Hey there, time traveller!
This article was published 12/5/2020 (296 days ago), so information in it may no longer be current.
As an unintentional consequence of the coronavirus pandemic, we are currently living through the largest social, economic and environmental experiment in modern history. Depending on the timing and degree of the restrictions imposed on large populations, the economic slowdown in different parts of the world is revealing important trends.
As an environmental engineer, I was interested in research on pandemic-related changes to pollution patterns. Nowhere is this more apparent than in air pollution for large urban environments. Two main questions have emerged in this context: to what extent have the lockdowns and resulting changes in economic activity impacted air quality, and does air pollution have an impact on the severity of health outcomes of viral respiratory diseases?
Living in Winnipeg, one of the cleanest-air cities of its size in the world, it is natural not to notice any changes locally. But there have been a number of news articles on sudden air quality improvements in such places as New Delhi, Wuhan, London and the entire region of northern Italy following government-imposed shutdowns. As a long-standing leader in measuring and dealing with air pollution, the city of Los Angeles presents a particularly stark case study.
Los Angeles has for many years been monitoring daily levels of air pollutants caused by the burning of fuels such as gasoline and diesel. The two indicators most closely related to traffic-generated air pollution are nitrogen dioxide (NO2) and particulate matter smaller than 2.5 micrometres in size (PM2.5).
Both of these parameters pose substantial human health hazards and are known precursers to lung cancer, heart disease, stroke and asthma. Globally, outdoor air pollution is conservatively estimated to cause 3.7 million premature deaths (mostly in low- and middle-income countries).
Since the state-imposed lockdown on March 19, Los Angeles has experienced the best air quality in its monitored history over the last 25 years. Considering PM2.5, which represent pollutants that can penetrate to the deepest parts of the lungs and cause the most severe problems, the average concentrations have never been lower, with as much as a 35 per cent reduction from the 20-year average, and 20 per cent reduction from the minimum reported in 2006 (comparing the same six-week time period).
It is expected that once stay-at-home orders are eased and traffic resumes back to the pre-pandemic normal, air pollution will quickly follow and emissions will revert to their baseline. This will present a second opportunity for studying the impact of this sudden change on a previously impossible scale. It will be a "shock-load" experiment with millions of participants, one that should truly reveal the value of clean air and the need for reduced emissions.
And what about the impact of poor air quality on viral respiratory diseases such as COVID-19? Recent studies have shown strong correlations between air pollution and the severity of disease outcomes for the coronavirus. Researchers in northern Italy have provided evidence that living in a high air-pollution area such as the hard-struck Lombardy region could be one of the main factors for much higher mortality (alongside an aging population and a relatively under-prepared health-care system).
The researchers provide data on how prolonged exposure to air pollution can cause chronic inflammation in the respiratory system, developing conditions that are more suitable for a viral attack.
Another recent study by scientists from Stanford University predicted that the lower particulate matter emissions caused by the two-month economic slowdown in China (Jan. 1 to March 1) could have saved many more lives than were lost due to the coronavirus. The authors point out that this is not an argument to intentionally slow down entire economies, or that pandemics are a net-positive for health, as the larger social and health impacts of poverty and unemployment cannot be overlooked, but that these data provide compelling arguments for cleaner air as a critical preventive health measure.
The first global pandemic in more than a century is proving to be a crisis of unparallelled difficulty in our lifetimes. The degree of human suffering, particularly for the elderly and immuno-compromised, and overall anxiety and mental anguish cannot be overstated. But, as in any crisis, there are valuable lessons to be learned and opportunities for transformational change.
As I take another deep breath of clean Manitoba air, I remain optimistic about emerging from this uncertain period with a renewed sense of action, commitment and strength. Our children deserve nothing less.
Nazim Cicek is a professor and associate head of the department of biosystems engineering at the University of Manitoba.