Increasing diversity of COVID-19 strains: insights into evolutionary divergence and public health

 To be clear, I am not a virologist, nor am I a public health expert. But I do know how to analyze patterns of evolutionary diversity. Research into the SARS-CoV-2 virus that has given rise to the COVID-19 pandemic has greatly enhanced our understanding of global disease dynamics, mRNA vaccines and public health responses to a global crisis. But the COVID-19 pandemic also has the potential to provide fundamental insights into basic ecological and evolutionary processes. 

While a lot has been written about how COVID-19 lock-downs have had noticeable repercussions on air quality and wildlife in cities, the virus lends itself as a microcosm into natural world dynamics. SARS-CoV-2 is now the most studied non-human organism on Earth, and we've witnessed its spread across the globe (which provides insights into invasion biology), it has spread exponentially in populations at times (showcasing the power of models to predict spread), and its rapid diversification is evolution in real time.

Understanding how SARS-CoV-2 strain diversity is generated is of fundamental importance for public health policies. And SARS-CoV-2 is evolving and diversifying. In Ontario, Canada, we have a wonderful resource from Public Health Ontario that publishes data on the evolution of strain diversity and provides a wonderful graphical interface. This interface focuses on the SARS-CoV-2 phylogeny (that is the evolutionary family tree connecting strains to their ancestors) in Ontario.

An example phylogeny

Using their open data, I addressed a simple question, is the evolutionary diversity (measured by the distances separating strains) increasing over time?

To test this, I calculated a statistical measure called the standardized effect size of the mean pairwise distances (SES.MPD) which quantifies the average distances separating strains standardized by random permutations (in this case 500 randomizations) so that a SES.MPD value of 0 means that the evolutionary diversity of a group of strains is no different than a same number of strains randomly selected from the phylogeny. Negative values mean that strains are more closely related on the phylogeny than you expect by chance (referred to as under-dispersed), and positive values mean strains are more distantly related (over-dispersed). I did these calculations for each month since the pandemic hit Ontario (March 2020) and for the seven different regions of Ontario.

Analysis of the standardized effect size of the mean pairwise distances (SES.MPD) of SARS-CoV-2 strains across the seven regions in Ontario since the start of the pandemic. The dashed horizontal line indicates a value of 0 (no different than random expectation) and points outside of the grey box are statistically significantly different than random.

What I found was that early on in the pandemic, the strains were under-dispersed, meaning that they were more closely related and genetically similar than expected by chance. But over time the dissimilarity between strains increases and by May 2021 (the last data in the graphs), many of Ontario's regions had significantly over-dispersed strains. This means that strains found in the populations in May 2021 were generally more dissimilar from one another than early on.

Why this matters is that vaccines and other treatments are typically developed on a single strain or from samples collected at a specific time point. If strains are relatively genetically similar, then it is highly probable that treatments will be successful across the strains. However, as strains diversify and become more dissimilar, then treatments might become less effective overall. 

Had the spreading infection been dominated by single strains, with very few newer strains replacing older ones, we would expect that the SES.MPD values remain below zero, and would make it easier to track strains and adapt treatments.

These patterns are also valuable for insights into ecology and evolution. We often look at SES.MPD values to interpret how different processes structure diversity (like competition, predation, pollution, etc.), but we often don't have good evidence of how historical evolutionary processes can drive SES.MPD differences. The plots above show that rapid evolutionary diversification results in linearly increasing SES.MPD values.

COVID-19 and nature: Is wildlife conservation also in “lockdown”?

Guest post by Nina Adamo, Masters of Environmental Science Candidate at the University of Toronto-Scarborough

Within the surge of news coverage for the COVID-19 pandemic, you may have heard about the increase in the reporting of wildlife sightings in some urban areas across the globe, such as in this CBC article. With less people venturing outside of their homes in efforts to prevent the spread of the coronavirus, the media in multiple countries around the globe have been reporting more sightings of wildlife that are usually rarely or uncommonly seen in suburban and urban areas.^6,7 This was the case when a herd of Kashmir goats were seen strolling through the deserted streets of a town in Wales during the lockdown.⁷

A herd of Kashmir goats roaming the empty streets of a town in Wales.³

This also happened in Toronto, Canada this past summer, where foxes were seen denning in typically busy areas of the city during lockdown.² To read more about the Tale of Toronto’s boardwalk foxes, check out this article in Maclean’s magazine. What does this unusual and greater number of wildlife sightings in urbanized areas mean for wildlife behaviour and wildlife conservation as a whole?

