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How Does Weather Affect My Asthma and COPD

How Does Weather Affect My Asthma and COPD?​

This is a very common question and one which after months of research, I have found has a number of factors. But once you understand the weather and the effects on the body and lungs, you gain a better understand of how to deal with these issues. So to get started, let’s look at the weather and what factors affect this.

What Weather Factors Affect Me and Why?

Have you ever noticed on weather readings that you have both a temperature and a feels like temperature. Looking at my phone today, the temperature says 20.2 oC, but the feels like says 18.2 oC. 

 

I never fully understood the difference until I started researching this question and here is why.

 

The temperature reading is the air temperature, but the feels like temperature is what the weather conditions feel like to your body and there are a number of conditions which are taken into to account to create the feels like temperature including humidity and wind chill factor.

Feels Like Temperature

Feels like temperature is what the body perceives the temperature is and is a combination of the following:

 

1.       Air temperature – The temperature of the air outside of our body,

 

2.       Humidity – Humidity can lower the “feels like temperature” by a few of degrees as it drops below 40%.

Humidity has a lot greater effect on the “feels like temperature”  at levels above 40%, for example, it has the ability to increase the feels like temperature by 4oC to to 20oC, as humidity raises above 40% and heads towards 80-100% humidity.

There are other effects, but this will be explained in more detail on the effects to the body and lungs later on.

 

3.       Wind Speed – Just as the humidity level changes the feels like temperature, but wind chill factor is opposite to humidity in that as wind speed increases above 0 km/hr, it actually cools the body and reduces the feels like temperature. Hence the name wind chill factor.

 

For example as wind speed increases from 0 km/hr through to 60 km/hr it has the effect of reducing the feels like temperature felt by the body from 0 oC at 0 km/hr through to  -3 oC  at 10 km/hr through to -9 oC. This is increased significantly as the air temperature drops.

There are other effects, but this will be explained in more detail on the effects to the body and lungs later on.

 

 

Now that we have explained the difference between air temperature and what factors effect the feels like temperature which is how the body perceives the weather conditions. Let’s explain the what the lungs would like as an ideal climate and the safer ranges and why they are important.

Optimal Climate for the Lungs and Safe Ranges

Optimal Climate within the Lungs

The optimal climatic conditions for our lungs to function are as follows:

1.       Core Body Temperature – 37 oC with a range of between 36 oC and 38 oC being normal

2.       Lung Air Humidity – 100%

3.       Air Quality Index (particle matter in the air we breathe) – 0

 

4.       pH Level – 7.4

Now it is important to understand that this is the climate which the body works towards maintaining in our lungs for optimal hygiene and mucus transportation. There is a big difference between what the climate of the lungs are and what the outside climate is to help the body to maintain this and there are a number of bodily functions which go into maintaining this climate.

 

Changes to outside factors like the weather, smoke, pollution, wind, etc… all upset this balance for a period of time and the body needs to adjust to this as efficiently as possible. I will explain this in more depth through the article of how the body handles these changes.

Optimal Outside Climate for the Lungs and Safe Ranges

Because our body is a massive heater which burns energy and is insulated, the requirements of the core body temperature are different to the optimal outside climate.

The optimal outside weather conditions and safety ranges are as follows:

1.       Feels Like Temperature – 28 oC (82 oF) with a safe range of between 0oC (32 oF) and 32oC (90 oF),

2.       Humidity – 40%, with a safe range of between 30% to 50%

3.       Wind Speed – 0 km/hr with a safe range of less than 19 km/hr (12 mph)

 

4.       Air Quality Index (pollution) – 0 with a safe level less than 50 

As explained above, wind speed and humidity have a direct relationship to how the body perceives the air temperature and outside climatic conditions (feels like temperature), but there are other effects which they have on the body.

 

These will be broken down now into each part, explaining the direct effects and why there are safe ranges.

Effects of Feels Like Temperature on the Body and Lungs

The feels like temperature has an effect on the core body temperature as well as the lungs.

For example, at the optimal outside temperature of 28 oC (82 oF), the body is easily able to maintain the core temperature of 37 oC with minimal change to bodily function.

