A dynamically structured matrix population model for insect life histories observed under variable environmental conditions

Various environmental drivers influence life processes of insect vectors that transmit human disease. Life histories observed under experimental conditions can reveal such complex links; however, designing informative experiments for insects is challenging. Furthermore, inferences obtained under controlled conditions often extrapolate poorly to field conditions. Here, we introduce a pseudo-stage-structured population dynamics model to describe insect development as a renewal process with variable rates. The model permits representing realistic life stage durations under constant and variable environmental conditions. Using the model, we demonstrate how random environmental variations result in fluctuating development rates and affect stage duration. We apply the model to infer environmental dependencies from the life history observations of two common disease vectors, the southern (Culex quinquefasciatus) and northern (Culex pipiens) house mosquito. We identify photoperiod, in addition to temperature, as pivotal in regulating larva stage duration, and find that carefully timed life history observations under semi-field conditions accurately predict insect development throughout the year. The approach we describe augments existing methods of life table design and analysis, and contributes to the development of large-scale climate- and environment-driven population dynamics models for important disease vectors.

Rate Coefficients for OH + NO (+N2) in the Fall-off Regime and the Impact of Water Vapor

The termolecular, association reaction between OH and NO is a source of nitrous acid (HONO), an important atmospheric trace gas. Rate coefficients for the title reaction as recommended by evaluation panels differ substantially at the temperatures and pressures that prevail in the Earth's boundary layer where the reaction is in the fall-off regime between low- and high-pressure limiting rate coefficients. Using pulsed laser methods for generation and detection of OH, we have reinvestigated the kinetics of the title reaction at pressures of 22-743 Torr (1 Torr = 1.333 hPa) and temperatures (273, 298, and 333 K) in pure N₂ and in N₂-H₂O bath gases. In situ optical absorption measurements were used to rule out any bias due to NO₂ or HONO impurities. Our rate coefficients (k₁) in N₂ bath gas are parametrized in terms of low-pressure (k₀) and high-pressure (k_∞) rate coefficients and a fall-off parameter (F_C) with k_1,0^N₂ = 7.24 × 10^-31 (T/300 K)^-2.17 cm⁶ molecule^-2 s^-1, k_1,∞ = 3.3 × 10^-12 (T/300 K)^-0.3 cm³ molecule^-1 s^-1, and F_C = 0.53. Used with the "Troe" expression for termolecular reactions, these parameters accurately reproduce the current data in the fall-off regime and also capture literature rate coefficients at extrapolated temperatures. The presence of water vapor was found to enhance the rate coefficients of the title reaction significantly. The low-pressure limiting rate coefficient in H₂O bath gas is a factor 5-6 larger than in N₂, at room temperature (k_1,0^H₂O = 4.55 × 10^-30 (T/300 K)^-4.85 cm⁶ molecule^-2 s^-1) indicating that H₂O is much more efficient in quenching the association complex HONO* through collisional energy transfer. Based on measurements in N₂-H₂O mixtures, a parametrization of k₁ including both N₂ and H₂O as third-body quenchers was derived. Neglecting the effect of H₂O results, e.g., in an underestimation of k₁ by >10% in the tropical boundary layer.

Synergistic HNO3-H2SO4-NH3 upper tropospheric particle formation

New particle formation in the upper free troposphere is a major global source of cloud condensation nuclei (CCN)^1-4. However, the precursor vapours that drive the process are not well understood. With experiments performed under upper tropospheric conditions in the CERN CLOUD chamber, we show that nitric acid, sulfuric acid and ammonia form particles synergistically, at rates that are orders of magnitude faster than those from any two of the three components. The importance of this mechanism depends on the availability of ammonia, which was previously thought to be efficiently scavenged by cloud droplets during convection. However, surprisingly high concentrations of ammonia and ammonium nitrate have recently been observed in the upper troposphere over the Asian monsoon region^5,6. Once particles have formed, co-condensation of ammonia and abundant nitric acid alone is sufficient to drive rapid growth to CCN sizes with only trace sulfate. Moreover, our measurements show that these CCN are also highly efficient ice nucleating particles-comparable to desert dust. Our model simulations confirm that ammonia is efficiently convected aloft during the Asian monsoon, driving rapid, multi-acid HNO₃-H₂SO₄-NH₃ nucleation in the upper troposphere and producing ice nucleating particles that spread across the mid-latitude Northern Hemisphere.