Fox kits on the boardwalk of Woodbine beach in the city of Toronto, Canada.⁴

The “rolling lockdowns” implemented as strategies to contain the novel coronavirus have severely restricted human activities, and have had cascading effects through public health systems and economies.⁶ What is less clear however, is what impacts this sudden change in human behaviour may have on wildlife and what the long-term implications are for the fate of wildlife conservation across the globe and into the future. The interaction between our societal response to COVID-19 and wildlife is a novel and emerging topic that scientists have only just begun to investigate. Unsurprisingly, initial findings tell a complex story, where lockdowns have had both positive and negative impacts on wildlife and the conservation of biodiversity.^1,5,6

Initial positive effects of lockdowns on the environment, in general, include reductions in industrial activities and manufacturing, and restrictions on the transport of natural resources, leading to a decrease in global emissions and an increase in air and water quality.^1,5 Other studies report decreases in noise pollution leading to an increase in sightings of animals in cities and harbours, along with reduced numbers of animals being killed by ships in waterways and by vehicles on roads.^1,6 Similarly, a study conducted in Italy, the first country to implement a lockdown, found a greater proportion of sightings of species such as the crested porcupine in suburban and urban areas in 2020 compared to previous years.⁶ The same study also found evidence for an increase in the abundance and breeding success of certain species of birds during lockdown in urban areas, likely due to general decrease in the presence of humans.⁶

A crucial point to consider about all of these positive observed effects is that many of these effects, such as the presence of uncommon animals in urban areas, are likely to only be temporary and prone to reversal once restrictions are lifted and humans begin to revert back to pre-lockdown behaviours.^5,6 It is also worth noting that many observed increases in animal numbers under lockdown conditions could have resulted from an increase in observation effort with more people participating in hobbies such as birding due to restrictions on other activities during lockdowns.⁶ Similarly, the greater detection of bird species could have been attributed to an increase in detection rates because of a reduction of background traffic noise with less traffic volume in lockdown conditions.⁶

There is great concern that the COVID-19 pandemic will severely hinder efforts to conserve biodiversity in the present as well as in the long term.⁶ During lockdown, there have been substantial delays in both species at risk management efforts and invasive species control programs,⁶ reduced funding available for conservation because of overstressed economies, reductions in wildlife-based tourism due to travel restrictions, and governmental capacity generally being prioritized for COVID-19 relief measures.^1,5 The pandemic has undoubtedly put a strain on our capacity for conservation, and many initiatives will be playing catch-up to make up for precious lost time, where many of these conservation efforts are focused on species that are already teetering on the brink.

Increased human threats to nature are also expected to occur as a result of the lockdowns.^5,6 As more people, especially in rural areas, are forced to navigate pandemic-driven economic downturns, they may have no choice but to turn to protected areas for resources.⁵ In addition to this, the reduced funding available for hiring patrol staff such as park rangers in protected areas can result in a lower likelihood of detecting poachers and can lead to an increase in illegal killing of wildlife, which has been the pattern already observed in multiple places across the globe including Europe, Africa, and Asia.^1,5,6

Schematic of the potential impacts of the COVID-19 pandemic on different areas related to the conservation of wildlife in Africa, with the arrows indicating the directionality of these impacts.⁵

The surge of research examining the interaction between societal response to COVID-19 and wildlife tells a complex story.⁶ Although there were some positive effects of the lockdown observed on wildlife, these will likely only be temporary until restrictions are lifted, but the potential negative impacts could have long-lasting effects on the conservation of biodiversity.^5,6 Furthermore, activities focused on the conservation of species and habitats can also help to reduce the risk of future pandemics as the restrictions put in place to protect certain species and their habitats can help to reduce our exposure to species that are a high risk for virus transfer to humans, leading to a lower risk of future outbreaks and subsequent pandemics.⁵

Overall, although the COVID-19 lockdowns have shown some initial positive impacts on the environment and wildlife, there are significant risks associated with these lockdowns that may negatively impact the effectiveness of wildlife conservation. In order to effectively prevent the accelerated loss of biodiversity that could result from lockdowns, countries must ensure funding for conservation actions is not neglected.