This in turn results in a core temperature in the lungs being at 37 oC, which is the optimal temperature for mucociliary transportation. This is the process in the lungs which is the first line of defence against any foreign particles from entering the lungs.

 

The mucociliary clearance process is responsible for capturing up to 90% of all foreign particles which enter the lungs from our breath, including but not limited to smoke, pollutants, bacteria, viruses and parasites like dust mites, mould spores, etc… 

Then mucociliary escalator transports these foreign particles up to the throat to be either coughed or swallowed to remove them from the airways and alveoli (air sacs) in our lungs.

How the Body Handles Cold Temperatures

LAs a means of heating the body to maintain the optimal core temperature of 37 oC, the body performs the following:

 

1.       The thyroid gland reduces hormones into the body to start a process of heating and storing heat doing the following.

2.       Increasing heart rate,

3.       Increasing blood pressure,

4.       Increasing metabolism

5.       Cause the muscles to shiver to generate heat

6.       Reducing the size of the blood vessels (vasoconstriction) in the skin to reduce heat loss and water loss,

7.       Reduce water loss from the kidneys to again reduce heat loss from the water loss

The issue is that as the temperature drops below 0 oC, the body’s ability to heat it up the body and reduce heat loss has reached its limits (there are exceptions to the rule). This is the point where it becomes dangerous for the body and normal bodily functions start to fail. 

What Happens in the Lungs to make us Cough in Cold Temperatures Below 0 oC?

The issue with cold air is that it doesn’t hold water very well, as it usually freezes water in the air below 0oC, making it heavy, i.e. causing ice and/or frost to build up on surfaces like grass, trees, cars, etc…

 

On top of this, cold air dries out particles which are breathed into the lungs. The lungs work on a principle of humidity and water vapour, i.e. water around a particle is attracted to water molecules in the mucus on the airway walls of the lungs to help capture the particles and transport them out of the lungs to be coughed out or swallowed as a part of the clearance process to maintain lung hygiene. 

The issues with cold air below 0oC cause 3 affects within the lungs.

1.       Reduced Humidity level of the lungs – As mentioned, the ideal humidity level in the lungs is 100%. With cold air of 0 oC or less entering the lungs, this has the potential to reduce the humidity level of the air in the lungs, resulting in dehydrating the mucus (making it stickier and harder to transport) and drying out the skin of the airway walls (epithelium). This in turn causes the airway walls to become dried out, causing redness, agitation (inducing a cough to remove the agitation) and potentially leading to inflammation and excess mucus secretion.

To better understand the effects, think of how the cold wind on the outside of our body dries out our skin as it blows across the skin. This draws out moisture and eventually causing redness if exposed too long.

 

The average wind speed outside of the body is around 10-19 km/hr or 6-12 miles/hr running across your skin. Comparing this to your lungs, you breathe about 12 breaths per minute with around 0.5 of a litres per breath. This gives you an average 6 litres of air rushing into and out of your lungs every minute. So, the process of drying of the mucus and skin of the airway walls becomes more accelerated.

 

This is what causes the coughing, brought about by the agitation. This is the lungs means of the lungs trying to expel what is causing the agitation, but in this case the agitation caused by the cold air which we are breathing in and not particles which can be expelled easier.

 

Mucus is actually a mesh net and not just a gel, it relies on the moisture of the mucus to attract and hold particles. If the particles are dried out, then they become smaller (due to lack of water vapour around them) and this means that the particles are less likely to become attracted to the mucus moisture, meaning that the particles travel further into the lungs and are more likely to travel through the mucus, becoming deposited onto the airway walls causing agitation and potentially infection. This may lead to inflammation and further mucus production.

 

 

2.       Reduced Mucociliary Transportation Rate – Due to the drop in temperature and drying of the mucus in the airways, the transportation rate may be reduced by as much as 54% at 0oC 0(based on a previous study), as the mucus becomes stickier and harder to transport. This is because the hairs find it harder to release the mucus bond for movement, hampering the transportation of the mucus to the throat to be swallowed or coughed out naturally. 