Prevalence of SARS-CoV-2 in Pregnant Women Assessed by RT-PCR in Franconia, Germany: First Results of the SCENARIO Study (SARS-CoV-2 prEvalence in pregNAncy and at biRth In FrancOnia)

Purpose Detection of SARS-CoV-2-infected pregnant women admitted to maternity units during a pandemic is crucial. In addition to the fact that pregnancy is a risk factor for severe COVID-19 and that medical surveillance has to be adjusted in infected women and their offspring, knowledge about infection status can provide the opportunity to protect other patients and healthcare workers against virus transmission. The aim of this prospective observational study was to determine the prevalence of SARS-CoV-2 infection among pregnant women in the hospital setting.

Material and Methods All eligible pregnant women admitted to the nine participating hospitals in Franconia, Germany, from 2 June 2020 to 24 January 2021 were included. COVID-19-related symptoms, secondary diseases and pregnancy abnormalities were documented. SARS-CoV-2 RNA was detected by RT-PCR from nasopharyngeal swabs. The prevalence of acute SARS-CoV-2 infection was estimated by correcting the positive rate using the Rogan–Gladen method. The risk of infection for healthcare workers during delivery was estimated using a risk calculator.

Results Of 2414 recruited pregnant women, six were newly diagnosed RT-PCR positive for SARS-CoV-2, which yielded a prevalence of SARS-CoV-2 infection of 0.26% (95% CI, 0.10 – 0.57%). Combining active room ventilation and wearing FFP2 masks showed an estimated reduction of risk of infection for healthcare workers in the delivery room to < 1%.

Conclusions The prevalence of newly diagnosed SARS-CoV-2 infection during pregnancy in this study is low. Nevertheless, a systematic screening in maternity units during pandemic situations is important to adjust hygienic and medical management. An adequate hygienic setting can minimise the calculated infection risk for medical healthcare workers during patientsʼ labour.

Global health burden of ambient PM2.5 and the contribution of anthropogenic black carbon and organic aerosols

Chronic exposure to fine particulate matter (PM_2.5) poses a major global health risk, commonly assessed by assuming equivalent toxicity for different PM_2.5 constituents. We used a data-informed global atmospheric model and recent exposure-response functions to calculate the health burden of ambient PM_2.5 from ten source categories. We estimate 4.23 (95% confidence interval 3.0-6.14) million excess deaths annually from the exposure to ambient PM_2.5. We distinguished contributions and major sources of black carbon (BC), primary organic aerosols (POA) and anthropogenic secondary organic aerosols (aSOA). These components make up to ∼20% of the total PM_2.5 in South and East Asia and East Africa. We find that domestic energy use by the burning of solid biofuels is the largest contributor to ambient BC, POA and aSOA globally. Epidemiological and toxicological studies indicate that these compounds may be relatively more hazardous than other PM_2.5 compounds such as soluble salts, related to their high potential to inflict oxidative stress. We performed sensitivity analyses by considering these species to be more harmful compared to other compounds in PM_2.5, as suggested by their oxidative potential using a range of potential relative risks. These analyses show that domestic energy use emerges as the leading cause of excess mortality attributable to ambient PM_2.5, notably in Asia and Africa. We acknowledge the uncertainties inherent in our assumed enhanced toxicity of the anthropogenic organic and BC aerosol components, which suggest the need to better understand the mechanisms and magnitude of the associated health risks and the consequences for regulatory policies. However our assessment of the importance of emissions from domestic energy use as a cause of premature mortality is robust to a range of assumptions about the magnitude of the excess risk.

