Air pollution statistics
It seems like there’s a new story about air pollution in the news every day. Here’s seven statistics that demonstrate why it’s important—and what you can do about it.
In November 2015, air pollution in Shenyang reached a level 56 times higher than WHO safe levels1.
The World Health Organization consider a maximum safe level of PM2.5—airborne particles smaller than 2.5 micrometers in diameter—as 25 µg/m³ over a 24-hour period and 10 µg/m³ as an annual mean2. So when pollution in Shenyang in China’s Liaoning province exceeded 1400 µg/m³ at the end of 2015, it was 56 times higher than the WHO daily safe limit. Visibility was reported to be just 100 metres and local hospitals saw an influx in the number of patients with breathing complaints.
Air pollution is responsible for 5.5 million deaths a year—the fourth greatest risk of death worldwide3.
The Global Burden of Disease project found that more than five-and-a-half million people die prematurely each year as a result of air pollution. The vast majority of these were in China and India where 1.6 million and 1.3 million lives are lost respectively to poor air quality. This makes air pollution the fourth greatest risk of death ahead of obesity, malnutrition, and alcohol and drug abuse.
Reducing PM2.5 would be more beneficial to life expectancy than eliminating car accidents and passive smoking, combined.
A UK government study investigated the impact of air pollution on life expectancy. It found that eliminating car accidents would extend life expectancy by two months and eradicating passive smoking would see a two-and-a-half-month increase in predicted life. But a 10 µg/m³ reduction—not elimination—of PM2.5 would increase life expectancy by seven-and-a-half months.
Spending three days in Delhi took six hours off US President Obama’s life expectancy4.
During a state visit to the Indian capital in 2015, President Obama spent three days inhaling the acrid air that the city’s residents face every day. PM2.5 levels averaged between 76 – 85 µg/m³ during his stay, which translated to a two-hour reduction in the President’s life expectancy for each day of the visit.
The Great Smog claimed the lives of 4,000 Londoners in 1952.
For four December days in 1952, a thick smog descended on London. Residents and power stations were burning increased levels of coal to cope with colder temperatures. And this combined with an anticyclone to cause cold, pollution-filled air to be trapped under a layer of warm air. Visibility plummeted to a few yards and in the weeks following the event an estimated 4,000 people died from pollution-related illness. Mortality rates remained higher than normal for months afterwards.
98.5% of particles in the air are smaller than 1 µm in diameter.
During the days of the Great Smog, particulate in the air was relatively coarse. But changes to fuels and how we convert it to energy have seen smaller particles emerge as the most common in our atmosphere. Now, particulate smaller than 1 µm in diameter (PM1) make up over 98% of the particles in the air around us by number. Unfortunately, PM1 is also much more harmful than larger particulate—travelling deep into our lungs and entering the bloodstream, rather than being caught in the nose and throat.
We spend around 90% of our time indoors where air pollution is estimated to be two to five times higher than outside.
Traditionally, we didn’t work indoors, shop indoors or spend our leisure time indoors. Nor did we travel to any of these places cocooned inside a vehicle. Now, we spend approximately 90% of our time indoors. And it is here that air quality is at its worst—around two to five times higher than the level of pollution found externally.
What can you do?
While it’s difficult to defend against air pollution outside, the right air filters can protect building inhabitants from the danger of airborne particulate inside. So, it’s important to choose a filter that’s capable of capturing the levels of pollution that it’s going to be up against. That means looking at the level of PM in your environment and comparing it with the filter’s performance. But it’s important not to over specify the filtration efficiency. Choosing a filter that offers more filtration efficiency than you really need risks choking the air flow and raising the energy consumption of your whole HVAC system.