 

As this process becomes slowed down and agitation occurs, more mucus is released to help reduce agitation of the airway walls, leading to coughing, reduced airway clearance (leading to wheezing and shortness of breath).

 

3.       Required Raising of the Core Temperature – Due to the cold temperature of your body, your body works towards increasing our core temperature, but the temperature outside of the body and inside of the lungs are both 0oC or below. To do this, your body increases heart rate, blood flow and your metabolism to increase heat production, whist constricting your capillaries in the skin and to the extremities, to reduce heat loss in the body.

 

 

With the increased obstruction in the airways, due to mucus build up and potential inflammation in the airways which may lead to reduced air flowing into and out of the lungs,   amplified by the faster blood flow and heart rate, this may see a reduction in O2 in the blood stream, leading to the brain detecting the low O2 and causing the sensation of shortness of breath (which can mean many things), but this sensation may bring on a number of conditions like panic attack, hyperventilating, agitation and inflammation from faster breathing, etc…

How the Body Handles Hot Temperatures

As a means of reducing the temperature of the body to maintain the optimal core temperature 37oC, the body performs the following:

1.       The thyroid gland reduces hormones into the body to reduce heating in the body and releasing as much heat as possible by doing the following.

2.       Decreasing heart rate,

3.       Decreasing blood pressure,

4.       Decreasing metabolism,

5.       Increasing the size of the blood vessels (vasodilation) in the skin to increase heat loss and water loss through sweating,

 

6.       Increasing water loss from the kidneys to again increase heat loss from the water excretion

The issue is that as the temperature increase above 32 oC, the body’s ability to reduce and increase heat loss has reached its limits (there are exceptions to the rule). This is where it becomes dangerous for the body and normal bodily functions start to fail.

What Happens in the Lungs to Make us Cough in Hot Temperatures above 32 oC?

Hot Temperatures Above 32 Degrees Celcius

The issue with hot air is that it dries and evaporates water from particles and the body. At these temperatures, the body is reducing the metabolism, heart rate and blood pressure to reduce heat production within the body, whilst also trying to release as much water as possible to help dissipate the heat within the body.

 

This causes dehydration in the body and any fluids like mucus, within the lungs become dehydrated due to the lack of water in the body, as it is using the release of water to help reduce as much heat as possible within the body. 

The issue with hot air above 32 oC also causes 3 affects within the lungs.

 

1.       Reduced Humidity level of the lungs – This is similar to cold air, in that the hot air dries out the air in the lungs, whist also dehydrating the mucus (making it stickier and harder to transport) and drying out the skin of the airway walls (epithelium). This in turn causes the airway walls to become dried out, causing redness, agitation (inducing a cough to remove the agitation) and potentially leading to inflammation and excess mucus secretion.

 

To help understand the effects, again think of how the hot wind on the outside of our body dries out our skin as it blows across the skin, this draws out moisture and eventually causing redness if exposed too long.

 

As previously mentioned in cold air below 0 oC, the process of drying of the mucus and skin of the airway walls becomes more accelerated. This is what causes the coughing brought about by the agitation. This is a means of the lungs trying to expel what is causing the agitation, but in this case the agitation caused by the hot air which we are breathing in and not particles.

 

If the particles are dried out, then they become smaller (due to lack of water vapour around them) and this means that the particles are less likely to become attracted to the mucus moisture, meaning that the particles travel further into the lungs and are more likely to travel through the mucus, becoming deposited onto the airway walls causing agitation and potentially infection. This may lead to inflammation and further mucus production.

 

2.       Reduced Mucociliary Transportation Rate – Due to the increase dehydration of the mucus, the transportation rate may be reduced as the mucus becomes stickier and harder to transport. This is because the hairs find it harder to release the mucus bond for movement, hampering the transportation of the mucus to the throat to be swallowed or coughed out naturally. 

 

As this process becomes slowed down and agitation occurs, more mucus is released to help reduce agitation of the airway walls, leading to coughing, reduced airway clearance (leading to wheezing and shortness of breath).

