{"id":87347,"date":"2025-06-01T06:41:24","date_gmt":"2025-06-01T06:41:24","guid":{"rendered":"https:\/\/exam.pscnotes.com\/mcq\/?p=87347"},"modified":"2025-06-01T06:41:24","modified_gmt":"2025-06-01T06:41:24","slug":"one-of-the-main-causes-of-air-pollution-in-cities-is-emissions-from-ve","status":"publish","type":"post","link":"https:\/\/exam.pscnotes.com\/mcq\/one-of-the-main-causes-of-air-pollution-in-cities-is-emissions-from-ve\/","title":{"rendered":"One of the main causes of air pollution in cities is emissions from ve"},"content":{"rendered":"<p>One of the main causes of air pollution in cities is emissions from vehicles like cars and trucks. Cars emit various pollutants which are bad for human health when inhaled, like<\/p>\n<ul>\n<li>1. Nitrogen oxides (NO<sub>x<\/sub>)<\/li>\n<li>2. Carbon monoxide (CO)<\/li>\n<li>3. Carbon dioxide (CO<sub>2<\/sub>)<\/li>\n<li>4. Benzene<\/li>\n<\/ul>\n<p>Which of the above pollutants are <i>not<\/i> tolerated by human beings even at very low levels ?<\/p>\n<p>[amp_mcq option1=&#8221;1 and 4 only&#8221; option2=&#8221;1 and 2 only&#8221; option3=&#8221;1, 2 and 3 only&#8221; option4=&#8221;1, 2 and 4 only&#8221; correct=&#8221;option4&#8243;]<\/p>\n<div class=\"psc-box-pyq-exam-year-detail\">\n<div class=\"pyq-exam\">\n<div class=\"psc-heading\">This question was previously asked in<\/div>\n<div class=\"psc-title line-ellipsis\">UPSC NDA-1 &#8211; 2016<\/div>\n<\/div>\n<div class=\"pyq-exam-psc-buttons\"><a href=\"\/pyq\/pyq-upsc-nda-1-2016.pdf\" target=\"_blank\" class=\"psc-pdf-button\" rel=\"noopener\">Download PDF<\/a><a href=\"\/pyq-upsc-nda-1-2016\" target=\"_blank\" class=\"psc-attempt-button\" rel=\"noopener\">Attempt Online<\/a><\/div>\n<\/div>\n<section id=\"pyq-correct-answer\">The question asks which pollutants are *not* tolerated by human beings *even at very low levels*. This typically refers to substances with high toxicity or carcinogenicity at trace concentrations.<br \/>\n1. Nitrogen oxides (NOx): Respiratory irritants, contribute to smog. Can cause respiratory problems at relatively low concentrations.<br \/>\n2. Carbon monoxide (CO): Highly toxic gas. Binds to haemoglobin more strongly than oxygen, impairing oxygen transport. Even low levels in inhaled air can be dangerous, especially over time.<br \/>\n3. Carbon dioxide (CO\u2082): A greenhouse gas and a natural component of air (around 400 ppm). It is not toxic at these ambient levels. High concentrations (e.g., > 5000 ppm or more) can cause adverse health effects or suffocation, but it is tolerated at &#8220;very low levels&#8221; (ambient levels).<br \/>\n4. Benzene: A volatile organic compound and a known human carcinogen. Exposure to benzene, even at very low concentrations over time, is linked to increased risk of cancer (e.g., leukemia).<br \/>\nConsidering the criteria &#8220;not tolerated even at very low levels&#8221;, CO and Benzene are clear candidates due to their high toxicity\/carcinogenicity at low exposures. NOx are also significant respiratory hazards at lower concentrations than CO\u2082. CO\u2082 is relatively non-toxic at typical atmospheric concentrations. Thus, NOx, CO, and Benzene fit the description better than CO\u2082.<\/section>\n<section id=\"pyq-key-points\">Certain pollutants like carbon monoxide (CO), benzene, and nitrogen oxides (NOx) pose health risks even at low exposure levels due to their toxicity, carcinogenicity, or irritant properties, whereas carbon dioxide (CO\u2082) is harmful primarily at high concentrations.<\/section>\n<section id=\"pyq-additional-information\">The term &#8220;tolerated at very low levels&#8221; is relative, but in the context of common air pollutants from vehicles, CO, NOx, and Benzene are regulated and considered hazardous at much lower concentrations than CO\u2082. CO\u2082 is regulated more as a climate change gas than a direct air toxic at ambient urban levels.