Pandemic Impact: Pollution Levels Plummet During Covid-19 Lockdown

The coronavirus pandemic has led to a reduction in pollution levels across the world. Hundreds of millions of people are currently in lockdown, resulting in fewer people travelling and commuting to work. This has led to a decrease in emissions of greenhouse gases, which has been observed by satellites tracking air pollution and in the form of clearer waters and skies.

In China, the first country to go into lockdown, satellite images released by NASA and the European Space Agency showed a reduction in the pollution cover over the country. Similarly, in Italy, one of the first countries outside of China to go into lockdown, there was a significant drop in nitrogen dioxide levels.

In the United States, satellite images over California and other parts of the country revealed a reduction in nitrogen dioxide. The reduction of this deadly pollutant was especially evident over San Francisco and the surrounding Bay Area, as well as over western Washington state, where Seattle is located.

While the reduction in pollution is a positive side effect of the coronavirus outbreak, scientists caution that this is only a temporary change.

How the coronavirus lockdown has improved air quality

The coronavirus lockdown has had a positive impact on air quality across the globe. With strict lockdown measures in place, many cities worldwide have seen improvements in their air quality as a result of reduced traffic and restricted outdoor activity.

In London, for example, there has been a "dramatic improvement" in air quality, according to the Mayor of London, Sadiq Khan. Oxford Street, one of the city's busiest areas, saw a 47% decrease in nitrogen dioxide (NO2), while Marylebone Road posted a 48% reduction. Similarly, in New York, Columbia University research found that carbon monoxide and carbon dioxide emissions fell by around 50% and 10%, respectively.

The European Space Agency's satellite images also showed a significant drop in air pollution in Italy, Spain, and France, the first European countries to impose lockdowns. The nitrogen dioxide levels in these countries saw a slump, and particulate matter (PM2.5) levels sharply decreased in London, Cardiff, and Bristol.

In India, the Air Quality Index (AQI) in New Delhi dropped to 93 last month, compared to 161 in March 2019. This improvement in air quality is a welcome change, as the World Health Organization (WHO) estimates that around 7 million people die annually due to air pollution.

While the lockdown measures have provided a temporary respite from air pollution, it is important to note that these improvements may be short-lived unless long-term solutions, such as the utilization of clean energy and efficient waste management systems, are implemented.

How the coronavirus lockdown has led to a reduction in greenhouse gas emissions

The coronavirus pandemic has had a significant impact on the environment, leading to a notable decrease in economic activities and a reduction in road transport and air travel. This has resulted in a drop in air pollution levels worldwide. Satellite images from the European Space Agency and NASA show a dramatic reduction in the amount of harmful greenhouse gas emissions in the atmosphere. The lockdown in China, for example, led to an estimated 25% reduction in energy use and emissions over a two-week period. Similarly, Italy, Spain, and France, which imposed early lockdowns, saw a significant decrease in nitrogen dioxide levels.

The coronavirus lockdown has also disrupted the emission-intensive airline industry, which accounts for 2.6% of global carbon dioxide emissions. With people opting to work from home and social distance, there has been a reduction in vehicle emissions and industrial activity, leading to fewer harmful particles in the air. This has resulted in improved air quality and potentially fewer premature deaths from breathing toxic air.

The pandemic has provided an opportunity for nature to take control, with animals and birds moving about freely and undisturbed. The reduction in motorboat activity in Venice, for example, has led to cleaner waterways. The lockdown has also positively impacted marine life, with olive ridley turtles laying eggs undisturbed on Odisha's Gahirmatha beach in India.

While the coronavirus lockdown has led to a short-term reduction in greenhouse gas emissions, it is unlikely to have a long-term impact on curbing global emissions. As countries return to normal industrial production levels and economic activities resume, air pollution levels are expected to rise again. However, the pandemic has offered a glimpse into the potential for a more sustainable future if long-term solutions, such as the utilisation of clean energy and efficient waste management systems, are implemented.

How the coronavirus lockdown has resulted in clearer waterways

The coronavirus lockdown has resulted in clearer waterways, with the reduction in pollution being observed on both a large and small scale. The lockdown has resulted in fewer people travelling and commuting to work, which has decreased emissions of greenhouse gases.