 

3.       Required Reduction of the Core Temperature – Due to the hot temperature of the body, your body works towards decreasing our core temperature. To do this, your body decreases heart rate, blood flow and your metabolism to reduce heat heating production, whist opening up your capillaries in the skin and extremities, to help release more heat through sweating.

 

With the increased obstruction in the airways, due to mucus build up and potential inflammation in the airways which may lead to reduced air flowing into and out of the lungs,   amplified by a slower blood flow and heart rate, this may see a reduction in O2 in the blood stream, leading to the brain detecting the low O2 and causing the sensation of shortness of breath (which can mean many things), but this sensation may bring on a number of conditions like panic attack, hyperventilating, agitation and inflammation from faster breathing, etc…

In Summary – How Do I Handle Extreme Temperatures?

The right balance in core body temperature of between 36 oC and 38 oC is essential for helping to balance the lung functionality. Once the temperature drops below or above these core temperatures, then it may result in coughing as the body tries to remove the irritants which are causing the airway walls to become dried out and agitated. Sadly, this is either the hot dry air, or the cold dry air which we are breathing, and it may result in consistent coughing.

 

The best way to handle this to breath through the nose and/or have a barrier like a clothing which can help hydrate and heat (for cold air) or cool (for hot air) the air before it enters the lungs.

How Does Humidity Affect Our Body and Lungs?

How Humidity Affects Temperature

Humidity has the largest effect on higher temperatures, increasing the feels like temperatures between 4 oC to 24 oC (7 oF -42 oF) or more as the air temperature increases above 27 oC (80 oF) and humidity reaches 100%. This is also called the heat index.

Humidity has 3 major effects on the body as follows;

 

1.       Regulating Core Body Temperature

 

High humidity (above 50%) reduces the ability for the body to reduce the core temperature by reducing the ability to release heat through the skin. If the temperature and humidity is causing the feels like temperature to be raised above 38 oC, it can result in dehydration as the body releases water to try and decrease temperature.

 

Low humidity (below 30%) causes the body to lose body heat by drawing water from the skin. This works at reducing the feels like temperature but only by a few degrees Celsius.

 

2.       Humidity Levels and Temperature in the Lungs

Lower humidity levels below 30% cause a drying effect of the air inside of the lungs. This is caused if the body’s core temperature starts dropping below 36 oC, resulting in vasoconstriction (constriction of the blood vessels in the epithelium (skin) in the airways to reduce heat loss. This effects the temperature in the lungs and results in drier mucus from heat loss of the body, along with the low humidity in the air in the lungs, resulting in slower mucus clearance and agitation to the airway walls causing a cough.

 

High humidity levels above 50% raises the core temperature and the air temperature in the body and lungs above 38oC, it has the effect of dehydration in the lungs, resulting in thicker mucus, dehydrated skin cells, resulting in slower mucus clearance and agitation to the airway walls causing a cough..

 

3.       Increased Pathogens or particles in the lungs  

High Humidity

Pathogens like bacteria, viruses and parasites like dust mites and mould spores flourish in higher humidity levels above 50%. This leads to a greater chance of asthma attacks, bronchitis (infection of the lungs) and also the foreign particle like smoke and dirt have more water around the molecules resulting in heavier particles which make them harder to clear and a higher chance of slowing the mucociliary escalator, leading to coughing.

 

 

Low Humidity

 

Low humidity means less water molecules around dirt and smoke, this means that the particles are smaller, can be picked up easier by the wind and if they are below PM5 in size, then they have a greater chance of slipping through the mucociliary escalator in the lungs, resulting in airway agitation, coughing and inflammation.

In Summary – How do I Handle Extreme Humidity Levels?

The right balance of humidity levels of 30% to 50% are essential for helping to trap foreign particles in water molecules in the air which we breathe. This assists with attraction of these particles towards the mucus on the airway walls as a part of the mucociliary escalatory for effective clearance out of the lungs. Levels outside of this range may result in affecting the mucociliary clearance process and efficiency, whilst also causing drying of the tissue on the airway walls causing coughing as it becomes agitated and inflamed.

During times of low humidity look at using humidifiers to put water into the air and help to increase the humidity up to the 30-50% level and bring wind chill factor into the equation (which I will talk about next) to help cool the body down.

