R rate for Covid-19 is higher in areas with poorer air quality – study

Pollution DOES increase coronavirus risk: R rate for Covid-19 is higher in areas where the air quality is poorer, study finds’

  • Researchers studied different factors such as population density and lockdown 
  • They compared those factors to the R rate and pollution levels in US locations
  • The team found a linear link between the R rate of the virus and pollution levels 

Areas with higher levels of air pollution are more likely to more Covid-19 cases, according to a new study that found a clear link between pollution and the R rate. 

Researchers from Washington University in St Louis compared the R rate in US towns and cities with population density and pollution estimates for each location. 

They found there was a higher R rate in places with greater levels of PM2.5 – particles of pollution – in the atmosphere compared to areas with a cleaner sky. 

The R rate is an indication of how fast Covid-19 is spreading, if it is above one then one person can spread the illness to more than one person.

The authors say someone’s health when they get Covid-19 impacts how ill they become and the same applies to how clean air is and fast the virus spreads.    

According to new research from the McKelvey School of Engineering at Washington University, pollution may bear part of the blame for the rapid proliferation of SARS-CoV-2, the virus responsible for the spread of COVID-19

Rajan Chakrabarty and colleagues examined 43 confounding factors including pollution levels, population density and any stay at home orders in April 2020 across US cities with the highest rate of R.

‘There was a strong, linear association between PM2.5 exposure and R,’ he said.

PM2.5 refers to ambient particles with a diameter of 2.5 micrometers or less; at that size, they can enter a person’s lungs and cause damage. 

For this reason, PM2.5 can be detrimental to respiratory health. But how this relates to the spread of COVID-19 through a population had yet to be explored.  

‘I was thinking, why, in the majority of the US states, have we had such a rapid spread of the virus?’ Chakrabarty said. 

‘We wanted to confine our study to the point when the shutdown was in place. For the most part, people did remain confined from early March until the end of April.’

The team decided to look at places where R was greater than one and in each location examine 43 different factors – including population density, age distribution, even time delays in states’ stay-at-home orders.

Then, using pollution estimates across the US between 2012 and 2017 the team looked for any relationships between R and pollution.

Researchers from Washington University in St Louis compared the R rate in US towns and cities with population density and pollution estimates for each location 

Using computer models they found that the R rate increased by 0.25 for every 10 per cent rise in sulfate, nitrogen dioxide or ammonium in PM2.5 particles.  

‘Annual mean PM2.5 national standards are set at or below 12 micrograms per cubic meter, below that you are supposed to be safe,’ Chakrabarty said. 

‘What we saw, the correlation we’re seeing is well below that standard.’, said Chakrabarty, suggesting the ‘safe exposure’ levels may be set too high.

They saw a rapid increase in R when PM2.5 exposure levels were below 6 micrograms per cubic meter.


PM is a mixture of solid particles and liquid droplets found in the air.

They are created from a variety of sources, including traffic, construction sites, unpaved roads, fields, smokestacks or fires.

Most particles form in the atmosphere as a result of reactions of chemicals such as sulfur dioxide and nitrogen oxides. 

Some PM, such as dust, dirt, soot, or smoke, is large or dark enough to be seen with the naked eye. 

Other PM is so small it can only be detected using an electron microscope. 

PM2.5 – of diameters that are generally 2.5 micrometers and smaller – differ from PM10 – 10 micrometers and smaller.

Source: US EPA 

Chakrabarty hypothesizes this initial increase in R, which is followed by a plateau once levels hit 6 micrograms per cubic meter, is a result of initial changes in condition; when the air is free of PM2.5, an individual is unaffected.  

The initial exposure is the catalyst for change in lung health, resulting in a change from non-susceptibility to susceptibility, which is reflected in the increasing R.

Basically as people are exposed to the particle matter, it impacts the lungs which in turn makes someone more susceptible to Covid-19 – and in turn increase the R rate.  

‘Decades of strict air quality regulations in the US have resulted in significant reductions of nitrogen dioxide levels,’ the authors wrote in the paper’s conclusion.

However, ‘recent reversal of environmental regulations which weaken limits on gaseous emissions from power plants and vehicles threaten the country’s future air quality scenario.’

‘Instead of working to resolve this issue, these reversals may be setting us up for another pandemic,’ Chakrabarty said. 

Previous studies published in July and August that also found a link between coronavirus and air pollution inspired the latest work by Chakrabarty.  

First, a July paper in the journal Science found that levels of susceptibility to COVID-19 is a driving factor for the pandemic; it is more important than temperature, which researchers initially thought might play an outsized role.

Then in August, research published in the Journal of Infection found that the highest number of cases of COVID-19 with severe illness were in places with higher pollution levels. 

Before that work, a Harvard study in April found a link between a severe spike in coronavirus deaths and air pollution from PM2.5 particles. 

Researchers found that even a small increase in PM2.5 concentration is linked to a significantly higher chance of death after contracting the coronavirus. 

The findings have been published in the journal Science of the Total Environment. 

Revealed: MailOnline dissects the impact greenhouse gases have on the planet – and what is being done to stop air pollution


Carbon dioxide

Carbon dioxide (CO2) is one of the biggest contributors to global warming. After the gas is released into the atmosphere it stays there, making it difficult for heat to escape – and warming up the planet in the process. 

It is primarily released from burning fossil fuels such as coal, oil and gas, as well as cement production. 

