My intuition has always been that air pollution is lowest at night because there are fewer cars on the road and fewer factories humming. Apparently I’m not alone: 139 voted for their guess about what time of day has the lowest PM2.5, and night time came in first: I also know people who […]
Category: Weather
Delhi’s Air Pollution Worse in Winter, Unhealthy All Year
Delhi’s air pollution has raised a lot of concern in the last few years. Awareness peaks in the winter and then wanes for the rest of the year. How well does this general awareness fit with the air quality data? We analyzed PM2.5 data from the pollution monitor at the US Embassy in New Delhi […]
When wind blows from the north, Beijing’s air quality becomes better
To the northwest of Beijing is sparsely populated Inner Mongolia. Thus, wind from there cleans things out. Here’s what happens on average to PM 2.5 levels with wind from different directions in Beijing: When wind comes from the south or east, PM 2.5 is above average. When wind comes from the north (on the far […]
When Wind Blows From This Direction, Shanghai’s Pollution is 5 Times More Likely to Be Toxic
Calvin Quek from Greenpeace analyzed how PM2.5 changes with depending on which way the wind is blowing in Shanghai: The data is simple. When the wind is coming from the industrialized areas to the west of Shanghai, toxic air pollution is more likely. When the wind blows in from the ocean, bad air days are much less likely. In Beijing, the […]
What time of day is air pollution lowest?
My intuition has always been that there is least air pollution at night because there are fewer cars on the road and fewer factories humming. Apparently I’m not alone: 139 voted for their guess about what time of day has the least air pollution (lowest PM 2.5), and night time came in first: I also know […]
Winter is Coming
Another year, another winter. As winter arrives in Beijing and soon in Shanghai, I got to wondering: how much worse is winter air in Beijing? To get to the bottom of it, I analyzed the last eight years of US Embassy PM 2.5 data for Beijing and Shanghai. I found that the capital’s air has […]
US Embassy Beijing reads AQI of 0! Are the summer skies always clear?
Map of today’s pollution levels across China – 9th September 2016. Source：http://aqicn.org What a glorious day in Beijing! Right now, the US Embassy in Beijing is giving a PM2.5 value of 0. Is summer normally this good? And what’s the pollution like in other parts of China right now? (Short answer: not good! Long answer: read […]
Is Summer Air Better than Winter Air?
Summer is here, bringing with it clearer skies and certainly cleaner air. Right? Summer always seems to drive out the dense clouds of pollution that suffocate many Indian cities. However, while summer air is in fact cleaner than air during other seasons, it’s still far from safe according to the standards set by the World […]
Does Spring bring better air to Delhi?
Delhi Winters are notoriously known for bad levels of air pollution, but we often hear that air gets cleaner come Spring. We were curious what was happening in our own backyard, so we put out our Dylos Particle Counter on a rooftop near our Saket office. The Particle Counter measures particle counts between 0.5 to 2.5 micron in size per […]
Winter is Coming, Brace Yourself
Another year, another blast of winter pollution. Breathe safe this winter! Thomas TalhelmThomas is a new Assistant Professor of Behavior Science at the University of Chicago Booth School of Business and the founder of Smart Air, a social enterprise to help people in China breathe clean air without shelling out thousands of dollars for expensive purifiers.