 

In times of high humidity, use dehumidifiers and fans to help decrease the air humidity to 30% to 50%.

How Does Wind Chill Factor Affect Our Body and Lungs?

Wind Chill Factor on Temperature

Wind chill factor has the opposite effect to humidity. Where humidity has the potential to increase temperature by up to 24oC, wind chill factor has the potential to reduce the feels like temperature by -26 oC. The difference is that the ideal wind speed is 0 km/hr, so there isn’t a below 0 km/hr effect, just an effect of wind faster than 0 km/hr.

The only change is temperature of the wind, so if air temperature is cold and warm air blows in from the sea, then it makes the feel like temperature warmer, where if it is the other way around, then it can make it feel very cold.

 

But for this exercise, lets look at how the speed of the wind negatively effects the feels like temperature based on the wind temperature being the same as the air temperature and not from another source (i.e. mountains, sea, etc…), as this complicates things more.

Wind Chill factor, like Humidity, has 3 major effects on the body as follows;

 

1.       Regulating Core Body Temperature

As the wind speed increases from 10 to 60 km/hr at 0 oC (which is on the outside of the body’s temperature range), the temperature change drops even further from -3 oC at 10 km/hr down to -9oC at 60 km/hr.

 

At this point, the body has increased the heart rate, metabolism and blood pressure to heat the body, as well as instigated vasoconstriction (constricting the blood vessels in the skin to reduce heat loss). It will also cause the muscles to shake as another means of trying to generate heat.

 

Wind Chill is not only cooling the skin further by drawing water from the skin and drying it out (water is used to expel heat in sweat and insulate the body in cold), but it is also pushing cool air into the lungs and cooling the body from the inside. Hence the feels like temperature feeling colder than the air temperature by 3 to 9 degrees below zero.

 

2.       Humidity Levels and Temperature in the Lungs

As mentioned in the above point, the wind chill factor lowers the temperature inside of the body and lungs, causing vasoconstriction in the lungs and reducing the temperature. This results in drier air, drying the mucus and airway walls, whilst slowing the mucociliary escalator transportation rate.

 

This results initially in agitation of the airway walls causing a cough and then inflammation of the airway walls and a build up of mucus leading to obstructions in the airways, making it harder to breathe with both inflamed and obstructed airways.

 

3.       More Smaller Particles in the lungs  

By air becoming colder and dryer, this causes less water molecules around dirt and smoke being breathed in and already in the mucus. This means that the particles are smaller, can be picked up easier by the wind and if they are below PM5 in size, then they have a greater chance of slipping through the mucociliary escalator in the lungs, resulting in airway agitation, coughing and inflammation. If the mucus has already trapped allergens, then these have the potential to become released and cause an asthma attack.

 

On top of this, if the wind speed is 20 km/hr or more, it has more change of picking up smoke and dust particles in the environment. If the day is low humidity and/or the ground hasn’t had much moisture, this increases the chance of creating a dust storm which has the chance of cause asthma attacks and COPD respiratory attacks.

In Summary – How do I Handle Extreme Wind Chill Factor?

Our body was designed to breathe in through our nose and not through our mouth. This is to give the body more time to add humidity and warmth to the air before entering the lungs and causing further drying effects. Adding and extra layer of clothing has the potential to warm the air will only help this process.

 

If the day is windy and you have to go outside, then you need to understand that if you can slow down the wind through extra clothing, whilst also reducing the chance of breathing in dust and smoke, then will only help your lungs.  

Conclusion

A very simple way to understand this is that the optimal outside weather conditions and safety ranges are as follows:

1.       Feels Like Temperature – 28 oC (82 oF) with a safe range of between 0oC (32 oF) and 32oC (90 oF),

2.       Humidity – 40%, with a safe range of between 30% to 50%

3.       Wind Speed – 0 km/hr with a safe range of less than 19 km/hr (12 mph)

4.       Air Quality Index (pollution) – 0 with a safe level less than 50 

If you can create an environment which meets this environment, then this is great. But it isn’t always possible to live in the ideal climate. So here are some pointers which should help.

