March 23, 2020

Jacob Schor ND, FABNO

Walking the dog down 22nd Street east to Kearney and home early this morning, I couldn’t help but notice what a beautiful day it is outside.  Partly this may be in reaction to the Op-Ed piece I had read by the retired astronaut Scott Kelly who wrote about the coping methods he found useful aboard the space station :

“… When I lived on the International Space Station for nearly a year, it wasn’t easy. When I went to sleep, I was at work. When I woke up, I was still at work. Flying in space is probably the only job you absolutely cannot quit.

But I learned some things during my time up there that I’d like to share — because they are about to come in handy again, as we all confine ourselves at home to help stop the spread of the coronavirus. ….”  Kelly suggests following a daily schedule, pacing yourself, and going outside:

“One of the things I missed most while living in space was being able to go outside and experience nature. After being confined to a small space for months, I actually started to crave nature — the color green, the smell of fresh dirt, and the feel of warm sun on my face. ” [1]

So perhaps it was with this exhortation in mind that I noticed that the air felt so fresh and clean this morning.  The difference was so perceptible that I came home and checked.  It wasn’t my imagination.  The air is cleaner.

Jonathan Watts and Niko Komenda article in the March 23,2020 issue of The Guardian is titled: “Coronavirus pandemic leading to huge drop in air pollution.”

They go on to describe what we are witnessing as the, 

“‘Largest scale experiment ever’ shows what is possible as satellite images reveal marked fall in global nitrogen dioxide levels.

“The coronavirus pandemic is shutting down industrial activity and temporarily slashing air pollution levels around the world, satellite imagery from the European Space Agency shows…

“Readings from ESA’s Sentinel-5P satellite show that over the past six weeks, levels of nitrogen dioxide (NO2) over cities and industrial clusters in Asia and Europe were markedly lower than in the same period last year.”

The Guardian’s online version of this story provides moving images that visually compare current nitrous oxide levels measured over China, Korea, Italy, and the U.K., with those from a year ago.  The difference is striking.

Brad Plumer and Nadja Popovich described a similar phenomenon occurring in the U.S. in yesterday’s NY Times. 

They graphically portray decreasing NO levels over Los Angeles, Seattle, and the New York metro area. [2]

You can watch air pollution levels drop over Europe and especially Italy via satellite  data from the first of the year via EcoWatch[3]

One doesn’t really need satellite photos.  One can look outside the window.  Or compare the photos that the Colorado Department of Health records of downtown constantly.

Here is a photo taken today:

Denver downtown, March 23, 2020. Today

And one taken March 3.  March 1 was cloudy so the comparison wouldn’t be fair.

Same time, same place twenty days ago….

You can play with this yourself at[4]

Why is this so interesting?  We know that many aspects of health are influenced by air pollution levels.

As air pollution worsens more people die from heart disease. 

A 2017 study analyzing data from China reported that for every  10 μg/m3  in NO2   deaths from heart disease increased by 2.71%. [5]

A 2015 study done in the US reported that for a similar increase in fine particulate air pollution there is a 12% increase in CVD deaths. [6]

Perhaps the most important study on this subject was published just ten days ago on March 13, 2020.  It was a comprehensive review and meta-analysis of past studies on air pollution and CVD mortality.  Data from 84 cohorts, comprising a total of 28,215,394 subjects, were combined.  Increases in fine particulate air pollutants were associated with increases in all measures of CVD, acute coronary events, stroke, and high blood pressure.  Mortality rates from CVD increased by 10% for the PM2.5 increases and 17% when the larger PM10 particles were tracked.  Increases in NO, what those pretty graphics were tracking in the news stories, are associated with a 17% increase in CVD mortality and a 23% increase in all-cause mortality. [7]

About 647,000 people die in the US each year from CVD.[8]  If our staying at home were to lower this figure by 10%, that would be significant.[9]

Slowing the economy as we have to put the brakes on Covid-19 is also slowing production of greenhouse gases associated with global warming.

The Scientific American reported on March 12th, that  “In China, the world’s largest carbon emitter, experts estimate that emissions over the past month have been about 25% lower than normal.”[10]

One might wonder, not unreasonably, if we might learn something useful about addressing climate change from current events and whether we might leverage the huge amounts of money that are about to be spent rescuing the economy to at the same time address the long term problems of climate change?  Today’s LA Times editorial asked that question this morning. [11]



[3] :

[4] :

Environ Pollut.
 2017 Oct;229:790-797. doi: 10.1016/j.envpol.2017.06.022. Epub 2017 Aug 7.

Association between air pollution and cardiovascular mortality in Hefei, China: A time-series analysis.

Zhang C1Ding R1Xiao C2Xu Y1Cheng H1Zhu F1Lei R1Di D3Zhao Q4Cao J5.