  

References

1. Bates, A. E., Primack, R. B., Moraga, P., & Duarte, C. M. (2020). COVID-19 pandemic and associated lockdown as a “Global Human Confinement Experiment” to investigate biodiversity conservation. Biological Conservation, 248, 108665. https://doi.org/10.1016/j.biocon.2020.108665
2. Dhopade, P. (2020, July 7). The tale of Toronto’s boardwalk foxes. Retrieved from https://www.macleans.ca/society/environment/toronto-boardwalk-foxes-coronavirus-lockdown/  
3. Furlong, C. (2020, April 5). A herd of Kashmir goats invaded a Welsh seaside resort after the coronavirus lockdown left the streets deserted. Wildlife take to the streets as people stay indoors. [Getty Images]. Retrieved October 26, 2020 from https://www.cbc.ca/news/world/photos-wildlife-animals-take-to-streets-as-people-take-shelter-indoors-1.5519538
4. Lautens, R. (2020, July 7). A few of the young kits at Woodbine Beach in Toronto; when passersby began taking selfies with the animals, a local wildlife centre intervened. The tale of Toronto’s boardwalk foxes. [Image]. Retrieved October 23, 2020 from https://www.macleans.ca/society/environment/toronto-boardwalk-foxes-coronavirus-lockdown/
5. Lindsey, P., Allan, J., Brehony, P., Dickman, A., Robson, A., Begg, C., Bhammar, H., Blanken, L., Breuer, T., Fitzgerald, K., Flyman, M., Gandiwa, P., Giva, N., Kaelo, D., Nampindo, S., Nyambe, N., Steiner, K., Parker, A., Roe, D., … Tyrrell, P. (2020). Conserving Africa’s wildlife and wildlands through the COVID-19 crisis and beyond. Nature Ecology & Evolution, 4(10), 1300–1310. https://doi.org/10.1038/s41559-020-1275-6
6. Manenti, R., Mori, E., Di Canio, V., Mercurio, S., Picone, M., Caffi, M., Brambilla, M., Ficetola, G. F., & Rubolini, D. (2020). The good, the bad and the ugly of COVID-19 lockdown effects on wildlife conservation: Insights from the first European locked down country. Biological Conservation, 249, 108728. https://doi.org/10.1016/j.biocon.2020.108728
7. Wildlife take to the streets as people stay indoors. (2020, April 5). Retrieved from https://www.cbc.ca/news/world/photos-wildlife-animals-take-to-streets-as-people-take-shelter-indoors-1.5519538

Re-imagining the purpose of conferences in a time of isolation

It is now trite to say that the COVID-19 pandemic has impacted many aspects of routine life, from our personal to our professional realities. Every part of academic life has been touched by the pandemic, reducing all aspects of our research endeavours to virtual platforms, from coursework and student mentoring to faculty meetings and conferences.  Zooming in and out of meetings has become the norm for all of us. While there are obvious restrictions to life on an e-platform, I see an opportunity for us to use it to our advantage, to increase the impact and extent of how we communicate our science.  
 

The obligatory Zoom lab meeting screen capture.

I’ve been involved with a number of e-activities including giving departmental seminars, giving a conference talk and helping to organize a weekly on-line seminar series (Ecology Live). These experiences have led me to think quite a bit about new opportunities for giving talks and sharing ideas and findings.

One obvious casualty of COVID-19 restrictions has been conferences -large gatherings are simply untenable even if some regions are starting to reopen some activities. Some conferences were simply canceled outright early on while others have switched to online formats. These e-conferences seem like the best-case scenario allowing for scientists to share their findings while observing gathering and travel restrictions. I gave a talk in an organized oral session in an e-conference and have been contemplating signing up for another.  But I have mixed feelings. Let me be clear, the decision to move to e-format is the best decision for these conferences that have had to respond to these unprecedented changes, but moving forward are there other ways to facilitate interaction and communication? To me, the answer is yes.

The cons of the e-conference:

1. Spontaneous conversations

I don’t think fitting a traditional conference into an e-format works all that well. The point of a conference, to me, is more about the random meetings and discussions with friends and collaborators, rather than the extensive back-to-back talks, for which I have a rather low limit that I can actively listen to.  These sporadic encounters, which often amount to valuable research outputs and collaborations, are lost in the e-conference.

