In this blog post, we will discuss “Does rain improve air quality?” Firstly, we will discuss the basics of air pollution. Then, we will briefly address the need for rain. Finally, we will outline the relationship between rains and air pollution. In the end, the article will provide practical solutions to improve air quality.
Does rain improve air quality?
Yes, rainfall improves air quality. The rain can aid in clearing the pollutants in the atmosphere. This process is called wet deposition. Various terms are used for this process, such as precipitation scavenging, wet removal, washout and rainout. The other factors which can alter air quality are as follows:
- Atmospheric Wind Speed
- Wind Direction
- Relative Humidity
Let’s first see what does air pollution means.
What is air pollution?
The introduction of harmful agents into the atmosphere is known as air pollution. The toxic agents are known as pollutants. These pollutants are derived from natural and human activities, and they can be chemical or biological.
Major pollutants present in the air are particulate matter (PM), ground-level ozone (O3), NO2, SO2, and CO. Air also has lead, allergens, bacteria, viruses and volatile organic compounds (VOCs).
Besides climate change, air pollution has become a significant environmental risk to human health.
What is Outdoor and Indoor pollution?
Air pollution in the outside environment is called outdoor pollution. The examples of outdoor pollution are as follows:
- Combustion of fossil fuel
- Cooking activities
- Energy generation and consumption
- Improper Solid Waste Management
- Industries and factories
- Household pollution
- Construction and demolition
Air pollution created inside any closed structure is called indoor pollution. The examples of indoor pollution are as follows:
- Household activities
- Perfumes and fresheners
- Cooking fuel/activities
- Poor ventilation
- Uncleaned furniture
There are two leading causes of air pollution- natural pollution (happened due to natural events like dust storms) and anthropogenic pollution (happened due to human activities like combustion of fossil fuels).
What is AQI, and what levels make it unhealthy?
WHO has set up the air quality guidelines to regulate the emissions; however, the United States Environmental Protection Agency (US EPA) has calculated its own AQI to safeguard the public health of Americans.
Environment Protection Agency (EPA) has determined the air quality index (AQI) to know the air quality you inhale. The table given below will show how the air quality index looks like.
|Air Quality Index (AQI)||Levels of Health Concern|
|(When the AQI is in this range)||(air quality conditions are)|
|0 to 50||Good|
|51 to 100||Moderate|
|101 to 150||Unhealthy for Sensitive group|
|151 to 200||Unhealthy|
|201 to 300||Very Unhealthy|
|301 to 500||Hazardous|
The primary purpose of AQI is to inform residents about the impact of local air quality on their health. The Environment Protection Agency calculates the AQI for five major pollutants: ground-level ozone, particulate matter, carbon monoxide, sulphur dioxide, and nitrogen dioxide.
The meaning of the Air quality index as mentioned earlier categories are as follows:
|Air quality is considered satisfactory; air pollution is of little or no risk.|
|Air quality is acceptable; some pollutants present in the air might be dangerous for a minority of people who are very sensitive to air pollution.|
|Members of sensitive groups may get ill effects. However, the general public is likely not to get affected.|
|This air quality level can pose a threat to everyone. However, members of sensitive people may experience more severe effects.|
|Emergency level of air quality; Entire population might be affected|
|Health alert: Every person breathing such air quality may get serious health issues.|
Thus, it is clear that excluding the first two levels are relatively good to venture out and to do various outdoor activities. However, the last three levels will give you or other adverse effects by inhaling dirty air.
Now, let’s see what rains are really for us.
Why are rains necessary for us?
Rains are essential for the survival of unicellular to multicellular organisms on the Earth. Everyone needs water to drink and maintain the proper metabolism of the body. Around 71% of the earth surface is covered with water. Your body also contains approximately 60% of water.
Rains and snow are essential elements in the Earth’s water cycle. These are the also primary source of water. Without rains, the water bodies on the Earth wouldn’t get filled up, disrupting the water cycle. Besides, rains also help in agriculture and energy production. Rains also have a cooling effect on the environment.
