{"id":7603,"date":"2019-03-07T12:03:53","date_gmt":"2019-03-07T04:03:53","guid":{"rendered":"https:\/\/smartairfilters.com\/?p=7603"},"modified":"2020-07-20T13:33:51","modified_gmt":"2020-07-20T05:33:51","slug":"so-you-thought-hong-kongs-pollution-comes-from-mainland-china","status":"publish","type":"post","link":"https:\/\/smartairfilters.com\/en\/blog\/so-you-thought-hong-kongs-pollution-comes-from-mainland-china\/","title":{"rendered":"So You Thought Hong Kong\u2019s Pollution Comes From Mainland China?"},"content":{"rendered":"<p>Air pollution is a <span><a href=\"https:\/\/smartairfilters.com\/en\/blog\/hong-kong-air-quality-pm2-5-data\/\">serious problem in Hong Kong<\/a><\/span>, and Hong Kongers often complain that the worst of it <span><a href=\"https:\/\/www.scmp.com\/news\/hong-kong\/health-environment\/article\/2060369\/hong-kong-shrouded-smog-posing-very-high-health\">comes from Mainland China<\/a><\/span>. Is that fact or a convenient scapegoat? After all, Hong Kong is a densely populated developed city with one of the busiest ports in the World &#8211; it is likely that they have <span><a href=\"https:\/\/www.scmp.com\/news\/hong-kong\/health-environment\/article\/2175592\/why-hong-kongs-air-so-polluted-and-what-can-we-do\">their own sources of pollution<\/a><\/span>. I set out to find data on where exactly Hong Kong\u2019s air pollution comes from.<\/p>\n<p>&nbsp;<\/p>\n<h3 style=\"text-align: center\">How Much of Hong Kong\u2019s Pollution Is Local?<\/h3>\n<p>One way to answer this question is see what happens to Hong Kong\u2019s air pollution when the wind blows from the Mainland. To do that, I analyzed data on Hong Kong\u2019s <span><a href=\"http:\/\/berkeleyearth.lbl.gov\/air-quality\/maps\/cities\/Hong_Kong\/\">PM2.5<\/a><\/span> and <span><a href=\"https:\/\/www.meteoblue.com\/en\/weather\/archive\/export\/hong-kong_hong-kong_1819729\">wind direction and speed<\/a><\/span> from 2016 to 2018.<\/p>\n<p><img fetchpriority=\"high\" decoding=\"async\" src=\"\/wordpress\/wp-content\/uploads\/2019\/03\/china-factory.jpg\" alt=\"Smog\" width=\"600\" height=\"400\" class=\"aligncenter wp-image-7604\" srcset=\"https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2019\/03\/china-factory.jpg 840w, https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2019\/03\/china-factory-300x200.jpg 300w, https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2019\/03\/china-factory-768x512.jpg 768w\" sizes=\"(max-width: 600px) 100vw, 600px\" \/><\/p>\n<p>&nbsp;<\/p>\n<h3 style=\"text-align: center\">Where Hong Kong\u2019s Pollution Comes From<\/h3>\n<p>Anytime the wind blows from the West-North-West to East-North-East (the arrows below), Hong Kong\u2019s air is coming from Mainland China. If most of Hong Kong\u2019s air pollution is coming from China, we should see air pollution spikes whenever the wind comes from that direction.<\/p>\n<p><img decoding=\"async\" src=\"\/wordpress\/wp-content\/uploads\/2019\/03\/map.png\" alt=\"Hong Kong's Pollution map\" width=\"600\" height=\"419\" class=\"aligncenter wp-image-7606\" srcset=\"https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2019\/03\/map.png 1770w, https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2019\/03\/map-300x209.png 300w, https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2019\/03\/map-768x536.png 768w, https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2019\/03\/map-1024x715.png 1024w\" sizes=\"(max-width: 600px) 100vw, 600px\" \/><\/p>\n<p>&nbsp;<\/p>\n<h3 style=\"text-align: center\">Does Wind Direction Affect PM2.5?<\/h3>\n<p>When the wind was blowing from directions not from Mainland China, the average PM2.5 level was 25 micrograms. In contrast, when the wind was blowing from Mainland China, the PM2.5 level was 29 micrograms, which is a 15% increase.<\/p>\n<p><img decoding=\"async\" src=\"\/wordpress\/wp-content\/uploads\/2019\/03\/pm2.5-level.png\" alt=\"wind direction increased Hong Kong's Pollution by 15%\" width=\"600\" height=\"584\" class=\"aligncenter wp-image-7609\" srcset=\"https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2019\/03\/pm2.5-level.png 1206w, https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2019\/03\/pm2.5-level-300x292.png 300w, https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2019\/03\/pm2.5-level-768x746.png 768w, https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2019\/03\/pm2.5-level-1024x995.png 1024w\" sizes=\"(max-width: 600px) 100vw, 600px\" \/><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"\/wordpress\/wp-content\/uploads\/2019\/03\/how-wind-in-HK-affects-pm-1.png\" alt=\"How wind affects Hong Kong's Pollution\" width=\"599\" height=\"491\" class=\"aligncenter wp-image-7614\" srcset=\"https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2019\/03\/how-wind-in-HK-affects-pm-1.png 1076w, https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2019\/03\/how-wind-in-HK-affects-pm-1-300x246.png 300w, https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2019\/03\/how-wind-in-HK-affects-pm-1-768x630.png 768w, https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2019\/03\/how-wind-in-HK-affects-pm-1-1024x839.png 1024w\" sizes=\"(max-width: 599px) 100vw, 599px\" \/><\/p>\n<p>This data gives two (somewhat contradictory) takeaways:<\/p>\n<ul>\n<li>Yes, Hong Kong\u2019s air pollution is 15% worse when the wind blows from the Mainland.