A mock debate at the last conference I attended before the pandemic

2. Child-care

Physical conferences have become better about providing childcare options for attendees. But, with e-conferences, the parents stuck at home with children might not have childcare options, making it difficult to attend whole sessions, and remain fully focused on the science. Added to this, is that the e-conference format with multiple concurrent sessions over the whole day is not that convenient for people at home, even without children.

3. Fees and funding

In my experience thus far, e-conferences appear to still be limiting attendance with still rather steep paywalls. The one I spoke in still had substantial fees to attend even though they were using what appeared to be university Zoom accounts. I totally understand that there are expenses, but the hefty fees limit an amazing opportunity to reach a broader audience.

Related to this, conferences traditionally are quite exclusive. Fees, travel, housing, visas and immigration all exclude people from different parts of the world, especially those who don’t have access to the same level of funding as researchers in North America and Europe. E-conferences can change this, but they have yet to. More than this, many of us are accustomed to being at institutions that bring in weekly seminar speakers, and again, people in other parts of the world have no opportunity to access these.

A route forward?

1. Seminars open for all

Working with the British Ecological Society to bring the weekly Ecology Live seminar series has been an incredible experience. Firstly, the BES has been amazingly supportive of this idea and helping to make it work. More than 3000 people have registered for this series, and from all over the world. The response from people has been phenomenal.

The lesson I take from this experience is that there is a demand for high-quality talks and that there are numerous colleagues from the global south who jump at the opportunity to hear from cutting-edge researchers. Many of these people are excluded from traditional, and likely online, conferences. If we are moving to an online format, accessibility and inclusion should be a motivating factor.

Obviously, there are expenses with delivering online content, but costs can be covered in other ways. Traditional conferences have sponsors and companies advertising their products in the main halls. These groups can still be engaged and in fact access to online audiences around the world and in permanent on-demand formats could be quite attractive to sponsors. We’ve now started including advertisements on the opening and closing slides of Ecology Live to keep the webinars free to watch.

2. Freed from time restrictions to conference length

Traditionally conferences are restricted to 3-5 days but switching to an online format means that societies are no longer subject to a conference structure. Without time limitations, e-conferences do not have to conform to sessions occurring simultaneously. By spreading talks over time, perhaps grouping by thematic topic areas, researchers would be able to attend far more talks than they would normally be able to in a traditional conference setting. I’d watch four 15-min talks on a specific area every couple of weeks.

3. A permanent record accessible by all, always

Many ecologists are quite overcome by a deluge of webinars, zoom meetings, etc. Taking the time to spend days in an e-conference is a daunting choice. Even if they are unable to watch talks live, conference organizers could make them permanent, searchable, and linkable. We post the Ecology Live talks to YouTube afterward and some of our earlier seminars have been viewed thousands of times. There is a general move towards open and transparent science, and free online talks that are permanently available is another step towards this. 

We live in a world where access to new ideas and hearing about cutting edge research is divided between the have and have-nots. Despite the limitations of COVID-19, given some planning, e-conferences can provide a powerful means to connecting the ecologists across the world, but there might be better ways forward to use these recent moves to on-line formats to better engage diverse audiences in a much more inclusive way.

 

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Have you attended an e-conference recently, or plan on attending one soon? Let me know your thoughts and opinions down below.

Publication Partners: a COVID-19 publication assistance program in conservation science

Researchers around the world are trying to keep up on work duties and responsibilities while being required to stay at home. For some people this means caring for young children or other family members, devising homeschooling, switching courses to online delivery, scheduling meetings with team members, receiving new duties from superiors, and perhaps worrying about job security. It is natural that these people may feel overwhelmed and that routine tasks, like checking references or proofreading manuscripts, might seem insurmountable.

However, for others, COVID-19 lockdowns have resulted in more time to push projects to completion and clear out backlogs. There is then inequality in the impact of COVID-19 restrictions on individuals.

These COVID-19 impacts on individuals not only have these unequal impacts on mental wellbeing and career trajectories but are on top of the desperate necessity of conservation science to continue. We win by having a greater diversity of experts communicating with one another.

Publication Partners is an attempt to address some of this COVID-19 impact inequality and to ensure that conservation science is still being published by assisting people with their manuscript preparation. This is a match-making service of the conservation community to bring researchers struggling with their current working conditions together with those that feel that have extra capacity and are willing to help others in this difficult time. The partner might be asked for publication advice, to assist with manuscript editing, help sorting and checking references, organizing tasks for revisions or preparing figures.