Das Exposom charakterisiert die Auswirkungen unserer Umwelt auf Stoffwechsel und Gesundheit

Aktuelle Befunde der großen globalen epidemiologischen Studien wie dem „Global Burden of Disease“-Projekt legen nahe, dass bereits jetzt nahezu ⅔ der jährlichen globalen Todesfälle ursächlich auf chronische nicht übertragbare Erkrankungen wie Atherosklerose oder Diabetes zurückzuführen sind. Dies liegt vor allem an der Überalterung der Menschen in westlichen Gesellschaften, aber auch einer zunehmenden Belastung durch Boden-, Wasser- und Luftverschmutzung, Lärmbelastung, mentale Stressfaktoren und weitere Umweltrisikofaktoren. Vor etwa 15 Jahren wurde das Exposom-Konzept etabliert, um die Auswirkungen unserer Umwelt auf die Gesundheit zu erforschen. Das Exposom beschreibt dabei die Summe aller Expositionen, die lebenslang auf uns einwirken und dabei biochemische und metabolische Prozesse in unserem Körper überwiegend ungünstig verändern und so zu Gesundheitsschäden und frühzeitigen Todesfällen beitragen. Mit dieser Übersicht wird das Exposom-Konzept anhand von ausgewählten Studien erklärt und seine Bedeutung für die zukünftige Gesundheitsforschung sowie die präventive Medizin, vor allem im Hinblick auf kardiovaskuläre Erkrankungen und Therapie, erläutert.

Revisiting future extreme precipitation trends in the Mediterranean

Global warming is anticipated to intensify the hydrological cycle. However, this is neither expected to be globally uniform nor is the relationship between temperature increase and rainfall intensities expected to be linear. The objective of this study is to assess changes in annual rainfall extremes, total annual precipitation, and their relationship in the larger Mediterranean region. We use an up-to-date ensemble of 33 regional climate simulations from the EURO-CORDEX initiative at 0.11° resolution. We analyse the significance of trends for 1951-2000 and 2001-2100 under a 'business-as-usual' pathway (RCP8.5). Our future projections indicate a strong north/south Mediterranean gradient, with significant, decreasing trends in the magnitude of daily precipitation extremes in the south and the Maghreb region (up to -10 mm/decade) and less profound, increasing trends in the north. Despite the contrasting future trends, the 50-year daily precipitation extremes are projected to strongly increase (up to 100%) throughout the region. The 100-year extremes, derived with traditional extreme value approaches from the 1951-2000 simulations, underestimate the magnitude of these extreme events in the 2001-2100 projections by 30% for the drier areas of the Mediterranean (200-500 mm average annual rainfall) and by up to 20-30% for the wetter parts of the region. These 100-year extremes can occur at any time in any Mediterranean location. The contribution of the wettest day per year to the annual total precipitation is expected to increase (5-30%) throughout the region. The projected increase in extremes and the strong reductions in mean annual precipitation in the drier, southern and eastern Mediterranean will amplify the challenges for water resource management.

Physical Activity in Polluted Air-Net Benefit or Harm to Cardiovascular Health? A Comprehensive Review

Both exposure to higher levels of polluted air and physical inactivity are crucial risk factors for the development and progression of major noncommunicable diseases and, in particular, of cardiovascular disease. In this context, the World Health Organization estimated 4.2 and 3.2 million global deaths per year in response to ambient air pollution and insufficient physical activity, respectively. While regular physical activity is well known to improve general health, it may also increase the uptake and deposit of air pollutants in the lungs/airways and circulation, due to increased breathing frequency and minute ventilation, thus increasing the risk of cardiovascular disease. Thus, determining the tradeoff between the health benefits of physical activity and the potential harmful effects of increased exposure to air pollution during physical activity has important public health consequences. In the present comprehensive review, we analyzed evidence from human and animal studies on the combined effects of physical activity and air pollution on cardiovascular and other health outcomes. We further report on pathophysiological mechanisms underlying air pollution exposure, as well as the protective effects of physical activity with a focus on oxidative stress and inflammation. Lastly, we provide mitigation strategies and practical recommendations for physical activity in areas with polluted air.