Remember that as simple rule to understand how the weather works is;

1.       >50% humidity increases feels like temperature,

2.       < 30% humidity decreases feels like temperature,

3.       Wind chill factor generally decreases temperature. 

Handling Hot Humid Days

If you have a hot humid day, then;

1.       Use an air conditioner or fan to create wind chill factor to reduce the temperature,

 

2.       Use a dehumidifier to reduce humidity and pathogens in the air

Handling Hot Dry Days

So if you have a hot dry day, then;

1.       Use an air conditioner or fan to create wind chill factor to reduce the temperature,

 

2.       Use a humidifier or use and drink water to increase humidity and improve hydration of the body

Handling Cold Days

If it is a cold day, then;

1.       Use a humidifier or use and drink to increase humidity (and temperature) and improve hydration of the body

2.       Use an air conditioner or heater to heat up the air temperature

 

3.       Add clothing to help keep you warm

What Happens with Exercise Asthma?

Exercise asthma usually occurs during cold weather or very hot dry or hot humid weather and this has to do with the following.

Cold Weather
Exercise
Asthma

In cold weather, the causes are as follows:

1.       Vasoconstriction of the blood vessels, causing the lung to become cold and dry,

2.       The drying of the mucus and slowing of the mucociliary escalator,

3.       Agitation of the airway walls, which leads to coughing,

 

4.       Eventual inflammation of the airway walls from either becoming dried out or pathogens and particles in the mucus causing the inflammation

Hot Dry Exercise Asthma

In hot dry weather, the causes are as follows:

1.       Vasodilation of the blood vessels, cause loss of water from the body through sweat which in turn causes dehydration of all fluids in the body including mucus,

2.       The drying of the mucus and slowing of the mucociliary escalator,

3.       Agitation of the airway walls, which leads to coughing,

 

4.       Eventual inflammation of the airway walls from either becoming dried out or pathogens and particles in the mucus causing the inflammation

Hot Humid Exercise Asthma

In hot humid weather, the causes are as follows:

1.       Vasodilation of the blood vessels, cause loss of water from the body through sweat which in turn causes dehydration of all fluids in the body including mucus,

2.       The drying of the mucus and slowing of the mucociliary escalator,

3.       Agitation of the airway walls, which leads to coughing,

 

4.       Eventual inflammation of the airway walls from either becoming dried out or pathogens and particles in the mucus causing the inflammation

5.   The high humidity can lead to higher numbers of pathogens including dust mites and mould spores which can lead to a higher chance of an asthma  attack.

Things which you can do to help include.

1.       Warming up in a warmer environment for cold weather asthma to help to warm your lungs and body before exercising in the cold weather,

2.       Wear warmer clothes when training so you help your body to stay warmer,

3.       Keep hydrated so your body can keep the right humidity in your lungs 

Why Do Sudden Changes in Temperature Make You Cough?

Sudden changes in temperature and/or humidity levels are usually from leaving an air-conditioned environment and walking into outside weather which is usually different in temperature and/or humidity levels. Sort of like jumping from a hot spa into freezing cold water.

The body goes into a state of shock as it suddenly needs to make drastic changes, whether it be to heat or cool the body suddenly. Forcing it to suddenly increase or decrease blood vessel sizes in the skin and airway walls and increase or decrease our heart rate, blood vessel and/or metabolism. The temperature and blood flow changes in the lungs for both conditions means drying of the lungs which can cause agitation of the airways walls leading to coughing, and if it stays cold or hot and dry, then it means you will cough for a period until your body catches up and regulates it’s balance state.

The best way to combat these temperature changes to make them as gradual as possible. i.e. don’t put on a warm coat before leaving the air conditioned office (this just leads to decreasing the body’s core temperature further), put the coat on just as your are entering the new climate, so you add warmth when needed. Use a scarf just as you leave the office to help warm the air entering your lungs. Simple things like this can help.   

