{"id":12763,"date":"2023-11-09T19:58:38","date_gmt":"2023-11-09T11:58:38","guid":{"rendered":"https:\/\/smartairfilters.com\/?p=12763"},"modified":"2023-11-09T20:00:09","modified_gmt":"2023-11-09T12:00:09","slug":"what-time-of-day-is-air-pollution-lowest-in-india","status":"publish","type":"post","link":"https:\/\/smartairfilters.com\/en\/blog\/what-time-of-day-is-air-pollution-lowest-in-india\/","title":{"rendered":"What Time of Day Is Air Pollution Lowest in India?"},"content":{"rendered":"<p style=\"margin-bottom: 0cm;text-align: justify\">When Smart Air polled people about <a href=\"https:\/\/smartairfilters.com\/en\/blog\/71-of-people-dont-know-pm2-5-lowest-at-this-time\/\">what time of day air pollution is lowest<\/a>, the most popular answer was the early morning, before the morning rush hour. But how accurate are our intuitions?<\/p>\n<p><img fetchpriority=\"high\" decoding=\"async\" src=\"\/wordpress\/wp-content\/uploads\/2020\/11\/Poll.png\" alt=\"Poll- When is PM2.5 Lowest\" class=\" wp-image-12764 aligncenter\" width=\"391\" height=\"429\" srcset=\"https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2020\/11\/Poll.png 772w, https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2020\/11\/Poll-548x600.png 548w, https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2020\/11\/Poll-274x300.png 274w, https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2020\/11\/Poll-768x842.png 768w, https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2020\/11\/Poll-600x658.png 600w\" sizes=\"(max-width: 391px) 100vw, 391px\" \/><\/p>\n<p style=\"text-align: justify\">To get to the bottom of it, Smart Air analyzed thousands of hours of PM2.5 data from the US Embassy for Delhi, Kolkata, Mumbai, Chennai, and Hyderabad (March 2015-August 2020). The results showed that most people&#8217;s intuitions were wrong.<\/p>\n<p><a href=\"https:\/\/smartairfilters.com\/en\/blog\/20-least-polluted-cities-in-india-2023\/\">Read more: 20 Least Polluted Cities in India (2023 Rankings)<\/a><\/p>\n<h3>Delhi Air Pollution<\/h3>\n<p>Delhi is often touted as the <a href=\"https:\/\/www.reuters.com\/article\/us-india-pollution-idUSKCN20K0UT\">most polluted city<\/a> in the world and that noteworthy pollution peaks in the morning. On average, Delhi&#8217;s PM2.5 peaks at 9 AM at 128 micrograms. That&#8217;s over 12 times the <a href=\"https:\/\/www.who.int\/en\/news-room\/fact-sheets\/detail\/ambient-(outdoor)-air-quality-and-health\">World Health Organization&#8217;s annual limit<\/a>.<\/p>\n<p><img decoding=\"async\" src=\"\/wordpress\/wp-content\/uploads\/2020\/11\/Delhis-Hourly-PM2.5-1024x576.png\" alt=\"Delhi's Hourly PM2.5\" class=\"aligncenter wp-image-12766\" width=\"750\" height=\"422\" srcset=\"https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2020\/11\/Delhis-Hourly-PM2.5-1024x576.png 1024w, https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2020\/11\/Delhis-Hourly-PM2.5-600x338.png 600w, https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2020\/11\/Delhis-Hourly-PM2.5-300x169.png 300w, https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2020\/11\/Delhis-Hourly-PM2.5-768x432.png 768w, https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2020\/11\/Delhis-Hourly-PM2.5.png 1280w\" sizes=\"(max-width: 750px) 100vw, 750px\" \/><\/p>\n<p>The air quality gradually improves as the day progress. This is no small difference. On average, Delhi sees roughly half as much PM2.5 at 5 PM (66 micrograms) compared to 9 AM.<\/p>\n<h3>Kolkata Air Pollution<\/h3>\n<p>Daily PM2.5 patterns are similar in the eastern city of Kolkata. Kolkata&#8217;s air quality is worst at midnight, with a second peak at 8 AM.<\/p>\n<p><img decoding=\"async\" src=\"\/wordpress\/wp-content\/uploads\/2020\/11\/Kolkatas-Hourly-PM2.5-1024x576.png\" alt=\"Kolkata's Hourly PM2.5\" class=\"aligncenter wp-image-12768\" width=\"750\" height=\"422\" srcset=\"https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2020\/11\/Kolkatas-Hourly-PM2.5-1024x576.png 1024w, https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2020\/11\/Kolkatas-Hourly-PM2.5-600x338.png 600w, https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2020\/11\/Kolkatas-Hourly-PM2.5-300x169.png 300w, https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2020\/11\/Kolkatas-Hourly-PM2.5-768x432.png 768w, https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2020\/11\/Kolkatas-Hourly-PM2.5.png 1280w\" sizes=\"(max-width: 750px) 100vw, 750px\" \/><\/p>\n<p>After the morning, Kolkata&#8217;s PM2.5 pollution falls steadily until the average low at 4 PM. As in Delhi, Kolkata&#8217;s daily variation is meaningful. On average, people outdoors at 4 PM will breathe 37% less PM2.5 pollution than people who are outdoors at midnight.