Environmental risk factors and cardiovascular diseases: a comprehensive review

Noncommunicable diseases (NCDs) are fatal for more than 38 million people each year and are thus the main contributors to the global burden of disease accounting for 70% of mortality. The majority of these deaths are caused by cardiovascular disease. The risk of NCDs is strongly associated with exposure to environmental stressors such as pollutants in the air, noise exposure, artificial light at night and climate change, including heat extremes, desert storms and wildfires. In addition to the traditional risk factors for cardiovascular disease such as diabetes, arterial hypertension, smoking, hypercholesterolemia and genetic predisposition, there is a growing body of evidence showing that physicochemical factors in the environment contribute significantly to the high NCD numbers. Furthermore, urbanization is associated with accumulation and intensification of these stressors. This comprehensive expert review will summarize the epidemiology and pathophysiology of environmental stressors with a focus on cardiovascular NCDs. We will also discuss solutions and mitigation measures to lower the impact of environmental risk factors with focus on cardiovascular disease.

Heart healthy cities: genetics loads the gun but the environment pulls the trigger

The world's population is estimated to reach 10 billion by 2050 and 75% of this population will live in cities. Two-third of the European population already live in urban areas and this proportion continues to grow. Between 60% and 80% of the global energy use is consumed by urban areas, with 70% of the greenhouse gas emissions produced within urban areas. The World Health Organization states that city planning is now recognized as a critical part of a comprehensive solution to tackle adverse health outcomes. In the present review, we address non-communicable diseases with a focus on cardiovascular disease and the urbanization process in relation to environmental risk exposures including noise, air pollution, temperature, and outdoor light. The present review reports why heat islands develop in urban areas, and how greening of cities can improve public health, and address climate concerns, sustainability, and liveability. In addition, we discuss urban planning, transport interventions, and novel technologies to assess external environmental exposures, e.g. using digital technologies, to promote heart healthy cities in the future. Lastly, we highlight new paradigms of integrative thinking such as the exposome and planetary health, challenging the one-exposure-one-health-outcome association and expand our understanding of the totality of human environmental exposures.

[Air pollution and cardiovascular diseases]

Air pollution in the environment and in households is responsible worldwide for almost 9 million preventable premature deaths per year and almost 800,000 such deaths within Europe. Air pollution therefore shortens life expectancy worldwide by almost 3 years. Smoking, a proven cardiovascular risk factor, shortens the mean life expectancy by 2.2 years. Epidemiological studies have shown that air pollution from fine and coarse particulate matter is associated with increased cardiovascular morbidity and mortality. Responsible for this are mainly cardiovascular diseases, such as coronary heart disease, heart attack, heart failure, stroke, hypertension and also diabetes, which are mainly caused or aggravated by fine particulate matter. After inhalation fine particulate matter can reach the brain directly and also reach the bloodstream via a transition process. There, the particles are absorbed by the blood vessels where they stimulate the formation of reactive oxygen species (ROS) in the vascular wall. They therefore promote the formation of atherosclerotic changes and in this way increase the cardiovascular risks, especially an increase in chronic ischemic heart disease and stroke. Recent studies also reported that in coronavirus disease 2019 (COVID-19) patients a high degree of air pollution is correlated with severe disease courses with cardiovascular complications and pulmonary diseases. This necessitates preventive measures, such as lowering of the upper limits for air pollutants. Individual measures to mitigate the health consequences of fine particulate matter are also discussed.

Air pollution declines during COVID-19 lockdowns mitigate the global health burden

The lockdown response to COVID-19 has resulted in an unprecedented reduction in global economic activity and associated air pollutant levels, especially from a decline in land transportation. We utilized a network of >10,000 air quality stations distributed over 34 countries during lockdown dates up until 15 May 2020 to obtain lockdown related anomalies for nitrogen dioxide, ozone and particulate matter smaller than 2.5 μm in diameter (PM_2.5). Pollutant anomalies were related to short-term health outcomes using empirical exposure-response functions. We estimate that there were a net total of 49,900 (11,000 to 90,000; 95% confidence interval) excess deaths and 89,000 (64,700 to 107,000) pediatric asthma emergency room visits avoided during lockdowns. In China and India alone, the PM_2.5-related avoided excess mortality was 19,600 (15,300 to 24,000) and 30,500 (5700 to 68,000), respectively. While the state of COVID-19 imposed lockdown is not sustainable, these findings illustrate the potential health benefits gained by reducing "business as usual" air pollutant emissions from economic activities primarily through finding alternative transportation solutions.

