限制。源头减排与修复是关键。
Heavy metals like lead, mercury, and cadmium resist degradation, bioaccumulate, and bind to sulfhydryl groups in proteins and enzymes, causing toxicity. Lead damages children's nervous systems and cognitive development, so lead in gasoline and paint is tightly restricted. Source reduction and remediation are key.
难度 进阶 · 适合 小学高段(9-12)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#重金属 #铅中毒 #生物富集
为什么湖泊里氮磷过多就会爆发藻类水华？
Why do too much nitrogen and phosphorus in a lake trigger explosive algal blooms?
藻类生长需要氮、磷等营养元素，而自然水体中磷往往是最稀缺的限制因子。生活污水、化肥流失和养殖废水把大量氮磷排进湖泊，磷不再稀缺，藻类就疯狂增殖，形成水华。藻类大量死亡后被细菌分解，耗尽水中溶解氧，鱼虾因缺氧窒息死亡，有些蓝藻还会释放毒素。因此治理水华的关键不是捞藻，而是切断外源氮磷输入、控制富营养化。
Algae need nutrients such as nitrogen and phosphorus, and in natural waters phosphorus is usually the scarcest limiting factor. Sewage, fertilizer runoff and aquaculture waste pour nitrogen and phosphorus into lakes, phosphorus stops being limiting, and algae explode into blooms. When the algae die, bacteria decomposing them consume dissolved oxygen, suffocating fish and shrimp, and some cyanobacteria even release toxins. That is why bloom control is not about skimming algae but about cutting off the external nitrogen and phosphorus loading that drives eutrophication.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#富营养化 #水华 #磷
臭氧为什么在天上的平流层保护我们，在地面却危害健康？
Why does ozone protect us in the stratosphere yet harm health at ground level?
平流层中的臭氧层（距地面约20到30公里）能强烈吸收太阳紫外线中的 UV-B，把它转变成热能，挡住对 DNA 有杀伤力的高能辐射，是地球的防晒伞。一旦臭氧被氯氟烃等物质消耗变薄，到达地面的紫外线增多，皮肤癌和白内障风险就会上升。而地面附近的臭氧却是光化学烟雾的成分，是强氧化剂，会刺激眼睛和呼吸道、损伤植物。同一种分子，在高层是保护伞，在近地面是污染物，关键看它所处的高度。
The ozone layer in the stratosphere, roughly 20-30 km up, absorbs most UV-B radiation from the sun, converting it to heat and blocking the high-energy rays that damage DNA - the planet's sunscreen. When ozone is depleted by chlorofluorocarbons, more ultraviolet reaches the ground and the risks of skin cancer and cataracts rise. Near the ground, however, ozone is a component of photochemical smog: a powerful oxidant that irritates the eyes and airways and damages plants. The same molecule is a shield high above and a pollutant at the surface - altitude decides its role.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#臭氧层 #紫外线 #氯氟烃
土壤中的重金属污染有哪些常见来源？为什么难以治理？
What are common sources of heavy-metal contamination in soil, and why is it hard to remediate?
土壤重金属（如镉、铅、砷）主要来自采矿冶炼、工业废水废渣、含重金属农药与大气沉降。它们大多不降解、易在表层累积并通过食物链放大，且常以多种化学形态存在，迁移转化复杂。因此修复常需钝化、植物提取或淋洗等长期工程手段。
Soil heavy metals such as cadmium, lead, and arsenic mainly come from mining and smelting, industrial wastewater and slag, metal-containing pesticides, and atmospheric deposition. They do not degrade, accumulate in surface layers, and biomagnify through food chains, often existing in multiple chemical forms with complex mobility. Remediation therefore needs long-term measures like immobilization, phytoextraction, or leaching.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#重金属 #土壤污染 #镉 #食物链
燃煤烟气里的二氧化硫是怎样一步步变成酸雨中的硫酸的？
How does the sulfur dioxide released by coal burning end up as sulfuric acid in acid rain?
关键一步是被氧化为三氧化硫或硫酸盐。燃煤排放的二氧化硫升入大气后，在晴天主要被羟基自由基逐步氧化；溶入云雾滴后，则在痕量铁、锰离子催化下被溶解氧更高效地氧化成硫酸盐，过氧化氢等也参与氧化。产物与水结合即得硫酸，使雨水酸度跌破约5.6的正常下限，形成酸雨。氮氧化物走类似路径生成硝酸，同样助长雨水变酸。
The decisive change is oxidation of sulfur dioxide to sulfate. In dry air, SO2 is converted mainly through attack by hydroxyl radicals, but once it dissolves into cloud or fog droplets it is oxidized far more efficiently by dissolved oxygen, with traces of iron and manganese acting as catalysts and hydrogen peroxide lending extra oxidizing power. The sulfate then combines with water to yield sulfuric acid, pushing rainfall below the natural acidity limit near pH 5.6. Nitrogen oxides follow an analogous route to nitric acid and deepen the problem.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-11-04
来源 · Source
Likens 与 Bormann,《Acid Rain: A Serious Regional Environmental Problem》,Science,1974 (DOI: 10.1126/science.184.4142.1176)
Likens & Bormann, 'Acid Rain: A Serious Regional Environmental Problem', Science, 1974, DOI: 10.1126/science.184.4142.1176
独立核验依据 · Independent verification: 核验依据 1 Crossref DOI 10.1126/science.184.4142.1176
#酸雨 #二氧化硫 #催化氧化
大气气溶胶是什么？它对气候和人体健康有什么影响？
What are atmospheric aerosols, and how do they affect climate and human health?