In the United States, approximately 70% of the annual precipitation returns to the atmosphere by evaporation and transpiration. The remaining 30% goes to the streams, lakes or oceans. While large monsoon patterns are observed in India, Southeast Asia and Australia, North America also witness one.
The North American Monsoon is one such weather pattern, where you can observe heavy precipitations in the Southwestern part of the United States and northern part of Mexico. This monsoon starts in July and ends in September. The North American Monsoon Rainfall comprises irregular but brief torrential thunderstorms.
They generally build up during the afternoons, intensifying due to the Earth’s surface. The rainfall in the United States is very sporadic, unlike Indian monsoons, where the rainfall pattern is regular. Therefore, there is a considerable variation in the intensity and distribution of rainfall. This can vary every year. You can notice some monsoons are very active, in other years the activity is very little. However, active monsoons are vital to breaking prolonged dry spells and drought conditions.
Many researchers have observed that rains can help clean the air. So let’s find out how does rainfall affect air quality.
How does rain improve air quality?
Let me first take you to a summer day cityscape. This city is soon going to witness thunderstorms. Thus, the weather is hot and humid. The busiest part of the city is mainly engulfed in toxic air pollutants such as carbon monoxide, oxides of gases and particulate matters released from the tail-pipe emissions.
All these gases and the weather conditions choke the air of the city. But suddenly, you get relief after the thundershowers start. The rain pouring down the town makes you breathe fresh air and feel lively. Yes, you observed or guessed right. Rainfall does surely improve the air quality. So let’s see in-depth how rain can alter air pollution levels.
The scientific association of rainfall and air pollution
First, the water vapour in the atmosphere, collected from the water cycle, cools and condenses on various particles present in the air such as dirt, dust and soot. Thus, that’s how the clouds are formed. When the clouds are fully saturated or, let’s say, full of water or moisture, they release water droplets or raindrops.
So, as this raindrop comes down from the atmosphere, it can attract innumerable other tiny aerosol particles to its area. All this process occurs before the raindrops hit the ground. This phenomenon is known as coagulation. In addition, this natural coagulation acts as a natural cleanser of the atmosphere. The coagulation process cleans the pollutants such as soot, sulphates and other organic particles.
The atmospheric chemists of MIT have also claimed that sufficient intensity and conditions of rains can clean the air. These researchers further observed various parameters which can help to improve the air quality. These factors are as follows:
- Diameter and concentration of aerosols
- The size of rain droplets
- Altitude of clouds
Some of the researchers at MIT executed experiments to observe the association between rainfall and air pollution. They carried out this experiment in MIT Collection Efficiency Chamber. It is a 3-foot-tall glass chamber that produces single droplets of rain at a monitored rate and size. First, the researchers introduced aerosol particles when these droplets of controlled dimensions fell through the chamber. Then, they observed the coagulation and measured its rate.
From these measurements, they further calculated the efficiency of rain’s coagulation. This efficiency revealed the capability of the droplets to attract the particles as they fall. The researchers observed exciting outcomes. First, they found out that smaller droplets are more likely to attract particles or pollutants. They noted that other conditions such as low relative humidity boost the coagulation process.
These results were recently published in the journal named Atmospheric Chemistry and Physics. The Victor P. Starr Career Development Professor of Atmospheric Chemistry, Dan Cziczo, said that these results symbolize the most precise coagulation values. He further recommended that these values may be helpful to predict the precipitation’s potential to clear a range of various pollutants in different environmental and meteorological conditions. He also added that the study of raindrops’ coagulation efficiency could help scientists evaluate rainfall patterns and their effect on air pollution in various cities. This discovery can further help address human health concerns and the impact of clouds on climate.
Further, scientists in air engineering have inferred that rain droplets’ electric charge plays a significant role in improving air quality. These electric charges also help fetch the pollutants of the atmosphere to the raindrop. In cases such as thunderstorms, many electric charges are generated and can boost the merging process further. Thus, thunderstorms and storms can help in decreasing air pollution.
