In September 2019, the Delhi government and Delhi Chief minister Arvind Kejriwal announced Delhi’s PM2.5 air pollution was down 25% in 2019 over the previous year. Yet there is doubt. Thewire.in 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 […]
Category: Air Pollution
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 […]
Smart Air Provides Clean Air to Automobile Giant Ford
Right after moving to their new office in the Chimes building in Gurgaon, Ford India was experiencing problems with outdoor particulate pollution (PM2.5) and chemicals (VOCs) off-gassing from new furniture, carpets, paints, and other remodeling work. To tackle these problems and protect the health of their staff, Ford India reached out to Smart Air in […]
What is PM0.3 and Why Is It Important?
What does “PM” mean? PM stands for particulate matter–particles in the air. These particles can be solids (like dust) or liquids (like drops of water). Some common sources of PM are car exhaust, smoke from coal-fired power plants, pollen spores, and dust from construction sites. Sometimes you’ll see “PM” followed by a number, like […]
What is the difference between the PM2.5 and AQI measurements?
There are some good answers here Richard Muller and Sandeep Chowdary. I’ll add a bit more explanation about PM 2.5 AQIs and a funny quirk about how they are calculated using stepwise linear functions. How is PM 2.5 AQI calculated? (Note: this is for the US AQI scale. We’ll be discussing different countries’ scales […]