<\/li>\n<li>However, even when no air is coming from the Mainland, Hong Kong still averages more than twice the <span><a href=\"https:\/\/www.who.int\/en\/news-room\/fact-sheets\/detail\/ambient-(outdoor)-air-quality-and-health\">WHO annual limit<\/a><\/span> of 10 micrograms.<\/li>\n<\/ul>\n<p>Thus, even without the influence of the Mainland, Hong Kong still has significant <span><a href=\"https:\/\/www.scmp.com\/news\/hong-kong\/health-environment\/article\/2175592\/why-hong-kongs-air-so-polluted-and-what-can-we-do\">sources of air pollution<\/a><\/span> from within.<\/p>\n<p>&nbsp;<\/p>\n<h3 style=\"text-align: center\">Does Wind Speed Affect PM2.5?<\/h3>\n<p>When there was no wind, the PM2.5 level averaged 24 micrograms. This is a few times over the <span><a href=\"https:\/\/www.who.int\/en\/news-room\/fact-sheets\/detail\/ambient-(outdoor)-air-quality-and-health\">WHO\u2019s annual limit<\/a><\/span> of 10 micrograms. This proves that even without external influence, Hong Kong\u2019s pollution is still significant.<\/p>\n<p>I repeated the analysis of PM2.5 level at low and high wind speeds and came up with the same conclusion (<a href=\"https:\/\/smartairfilters.com\/en\/blog\/so-you-thought-hong-kongs-pollution-comes-from-the-mainland-supplemental-data\/\">see details here<\/a>).<\/p>\n<p>&nbsp;<\/p>\n<p><strong>Bottomline: <\/strong>Wind direction and speed marginally affect air pollution in Hong Kong. When wind blows from Mainland China, PM2.5 levels in Hong Kong increases 10 \u2013 20%. However, the main sources of air pollution still come from within the city. Hong Kong should take measures to reduce their own sources of air pollution.<\/p>\n<p>&nbsp;<\/p>\n<p><strong>Caveat:\u00a0<\/strong>This data is for particulate pollution. Particulate \u201c<span><a href=\"http:\/\/www.who.int\/mediacentre\/factsheets\/fs313\/en\/\">affects more people than any other pollutant<\/a>s<\/span>,\u201d but there are also gas pollutants like ozone and NO2.\u00a0<span><a href=\"http:\/\/www.hongkongcan.org\/doclib\/2013%20half%20year%20air%20quality%20review_ENG.pdf\">According to this data<\/a><\/span>, Hong Kong also has unsafe levels of NO2, SO2, and ozone.<\/p>\n<p>&nbsp;<\/p>\n<p>If I were in Hong Kong, I would protect myself from air pollution by following these <span><a href=\"https:\/\/smartairfilters.com\/en\/blog\/hong-kong-air-quality-pm2-5-data\/\">measures<\/a><\/span>.<\/p>\n<p>Breathe safe, Hong Kong!<\/p>\n<p><strong><span>\u00a0<\/span><\/strong><\/p>\n<p><strong><span>\u00a0<\/span><\/strong><\/p>","protected":false},"excerpt":{"rendered":"<p>Air pollution is a serious problem in Hong Kong, and Hong Kongers often complain that the worst of it comes from Mainland China. Is that fact or a convenient scapegoat? After all, Hong Kong is a densely populated developed city with one of the busiest ports in the World &#8211; &#8230; <\/p>\n<p class=\"read-more-container\"><a title=\"So You Thought Hong Kong\u2019s Pollution Comes From Mainland China?\" class=\"read-more button\" href=\"https:\/\/smartairfilters.com\/en\/blog\/so-you-thought-hong-kongs-pollution-comes-from-mainland-china\/#more-7603\" aria-label=\"Read more about So You Thought Hong Kong\u2019s Pollution Comes From Mainland China?\">Read more<\/a><\/p>\n","protected":false},"author":4300,"featured_media":7604,"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":[17,126,257,261],"tags":[272,357,74,195,240,201],"class_list":["post-7603","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-air-pollution","category-smart-air-news","category-pm2-5","category-weather","tag-air-pollution","tag-hong-kong","tag-pm2-5","tag-weather","tag-who","tag-wind","resize-featured-image"],"acf":[],"_links":{"self":[{"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/posts\/7603","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\/4300"}],"replies":[{"embeddable":true,"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/comments?post=7603"}],"version-history":[{"count":14,"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/posts\/7603\/revisions"}],"predecessor-version":[{"id":11572,"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/posts\/7603\/revisions\/11572"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/media\/7604"}],"wp:attachment":[{"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/media?parent=7603"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/categories?post=7603"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/tags?post=7603"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}