<\/p>\n<h3>Mumbai Air Pollution<\/h3>\n<p>Mumbai&#8217;s PM2.5 air pollution peaks at 9 AM, on average.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"\/wordpress\/wp-content\/uploads\/2020\/11\/Mumbais-Hourly-PM2.5-1024x576.png\" alt=\"Mumbai's Hourly PM2.5\" class=\"aligncenter wp-image-12769\" width=\"750\" height=\"422\" srcset=\"https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2020\/11\/Mumbais-Hourly-PM2.5-1024x576.png 1024w, https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2020\/11\/Mumbais-Hourly-PM2.5-600x338.png 600w, https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2020\/11\/Mumbais-Hourly-PM2.5-300x169.png 300w, https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2020\/11\/Mumbais-Hourly-PM2.5-768x432.png 768w, https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2020\/11\/Mumbais-Hourly-PM2.5.png 1280w\" sizes=\"(max-width: 750px) 100vw, 750px\" \/><\/p>\n<p>Mumbai&#8217;s PM2.5 then reaches the average low at 4 PM.<\/p>\n<h3>Chennai Air Pollution<\/h3>\n<p>The picture starts changing further south in India. As in most cities, Chennai&#8217;s PM2.5 is highest at 8 AM and lowest at 3 PM.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"\/wordpress\/wp-content\/uploads\/2020\/11\/ChennaisHourly-PM2.5-1024x576.png\" alt=\"Chennai'sHourly PM2.5\" class=\"aligncenter wp-image-12770\" width=\"750\" height=\"422\" srcset=\"https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2020\/11\/ChennaisHourly-PM2.5-1024x576.png 1024w, https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2020\/11\/ChennaisHourly-PM2.5-600x337.png 600w, https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2020\/11\/ChennaisHourly-PM2.5-300x169.png 300w, https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2020\/11\/ChennaisHourly-PM2.5-768x432.png 768w, https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2020\/11\/ChennaisHourly-PM2.5.png 1249w\" sizes=\"(max-width: 750px) 100vw, 750px\" \/><\/p>\n<p style=\"margin: 0cm;text-align: justify\">However, unlike northern India, Chennai&#8217;s air pollution is the lowest in the middle of the night. On average, Chennai&#8217;s PM2.5 is lowest from 1 to 3 AM.<\/p>\n<p style=\"margin: 0cm;text-align: justify\"><b><span style=\"font-family: 'Avenir',sans-serif\">\u00a0<\/span><\/b><\/p>\n<h3 style=\"margin: 0cm;text-align: justify\">Hyderabad Air Pollution<\/h3>\n<p style=\"margin: 0cm;text-align: justify\">Hyderabad&#8217;s air quality pattern is virtually identical to Chennai\u2019s: a dip in the middle of the night and a dip in the afternoon.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"\/wordpress\/wp-content\/uploads\/2020\/11\/Hyderabads-Hourly-PM2.5-1024x576.png\" alt=\"Hyderabad's Hourly PM2.5\" class=\"aligncenter wp-image-12771\" width=\"750\" height=\"422\" srcset=\"https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2020\/11\/Hyderabads-Hourly-PM2.5-1024x576.png 1024w, https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2020\/11\/Hyderabads-Hourly-PM2.5-600x338.png 600w, https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2020\/11\/Hyderabads-Hourly-PM2.5-300x169.png 300w, https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2020\/11\/Hyderabads-Hourly-PM2.5-768x432.png 768w, https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2020\/11\/Hyderabads-Hourly-PM2.5.png 1280w\" sizes=\"(max-width: 750px) 100vw, 750px\" \/><\/p>\n<p>As in Delhi, Hyderabad&#8217;s air pollution peaks at 8 AM.<\/p>\n<h2 style=\"text-align: center\">Pollution and Time of Day Worldwide<\/h2>\n<p>India is not alone. Smart Air&#8217;s analysis of air quality patterns <a href=\"https:\/\/smartairfilters.com\/en\/blog\/when-is-pm-2-5-the-lowest\/\">air quality patterns in China<\/a> showed similar trends. <a href=\"https:\/\/pubs.acs.org\/doi\/abs\/10.1021\/acs.estlett.8b00573?journalCode=estlcu\">A 2018 study<\/a> analyzed data from all around the world and found a similar pattern\u2014PM2.5 tends to be lowest in the afternoon.