When a billion people in China (and quite a few expats) woke up to the severe air pollution in almost every city in China, it forced a billion people to become experts in a complicated scientific question: Do masks work? Since then, I’ve given talks with hundreds of people all around China about how to protect […]
Tag: health
Do purifiers depend on the placebo effect, or do they really have health benefits?
I’ve seen people ask if air purifiers depend on the placebo effect or do they actually work. I think this is a good question because we should not confuse the outcomes of (1) objectively reducing pollutants in the air versus (2) health effects. There are two things we know about purifiers and one really […]
NPR got these facts about masks wrong
As wildfires were raging across the American West this summer, NPR ran a story on what people can do to protect themselves from all that air pollution. As a non-expert nerd who has dedicated years to understanding how to live under Beijing’s particulate cloud, I was eager to see what the story got right and […]
Is It True That Masks Last Just One Day?
We posted info and data on our findings on whether masks really can stop pollution. My judgment after reading up on mask tests and testing them myself is that the science is pretty well settled. Masks do work. But there are still mysteries that need answers. Perhaps the biggest mystery out there is how long […]
San Francisco’s Air Pollution
A friend of mine just sent me this map of air pollution in San Francisco from the San Francisco Chronicle. Using the latest PM2.5 data, I created a map for China using the same scale: Based on that scale, China’s best city (which is Haikou, according to the World Health Organization database) would still be double the […]
How’s the Air in Nepal?
A user on Quora asked recently how bad the air pollution in Nepal is. Nepal has glorious mountains and shining temples. But how is the air? I checked the World Health Organization’s global PM2.5 database. According to that database, Kathmandu’s PM2.5 particulate pollution averaged 49 micrograms/m3 in 2013: That’s just about double the […]
Is Asbestos a Problem in India?
What is Asbestos? Asbestos is a mineral that makes a great fiber. People use that fiber in lots of building materials, like insulation, paints, electric wiring, wall boards, and floor tiles. It might be all around us. Should I Be Concerned? When any of these materials break apart, the asbestos can become airborne […]
Is Asbestos a Problem in China?
Asbestos is a commonly used material in China that may be more dangerous than formaldehyde. So why do so few people talk about asbestos in China? One day a few years ago, a Chinese friend of mine asked me about jiaquan (甲醛). “Huh?” I had to look it up. Turns out it means “formaldehyde.” At that point, […]
How much pollution do we breathe every day?
How much pollution do we actually breathe in every day? Are masks or air purifiers more benefiting to our health? Do we really need both? The answer to this comes down to how and where we are spending most of our time every day. There are two possible theories: masks might seem more effective since when […]
Are Purifiers Useless If Windows are Opened?
Tests show that keeping the doors and windows closed will keep particulate levels at 50% less than outdoor air on average. But some people really want to keep their windows open. For some people, it’s an old wive’s tale that windows must be kept open. For others, it’s a way to reduce chemicals coming from […]