Author information


In recent years, air pollution has become an alarming problem in China. However, evidence on the effects of air pollution on cardiovascular mortality is still not conclusive to date. This research aimed to assess the short-term effects of air pollution on cardiovascular morbidity in Hefei, China. Data of air pollution, cardiovascular mortality, and meteorological characteristics in Hefei between 2010 and 2015 were collected. Time-series analysis in generalized additive model was applied to evaluate the association between air pollution and daily cardiovascular mortality. During the study period, the annual average concentration of PM10, SO2, and NO2 was 105.91, 20.58, and 30.93 μg/m3, respectively. 21,816 people (including 11,876 man, and 14,494 people over 75 years of age) died of cardiovascular diseases. In single pollutant model, the effects of multi-day exposure were greater than single-day exposure of the air pollution. For every increase of 10 μg/m3 in SO2, NO2, and PM10 levels, CVD mortality increased by 5.26% (95%CI: 3.31%-7.23%), 2.71% (95%CI: 1.23%-4.22%), and 0.68% (95%CI: 0.33%-1.04%) at a lag03, respectively. The multi-pollutant models showed that PM10 and SO2 remained associated with CVD mortality, although the effect estimates attenuated. However, the effect of NO2 on CVD mortality decreased to statistically insignificant. Subgroup analyses further showed that women were more vulnerable than man upon air pollution exposure. These findings showed that air pollution could significantly increase the CVD mortality.

Copyright © 2017 Elsevier Ltd. All rights reserved.

Circ Res.
 2015 Jan 2;116(1):108-15. doi: 10.1161/CIRCRESAHA.116.305060. Epub 2014 Oct 27.

Relationships between fine particulate air pollution, cardiometabolic disorders, and cardiovascular mortality.

Pope CA 3rd1Turner MC2Burnett RT2Jerrett M2Gapstur SM2Diver WR2Krewski D2Brook RD2.

Author information



Growing evidence suggests that long-term exposure to fine particulate matter (PM2.5) air pollutioncontributes to risk of cardiovascular disease (CVD) morbidity and mortality. There is uncertainty about who are most susceptible. Individuals with underlying cardiometabolic disorders, including hypertension, diabetes mellitus, and obesity, may be at greater risk. PM2.5 pollution may also contribute to cardiometabolic disorders, augmenting CVD risk.


This analysis evaluates relationships between long-term PM2.5 exposure and cardiometabolic disease on risk of death from CVD and cardiometabolic conditions.


Data on 669 046 participants from the American Cancer Society Cancer Prevention Study II cohort were linked to modeled PM2.5 concentrations at geocoded home addresses. Cox proportional hazards regression models were used to estimate adjusted hazards ratios for death from CVD and cardiometabolic diseases based on death-certificate information. Effect modification by pre-existing cardiometabolic risk factors on the PM2.5-CVD mortality association was examined. PM2.5 exposure was associated with CVD mortality, with the hazards ratios (95% confidence interval) per 10 μg/m(3) increase in PM2.5 equal to 1.12 (1.10-1.15). Deaths linked to hypertension and diabetes mellitus (mentioned on death certificate as either primary or contributing cause of death) were also associated with PM2.5. There was no consistent evidence of effect modification by cardiometabolic disease risk factors on the PM2.5-CVD mortality association.


Pollution-induced CVD mortality risk is observed for those with and without existing cardiometabolic disorders. Long-term exposure may also contribute to the development or exacerbation of cardiometabolic disorders, increasing risk of CVD, and cardiometabolic disease mortality.

© 2014 American Heart Association, Inc.

[7]  J Evid Based Med. 2020 Mar 13. doi: 10.1111/jebm.12380. [Epub ahead of print]

A time-to-event analysis on air pollutants with the risk of cardiovascular disease and mortality: A systematic review and meta-analysis of 84 cohort studies.

Pranata R1, Vania R1, Tondas AE2, Setianto B3, Santoso A3.

Author information



Air pollution is one of the most substantial problems globally. Aerodynamic toxic of particulate matter with <10 mm in diameter (PM10 ), or <2.5 mm (PM2.5 ), as well as nitric dioxide (NO2 ), have been linked with health issues. We aimed to perform a comprehensive analysis of the time-to-event for different types of air pollutants on cardiovascular disease (CVD) events based on cohort studies.


A comprehensive search on topics that assesses air pollution and cardiovascular disease with keywords up until July 2019 was performed.


There were a total of 28 215 394 subjects from 84 cohorts. Increased PM2.5 was associated with composite CVD [HR 1.10 (1.02, 1.19)], acute coronary events [HR 1.15 (1.12, 1.17)], stroke [HR 1.13 (1.06, 1.19)], and hypertension [HR 1.07 (1.01, 1.14)], all-cause mortality [HR 1.07 (1.04, 1.09)], CVD mortality [HR 1.10 (1.07, 1.12)], and ischemic heart disease (IHD) mortality [HR 1.11 (1.07, 1.16)]. Association with AF became significant after removal of a study. Increased PM10 was associated with heart failure [HR 1.25 (1.04, 1.50)], all-cause mortality [HR 1.16 (1.06, 1.27)], CVD mortality [HR 1.17 (1.04, 1.30)], and IHD mortality [HR 1.03 (1.01, 1.05)]. Increased of NO2 was associated with increased composite CVD [HR 1.15 (1.02, 1.29)], atrial fibrillation [HR 1.01 (1.01, 1.02)], acute coronary events [HR 1.08 (1.02, 1.13)], all-cause mortality [HR 1.23 (1.14, 1.32)], CVD mortality [HR 1.17 (1.10, 1.25)], and IHD mortality [HR 1.05 (1.03, 1.08)].


Air pollutants are associated with an increased incidence of cardiovascular diseases, all-cause mortality, and CVD mortality.

© 2020 Chinese Cochrane Center, West China Hospital of Sichuan University and John Wiley & Sons Australia, Ltd.