The average monthly concentration of CO2 in the Earth’s atmosphere, as of April 2019, is 413 parts per million (ppm). Before the Industrial Revolution, the concentration was just 280 ppm. 

CO2 concentration has fluctuated over the last 800,000 years between 180 to 280ppm, but has been vastly accelerated by pollution caused by humans. 

Nitrogen dioxide 

The gas nitrogen dioxide (NO2) comes from burning fossil fuels, car exhaust emissions and the use of nitrogen-based fertilisers used in agriculture.

Although there is far less NO2 in the atmosphere than CO2, it is between 200 and 300 times more effective at trapping heat.

Sulfur dioxide 

Sulfur dioxide (SO2) also primarily comes from fossil fuel burning, but can also be released from car exhausts.

SO2 can react with water, oxygen and other chemicals in the atmosphere to cause acid rain. 

Carbon monoxide 

Carbon monoxide (CO) is an indirect greenhouse gas as it reacts with hydroxyl radicals, removing them. Hydroxyl radicals reduce the lifetime of carbon dioxide and other greenhouse gases. 


What is particulate matter?

Particulate matter refers to tiny parts of solids or liquid materials in the air. 

Some are visible, such as dust, whereas others cannot be seen by the naked eye. 

Materials such as metals, microplastics, soil and chemicals can be in particulate matter.

Particulate matter (or PM) is described in micrometres. The two main ones mentioned in reports and studies are PM10 (less than 10 micrometres) and PM2.5 (less than 2.5 micrometres).

Air pollution comes from burning fossil fuels, cars, cement making and agriculture 

Scientists measure the rate of particulates in the air by cubic metre.

Particulate matter is sent into the air by a number of processes including burning fossil fuels, driving cars and steel making.

Why are particulates dangerous?

Particulates are dangerous because those less than 10 micrometres in diameter can get deep into your lungs, or even pass into your bloodstream. Particulates are found in higher concentrations in urban areas, particularly along main roads. 

Health impact

What sort of health problems can pollution cause?

According to the World Health Organization, a third of deaths from stroke, lung cancer and heart disease can be linked to air pollution. 

Some of the effects of air pollution on the body are not understood, but pollution may increase inflammation which narrows the arteries leading to heart attacks or strokes. 

As well as this, almost one in 10 lung cancer cases in the UK are caused by air pollution. 

Particulates find their way into the lungs and get lodged there, causing inflammation and damage. As well as this, some chemicals in particulates that make their way into the body can cause cancer. 

Deaths from pollution 

Around seven million people die prematurely because of air pollution every year. Pollution can cause a number of issues including asthma attacks, strokes, various cancers and cardiovascular problems. 


Asthma triggers

Air pollution can cause problems for asthma sufferers for a number of reasons. Pollutants in traffic fumes can irritate the airways, and particulates can get into your lungs and throat and make these areas inflamed. 

Problems in pregnancy 

Women exposed to air pollution before getting pregnant are nearly 20 per cent more likely to have babies with birth defects, research suggested in January 2018.

Living within 3.1 miles (5km) of a highly-polluted area one month before conceiving makes women more likely to give birth to babies with defects such as cleft palates or lips, a study by University of Cincinnati found.

For every 0.01mg/m3 increase in fine air particles, birth defects rise by 19 per cent, the research adds. 

Previous research suggests this causes birth defects as a result of women suffering inflammation and ‘internal stress’. 

What is being done to tackle air pollution? 

Paris agreement on climate change

The Paris Agreement, which was first signed in 2015, is an international agreement to control and limit climate change. 

It hopes to hold the increase in the global average temperature to below 2°C (3.6ºF) ‘and to pursue efforts to limit the temperature increase to 1.5°C (2.7°F)’.

Carbon neutral by 2050 

The UK government has announced plans to make the country carbon neutral by 2050. 

They plan to do this by planting more trees and by installing ‘carbon capture’ technology at the source of the pollution.

Some critics are worried that this first option will be used by the government to export its carbon offsetting to other countries.

International carbon credits let nations continue emitting carbon while paying for trees to be planted elsewhere, balancing out their emissions.

No new petrol or diesel vehicles by 2040

In 2017, the UK government announced the sale of new petrol and diesel cars would be banned by 2040.  

However,  MPs on the climate change committee have urged the government to bring the ban forward to 2030, as by then they will have an equivalent range and price.

The Paris Agreement, which was first signed in 2015, is an international agreement to control and limit climate change. Pictured: air pollution over Paris in 2019.

Norway’s electric car subsidies

The speedy electrification of Norway’s automotive fleet is attributed mainly to generous state subsidies. Electric cars are almost entirely exempt from the heavy taxes imposed on petrol and diesel cars, which makes them competitively priced.

A VW Golf with a standard combustion engine costs nearly 334,000 kroner (34,500 euros, $38,600), while its electric cousin the e-Golf costs 326,000 kroner thanks to a lower tax quotient. 

Criticisms of inaction on climate change

The Committee on Climate Change (CCC) has said there is a ‘shocking’ lack of Government preparation for the risks to the country from climate change. 

The committee assessed 33 areas where the risks of climate change had to be addressed – from flood resilience of properties to impacts on farmland and supply chains – and found no real progress in any of them.

The UK is not prepared for 2°C of warming, the level at which countries have pledged to curb temperature rises, let alone a 4°C rise, which is possible if greenhouse gases are not cut globally, the committee said.

It added that cities need more green spaces to stop the urban ‘heat island’ effect, and to prevent floods by soaking up heavy rainfall. 

Source: Read Full Article