The idea is that the Publication Partners would normally be contributing less than would be expected for authorship and thus will be listed in the acknowledgments of the resulting paper. Publication Partners will match volunteers with those requesting support.

To volunteer or request a partner, please see this document with contact instrucitons.

As a journal editor, I see this a valuable and much needed assistance strategy. And I’m not alone. Many of the most important conservation journals have signaled their support and welcome submissions using this service. The journals support Publication Partners includes (please note that the list of journals is being updated and so will change over time):

Avocetta - Journal of Ornithology 

Biological Conservation

Conservation Biology

Conservation Evidence

Conservation Letters 

Conservation Physiology

Conservation Science and Practice

Ecological Solutions and Evidence

Endangered Species Research

Functional Ecology 

Global Ecology and Conservation

IBIS– International Journal of Avian Science

Journal of Animal Ecology

Journal of Applied Ecology

Journal of Ecology

Journal of Insect Conservation

Methods in Ecology and Evolution

Mires and Peat

Natural History Sciences 

Oryx

People and Nature 

Restoration Ecology

RIO - Rivista italiana di ornitologia - Research in Ornithology

Tropical Conservation Science

Wildfowl

 *Thanks to Bill Sutherland for sharing his thoughts on this post.

Early evidence that governmental responses to COVID-19 reduce urban air pollution

There is no doubt that the global spread of COVID-19 represents the defining crisis of the last decade. Governments around the world have scrambled to try to reduce person-to-person spread and deal with pressures on public health infrastructure. Regions with community spread have almost universally faced restrictions on travel, business and social activities. These restrictions are designed to reduce the exponential spread of COVID-19 (that is, to flatten the curve), these restrictions will also have a large number of other economic, social and environmental repercussions. Here, I ask a simple question: Has reductions in economic activity and movement caused by governmental responses to COVID-19 improved air quality in cities? I compare February 2019 and 2020 air quality measures and show that six cities that were impacted early by government restrictions in response to COVID-19 show consistent declines in five of six major air pollutants compared to cities that were impacted later (the text in this post has been modified from Cadotte 2020).

One of the most pernicious and inevitable consequences of urbanization and industrialization is the release of air pollutants. The WorldHealth Organization (WHO) estimates that about 90% of urban residents experience air pollution that exceeds WHO guidelines and that air pollution is responsible for more than four million premature deaths annually (World Health Organization 2018). Air quality is adversely affected by the aerosol release of a number of chemical compounds from agriculture, manufacturing, combustion engines and garbage incineration, and is usually assessed by measuring the atmospheric concentrations of six key pollutants: fine particulate matter (PM_2.5), course particulate matter (PM₁₀), ground-level ozone (O₃), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), and carbon monoxide (CO). These pollutants have a number of serious human health impacts (Table 1). Reducing inputs of these pollutants into urban areas requires a combination of technological advancement and behaviour change that can be stimulated by governmental regulations and incentives.

Table 1: The six commonly measured air pollutants in cities and their human health impacts.

Alterations of human, transport and industrial activity are usually the result of long-term economic and behavioural change and difficult to legislate under normal situations. However, the recent emergence of the global COVID-19 pandemic has had clear epidemiological impacts with, as of March 25, 2020, almost half a million confirmed infections and close to 20,000 deaths (World Health Organization 2020). This pandemic has resulted in emergency measures attempting to reduce transmission rates that limit activity, movement and commerce in jurisdictions around the world. While these emergency measures are critically important to limit the spread and impact of the coronavirus, they also provide a glimpse into how governmental calls for behavioural change can alter air pollution levels in cities.

Early evidence reveals that pollution levels have dropped in places that have undergone COVID-19 shutdowns. As Marshall Burke showed in a blog post,  PM_2.5 and PM₁₀, levels are lower than expected in parts of China. Here I examine January and February 2020 AQI levels for the six pollutants in Wuhan to what would be expected under normal circumstances. I further compare the change in February air pollution levels over the past two years in six cities that instituted emergency measures by the end of February (early impacted cities) to 11 cities that did not declare states of emergency until March (later impacted cities) using freely available air monitoring data (World Air Quality Index Project 2020) -see Table 2 for a list of cities.