To prove the relation of electric charges, that means the effectiveness of thunderstorms, Dan Cziczo, with a team of researchers, constructed a new chamber with a single-droplet generator. This newly updated instrument can generate single droplets of specified size, frequency, and charge. Generally, droplet generators contribute a high amount of electric charge onto a droplet. Thus, the team used a small radioactive source to remove a small charge from each droplet. Further, the group of researchers also introduced aerosol particles or pollutants of specific size into the lower area of the chamber. So, as the droplets fell on the ground, the residual salts were piped through a single particle mass spectrometer. This helped to determine if salt and the droplet attracted an aerosol.
These researchers also performed many rounds of experiments and research, where they varied the relative humidity of the chamber and differed the droplet size and frequency. They also studied the coagulation efficiency for each round and derived that the small size of droplets was more effective to attract aerosols in conditions such as lower relative humidity.
Researchers have also deduced that the rainwater from the skies can wash off the air pollutants such as particulate matter and ozone from haze and smog and pollens from the plants. Thus, this improves the air quality a lot. Accordingly, rains act as a natural eliminator of the ecosystem. Hefty rain can reduce up to 30% of airborne pollutants.
Further, Cziczo said that challenges such as climate change and global warming would alter cloud formation. The clouds play a crucial role in balancing the radiative budget. This means that clouds help trap the right amount of heat and sunlight; it balances the heat exchange of earth and atmosphere. He additionally emphasized that it is essential to establish the association of clouds, water droplets and the air pollution present in the atmosphere. Margaret Tolbert, a professor of chemistry and biochemistry at the University of Colorado, stated that there should be more research in this association to understand the role of rain and fog droplets can diminishing the aerosol particles. She further advised that understanding the microphysics of aerosols will eventually aid in forecasting air quality and climate change, as aerosols play a significant part in both processes.
Even though rains can help you breathe clean air by literally washing down the particulate matter and pollens from the atmosphere, it gets delivered into the ground. Such a type of condition is known as a wet deposition. This washout process is also called precipitation scavenging, rainout or wet removal. Researchers and engineers attempt to develop aerial sprays of water and other liquids to improve air quality by this exact mechanism. Some scientific evidence has observed that mostly large particles are removed from the scavenging by precipitation. Tiny particles less than 1 micrometre in diameter are washed out by heavy rains.
As they say, every cloud has silver linings. Similarly, a gloomy and cloudy rainy day can add colours to your life and make breathing easier.
Below, I will provide detailed solutions to improve air quality.
What can I do to protect myself from air pollution?
I will elaborate on some of the measures to protect yourself from air pollution.
You can also fight the effects of air pollution by maintaining personal hygiene:
- You can cut your nails short to avoid the accumulation of dirt.
- You can also practice mouth gargling after coming home to free your mouth from unwanted guests.
- You can also brush twice a day to keep airborne infections at bay.
- You can also take steam therapy at home to cleanse your lungs.
Smoking cigarettes, hookahs (shisha), electric vape or any other types of cigars are not at all suitable for your health. It’s best to stop smoking. Active and passive smoking provides the direct entry of harmful pollutants into your body. This causes the risk to your respiration and other organs dependent on it.
Physical activities have many benefits to your body. It not only improves your stamina and immunity levels but also helps to increase your lung capacity. Yoga, sanas, swimming, running, cycling, brisk walking and dancing are some of the best forms of exercise to improve your health.
The majority of people in the world don’t breathe properly. However, correct breathing techniques can keep illnesses due to air pollution at bay. A pranayama is a form of yoga asana which helps to improve breathing methods and lung functionality.
Some of the pranayama types that help you fight air pollution are Kapalbhati, Anulom Vilom, Chandra Nadi, Surya Nadi and Bhastrika. It is strongly recommended to learn this art of breath from a well-certified yoga trainer.
You can also increase your lung muscles by simply taking a deep breath and holding it for a count of 10. Then, slowly breathe out the air. If you can keep your breath for a longer time, then you have good lungs health.