Regional and global contributions of air pollution to risk of death from COVID-19

AIMS

The risk of mortality from the coronavirus disease that emerged in 2019 (COVID-19) is increased by comorbidity from cardiovascular and pulmonary diseases. Air pollution also causes excess mortality from these conditions. Analysis of the first severe acute respiratory syndrome coronavirus (SARS-CoV-1) outcomes in 2003, and preliminary investigations of those for SARS-CoV-2 since 2019, provide evidence that the incidence and severity are related to ambient air pollution. We estimated the fraction of COVID-19 mortality that is attributable to the long-term exposure to ambient fine particulate air pollution.

METHODS AND RESULTS

We characterized global exposure to fine particulates based on satellite data, and calculated the anthropogenic fraction with an atmospheric chemistry model. The degree to which air pollution influences COVID-19 mortality was derived from epidemiological data in the USA and China. We estimate that particulate air pollution contributed ∼15% (95% confidence interval 7-33%) to COVID-19 mortality worldwide, 27% (13 - 46%) in East Asia, 19% (8-41%) in Europe, and 17% (6-39%) in North America. Globally, ∼50-60% of the attributable, anthropogenic fraction is related to fossil fuel use, up to 70-80% in Europe, West Asia, and North America.

CONCLUSION

Our results suggest that air pollution is an important cofactor increasing the risk of mortality from COVID-19. This provides extra motivation for combining ambitious policies to reduce air pollution with measures to control the transmission of COVID-19.

Model Calculations of Aerosol Transmission and Infection Risk of COVID-19 in Indoor Environments

The role of aerosolized SARS-CoV-2 viruses in airborne transmission of COVID-19 has been debated. The aerosols are transmitted through breathing and vocalization by infectious subjects. Some authors state that this represents the dominant route of spreading, while others dismiss the option. Here we present an adjustable algorithm to estimate the infection risk for different indoor environments, constrained by published data of human aerosol emissions, SARS-CoV-2 viral loads, infective dose and other parameters. We evaluate typical indoor settings such as an office, a classroom, choir practice, and a reception/party. Our results suggest that aerosols from highly infective subjects can effectively transmit COVID-19 in indoor environments. This "highly infective" category represents approximately 20% of the patients who tested positive for SARS-CoV-2. We find that "super infective" subjects, representing the top 5-10% of subjects with a positive test, plus an unknown fraction of less-but still highly infective, high aerosol-emitting subjects-may cause COVID-19 clusters (>10 infections). In general, active room ventilation and the ubiquitous wearing of face masks (i.e., by all subjects) may reduce the individual infection risk by a factor of five to ten, similar to high-volume, high-efficiency particulate air (HEPA) filtering. A particularly effective mitigation measure is the use of high-quality masks, which can drastically reduce the indoor infection risk through aerosols.

Model Calculations of Aerosol Transmission and Infection Risk of COVID-19 in Indoor Environments

The role of aerosolized SARS-CoV-2 viruses in airborne transmission of COVID-19 has been debated. The aerosols are transmitted through breathing and vocalization by infectious subjects. Some authors state that this represents the dominant route of spreading, while others dismiss the option. Here we present an adjustable algorithm to estimate the infection risk for different indoor environments, constrained by published data of human aerosol emissions, SARS-CoV-2 viral loads, infective dose and other parameters. We evaluate typical indoor settings such as an office, a classroom, choir practice, and a reception/party. Our results suggest that aerosols from highly infective subjects can effectively transmit COVID-19 in indoor environments. This "highly infective" category represents approximately 20% of the patients who tested positive for SARS-CoV-2. We find that "super infective" subjects, representing the top 5-10% of subjects with a positive test, plus an unknown fraction of less-but still highly infective, high aerosol-emitting subjects-may cause COVID-19 clusters (>10 infections). In general, active room ventilation and the ubiquitous wearing of face masks (i.e., by all subjects) may reduce the individual infection risk by a factor of five to ten, similar to high-volume, high-efficiency particulate air (HEPA) filtering. A particularly effective mitigation measure is the use of high-quality masks, which can drastically reduce the indoor infection risk through aerosols.

