Air pollution and Covid-19 linked by UCD researcher

Orlaith Doherty investigates what UCD’s Professor Francesco Pilla study on air pollution changes over lockdown has yielded and how we can keep our fundamental right to clean air a reality

The World Health Organisation (WHO) in their ‘Ambient Air Pollution’ report in 2016 reported that air pollution is a major cause of premature death and illness worldwide. The most critical air pollutants are particulate matter (PM), ozone (O3), nitrogen dioxide (NO2) and sulfur dioxide (SO2). These chemicals are emitted largely through motorized transport, burning of fossil fuels for home heating, and industrial emissions. However, PM is generally considered the main player in air pollution. 

PM can come in the form of ‘PM 10’ or ‘PM 2.5’. The numbers represented the size of the particles in the air, with PM 10 particles being 10 microns or micrometres or greater in diameter and PM 2.5 being 2.5 microns or less in diameter. The WHO considers PM 2.5 to be the most hazardous air pollutant to human health as the inhalation of very small particles into the lungs can penetrate and accumulate in lung tissue where it can enter the bloodstream, creating risk for heart, lung disease, and stroke. It has been linked to the causation of asthma in the developing respiratory systems of children as well as exacerbating other respiratory conditions, such as cystic fibrosis. 

“In 2018, the Environmental Protection Agency (EPA) reported that approximately 1,180 premature deaths in Ireland were caused due to poor air quality.”

In 2016, 91% of the world’s population was living in places that the WHO classed as below breathable air quality guidelines. Their report states that air pollution was the cause of approximately 1 in 9 deaths worldwide. In 2018, the Environmental Protection Agency (EPA) reported that approximately 1,180 premature deaths in Ireland were caused due to poor air quality. The country’s main human-driven sources of PM 2.5 was road traffic and the burning of solid fuels for home heating. 

University College Dublin Professor, Francesco Pilla, is one of the principal investigators co-ordinating an EU-funded project called iSCAPE, which stands for Improving the Smart Control of Air Pollution in Europe. The iSCAPE project is looking at ways we can design structures in communities in six cities across Europe to reduce exposure to air pollutants, building awareness of how cities and people can reduce air pollution. This month he co-wrote an article published in the Environmental Research Journal examining the status and impact of improved air quality in world cities due to COVID-19 mandatory lockdowns causing a temporary reduction in human-driven emissions, namely reduced traffic emissions. 

Due to the emergence of the COVID-19 pandemic, countries across the world imposed mandatory lockdowns to restrict human-mobility. This triggered the reduction of motorized traffic, which is one of the key sources of urban air pollution. Professor Francesco Pilla’s research work has made an effort to evaluate the air pollution levels of many key air pollutants after the implementation of these COVID-19 restrictions. Professor Pilla and his team performed their assessments on key air pollutants by combining both satellite and ground measurements. 

“This also suggests that the controlled motorization traffic pollution and limiting of other unsustainable human activities could be the most effective ways of improving the air quality of cities. ”

A total of 20 cities had been selected to evaluate the impact of lockdown on air quality. These cities are Antwerp, Barcelona, Brussels, Chicago, Cologne, Denver, Frankfurt, London, Los Angeles, Madrid, Milan, New York, Paris, Philadelphia, Rotterdam, São Paulo, Tehran, Turin, and Utrecht. These cities were considered based on two criteria: high air pollution and high COVID-19 casualties. 

They estimated the variations in air pollution levels over time across different locations during the lockdown period from 1 February to 11 May in 2020 using a reference from the same period in 2019. The satellite remote sensing technology they used to analyse air pollutants in the listed cities was called TROPOMI. This stands for ‘TROPOspheric Monitoring Instrument’. It is an instrument attached to the Copernicus Sentinel-5 precursor satellite, which was launched by the European Space Agency in 2017 to perform atmospheric measurements with a high spatio-temporal resolution that is used for air quality assessment and climate forecasting. 

Ground monitored air quality data was collected from different governmental sources such as the American and European Environmental Protection Agencies, and open data repositories, like the Google Earth Engine cloud platform. The ground monitored air quality data was collected on three key air pollutants: NO2, PM 2.5, and PM 10 covering the time period of 1st February to 11th May in both 2019 and 2020.

The research demonstrated a strong connection between the decline in traffic volumes and a reduction of NO2, PM 2.5, and PM 10 emissions across the cities. Specifically, it found that between the cities assessed during the study time period, an estimated 1,310, 401, and 430 premature cause-specific deaths respectively were avoided by the reduction of emissions by the mandatory lockdowns. 

This also suggests that the controlled motorization traffic pollution and limiting of other unsustainable human activities could be the most effective ways of improving the air quality of cities. In reality, that would include policies based on an extensive rollout of active transport walking and cycling infrastructure, more comprehensive and electrified public transport amenities, and great provision of green space in cities to aid in the diffusion of pollution. The results of Professor Pilla’s study can be used as a reference to introduce new public policies for promoting these critical public health policies to mitigate the hazards of air pollution towards our health -not to mention the cardiovascular benefits of being more active with the greater, more accessible active transport facilities.

Many city government authorities, including in Dublin, have capitalized on the opportunity COVID-19 has given to rollout active transport infrastructure. The Dun Laoghaire Rathdown County Council have most notably rolled out extensive protected bike lanes and extended pedestrian footpaths in their jurisdiction. The protected cycle lane from Blackrock to Dun Laoghaire has been enjoyed by everyone from young children to older adults over the last year and is a snapshot into the healthier potential of our city. This study, co-investigated by UCD Professor Francesco Pilla, helps support these initiatives beyond their purpose for COVID-19, and to look towards the future to help us rebuild healthier, more accessible, and less polluted cities.