Always go for a well-balanced diet to remain fit and strong. Consistent eating of junk and fast food will increase the risk of obesity and other diseases. In addition, such people are more vulnerable to the adverse effects of air pollution. Instead, add more fresh veggies and fruits to your diet. Also, you can consume less meat to minimise carbon footprints.
You can also add anti-inflammatory foods as these types of food help to cleanse your lungs effectively. Anti-inflammatory foods which I recommend are:
Immunity booster drinks
You can do your immunity booster drinks by using readily available items in your kitchen. Immunity booster drinks help to cleanse your lungs. Some of the DIY immunity booster drinks are as follows:
- Take a glass of warm white milk. Add half a teaspoon of turmeric powder to it. Also, add two strands of saffron to it. Drink it at night before sleeping. You will get good sleep, and you will be relieved from chest congestion.
- Boil water by adding half cinnamon stick. Drink the spice-infused water once a day. Your sinuses would be cleared up.
- Buy an excellent green tea. Prepare a green tea by following the packet instructions. Have it whenever you feel irritation in your throat.
- Take some crushed 1 or 2 peppercorns, a half-inch of a blade of lemongrass and 1 inch of grated ginger and half a teaspoon of turmeric powder. Add everything in one glass of boiling water and reduce it to half a glass. Drink two tablespoons of this spice-infused warm water every after three hours. Adding honey is optional.
- You can also drink warm water and add honey if you want. Honey helps to relieve throat irritation.
Mask can prevent you from inhaling the polluted air. You would be able to work in contaminated areas without any fear of allergy infections and stress.
Masks I recommend
|Name||Why I recommend it|
|BASE CAMP CROSSDUST MASK||EAPI Filter Technology & Advanced NanotechnologyUser FriendlyMore Durable Six layers face maskFilter materials of the dust mask: Double-Layer Melt-blown with Electrostatic Adsorption Performance, Activated carbon, Non-woven Polypropylene|
|NIOSH approved N95 mask||Four layers mask Flexible nose pad, dual strapsDisposable maskEasy to breathe|
|BASE CAMP Reusable Cloth Face Mask||Three layers mask; 100% cotton Skin-friendly and breathablePocket to add additional filterReusable Mask|
How can I individually reduce air pollution?
You can always try your level best to minimise air pollution. The following are the methods to reduce air pollution at an individual level.
Encourage tree plantation drives amongst the communities. You can be a green saviour of your region. Trees are the natural air purifiers of the environment, and it supplies us with clean air.
Municipal councils or the local authorities can develop urban forests to increase the green cover of the locality. They can also plan to create vertical green walls to improve oxygen levels of the region naturally. But don’t forget to plant only indigenous trees.
Human/ religious celebrations in eco-friendly ways
Nowadays, many couples celebrate gender (of their baby) revealing parties by bursting firecrackers. But, unfortunately, these firecrackers can transform into massive wildfires if they are burst near trees.
Thus, you can celebrate such celebrations by planting trees in your nearby barren land. Bursting firecrackers on any religious, festive or personal occasion are only going to harm your loved ones.
You can also celebrate Christmas by not cutting Christmas Trees. Instead, you can buy artificial ones and use them in the coming years too.
Single-use plastic has been one of the major concerns in the environment. Plastic pollution indirectly contributes to the degradation of air quality. Plastic, when burned, releases various toxic gases such as dioxins into the air.
Encourage alternative use of the plastic product. For example, you can wear a cloth bag for shopping. You can also carry your travel cutlery set to a restaurant. Additionally, you can take your water bottle instead of purchasing a packaged drinking water bottle every time.
Use of public transportation
Increase the use of public transport to reduce air pollution and traffic congestion. You can also try carpooling or the cab sharing option. Then, you can also use bicycles instead of scooters. Lastly, you can always opt for walking a shorter distance.