Guidelines for Modeling and Reporting Health Effects of Climate Change Mitigation Actions

BACKGROUND

Modeling suggests that climate change mitigation actions can have substantial human health benefits that accrue quickly and locally. Documenting the benefits can help drive more ambitious and health-protective climate change mitigation actions; however, documenting the adverse health effects can help to avoid them. Estimating the health effects of mitigation (HEM) actions can help policy makers prioritize investments based not only on mitigation potential but also on expected health benefits. To date, however, the wide range of incompatible approaches taken to developing and reporting HEM estimates has limited their comparability and usefulness to policymakers.

OBJECTIVE

The objective of this effort was to generate guidance for modeling studies on scoping, estimating, and reporting population health effects from climate change mitigation actions.

METHODS

An expert panel of HEM researchers was recruited to participate in developing guidance for conducting HEM studies. The primary literature and a synthesis of HEM studies were provided to the panel. Panel members then participated in a modified Delphi exercise to identify areas of consensus regarding HEM estimation. Finally, the panel met to review and discuss consensus findings, resolve remaining differences, and generate guidance regarding conducting HEM studies.

RESULTS

The panel generated a checklist of recommendations regarding stakeholder engagement: HEM modeling, including model structure, scope and scale, demographics, time horizons, counterfactuals, health response functions, and metrics; parameterization and reporting; approaches to uncertainty and sensitivity analysis; accounting for policy uptake; and discounting.

DISCUSSION

This checklist provides guidance for conducting and reporting HEM estimates to make them more comparable and useful for policymakers. Harmonization of HEM estimates has the potential to lead to advances in and improved synthesis of policy-relevant research that can inform evidence-based decision making and practice. https://doi.org/10.1289/EHP6745.

Environmental Factors Such as Noise and Air Pollution and Vascular Disease

Significance: According to the World Health Organization, noncommunicable diseases are the globally leading cause of mortality. Recent Advances: About 71% of 56 million deaths that occurred worldwide are due to noncommunicable cardiovascular risk factors, including tobacco smoking, unhealthy diets, lack of physical activity, overweight, arterial hypertension, diabetes, and hypercholesterolemia, which can be either avoided or substantially reduced. Critical Issues: Thus, it is estimated that 80% of premature heart disease, stroke, and diabetes can be prevented. More recent evidence indicates that environmental stressors such as noise and air pollution contribute significantly to the global burden of cardiovascular disease. In the present review, we focus primarily on important environmental stressors such as transportation noise and air pollution. We discuss the pathophysiology of vascular damage caused by these environmental stressors, with emphasis on early subclinical damage of the vasculature such as endothelial dysfunction and the role of oxidative stress. Future Directions: Lower legal thresholds and mitigation measures should be implemented and may help to prevent vascular damage.

Cardiovascular disease burden from ambient air pollution in Europe reassessed using novel hazard ratio functions

Aims

Ambient air pollution is a major health risk, leading to respiratory and cardiovascular mortality. A recent Global Exposure Mortality Model, based on an unmatched number of cohort studies in many countries, provides new hazard ratio functions, calling for re-evaluation of the disease burden. Accordingly, we estimated excess cardiovascular mortality attributed to air pollution in Europe.

Methods and results

The new hazard ratio functions have been combined with ambient air pollution exposure data to estimate the impacts in Europe and the 28 countries of the European Union (EU-28). The annual excess mortality rate from ambient air pollution in Europe is 790 000 [95% confidence interval (95% CI) 645 000–934 000], and 659 000 (95% CI 537 000–775 000) in the EU-28. Between 40% and 80% are due to cardiovascular events, which dominate health outcomes. The upper limit includes events attributed to other non-communicable diseases, which are currently not specified. These estimates exceed recent analyses, such as the Global Burden of Disease for 2015, by more than a factor of two. We estimate that air pollution reduces the mean life expectancy in Europe by about 2.2 years with an annual, attributable per capita mortality rate in Europe of 133/100 000 per year.

