While the world was on lockdown, factories shut down, the streets were empty, and the air got cleaner. In the 2020 World Air Quality Report, researchers found that the air quality improved for 84% of countries as a result of the lockdown.
However, this improvement will not last once the world resumes daily activities.
The level of reductions varied wildly across the board. With some of the biggest reductions coming from cities like Singapore, Beijing, and Bangkok. They experienced a 25%, 23%, and 20% reduction in air pollution respectively.
Many other cities saw similar shifts in the right direction, and some did not. For instance, Los Angeles actually saw a 1% increase in air pollution. This was a result of the large-scale forest fires in the area, though.
How Did the Report Measure Air Quality?
Air quality can mean a lot of different things in 2021, so let’s take a closer look at the report.
This report focused on measured PM 2.5 levels in cities around the world. It is important to note that measurements in Africa and South America were not available. The measurement devices are simply not publicly available in these regions.
Researchers compared the data to previous years and then checked to see if they were with the World Health Organization’s (WHO) range for safe PM 2.5 levels.
In some cases, it could even measure the number of days a city was within the WHO guidelines.
However, the instruments used to collect this information are prone to some degree of error. Thus, the report recommends looking at the data as a trend instead of an absolute.
Why Only Measure PM 2.5?
Particulate Matter 2.5 (PM 2.5) are particles that are two and one-half microns or less in width. These particles are small enough to be breathed in and can damage respiratory systems for both animals and humans.
These particles are released from various sources indoors and outdoors. Some of these include car exhaust, burning fuel or wood, construction projects, and more. Many countries set strict guidelines to limit PM 2.5 generation.
However, the standards vary wildly from one country to another.
Extended exposure to these particles can lead to shorter lifespans and make respiratory diseases, like Asthma or Covid-19, far more deadly.
High Air Pollution Events Affected Results
Many areas around the world still experienced huge air pollution events in their regions. And these events have links with climate change.
For instance, I mentioned that despite lockdown conditions, Los Angeles still saw a 1% increase in PM 2.5. That is the result of having the worst fire season in Californian history.
These types of events affected many cities around the world and in some cases erased any improvements that came from the lockdown conditions.
That said, the air quality would be much worse in normal conditions. If the world wants to improve air quality, humanity has got a lot of work ahead.
Robert has been following and writing about environmental stories for years at GreenGeeks. He believes that highlighting environmentally friendly practices can help promote change in every household.