Table 2: The eleven cities used in this analysis, the month that emergency measures were enacted and two- to six-year AQI averages of the pollutants

City-data come from monitoring agencies listed at the end of this post

Wuhan, China was the epicenter for the December 2019 emergence and the first person-to-person spread of the novel coronavirus.  In response, authorities initiated a series drastic measures limiting human movement and activity in Wuhan and large parts of Hubei province by the end of January. Three air pollutants: PM_2.5, PM₁₀ and NO₂ all showed substantial January and February declines in Air Quality Index (AQI) (U.S.Environmental Protection Agency 2014) values over 2019 levels for those months and what would be expected from long-term trends (Fig. 1). These long-term declining air pollution trends do reveal that China’s recentpollution reduction and mitigation efforts are steadily paying off, but the government-enforced restrictions further reduced pollution levels. The expected air pollution values predicted by temporal trends (red dashed lines in Fig. 1) are all substantially higher than the observed levels, with observed values being between 13.85% lower than expected for January PM_2.5 and 33.93% lower for January NO₂. Further, the reductions in the pollutants shown in Fig. 1 increased the number of days where pollutant concentrations were categorized as ‘good’ (0 < AQI < 50) or ‘moderate’ (51 < AQI < 100) according to the AQI. The three other pollutants: SO₂, O₃ and CO, all showed idiosyncratic or non-significant changes, mostly because their levels have already reduced significantly over time or appear quite variable (Fig. 2). 

Fig. 1. Temporal patterns of Air Quality Index (AQI) PM_2.5, PM₁₀ and NO₂ values in Wuhan, China. Both January and February, 2020 values show significant declines compared to 2019 levels and to that predicted from long-term trends (red dashed line).

Fig. 2. Temporal patterns of Air Quality Index (AQI) SO₂, O₃ and CO values in Wuhan, China.

Once COVID-19 moved to other jurisdictions, and confirmations of community spread emerged in February 2020, emergency measures, like those in Hubei province, were instituted to limit human movement and interaction. The cities subjected to February restrictions include, in addition to Wuhan, Hong Kong, Kyoto, Milan, Seoul and Shanghai, and the AQI values from these cities were compared to other cities that did not see the impacts of the novel coronavirus or have emergency restrictions in place until well into March. Log-response ratios between the air concentrations of pollutants observed in February 2020 to those from February 2019 reveal that all air pollutants except O₃ show a decline in the 2020 values for the early impacted cities (Fig. 3). For later impacted cities, there is no overall trend in changes in the concentrations of pollutants between 2020 and 2019 and the individual cities in this group showed less consistency in the differences between years (Fig. 3). 

Fig. 3. Log response ratios for Air Quality Index (AQI) PM_2.5, PM₁₀, NO₂, O₃, SO₂ and CO values between February 2019 and February 2020 values. Negative values indicate a decline in 2020. The green symbols indicate values from an assortment of cities that did not have emergency measures in place until March, 2020 (later impacted cities) and orange symbols are for cities that were impacted by the end of February.

These results indicate consistent air pollution reduction in cities impacted early by the spread of the novel coronavirus. However, the analyses presented here require further investigation as governments increasingly restrict activity world-wide, and some are discussing the possibility of prematurely lifting restrictions in order to spur economic growth. Further, the data analyzed here present point estimates of air quality but air pollution impacts are not homogeneous through urban landscapes and is influenced by spatial variation in industrial activities and transportation (Adams & Kanaroglou 2016). Thus, as higher resolution spatial air pollution data become available, it would be valuable to see how reduced activity affects air quality in different parts of cities.

This analysis of early data indicates that governmental policies that directly reduce human activity, commercial demand and transportation can effectively and quickly reduce urban air pollution. While the COVID-19 pandemic represents a serious risk for health and wellbeing of populations globally, especially those living in high density urban areas, the impacts of air pollution are equally consequential. If governments are willing to expend trillions of dollars in direct funding and indirect economic costs to combat this disease, then why do these same governments permit or even subsidize activities that emit air pollution? Maybe the lessons learned with COVID-19 can serve as the impetus for further action. Perhaps mandating changes to economic or transportation activity or investing in clean technology would better protect human health from the effects of air pollution.

