Researchers around the world have noted a major decline in air pollution associated with coronavirus-related lockdowns and travel restrictions. But the outcome is not reflected only in esoteric data sets. In recent weeks, residents of major cities in the Americas, Europe and Asia have been able to simply look upwards to see stunning improvements in atmospheric clarity.
The news is certainly good for stargazers and outdoor athletes. However, levels of air pollution have life-or-death implications for much of the human population, especially in urban areas. The World Health Organization asserts that over 4 million premature deaths per year are related to ambient, outdoor air pollution. Regularly breathing in dirty particulate matter can cause strokes, heart disease, chronic obstructive pulmonary disease, lung cancer and acute respiratory infections. Further, an April 5 study published by biostatistics researchers at Harvard concludes that only a small increase in concentration of dangerous particulate matter (known as PM 2.5) can cause a 15% increase in the COVID-19 mortality rate. The study looked at COVID-19 outcomes across 3,080 counties in the United States.
During the lockdown of 17 cities in Hubei province, levels of fossil fuel byproduct nitrogen dioxide in China dropped as much as 30%. Marshall Burke, a Stanford earth science researcher estimates that the 2-month industrial respite saved over 70,000 lives that would have been lost to pollution related illnesses. However, environmentalists warn that the gains will likely be reversed as the Chinese economy attempts to make up for lost time. China reportedly responded to the 2008 financial crisis with a stimulus program that caused an unprecedented spike in pollution.
The United States
Various organizations have measured notable drops in air pollution across American cities. NASA satellite imagery, shown below, clearly demonstrates the before-and-after contrast in nitrogen dioxide concentration. Los Angeles has recorded some of the most significant changes during the pandemic, with a 40% drop in PM 2.5 levels related to an 80% decline in auto traffic. Indeed, on Tuesday April 7 it registered the cleanest air of almost any major city in the world. That’s a major achievement for a city that has been ranked the smoggiest in the country in 19 of the last 20 years.
With a population of 1.3 billion people, India has 21 of the world’s 30 most polluted cities. Its people experience disturbingly high rates of respiratory disease and tuberculosis. However, since the March 24 start of its nationwide lockdown air pollution has absolutely plummeted. In New Delhi, perhaps the most polluted city on earth, both PM 2.5 and nitrogen dioxide levels dropped by more than 70% in the span of just one week. Residents of cities in Punjab have been afforded their first naked-eye views of the distant Himalayas in at least 30 years.