In Noida, India, a Nilgai was spotted walking on a usually busy road. In Kerala's Kozhikode, a critically endangered Malabar civet was seen walking on the road. Animals are taking back their spaces, with quieter streets, empty parking lots, and deserted parks. The subdued humdrum surrounding tourism and the reduced number of motorboats in Venice have led to cleaner waterways.

Satellite images from NASA and the European Space Agency (ESA) show a noticeable decrease in smog, first in China and then in Italy. The shutdown in the Po Valley, one of Europe's most polluted areas, has made the decline of some pollutants visible to the naked eye. Nitrogen dioxide (NO2), which causes the premature death of 14,600 people every year in Italy alone, has reduced significantly. The European Space Agency's satellite image showed a drastic drop in air pollution in Italy.

The lockdown in Northern Italy, one of Western Europe's pollution hotspots, has resulted in a 40% decrease in nitrogen dioxide levels. This figure represents most of the nitrogen dioxide emissions in Europe.

The coronavirus crisis has been described as one of the world's largest-scale experiments in reducing emissions and air pollution. It has been described as a "trial run" for what could be achieved if all governments took global measures to develop a low-carbon economy.

How the coronavirus lockdown has led to a decrease in noise pollution

The COVID-19 lockdown has led to a decrease in noise pollution, with the world experiencing the most dramatic reduction in anthropogenic seismic noise in recorded history. The lockdown has resulted in less economic activity, including a drop in road transport, and the shutdown of factories, commercial establishments, and vehicular movement. This has led to a significant drop in pollution levels across the world.

The decrease in noise pollution during the lockdown has been observed and studied by scientists and researchers worldwide. According to a study by seismologist Thomas Lecocq of the Royal Observatory of Belgium, there was a significant drop in high-frequency anthropogenic seismic noise during the lockdown. This reduction in noise pollution was most pronounced in high-density areas, such as cities, but it was also noted in low-density rural areas and isolated stations, such as one located roughly 150 meters below the Black Forest in Germany.

The decrease in noise pollution has had several positive impacts. Firstly, it has provided a quieter environment for people, reducing stress levels and the risk of hearing loss. Additionally, the reduced noise pollution has benefited wildlife, allowing animals and birds to move about more freely. The lockdown has also led to a decrease in air and water pollution, with emissions of greenhouse gases, nitrogen dioxide, and carbon monoxide falling significantly. This has resulted in cleaner air and improved water quality in many parts of the world.

The COVID-19 lockdown has offered a unique opportunity to study the impact of human activity on the environment and to assess the extent of anthropogenic noise. By comparing pre-pandemic and lockdown data, scientists can better characterise human-generated noise and differentiate it from natural noise. This will help improve seismic monitoring and the detection of seismic hazards in the future.

How the coronavirus lockdown has led to a reduction in light pollution

The COVID-19 lockdown has led to a clear drop in air pollution levels, and astronomers have been keen to see if restrictions have reduced light pollution levels. The lockdown has been a 'natural experiment' in understanding the relationship between human activity and the environment.

The main source of information on global night-time light emissions is the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument, which is aboard the Suomi NPP satellite. The problem with using this dataset to compare light pollution before and during the pandemic is that the images are taken at 1:30 am local time, long after most people have gone to sleep and turned off their lights.

To overcome this, Máximo Bustamante-Calabria at the Astrophysical Institute of Andalucía, and his team, combined satellite imagery with local ground measurements of sky brightness in Granada, Spain. They collected data before the pandemic and during the lockdown from mid-March to the end of May 2020.

The data revealed that during the lockdown, the overall light output of the city had decreased by around 20%. This drop was even more pronounced in the blue end of the light spectrum, with a 45% decrease in sky brightness. This is due to the reduction in vehicle headlights, private lighting, and ornamental illumination of city monuments.

The lockdown has meant a dramatic decrease in rush-hour traffic, leading to fewer headlights in towns and cities during the darker months. These lights are usually metal halide or LED lamps that produce a blue-white light. Most of these lights are turned off by the early hours and are missed by the satellite imagery. VIIRS data does not record any significant difference in the light emission of cities before and during lockdown. Given that outdoor activity decreased by up to 90% during the lockdown, Bustamante-Calabria concludes that late-night emissions are dominated by permanent lighting that doesn't respond to the behaviour of citizens. This is a waste of energy and resources and a source of frustration for amateur astronomers.

The lockdown has also meant a reduction in light pollution from towns and cities, as office buildings closed, evening traffic jams lessened, and large-scale gatherings were cancelled.

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