References

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2. Stanley A. Morain, Amelia M. Budge, Environmental Tracking for Public Health Surveillance, https://books.google.com.au/books?id=D9DKBQAAQBAJ&pg=PA131 

 

3. Ximena M. Bustamante-Marin and Lawrence E. Ostrowski, Cilia and Mucociliary Clearance, Cold Spring Harb Perspect Biol. 2017 Apr; 9(4): a028241. doi: 10.1101/cshperspect.a028241  and https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5378048/ 

 

4. Alison Pieterse & Susan D. Hanekom, Criteria for enhancing mucus transport: a systematic scoping review, Multidisciplinary Respiratory Medicine volume, Multidisciplinary Respiratory Medicine volume 13, Article number: 22 (2018) Cite this article 06 July 2018, https://mrmjournal.biomedcentral.com/articles/10.1186/s40248-018-0127-6 

 

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10. Stanley A. Morain, Amelia M. Budge, Environmental Tracking for Public Health Surveillance, https://books.google.com.au/books?id=D9DKBQAAQBAJ&pg=PA131 

 

11. Ximena M. Bustamante-Marin and Lawrence E. Ostrowski, Cilia and Mucociliary Clearance, Cold Spring Harb Perspect Biol. 2017 Apr; 9(4): a028241. doi: 10.1101/cshperspect.a028241 and https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5378048/ https://www.maxill.com/us/downloads/dl/file/id/23/isopropyl_alcohol_70_sds.pdf 

 

12. Alison Pieterse & Susan D. Hanekom, Criteria for enhancing mucus transport: a systematic scoping review, Multidisciplinary Respiratory Medicine volume, Multidisciplinary Respiratory Medicine volume 13, Article number: 22 (2018) Cite this article 06 July 2018, https://mrmjournal.biomedcentral.com/articles/10.1186/s40248-018-0127-6 

 

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14. How does the temperature of ocean water vary? – https://oceanexplorer.noaa.gov/facts/temp-vary.html#:~:text=At%20high%20latitudes%2C%20ocean%20waters,%C2%B0F)%20near%20the%20poles. 

 

15. Does Humidity Affect COPD?, https://lunginstitute.com/blog/does-humidity-affect-copd/

 

16. Heat Index Calculator, https://www.weather.gov/epz/wxcalc_heatindex 

 

17. COPD and Humidity, https://www.healthline.com/health/copd/humidity

 

18. Heat Index Information, https://www.weather.gov/safety/heat-index  

 

19. Heat index, https://en.wikipedia.org/wiki/Heat_index 

 

20. Hot and Cold: Extreme Temperature Safety, https://www.healthline.com/health/extreme-temperature-safety 

 

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22. Victor E. Del Bene., Chapter 218 Temperature, Clinical Methods: The History, Physical, and Laboratory Examinations. 3rd edition., https://www.ncbi.nlm.nih.gov/books/NBK331/ 

 

23. Jeffery W. Walker, When air is the same temperature as our body, why do we feel hot?, April 8, 2009 https://www.scientificamerican.com/article/why-people-feel-hot/ 

 

24. Effect of Wind Speed and Relative Humidity on Atmospheric Dust Concentrations in Semi-Arid Climates, Janae Csavina,a Jason Field,b Omar Félix,a Alba Y. Corral-Avitia,c A. Eduardo Sáez,a and Eric A. Bettertond, Sci Total Environ. 2014 Jul 15; 487: 82–90., https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4072227/ 

 

25. Beaufort Wind Scale, http://www.disastercenter.com/convert.htm 

 

26. What Is Wind Chill, and How Does It Affect the Human Body? https://www.smithsonianmag.com/science-nature/what-wind-chill-and-how-does-it-affect-human-body-180971376/  

 

27. Revised Wind Chill Calculator, http://romseyaustralia.com/windchill.html 

 

28. The response ranges of pulmonary function and the impact criteria of weather and industrial influence on patients with asthma living in Vladivostok, Lyudmila V. Veremchuk, Elena E. Mineeva, Tatyana I. Vitkina, Elena A. Grigorieva, Tatyana A. Gvozdenko & Kirill S. Golokhvast,Journal of Environmental Health Science and Engineering volume 18, pages235–242(2020), https://link.springer.com/article/10.1007/s40201-020-00458-z 

 

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