Cited sources

Adams, M.D. & Kanaroglou, P.S. (2016) Mapping real-time air pollution health risk for environmental management: Combining mobile and stationary air pollution monitoring with neural network models. Journal of environmental management, 168, 133-141.
Cadotte, M. W. (2020) Early evidence that COVID-19 government policies reduce urban air pollution. Retrieved from eartharxiv.org/nhgj3

Cesaroni, G., Forastiere, F., Stafoggia, M., Andersen, Z.J., Badaloni, C., Beelen, R., Caracciolo, B., de Faire, U., Erbel, R. & Eriksen, K.T. (2014) Long term exposure to ambient air pollution and incidence of acute coronary events: prospective cohort study and meta-analysis in 11 European cohorts from the ESCAPE Project. Bmj, 348, f7412.

Fann, N., Lamson, A.D., Anenberg, S.C., Wesson, K., Risley, D. &Hubbell, B.J. (2012) Estimating the National Public Health Burden Associated with Exposure to Ambient PM2.5 and Ozone. Risk Analysis, 32, 81-95.

Greenberg, N., Carel, R.S., Derazne, E., Bibi, H., Shpriz, M., Tzur, D. & Portnov, B.A. (2016) Different effects of long-term exposures to SO2 and NO2 air pollutants on asthma severity in young adults. Journal of Toxicology and Environmental Health, Part A, 79, 342-351.

Kampa, M., & E. Castanas. (2008) Human health effects of air pollution. Environmental Pollution, 151, 362-367.

Khaniabadi, Y.O., Goudarzi, G., Daryanoosh, S.M., Borgini, A., Tittarelli, A. & De Marco, A. (2017) Exposure to PM 10, NO 2, and O 3 and impacts on human health. Environmental science and pollution research, 24, 2781-2789.

Raaschou-Nielsen, O., Andersen, Z.J., Beelen, R., Samoli, E., Stafoggia, M., Weinmayr, G., Hoffmann, B., Fischer, P., Nieuwenhuijsen, M.J. & Brunekreef, B. (2013) Air pollution and lung cancer incidence in 17 European cohorts: prospective analyses from the European Study of Cohorts for Air Pollution Effects (ESCAPE). The lancet oncology, 14, 813-822.

U.S. Environmental Protection Agency (2014) AQI: Air Quality Index. Office of Air Quality Planning and Standards, Research Triangle Park, NC.

World Air Quality Index Project (2020) https://waqi.info/.

World Health Organization (2018) Ambient (outdoor) air pollution: https://www.who.int/news-room/fact-sheets/detail/ambient-(outdoor)-air-quality-and-health.

World Health Organization (2020) Coronavirus disease 2019 (COVID-19), Situation Report –65.

City air quality monitoring agencies:

¹ Division of Air Quality Data, Air Quality and Noise Management Bureau, Pollution Control Department, Thailand (http://aqmthai.com).

² Delhi Pollution Control Committee (http://www.dpccairdata.com).

³ Hong Kong Environmental Protection Department (http://www.epd.gov.hk).

⁴BMKG | Badan Meteorologi, Klimatologi dan Geofisika (http://www.bmkg.go.id).

⁵South African Air Quality Information System - SAAQIS (http://saaqis.environment.gov.za).

⁶ Japan Atmospheric Environmental Regional Observation System (http://soramame.taiki.go.jp/).

⁷ UK-AIR, air quality information resource - Defra, UK (http://uk-air.defra.gov.uk).

⁸ South Coast Air Quality Management District (AQMD) (http://www.aqmd.gov/).

⁹ INECC - Instituto Nacional de Ecología y Cambio Climático (http://sinaica.inecc.gob.mx).

¹⁰ Agenzia Regionale per la Protezione dell'Ambiente della Lombardia (http://ita.arpalombardia.it).

¹¹ CETESB - Companhia Ambiental do Estado de São Paulo (http://cetesb.sp.gov.br).

¹² Department of Public Health of the Sarajevo Canton (http://mpz.ks.gov.ba/).

¹³ Air Korea Environment Corporation (http://www.airkorea.or.kr).

¹⁴ Shanghai Environment Monitoring Center (http://sthj.sh.gov.cn).

¹⁵ Israel Ministry of Environmental Protection (http://www.svivaaqm.net).

¹⁶ Air Quality Ontario - the Ontario Ministry of the Environment and Climate Change (http://www.airqualityontario.com/).

¹⁷ Wuhan Environmental Protection Bureau (http://www.whepb.gov.cn/).