<\/section>\n","protected":false},"excerpt":{"rendered":"<p>One of the main causes of air pollution in cities is emissions from vehicles like cars and trucks. Cars emit various pollutants which are bad for human health when inhaled, like 1. Nitrogen oxides (NOx) 2. Carbon monoxide (CO) 3. Carbon dioxide (CO2) 4. Benzene Which of the above pollutants are not tolerated by human &#8230; <\/p>\n<p class=\"read-more-container\"><a title=\"One of the main causes of air pollution in cities is emissions from ve\" class=\"read-more button\" href=\"https:\/\/exam.pscnotes.com\/mcq\/one-of-the-main-causes-of-air-pollution-in-cities-is-emissions-from-ve\/#more-87347\">Detailed Solution<span class=\"screen-reader-text\">One of the main causes of air pollution in cities is emissions from ve<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1093],"tags":[1098,1136,1137],"class_list":["post-87347","post","type-post","status-publish","format-standard","hentry","category-upsc-nda-1","tag-1098","tag-environment-and-ecology","tag-pollution","no-featured-image-padding"],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v22.2 (Yoast SEO v23.3) - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>One of the main causes of air pollution in cities is emissions from ve<\/title>\n<meta name=\"description\" content=\"The question asks which pollutants are *not* tolerated by human beings *even at very low levels*. This typically refers to substances with high toxicity or carcinogenicity at trace concentrations. 1. Nitrogen oxides (NOx): Respiratory irritants, contribute to smog. Can cause respiratory problems at relatively low concentrations. 2. Carbon monoxide (CO): Highly toxic gas. Binds to haemoglobin more strongly than oxygen, impairing oxygen transport. Even low levels in inhaled air can be dangerous, especially over time. 3. Carbon dioxide (CO\u2082): A greenhouse gas and a natural component of air (around 400 ppm). It is not toxic at these ambient levels. High concentrations (e.g., &gt; 5000 ppm or more) can cause adverse health effects or suffocation, but it is tolerated at &quot;very low levels&quot; (ambient levels). 4. Benzene: A volatile organic compound and a known human carcinogen. Exposure to benzene, even at very low concentrations over time, is linked to increased risk of cancer (e.g., leukemia). Considering the criteria &quot;not tolerated even at very low levels&quot;, CO and Benzene are clear candidates due to their high toxicity\/carcinogenicity at low exposures. NOx are also significant respiratory hazards at lower concentrations than CO\u2082. CO\u2082 is relatively non-toxic at typical atmospheric concentrations. Thus, NOx, CO, and Benzene fit the description better than CO\u2082. Certain pollutants like carbon monoxide (CO), benzene, and nitrogen oxides (NOx) pose health risks even at low exposure levels due to their toxicity, carcinogenicity, or irritant properties, whereas carbon dioxide (CO\u2082) is harmful primarily at high concentrations.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/exam.pscnotes.com\/mcq\/one-of-the-main-causes-of-air-pollution-in-cities-is-emissions-from-ve\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"One of the main causes of air pollution in cities is emissions from ve\" \/>\n<meta property=\"og:description\" content=\"The question asks which pollutants are *not* tolerated by human beings *even at very low levels*. This typically refers to substances with high toxicity or carcinogenicity at trace concentrations. 1. Nitrogen oxides (NOx): Respiratory irritants, contribute to smog. Can cause respiratory problems at relatively low concentrations. 2. Carbon monoxide (CO): Highly toxic gas. Binds to haemoglobin more strongly than oxygen, impairing oxygen transport. Even low levels in inhaled air can be dangerous, especially over time. 3. Carbon dioxide (CO\u2082): A greenhouse gas and a natural component of air (around 400 ppm). It is not toxic at these ambient levels. High concentrations (e.g., &gt; 5000 ppm or more) can cause adverse health effects or suffocation, but it is tolerated at &quot;very low levels&quot; (ambient levels). 4. Benzene: A volatile organic compound and a known human carcinogen. Exposure to benzene, even at very low concentrations over time, is linked to increased risk of cancer (e.g., leukemia). Considering the criteria &quot;not tolerated even at very low levels&quot;, CO and Benzene are clear candidates due to their high toxicity\/carcinogenicity at low exposures. NOx are also significant respiratory hazards at lower concentrations than CO\u2082. CO\u2082 is relatively non-toxic at typical atmospheric concentrations. Thus, NOx, CO, and Benzene fit the description better than CO\u2082. Certain pollutants like carbon monoxide (CO), benzene, and nitrogen oxides (NOx) pose health risks even at low exposure levels due to their toxicity, carcinogenicity, or irritant properties, whereas carbon dioxide (CO\u2082) is harmful primarily at high concentrations.