大气气溶胶是悬浮于空气中的固体或液体微粒（如硫酸盐、黑碳、矿物尘），粒径多在 0.01–10 μm。它们通过散射和吸收太阳辐射产生冷却或加热的辐射强迫，并作为云凝结核改变云特性；细颗粒物（PM2.5）可深入肺部引发呼吸与心血管疾病。
Atmospheric aerosols are solid or liquid particles suspended in air—such as sulfates, black carbon, and mineral dust—mostly 0.01–10 μm in size. They exert radiative forcing by scattering and absorbing sunlight and act as cloud condensation nuclei that alter clouds; fine PM2.5 penetrates deep into lungs and drives respiratory and cardiovascular disease.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#气溶胶 #PM2.5 #辐射强迫 #云凝结核
氯氟烃（CFC）是怎样破坏平流层臭氧层的？这一发现有何历史意义？
How do chlorofluorocarbons (CFCs) destroy stratospheric ozone, and what is the historical significance of this discovery?
CFC在平流层被紫外线光解释放出活泼的氯原子，氯原子催化地使臭氧（O3）分解为氧气（O2），且自身不被消耗、可反复破坏大量臭氧分子。1974年马里奥·莫利纳和舍伍德·罗兰提出这一机理，推动了《蒙特利尔议定书》禁限CFC，二人获1995年诺贝尔化学奖。
In the stratosphere, UV light photolyzes CFCs to release reactive chlorine atoms, which catalytically convert ozone (O3) into oxygen (O2) without being consumed, so one chlorine atom destroys many ozone molecules. Mario Molina and Sherwood Rowland proposed this mechanism in 1974, leading to the Montreal Protocol phasing out CFCs; they received the 1995 Nobel Prize in Chemistry.
难度 进阶 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#氯氟烃 #臭氧层 #光解 #催化 #蒙特利尔议定书
温室效应是怎么回事？哪些气体被称为“温室气体”？
How does the greenhouse effect work, and which gases are called 'greenhouse gases'?
太阳辐射透过大气加热地面，地面再以红外长波辐射散热，而二氧化碳、甲烷、水蒸气等气体能吸收并重新辐射这部分热量，使地表比没有大气时更温暖，这就是温室效应。主要的温室气体包括二氧化碳（CO2）、甲烷（CH4）、氧化亚氮（N2O）和水蒸气，其中人为增加的CO2最受关注。
Solar radiation passes through the atmosphere and warms the ground, which then emits infrared long-wave radiation; gases such as carbon dioxide, methane, and water vapor absorb and re-radiate this heat, keeping the surface warmer than it would be without an atmosphere—this is the greenhouse effect. The main greenhouse gases are carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and water vapor, with human-added CO2 of greatest concern.
难度 入门 · 适合 小学低段(6-8)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#温室效应 #温室气体 #二氧化碳 #甲烷 #红外辐射
酸雨是怎么形成的？它对环境和建筑有什么危害？
How does acid rain form, and what harm does it do to the environment and buildings?
酸雨主要源于煤和石油燃烧排放的二氧化硫（SO2）与氮氧化物（NOx），它们在大气中氧化并溶于水，形成硫酸和硝酸使雨水pH降低（常低于5.6）。酸雨会酸化湖泊土壤、伤害植物，并腐蚀大理石、石灰岩等含碳酸钙的建筑与雕像。
Acid rain mainly arises from sulfur dioxide (SO2) and nitrogen oxides (NOx) emitted by burning coal and oil; these oxidize in the atmosphere and dissolve in water to form sulfuric and nitric acids, lowering rainwater pH (often below 5.6). It acidifies lakes and soils, harms plants, and corrodes buildings and statues made of carbonate rocks such as marble and limestone.
难度 入门 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#酸雨 #二氧化硫 #氮氧化物 #pH #酸化
二氧化碳只占大气的万分之四左右，为什么却能左右整个地球的气温？
Carbon dioxide makes up only about four hundredths of a percent of the air — how can such a trace gas steer the temperature of the whole planet?
因为它能拦住地球散出的红外线。地表受热后以长波红外向外辐射，峰值在10微米附近；氮气和氧气是对称双原子分子，振动不产生偶极矩变化，对这些波长毫无反应。CO2的不对称伸缩与弯曲振动却伴随偶极矩变化，恰好强烈吸收15微米一带的红外光，而这正处地球长波辐射的主波段；吸收的能量又朝四面八方再辐射，一部分折回地面。含量虽少，吸收带位置却极关键，微量增长即可抬高全球辐射平衡温度。
Because it intercepts the infrared radiation Earth sends back out. Heated ground radiates longwave energy peaking near 10 micrometers; nitrogen and oxygen, symmetric diatomic molecules whose vibrations involve no dipole change, ignore those wavelengths completely. CO2 behaves differently: its asymmetric-stretch and bending vibrations change its dipole moment, so it absorbs strongly around 15 micrometers, squarely inside the main longwave band, then re-emits the energy in all directions, some returning to the surface. Tiny concentration, yet the band position is decisive — even small increases raise the planetary radiative equilibrium temperature.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-11-04
来源 · Source
S. Arrhenius,《XXXI. On the influence of carbonic acid in the air upon the temperature of the ground》,Philosophical Magazine 41, 237-276,1896 (DOI: 10.1080/14786449608620846)
S. Arrhenius, 'XXXI. On the influence of carbonic acid in the air upon the temperature of the ground', Philosophical Magazine 41, 237-276, 1896, DOI: 10.1080/14786449608620846
独立核验依据 · Independent verification: 核验依据 1 Crossref DOI 10.1080/14786449608620846
#温室效应 #二氧化碳 #红外吸收