<commit_before>---
layout: post
cover: 'assets/images/cardboard.jpg'
title:  "Beijing Pollution"
date:   2016-01-13 05:00:00
tags: Health Beijing China
subclass: 'post tag-test tag-content'
navigation: False
categories: 'gully'
logo: 'assets/images/delivery_human.png'
author: 'gully'
nickname: gully
bio: "I'm a PhD in Astronomy from the University of Texas at Austin.  I like experiments,  behavioral economics, bicycle riding, data science, and Indian food."
image: 'assets/images/gully_face_square.png'
baseurl: "/"
---

In a word association game, what would you say when prompted with the word "Beijing"?  I suspect most Americans' responses would include the words "China", "Olympics", "city", and "pollution".  Pollution was among our chief concerns before moving here.  When we spoke with travellers who lived here, we would ask "What's the deal with the pollution?".  The answer depends on who you ask.  Four and a half months into our journey here, we can offer our answer to a question that we'll probably be answering for years to come.

### What's the deal with the pollution?

The deal is that sometimes it gets really polluted in Beijing.  There are two words to that statement that we will dissect.  First is the *somtimes* and second is the *really*.

### *Sometimes*

*Sometimes* means that it's not always polluted here, which is a misconception that I had, and a misconception that is probably shared among many outsiders.  When I got out of the Beijing airport and breathed the Beijing air, it reminded me of a forgettable scene from the movie *12 Monkeys*, a lesser-known early nineties Brad Pitt flick with a killer soundtrack.  The scene I have in mind is towards the end (spoiler alert), when the perpetrator of a biological terror attack opens---upon request by a customs agent---a vile of odorless, clear gas in an airport lobby.  The toxin has just silently infected him and the agent, and was now permeating the air around them.  The perp's grimmace as he quietly acknowledges the toxic air around him must have been mirrored in my own face when I surveyed the Beijing air for the first time.  *WAS IT OKAY TO BREATHE?*.  I slowly took longer and longer breaths as I became comfortable with the fact that the air was just fine.  The next morning when we woke up at our friends' place in Chaoyangmen, Beijing we saw beautiful blue skies.  What's the deal with that?

Beijing is only polluted when the air is still for a few days.  When there is no *wind*, the air stagnates, and the pollution has nowhere to go.  It just builds up.  So naturally when Beijing is *windy*, the pollution gets blown away to somewhere else (sorry rest of the world), and the air is clear.  

The change in wind direction and strength can be sudden.  Chelsey and I went 



- What it's like here.
	- Before we moved here
	- The appearance of the sun
- Wind 
	- The wind controls the pollution
	- Can be sudden
- Tracking the pollution
	- App
- Protective measures
	- Masks
	- Air purifiers
	- Smart airs
	- Ozone purifier
- Health risks
	- Links to articles<commit_msg>some more content to the pollution post.<commit_after>---
layout: post
cover: 'assets/images/cardboard.jpg'
title:  "Beijing Pollution"
date:   2016-01-13 05:00:00
tags: Health Beijing China
subclass: 'post tag-test tag-content'
navigation: False
categories: 'gully'
logo: 'assets/images/delivery_human.png'
author: 'gully'
nickname: gully
bio: "I'm a PhD in Astronomy from the University of Texas at Austin.  I like experiments,  behavioral economics, bicycle riding, data science, and Indian food."
image: 'assets/images/gully_face_square.png'
baseurl: "/"
---

In a word association game, what would you say when prompted with the word "Beijing"?  I suspect most Americans' responses would include the words "China", "Olympics", "city", and "pollution".  Pollution was among our chief concerns before moving here.  When we spoke with travellers who lived here, we would ask "What's the deal with the pollution?".  The answer depends on who you ask.  Six months into our journey here, we can offer our answer to a question that we'll probably be answering for years to come.

### What's the deal with the pollution?

The deal is that sometimes it gets really polluted in Beijing.  There are two words to that statement that we will dissect.  First is the *somtimes* and second is the *really*.

