{"id":4812,"date":"2017-10-13T11:28:46","date_gmt":"2017-10-13T03:28:46","guid":{"rendered":"https:\/\/smartairfilters.com\/?p=4812"},"modified":"2020-07-15T11:57:01","modified_gmt":"2020-07-15T03:57:01","slug":"pm2-5-worse-subway","status":"publish","type":"post","link":"https:\/\/smartairfilters.com\/en\/blog\/pm2-5-worse-subway\/","title":{"rendered":"Is PM2.5 Worse on the Subway?"},"content":{"rendered":"

\"\"<\/p>\n

I wear a pollution mask in Beijing, and I’ve always taken it off when I get into the subway. That’s because I’ve always assumed air in the subway is better than outside. But am I right to take it off?<\/p>\n

I\u2019ve heard a lot of Beijingers debating whether air in the subway is any better than outside, so I asked\u00a0Smart Air<\/a>\u00a0member Ted to go out and get some real data. Ted took out a portable laser particle counter:<\/p>\n

\"\"<\/p>\n

 <\/p>\n

And he took air samples inside and outside of 10 subway stops around the city on two December days:<\/p>\n

\"\"<\/p>\n

 <\/p>\n

Here’s what we found comparing particulate outside (blue) to the subway platform (red):<\/p>\n

\"\"<\/p>\n

The particle counts varied a lot but, on average, platform air was worse than outdoor air:<\/p>\n

\"\"<\/p>\n

That surprised me! I was wrong to take off my mask in the subway.<\/p>\n

 <\/p>\n

Inside the Subway Car<\/h3>\n

Next, we compared air\u00a0inside the subway car\u00a0versus outdoor air. Maybe the air is better there because it\u2019s a closed space and they often run the air system?<\/p>\n

\"\"<\/p>\n

Again, it varied a lot, but air was worse in the subway car than outside on average:<\/p>\n

\"\"<\/p>\n

Conclusion 1:<\/strong>\u00a0If I need to wear a mask outside, I need to wear it in the subway too.<\/p>\n

Conclusion 2:\u00a0<\/strong>On average, PM2.5 in the subway is at least as bad as outside, sometimes much worse.<\/p>\n

 <\/p>\n

Is This A Reliable Finding?<\/h3>\n

This data is only from two days, so are these findings reliable? A study from the Rock Environment and Energy Institute ran tests in Beijing and also\u00a0found higher levels of particulate on subways<\/a>. The findings from these two studies suggest that air is reliably worse in Beijing subways.<\/p>\n

So remember to wear your mask on the subway too!<\/p>","protected":false},"excerpt":{"rendered":"

I wear a pollution mask in Beijing, and I’ve always taken it off when I get into the subway. That’s because I’ve always assumed air in the subway is better than outside. But am I right to take it off? I\u2019ve heard a lot of Beijingers debating whether air in … <\/p>\n

Read more<\/a><\/p>\n","protected":false},"author":1035,"featured_media":0,"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":[17,264,257],"tags":[75,216],"class_list":["post-4812","post","type-post","status-publish","format-standard","hentry","category-air-pollution","category-indoor-air","category-pm2-5","tag-beijing","tag-subway"],"acf":[],"_links":{"self":[{"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/posts\/4812","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\/1035"}],"replies":[{"embeddable":true,"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/comments?post=4812"}],"version-history":[{"count":12,"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/posts\/4812\/revisions"}],"predecessor-version":[{"id":11508,"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/posts\/4812\/revisions\/11508"}],"wp:attachment":[{"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/media?parent=4812"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/categories?post=4812"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/tags?post=4812"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}