夜雨聆风题目
This summer, wildfires have scorched tens of thousands of acres across western North America, with hazardous smoke spreading far beyond burn zones. Just as in 2021 and 2023, smoke from Canadian wildfires has drifted south, shrouding major US. cities in a thick, unhealthy haze. Health officials across the region advise people to stay indoors as much as possible when smoke is visible and detectable by smell.
Wildfire smoke contains a mixture of gases and tiny particles（微粒）, including ozone, carbon monoxide and particulate matter - pollutants linked to respiratory and cardiovascular illnesses, according to a study in the Journal of the American Heart Association. For healthy people, short-term exposure may cause eye stinging or coughing fits, but long-term repeated effects remain unclear. “People were once exposed once or twice in a lifetime,” says Keith Bein, an atmospheric scientist. “Now it’s happening every summer and for longer.” A 2023 Nature study found these wildfire trends have stalled and even reversed progress in improving US. air quality, and climate change will amplify the health threat as wildfires grow more frequent and intense.
In the US., air quality is measured by the Air Quality Index (AQI). Its scale measures the levels of five major pollutants. Of all the pollutants, PM2.5 raises the most concern. These particles can penetrate deep into the lungs. The body dispatches immune cells to attack them, but unlike viruses, the particles cannot be broken down, triggering long-lasting inflammation（炎症） that damages lungs, kidneys, liver and possibly the brain, explains environmental health scientist Sarah Henderson.
For people with COPD, this extra inflammation sharply worsens symptoms. Particles may even enter the bloodstream, causing systemic inflammation. Research also links wildfire smoke to cardiovascular risks. Elderly people, low-income communities and those with poor healthcare access are the most vulnerable groups.
Once made up mainly of natural plant materials, modern wildfire smoke also carries chemicals from burning synthetic goods in suburban homes. The CDC recommends staying indoors with air purifiers, and avoiding gas cooking and vacuuming that worsen indoor pollution. N95 respirators are advised for outdoor trips, as regular surgical masks offer little protection. Bein notes individual action has limits, and long-term policies are needed to address the climate-driven crisis.
(Adapted from National Geographic)
1. What can we learn from the 2023 Nature study?
A. Climate change is the direct cause of frequent wildfires.
B. Wildfires have become less intense thanks to air quality policies.
C. Wildfire trends have set back US. air quality improvement.
D. Health threats caused by wildfire smoke will be soon controlled.
2. Why does PM2.5 do great harm to human health?
A. It directly destroys the human immune system.
B. It cannot be cleared by the body’s immune reaction.
C. It is the root cause of asthma and COPD.
D. It mainly targets the brain and heart organs.
3. What can be inferred from the text?
A. The US. has kept improving its air quality steadily.
B. Wildfire smoke components are more complex nowadays.
C. Surgical masks work effectively against wildfire smoke.
D. Long-term wildfire smoke exposure causes permanent brain damage.
4. What is the text mainly intended to do?
A. Explain health impacts of wildfire smoke and protective tips.
B. Analyze the main causes of frequent wildfires in the US.
C. Introduce the function of the AQI system.
D. Put forward long-term solutions to wildfire problems.
答案
1.C
2.B
3.B
4.A
解析
1. 根据第二段"... and climate change will amplify the health threat as wildfires grow more frequent and intense."可知，
A：原文仅说明气候变化会加剧野火带来的健康威胁，并未指出气候变化是野火频发的直接原因，排除。
B：原文明确提到随着气候变暖，野火更频繁、火势更猛，而非强度降低，排除。
C：野火频发的趋势已经阻碍甚至逆转了美国空气质量的改善进程，选项中set back是原文stalled and reversed的同义替换，选项正确。
D：全文未提及野火烟雾带来的健康威胁将很快得到控制，排除。
2. 根据第三段“the body dispatches immune cells to attack them, but unlike viruses, the particles cannot be broken down”可知，
A：人体会主动调动免疫细胞攻击PM2.5，并非PM2.5直接破坏免疫系统，排除
B：PM2.5无法被人体的免疫反应分解清除，进而引发持续炎症造成损伤，这是其危害健康的核心机制，选项正确
C：根据"For people with COPD, this extra inflammation sharply worsens symptoms."可知，COPD是本身存在的基础疾病，PM2.5会加重其症状，并非致病根源；且原文未提及哮喘，排除。
D：根据"... triggering long-lasting inflammation that damages lungs, kidneys, liver and possibly the brain"可知，PM2.5引发的炎症会损害肺、肾、肝、大脑等多个器官，并非主要针对大脑和心脏，排除。
3.