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/exam.pscnotes.com\/mcq\/one-of-the-main-causes-of-air-pollution-in-cities-is-emissions-from-ve\/\" \/>\n<meta property=\"og:site_name\" content=\"MCQ and Quiz for Exams\" \/>\n<meta property=\"article:published_time\" content=\"2025-06-01T06:41:24+00:00\" \/>\n<meta name=\"author\" content=\"rawan239\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"rawan239\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"2 minutes\" \/>\n<!-- \/ Yoast SEO Premium plugin. -->","yoast_head_json":{"title":"One of the main causes of air pollution in cities is emissions from ve","description":"The question asks which pollutants are *not* tolerated by human beings *even at very low levels*. This typically refers to substances with high toxicity or carcinogenicity at trace concentrations. 1. Nitrogen oxides (NOx): Respiratory irritants, contribute to smog. Can cause respiratory problems at relatively low concentrations. 2. Carbon monoxide (CO): Highly toxic gas. Binds to haemoglobin more strongly than oxygen, impairing oxygen transport. Even low levels in inhaled air can be dangerous, especially over time. 3. Carbon dioxide (CO\u2082): A greenhouse gas and a natural component of air (around 400 ppm). It is not toxic at these ambient levels. High concentrations (e.g., > 5000 ppm or more) can cause adverse health effects or suffocation, but it is tolerated at \"very low levels\" (ambient levels). 4. Benzene: A volatile organic compound and a known human carcinogen. Exposure to benzene, even at very low concentrations over time, is linked to increased risk of cancer (e.g., leukemia). Considering the criteria \"not tolerated even at very low levels\", CO and Benzene are clear candidates due to their high toxicity\/carcinogenicity at low exposures. NOx are also significant respiratory hazards at lower concentrations than CO\u2082. CO\u2082 is relatively non-toxic at typical atmospheric concentrations. Thus, NOx, CO, and Benzene fit the description better than CO\u2082. Certain pollutants like carbon monoxide (CO), benzene, and nitrogen oxides (NOx) pose health risks even at low exposure levels due to their toxicity, carcinogenicity, or irritant properties, whereas carbon dioxide (CO\u2082) is harmful primarily at high concentrations.","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/exam.pscnotes.com\/mcq\/one-of-the-main-causes-of-air-pollution-in-cities-is-emissions-from-ve\/","og_locale":"en_US","og_type":"article","og_title":"One of the main causes of air pollution in cities is emissions from ve","og_description":"The question asks which pollutants are *not* tolerated by human beings *even at very low levels*. This typically refers to substances with high toxicity or carcinogenicity at trace concentrations. 1. Nitrogen oxides (NOx): Respiratory irritants, contribute to smog. Can cause respiratory problems at relatively low concentrations. 2. Carbon monoxide (CO): Highly toxic gas. Binds to haemoglobin more strongly than oxygen, impairing oxygen transport. Even low levels in inhaled air can be dangerous, especially over time. 3. Carbon dioxide (CO\u2082): A greenhouse gas and a natural component of air (around 400 ppm). It is not toxic at these ambient levels. High concentrations (e.g., > 5000 ppm or more) can cause adverse health effects or suffocation, but it is tolerated at \"very low levels\" (ambient levels). 4. Benzene: A volatile organic compound and a known human carcinogen. Exposure to benzene, even at very low concentrations over time, is linked to increased risk of cancer (e.g., leukemia). Considering the criteria \"not tolerated even at very low levels\", CO and Benzene are clear candidates due to their high toxicity\/carcinogenicity at low exposures. NOx are also significant respiratory hazards at lower concentrations than CO\u2082. CO\u2082 is relatively non-toxic at typical atmospheric concentrations. Thus, NOx, CO, and Benzene fit the description better than CO\u2082. Certain pollutants like carbon monoxide (CO), benzene, and nitrogen oxides (NOx) pose health risks even at low exposure levels due to their toxicity, carcinogenicity, or irritant properties, whereas carbon dioxide (CO\u2082) is harmful primarily at high concentrations.","og_url":"https:\/\/exam.pscnotes.com\/mcq\/one-of-the-main-causes-of-air-pollution-in-cities-is-emissions-from-ve\/","og_site_name":"MCQ and Quiz for Exams","article_published_time":"2025-06-01T06:41:24+00:00","author":"rawan239","twitter_card":"summary_large_image","twitter_misc":{"Written by":"rawan239","Est. reading time":"2 