Alternative use of fossil fuel
It would be best to try switching to other fuel alternatives. For example, don’t use wood for the fireplace. Instead, you can wear multiple layers of clothes for warmth. In this way, you can conserve energy. Additionally, you can also install solar panels on house roofs to convert solar energy into electricity.
You can also buy electric and hybrid vehicles to minimise tailpipe emissions. Finally, propose or discuss a plan with your mayor or any relevant local authority to promote your region’s renewable energy sector.
Reduction of personal carbon footprints
You can also keep a check on your carbon footprints. For example, you can delete unwanted photos, videos or emails from clouds and email boxes as and when possible. Unfortunately, this unwanted stuff takes a lot of energy, which indirectly contributes to air pollution.
You can also switch off the lights and electrical appliances of the vacant rooms. Try buying local products instead of imported ones. Be vocal about them. You can also discover your own country rather than travelling to different ones.
Air pollution is unpredictable; air pollution in your vicinity can affect people living in Asia and vice-a-versa. However, you can create public awareness about air pollution amongst your community by teaching and interacting with your kids about the importance of good air.
Educate youth by telling them the ill effects of poor air quality. Then, let your country’s future know that they deserve a better place to live!
How can the local authorities improve the air quality of your region?
You can always observe the changes happening in your surrounding nature. If you experience bad air quality or any activities producing air pollution, you can always concern relevant local authorities or the mayor.
Here are some methods which local authorities can do.
Proper disposal of waste
Improper solid waste management of an area is an invitation to many diseases and infections. In addition, burning solid waste in public can cause air pollution, although such practices are rare in the US.
The wastes are mainly disposed of in the engineered landfills and recycled before final disposal to landfills and waste incinerators.
In addition, waste incinerators help to convert waste into energy.
However, many researchers have claimed that gasification technology or waste-to-energy technology may release harmful gaseous contaminants. Thus, it is necessary that waste collectors rigorously segregate the waste before sending it to waste incinerators.
The best solution is to minimise waste at a personal level. Statistically, 70% of the waste generated can be recycled effectively. Thus, strive to recycle your waste at a personal level as much as possible.
Reducing air pollution from agriculture
Stubble burning is still practised in some parts of the US. This event contributes to the degradation of air. Local authorities can help farmers convert this waste into cattle fodder or be transformed into pellets as fuel. In addition, farmers should stop the usage of harmful pesticides or fertilisers to decrease air pollution.
How can I reduce indoor air pollution?
Maintaining household or indoor hygiene
You can decrease poor air quality by adequately maintaining indoor hygiene. For example, you can frequently clean your cupboards and open decks to avoid an accumulation of dust particles. You can then vacuum your carpets and sofas at least twice a week.
Make sure your doggies and cats are well-groomed. Use chimneys and exhaust fans in kitchens. You can also install an exhaust fan in washrooms. Always make sure you are keeping your house well ventilated.
Keep doors and windows open when possible. Maintain the health of electric appliances such as heaters, humidifiers, AC, fans, air ducts and so on at regular intervals of the year. Avoid overuse of strong perfumes or strong scented candles indoors. You can additionally use indoor plants to make your indoors more lively and fresh.
Indoor plants do the same work as outdoor ones- they help to purify indoor air naturally. These indoor plants are also easy to maintain.
The indoor plants which I recommend are as follows:
- Snake plant
- English Ivy
- Peace Lily
- Red-Edged Dracaena
- Boston Fern
- Spider Plant
- Weeping fig
- Bamboo Palm
- Rubber Plant
Air purifiers help to improve indoor air quality. The risk of getting air pollution-related diseases decreases due to the use of air purifiers. Air purifiers having good HEPA filters do an adequate job of filtering pollutants.