Conclusion

We provide new data based on novel hazard ratio functions suggesting that the health impacts attributable to ambient air pollution in Europe are substantially higher than previously assumed, though subject to considerable uncertainty. Our results imply that replacing fossil fuels by clean, renewable energy sources could substantially reduce the loss of life expectancy from air pollution.

COVID-19 lockdowns cause global air pollution declines

The lockdown response to coronavirus disease 2019 (COVID-19) has caused an unprecedented reduction in global economic and transport activity. We test the hypothesis that this has reduced tropospheric and ground-level air pollution concentrations, using satellite data and a network of >10,000 air quality stations. After accounting for the effects of meteorological variability, we find declines in the population-weighted concentration of ground-level nitrogen dioxide (NO₂: 60% with 95% CI 48 to 72%), and fine particulate matter (PM_2.5: 31%; 95% CI: 17 to 45%), with marginal increases in ozone (O₃: 4%; 95% CI: -2 to 10%) in 34 countries during lockdown dates up until 15 May. Except for ozone, satellite measurements of the troposphere indicate much smaller reductions, highlighting the spatial variability of pollutant anomalies attributable to complex NO_x chemistry and long-distance transport of fine particulate matter with a diameter less than 2.5 µm (PM_2.5). By leveraging Google and Apple mobility data, we find empirical evidence for a link between global vehicle transportation declines and the reduction of ambient NO₂ exposure. While the state of global lockdown is not sustainable, these findings allude to the potential for mitigating public health risk by reducing "business as usual" air pollutant emissions from economic activities. Explore trends here: https://nina.earthengine.app/view/lockdown-pollution.

COVID-19 lockdowns cause global air pollution declines

The lockdown response to coronavirus disease 2019 (COVID-19) has caused an unprecedented reduction in global economic and transport activity. We test the hypothesis that this has reduced tropospheric and ground-level air pollution concentrations, using satellite data and a network of >10,000 air quality stations. After accounting for the effects of meteorological variability, we find declines in the population-weighted concentration of ground-level nitrogen dioxide (NO₂: 60% with 95% CI 48 to 72%), and fine particulate matter (PM_2.5: 31%; 95% CI: 17 to 45%), with marginal increases in ozone (O₃: 4%; 95% CI: -2 to 10%) in 34 countries during lockdown dates up until 15 May. Except for ozone, satellite measurements of the troposphere indicate much smaller reductions, highlighting the spatial variability of pollutant anomalies attributable to complex NO_x chemistry and long-distance transport of fine particulate matter with a diameter less than 2.5 µm (PM_2.5). By leveraging Google and Apple mobility data, we find empirical evidence for a link between global vehicle transportation declines and the reduction of ambient NO₂ exposure. While the state of global lockdown is not sustainable, these findings allude to the potential for mitigating public health risk by reducing "business as usual" air pollutant emissions from economic activities. Explore trends here: https://nina.earthengine.app/view/lockdown-pollution.

COVID-19 lockdowns cause global air pollution declines

The lockdown response to coronavirus disease 2019 (COVID-19) has caused an unprecedented reduction in global economic and transport activity. We test the hypothesis that this has reduced tropospheric and ground-level air pollution concentrations, using satellite data and a network of >10,000 air quality stations. After accounting for the effects of meteorological variability, we find declines in the population-weighted concentration of ground-level nitrogen dioxide (NO2: 60% with 95% CI 48 to 72%), and fine particulate matter (PM2.5: 31%; 95% CI: 17 to 45%), with marginal increases in ozone (O3: 4%; 95% CI: -2 to 10%) in 34 countries during lockdown dates up until 15 May. Except for ozone, satellite measurements of the troposphere indicate much smaller reductions, highlighting the spatial variability of pollutant anomalies attributable to complex NOx chemistry and long-distance transport of fine particulate matter with a diameter less than 2.5 µm (PM2.5). By leveraging Google and Apple mobility data, we find empirical evidence for a link between global vehicle transportation declines and the reduction of ambient NO2 exposure. While the state of global lockdown is not sustainable, these findings allude to the potential for mitigating public health risk by reducing "business as usual" air pollutant emissions from economic activities. Explore trends here: https://nina.earthengine.app/view/lockdown-pollution.