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"\/wordpress\/wp-content\/uploads\/2020\/11\/Air-Quality-Around-the-World.png\" alt=\"Air Quality Around the World\" class=\"size-full wp-image-12772 aligncenter\" width=\"612\" height=\"435\" srcset=\"https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2020\/11\/Air-Quality-Around-the-World.png 612w, https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2020\/11\/Air-Quality-Around-the-World-600x426.png 600w, https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2020\/11\/Air-Quality-Around-the-World-300x213.png 300w\" sizes=\"(max-width: 612px) 100vw, 612px\" \/><\/p>\n<p><strong>Read more: <\/strong>It seems odd that that air pollution is the <strong>lowest<\/strong> during afternoon rush hour?\u00a0This phenomenon explains <a href=\"https:\/\/www.quora.com\/Are-there-specific-reasons-for-pollution-to-be-worse-towards-the-end-of-the-year\">why pollution is worse at night<\/a>.<\/p>\n<p>But keep in mind that none of the five cities average air below the <a href=\"https:\/\/www.who.int\/news-room\/fact-sheets\/detail\/ambient-(outdoor)-air-quality-and-health\">WHO annual limit<\/a> at any time of day.<\/p>\n\n\n<pre class=\"wp-block-code\"><code>&#091;bottomline title=\"Bottom Line:\"]In India's five biggest cities, PM2.5 air pollution is highest in the morning and lowest in the afternoon. So, if you\u2019re planning exercising outside, you\u2019re usually best off in the afternoon.&#091;\/bottomline]<\/code><\/pre>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"900\" height=\"500\" src=\"https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2023\/11\/CLEAN-AIR.jpg\" alt=\"\" class=\"wp-image-28073\" srcset=\"https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2023\/11\/CLEAN-AIR.jpg 900w, https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2023\/11\/CLEAN-AIR-600x333.jpg 600w, https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2023\/11\/CLEAN-AIR-300x167.jpg 300w, https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2023\/11\/CLEAN-AIR-768x427.jpg 768w\" sizes=\"(max-width: 900px) 100vw, 900px\" \/><\/figure><\/div>\n\n\n<div class=\"wp-block-buttons is-content-justification-center is-layout-flex wp-container-core-buttons-is-layout-16018d1d wp-block-buttons-is-layout-flex\">\n<div class=\"wp-block-button\"><a class=\"wp-block-button__link wp-element-button\" href=\"https:\/\/smartairfilters.com\/en\/shop\/retailers\/india\/\">Visit India Clean Air Shop<\/a><\/div>\n<\/div>","protected":false},"excerpt":{"rendered":"<p>When Smart Air polled people about what time of day air pollution is lowest, the most popular answer was the early morning, before the morning rush hour. But how accurate are our intuitions? To get to the bottom of it, Smart Air analyzed thousands of hours of PM2.5 data from &#8230; <\/p>\n<p class=\"read-more-container\"><a title=\"What Time of Day Is Air Pollution Lowest in India?\" class=\"read-more button\" href=\"https:\/\/smartairfilters.com\/en\/blog\/what-time-of-day-is-air-pollution-lowest-in-india\/#more-12763\" aria-label=\"Read more about What Time of Day Is Air Pollution Lowest in India?\">Read more<\/a><\/p>\n","protected":false},"author":2882,"featured_media":12774,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_relevanssi_hide_post":"","_relevanssi_hide_content":"","_relevanssi_pin_for_all":"","_relevanssi_pin_keywords":"","_relevanssi_unpin_keywords":"","_relevanssi_related_keywords":"","_relevanssi_related_include_ids":"","_relevanssi_related_exclude_ids":"","_relevanssi_related_no_append":"","_relevanssi_related_not_related":"","_relevanssi_related_posts":"","_relevanssi_noindex_reason":"","footnotes":""},"categories":[17,260,257,261],"tags":[272,27,225,269,74],"class_list":["post-12763","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-air-pollution","category-air-pollution-health-effects","category-pm2-5","category-weather","tag-air-pollution","tag-delhi","tag-health","tag-india","tag-pm2-5","resize-featured-image"],"acf":[],"_links":{"self":[{"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/posts\/12763","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/users\/2882"}],"replies":[{"embeddable":true,"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/comments?post=12763"}],"version-history":[{"count":9,"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/posts\/12763\/revisions"}],"predecessor-version":[{"id":28190,"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/posts\/12763\/revisions\/28190"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/media\/12774"}],"wp:attachment":[{"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/media?parent=12763"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/categories?post=12763"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/tags?post=12763"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}