A：第二段明确指出野火趋势让美国空气质量改善进程停滞甚至倒退，并非持续稳步提升，排除。
B：根据最后一段“Once made up mainly of natural plant materials, modern wildfire smoke also carries chemicals from burning synthetic goods in suburban homes”可推知，过去野火烟雾主要由天然植物燃烧产生，如今还包含城郊住宅中合成制品燃烧产生的化学物质，成分比过去更复杂，选项正确。
C：最后段提到“regular surgical masks offer little protection”，普通外科口罩对野火烟雾几乎没有防护作用，排除。
D：原文仅说明炎症“possibly the brain”（可能影响大脑），并未证实长期暴露会造成永久性脑损伤，排除。
4.
A：文章前半部分介绍了野火烟雾的成分、PM2.5的致病原理、对呼吸系统和心血管的危害以及易感人群，后半部分给出了疾控中心推荐的防护措施，全文核心是说明野火烟雾对健康的影响以及相关防护方法，选项正确。
B：文章仅提及气候变化会加剧野火，并未深入分析野火频发的主要原因，排除。
C：空气质量指数仅在第三段简要提及，并非全文核心内容，排除。
D：长期政策仅在文末作为补充观点简要提及，排除
主旨
本文以北美野火烟雾大范围扩散为背景，依次介绍了野火烟雾的污染物成分、PM2.5损伤人体的核心机制、对呼吸与心血管系统的健康危害及高危易感人群，同时给出了官方推荐的个人防护措施，最后点明个人防护作用有限，解决危机的根本在于长期的气候治理与政策干预。
译文
今年夏季，北美西部数万英亩土地遭野火焚毁，而有毒烟雾的扩散范围远远超出了火场区域。与2021年和2023年的情况一样，加拿大野火产生的烟雾向南飘散，让美国多座大城市笼罩在浓重有毒的烟雾中。当地卫生部门建议，只要能看见、闻到烟雾，民众就应尽量待在室内。
《美国心脏协会期刊》的一项研究显示，野火烟雾包含多种气体与微小颗粒物，其中包括臭氧、一氧化碳和可吸入颗粒物——这些污染物均与呼吸系统及心血管疾病相关。对于健康人群而言，短期暴露在烟雾中可能会出现眼睛刺痛、剧烈咳嗽等症状，但长期反复接触的影响目前尚无定论。大气科学家基思·拜因表示：“过去人们一生可能只会遭遇一两次这种情况，如今每年夏天都会出现，而且持续时间越来越长。”2023年发表在《自然》上的一项研究发现，野火频发的趋势已经阻滞甚至逆转了美国空气质量改善的进程；随着气候持续变暖，野火发生得更频繁、火势更大，烟雾带来的健康威胁也会进一步加剧。
美国采用空气质量指数（AQI）衡量空气质量，该指数通过分级标准监测五种主要污染物的浓度。在所有污染物中，细颗粒物（PM2.5）最受关注。这种超细颗粒能够深入肺部深处。环境健康科学家萨拉·亨德森解释道，人体会调动免疫细胞攻击这些颗粒，但与病毒不同，这些颗粒物无法被免疫细胞分解，进而引发持续性炎症，损害肺部、肾脏、肝脏，甚至可能影响大脑。
对于慢性阻塞性肺疾病（COPD）患者来说，这种额外的炎症会大幅加重病症。颗粒物甚至可能进入血液，引发全身炎症。研究还证实，野火烟雾会带来心血管疾病风险。老年人、低收入群体以及医疗资源匮乏的人群是受影响最大的高危群体。
以往野火烟雾主要由天然植物燃烧产生，而如今城郊住宅中的合成制品被引燃，还会向烟雾中释放多种化学物质。美国疾控中心建议：居家时使用空气净化器，避免燃气灶烹饪、吸尘等会加重室内污染的行为；如需外出，应佩戴N95防护口罩，普通外科口罩几乎起不到防护作用。拜因强调，个人防护的作用有限，要解决这场由气候变化驱动的危机，必须出台长期政策。