Air Purifiers I recommend are as follows:
|Name||Why I recommend it|
|Blueair Pro XL Air Purifier||99.7% of airborne pollutants such as mould, allergens, smoke particles and pollens are captured.|
|AIRMEGA 400S||Reduction of 99.97% of particulates of 0.3 microns. Also responsible for reducing more than 99% of VOCs, NH3 and CH3CHO.Washable and permanent pre-filters are available|
|Blueair Pure 121||Includes 3-part filtration system. Captures 99% of common airborne PM 2.5 pollutants such as allergens, odours, smoke, mould spores, dust mites and pet dander.An activated carbon filter removes common odours caused by smoke, pets, and gases (VOCs) and smoke caused by wildfires.|
The humidity levels in the office should be maintained between 30 and 50% in the office. This range helps to keep dust mites, mould and other allergens under control. In addition, when AC or heater makes the air in the room dry, humidifiers can maintain correct humidity levels.
Humidifiers I recommend
|Name||Why I recommend it|
|Amazon Basics Ultrasonic Cool Mist Humidifier||4 litre of tank capacityAuto shut-off feature and 12 or 24-hour timer settingsIt can be used in both seasons|
|MOVTIP Humidifier||Portable Mini-humidifier500 ml capacity, still produces longer mistsEasy to operate|
|LEVOIT Humidifier||It can be used for both seasons6 litres of capacity Easy to clean and has a remote control|
Dehumidifiers also work similarly to humidifiers. It controls the high levels of humidity in the office.
Dehumidifiers I recommend
|Name||Why I recommend it|
|Pro Breeze Dehumidifier||Can extract 50 pints of moisture a dayEnergy-saving auto-off systemBuilt-in Humidity sensor|
|HOmeLabs Dehumidifier||Eliminates moistness, odour controllerEasy to cleanRemovable water tank|
|TCL Portable Dehumidifier||20 pints of moisture removed per dayIt can be operated at low temperatures tooEasy to maintain|
Other FAQs about Air Quality that you may be interested in.
This blog post discussed “Does rain improve air quality?”. Firstly, we discussed the basics of air pollution. Then, we briefly addressed the need for rain. Finally, we outlined the relation between rains and air pollution. In the end, the article provided practical solutions to improve air quality.
Frequently Asked Questions (FAQs): Does rain improve air quality?
How does pollution affect rain and water?
Air pollutants cause rainwater to be acidic. These contaminants can develop into toxic gases and combine heavy metals like Pb into rainwater.
Does pollution increase rain?
Environmental scientists around the globe have concluded that air pollution can decrease or increase rainfall; it depends on the local ecological conditions. Due to rising pollution levels, the intensity of rains rises at first, reaches a maximum peak, and finally falls off sharply at very high aerosol concentrations.
How does pollution affect the weather?
Air pollution affects the weather tremendously. The gaseous emissions are believed to have involved rainfall since the 1920s. Air contaminants can seed raindrop formation and change the rain cloud formation and rainfall pattern. In the United States, many cases of delaying rainfall have caused ferocious summer storms.
What happens to rain when the air contains pollutants?
Rainfall can benefit you; the rain can wash off common air pollutants such as pollens and allergens. This phenomenon is called Wet deposition.
What pollutants are in the rainwater?
The pollutants present in the rainwater are as follows:
What are the effects of air pollution?
The effects of air pollution are as follows:
- Damage to human health
- Economic losses
- Degradation of biodiversity and wildlife
- Depletion of natural resources
- Fluctuating weather conditions
- Greenhouse effects
- Global warming
Chu, J., Can rain clean the atmosphere? MIT News | Massachusetts Institute of Technology. Available at: https://news.mit.edu/2015/rain-drops-attract-aerosols-clean-air-0828
Does rain clean the air? LAMI. Available at: https://www.lamigroup.net/information/water/does-rain-clean-the-air/
Korber, R., 2019. Air pollution on a rainy day: Understanding Weather & Air Quality. Air Pollution on a Rainy Day: Understanding Weather & Air Quality. Available at: https://blog.breezometer.com/air-pollution-weather-rainy-day
Marks, J., 2019. North American monsoon. Geography Realm. Available at: https://www.geographyrealm.com/north-american-monsoon/
The effect of rain on air pollution (case study included). AQI India. Available at: https://www.aqi.in/blog/effect-of-rain-on-air-pollution/