### *Sometimes*

*Sometimes* means that it's **not always polluted here**, which is a misconception that I had, and a misconception that is probably shared among many outsiders.  When I got out of the Beijing airport and breathed the Beijing air, it reminded me of [a forgettable scene from the movie 12 Monkeys](https://youtu.be/5Zht43WrCmk?t=7m55s), a lesser-known early nineties Brad Pitt flick with a killer soundtrack.  The scene I have in mind is towards the end (spoiler alert), when the perpetrator of a biological terror attack opens---upon request by a customs agent---a vile of odorless, clear gas in an airport lobby.  The toxin has just silently infected him and the agent, and was now permeating the air around them.  The perp's grimmace as he quietly acknowledges the toxic air around him must have been mirrored in my own face when I surveyed the Beijing air for the first time.  *WAS IT OKAY TO BREATHE?*.  I slowly took longer and longer breaths as I became comfortable with the fact that the air was **just fine**.  The next morning when we woke up at our friends' place in Chaoyangmen, Beijing we saw beautiful blue skies.  What's the deal with that?

Beijing is only polluted when the air is still for a few days.  When there is no *wind*, the air stagnates, and the pollution has nowhere to go.  It just builds up.  So naturally when Beijing is *windy*, the pollution gets blown away to somewhere else (sorry rest of the world), and the air is clear.  

The change in wind direction and strength can be sudden.  Chelsey and I appreciated this for the first time on a scooter ride home from the Modernista Jazz bar on a cool night in October 2015.  On the way to Modernista we lamented how bad the pollution was, and donned the conspicuous face masks on our journey.  When we left the venue a mere 90 minutes later, the air was crystal clear, and the stars were shining.  The wind had abruptly cleared the stagnant air.  Our experience was borne out in the data when we consulted our phones later.

### The *Really* part, or "Show me the data"

In order to understand "really", we need to move from qualitative to quantitative, which is something I am good at: numbers.  There are a few numbers that matter here.  One is the ubiquitous [Air Quality Index](https://en.wikipedia.org/wiki/Air_quality_index), commonly called the AQI.  The AQI combines several disparate measures of air quality into a single number, just like how we can summarize the weather with a single temperature.  Unfortunately there is no international standard AQI scale.  Each country/region uses slightly different scales, making converting among them even more difficult than recalling Fahrenheit to Celsius.  

Nevertheless, the scale in China is roughly 0-500 AQI.  Strictly speaking, a lower bound makes sense (zero particulates in the air), but an upper bound does not make sense, in the same way that an upper bound on temperature does not really make sense.  I suppose the upper bound on AQI could be when the air is so dense with particles that fusion can occur, or something less drastic, like our lungs are filled with sand.  The truth is that an AQI of 500 effectively means "holy shit it is really freaking polluted."  We have experienced 3 or 4 of these types of episodes, and they are *wild*.  But rare.  They get a lot of attention in the news because the photos look so dramatic.

To put the numbers in perspective, today in Austin Texas the AQI was about 40.  Right now in Beijing, the AQI is about 100.  Looking through the last month of data for the US, I can find [instances of AQI as high as 150](https://airnow.gov/index.cfm?action=airnow.mapsarchivedetail&domainid=53&mapdate=20160212&tab=1), though again with the caveat that the scales might be slightly different, etc.  I think these are the same scales though (0-500 range).  The normal state in the US is "good" or 0-50 and green color.  The normal in Beijing seems to be closer to the 100-200 mark (orange or red).  These categories are considered "unhealthy for sensitive groups", or just plain old "unhealthy".  




- What it's like here.
	- Before we moved here
	- The appearance of the sun
- Wind 
	- The wind controls the pollution
	- Can be sudden
- Tracking the pollution
	- App
- Protective measures
	- Masks
	- Air purifiers
	- Smart airs
	- Ozone purifier
- Health risks
	- Links to articles
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