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/exam.pscnotes.com\/mcq\/one-of-the-main-causes-of-air-pollution-in-cities-is-emissions-from-ve\/","url":"https:\/\/exam.pscnotes.com\/mcq\/one-of-the-main-causes-of-air-pollution-in-cities-is-emissions-from-ve\/","name":"One of the main causes of air pollution in cities is emissions from ve","isPartOf":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#website"},"datePublished":"2025-06-01T06:41:24+00:00","dateModified":"2025-06-01T06:41:24+00:00","author":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/5807dafeb27d2ec82344d6cbd6c3d209"},"description":"The question asks which pollutants are *not* tolerated by human beings *even at very low levels*. This typically refers to substances with high toxicity or carcinogenicity at trace concentrations. 1. Nitrogen oxides (NOx): Respiratory irritants, contribute to smog. Can cause respiratory problems at relatively low concentrations. 2. Carbon monoxide (CO): Highly toxic gas. Binds to haemoglobin more strongly than oxygen, impairing oxygen transport. Even low levels in inhaled air can be dangerous, especially over time. 3. Carbon dioxide (CO\u2082): A greenhouse gas and a natural component of air (around 400 ppm). It is not toxic at these ambient levels. High concentrations (e.g., > 5000 ppm or more) can cause adverse health effects or suffocation, but it is tolerated at \"very low levels\" (ambient levels). 4. Benzene: A volatile organic compound and a known human carcinogen. Exposure to benzene, even at very low concentrations over time, is linked to increased risk of cancer (e.g., leukemia). Considering the criteria \"not tolerated even at very low levels\", CO and Benzene are clear candidates due to their high toxicity\/carcinogenicity at low exposures. NOx are also significant respiratory hazards at lower concentrations than CO\u2082. CO\u2082 is relatively non-toxic at typical atmospheric concentrations. Thus, NOx, CO, and Benzene fit the description better than CO\u2082. Certain pollutants like carbon monoxide (CO), benzene, and nitrogen oxides (NOx) pose health risks even at low exposure levels due to their toxicity, carcinogenicity, or irritant properties, whereas carbon dioxide (CO\u2082) is harmful primarily at high concentrations.","breadcrumb":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/one-of-the-main-causes-of-air-pollution-in-cities-is-emissions-from-ve\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/exam.pscnotes.com\/mcq\/one-of-the-main-causes-of-air-pollution-in-cities-is-emissions-from-ve\/"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/exam.pscnotes.com\/mcq\/one-of-the-main-causes-of-air-pollution-in-cities-is-emissions-from-ve\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/exam.pscnotes.com\/mcq\/"},{"@type":"ListItem","position":2,"name":"UPSC NDA-1","item":"https:\/\/exam.pscnotes.com\/mcq\/category\/upsc-nda-1\/"},{"@type":"ListItem","position":3,"name":"One of the main causes of air pollution in cities is emissions from ve"}]},{"@type":"WebSite","@id":"https:\/\/exam.pscnotes.com\/mcq\/#website","url":"https:\/\/exam.pscnotes.com\/mcq\/","name":"MCQ and Quiz for Exams","description":"","potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/exam.pscnotes.com\/mcq\/?s={search_term_string}"},"query-input":"required name=search_term_string"}],"inLanguage":"en-US"},{"@type":"Person","@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/5807dafeb27d2ec82344d6cbd6c3d209","name":"rawan239","image":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/image\/","url":"https:\/\/secure.gravatar.com\/avatar\/761a7274f9cce048fa5b921221e7934820d74514df93ef195a9d22af0c1c9001?s=96&d=mm&r=g","contentUrl":"https:\/\/secure.gravatar.com\/avatar\/761a7274f9cce048fa5b921221e7934820d74514df93ef195a9d22af0c1c9001?s=96&d=mm&r=g","caption":"rawan239"},"sameAs":["https:\/\/exam.pscnotes.com"],"url":"https:\/\/exam.pscnotes.com\/mcq\/author\/rawan239\/"}]}},"amp_enabled":true,"_links":{"self":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/posts\/87347","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/comments?post=87347"}],"version-history":[{"count":0,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/posts\/87347\/revisions"}],"wp:attachment":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/media?parent=87347"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/categories?post=87347"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/tags?post=87347"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}