Can a simple fan and filter really clean large spaces? Seven years ago, Smart Air started when PhD student Thomas strapped together a DIY air purifier to survive a polluted Beijing winter. Founder Thomas Talhelm’s first DIY air purifier Thomas published test data on the purifier showing that it worked, then shared to the world […]
Category: Air Pollution
How many trees need to be planted to solve Delhi’s air pollution?
When Delhi’s air pollution spikes, netizens in the nation’s capital often bring up the solution of planting trees. For instance, this user on the question-answer site Quora asks “how many trees does Delhi need to combat its air pollution problem?” However, environmental research suggests that planting trees are an incredibly inefficient way to reduce air […]
How long does the Sqair’s HEPA filter last?
After launching the world’s most cost-effective purifier (the Sqair), we started testing the HEPA lifespan. I’ve long been skeptical of the lifespan numbers purifier companies give because (1) they provide no empirical justification for the number and (2) they give the same numbers in Switzerland or Delhi. Yet clearly the HEPA would last less time […]
Did Delhi’s Air Pollution Drop 25% in 2019? What The Data Says
The Delhi government and Delhi Chief minister Arvind Kejriwal announced Delhi’s PM2.5 air pollution was down 25% in 2016-2018 compared to 2012-2014. Yet there is doubt. Thewire.in, for one, expressed skepticism about this claim. As data-driven nerds, we wanted to let the numbers answer this question. So we dug into the Delhi PM2.5 data […]
How many trees need to be planted to help to solve China’s air pollution?
Planting trees would be a very inefficient way to clean air pollution. Let me break down the effect of trees into (1) sucking up particulate and (2) giving particles a place to land. 1. How much particulate air pollution do trees suck up? Let’s talk about the most commonly talked about pollutant: particulate pollution (PM […]
Can HEPA filters capture nanoparticles?
Many big purifier companies claim only their HEPA filters capture nanoparticles, like this Molekule ad. Although this claim is false, even journalists repeat this myth. Why is this belief so pervasive? One reasonable explanation is that the definition of “HEPA” leads people down that route. For example, this definition on Wikipedia […]
Can you clean a car air filter with compressed air?
Working on DIY air purifiers for over 6 years, I’ve heard from a lot of people who have strong intuitions about cleaning car air filters. People tell me they wash their vehicle’s air filter, vacuum it, or bang it really hard. Opinions are plenty, but what about real, hard data? Can you clean air filters […]
How’s the Air Quality in Tangshan?
There are reasons to be pessimistic. Tangshan is a largely industrial city in Hebei province, which is the industrial heartland of China and one of the most polluted provinces. Tangshan also boasts one of China’s top 10 busiest ports. To get some hard data on this question, Smart Air analyzed PM2.5 air quality data from […]
Did Bangalore’s Air Quality Get Better in 2018?
Analyzing air quality data from the Berkeley Earth Project, Smart Air found that Bangalore’s air quality worsened by 7% in 2018 compared to 2017. This puts Bangalore at about 4 times the World Health Organization’s annual limit. Bangalore Air Pollution by Month Breaking down the data by month reveals exactly when air pollution was […]
Is Beijing or Delhi air worse?
Beijing and Delhi often make headlines for air polluted cities, but which city has worse air? I wanted to get some hard numbers on how the two cities’ air quality compare. The Data To do that, I analyzed PM2.5 data from the US Embassies in Delhi and government monitors in Beijing from 2015 to […]