Credit: DW/ C.Furlan

Coronavirus forces drops in air pollution in atmosphere _temporarily

Climate scientists say long-term solutions to address air pollution problems including climate change are still needed, including shifts in economic paradigms

From satellites around the world, climate scientists have observed a glimpse of changes in the atmosphere; key air pollutants are dropping while several economic activities and lifestyles have been shifted or shut down due to the outbreaks of Coronavirus worldwide.

At the US National Center for Atmospheric Research, atmospheric chemistry observation and modeling scientists have learned that the large scale lockdown in China early in the year has resulted in significant decreases in atmospheric pollution, as captured by multiple satellite observations.

They said while releasing their results this week that these observations highlight the significant role that human activities are playing in modifying the environment, and also provide an opportunity to understand, verify, and quantify the impact of various activities.

However, some other scientists, while acknowledging these points, have also cautioned that these drops of the air pollutants are just temporary and long-term solutions to address these complicated air pollution problems are still needed.

Nasa maps showing concentrations of NO2 over China between January and February. 
Credit: NASA

The ACOM scientists have monitored the changes in tropospheric carbon monoxide (CO) over eastern China using data from NASA satellites.

They have found the changes between the early lockdown period ( February 1 to March 10, 2020) and the same period in the 2019 season; 30 to 45% peak reductions in CO.

Significant changes are also observed in Nitrogen Dioxide NO2 with around 70% peak reductions during the same period.

“These similarities and differences in the changes of the two pollutants provide a research opportunity for quantifying their sources”

“These data provide insight into pollution emissions in China, and also how much human activities are modifying the atmosphere,” the scientists noted.

However, they cautioned that to quantify changes in emitted pollution, careful quantitative analysis is needed to account for satellite sampling differences and annual variations in meteorology, including the effects of cloud coverage, and other pollution sources such as wildfires.

The ACOM scientists’ findings are echoed by those from Europe.

The European Environment Agency has taken a look at the impacts of the measures against the spread of the Coronavirus on air quality in Europe this week too, and it has found a drop in air pollution, especially due to reduced traffic in cities.

The EEA’s data for recent weeks, taken from a network of more than 4,000 local air pollution measurement stations across Europe, show how concentrations of nitrogen dioxide (NO2), a pollutant mainly emitted by road transport, have decreased in many Italian cities.

For example, in Milan, the capital of Lombardy which is the hardest hit by the Coronavirus, average concentrations of NO2 for the past four weeks have been at least 24 % lower than four weeks earlier this year.

And the average concentration during the week of 16-22 March alone was 21 % lower than for the same week in 2019.

In Bergamo of the same state, there has been a constant decline in NO2 pollution over the past four weeks with the average concentration during the week of 16-22 March was 47 % lower than for the same week in 2019.

And in Rome, average NO2 concentrations for the past four weeks were 26-35 % lower than for the same weeks in 2019.

Credit: European Space Agency

The EEA said similar trends can be seen in other European cities where lockdown measures have been implemented during the week of 16-22 March.

For example, in Barcelona of Spain, the average NO2 levels went down by 40 % from one week to the next. Compared with the same week in 2019, the reduction was 55 %, the agency said.

However, EEA’s Executive Director, Hans Bruyninckx, remarked that addressing long-term air quality problems requires ambitious policies and forward-looking investments.

“The current crisis and its multiple impacts on our society work against what we are trying to achieve, which is a just and well-managed transition towards a resilient and sustainable society,” said Mr Bruyninckx.

Critical air pollutant like Carbon Dioxide (CO2) has also been reported to have decreased along with other pollutants.

Carbon Brief stated that key industries in China were operating at much lower-than-normal levels during the quarantine.

Oil refinery operations in Shandong province, for instance, were cited as being at their lowest since 2015. And the average coal consumption at power plants also reached a four-year low.

As a result, CO2 emissions were at least 25 percent lower in the two weeks following the Lunar New Year compared to 2019, it noted.

However, that decrease in CO2 emissions for two weeks means it would only reduce annual totals by approximately 1 percent, it further noted.

Credit: WMO

The World Meteorological Organization (WMO) said there have been localized improvements in air quality following efforts to control the Coronavirus pandemic, but it is too early to assess the implications for “concentrations” of greenhouse gases which are responsible for a critical problem of long-term climate change.

Carbon dioxide levels, it said, at key observing stations have so far this year been higher than last year.

Any cuts in emissions as a result of the economic crisis triggered by the virus therefore are not a substitute for concerted Climate Action, the organisation noted.

WMO cited data from the US National Oceanic and Atmospheric Administration, saying the February monthly average of atmospheric CO2 at Mauna Loa observatory in Hawaii, the world’s longest continual observing station and a benchmark station of the Global Atmosphere Watch Network, was 414.11 parts per million, compared to 411.75 ppm in February 2019.

And according to Australia’s meteorological agency, CSIRO, another benchmark station, Cape Grim in Tasmania, average CO2 levels were 408.3 ppm in February, up from 405.66 ppm in February 2019, it cited.

WMO said emissions are different from concentrations as the latter present what remains in the atmosphere.

So, it is too early to draw firm conclusions on the significance of this economic slowdown on atmospheric greenhouse gas concentrations, the organisation pointed.

The economic slowdown, WMO noted, even sprung back before with emissions growth.

As citing a study in Nature Climate Change, it said the 2008-2009 global financial crisis was followed by strong emissions growth in emerging economies, a return to emissions growth in developed economies and an increase in the fossil fuel intensity of the world economy.

WMO Secretary-General Petteri Taalas said past experience rather suggests that emissions declines during economic crises are followed by a rapid upsurge.

We need to change that trajectory, he said.

“Now is the time to consider how to use economic stimulus packages to support a long-term switch to more environmentally and climate-friendly business and personal practices.

“The world needs to demonstrate the same unity and commitment to climate action and cutting greenhouse gas emissions as to containing the Coronavirus pandemic. Failure in climate change mitigation could lead to greater human life and economic losses during the coming decades,” Mr Taalas said.