How does air pollution cause acid rain?

In this blog post, we will discuss “How does air pollution cause acid rain?” Firstly, we will talk about air pollution. Then, we will also discuss the essentiality of the rains. After that, we will highlight the connection between rains and pollutants. In the end, the article will provide practical solutions to improve air quality.

How does air pollution cause acid rain?

Acid rains are caused due to mixing of hazardous airborne pollutants into the atmosphere with water droplets and clouds. Acid rains, also known as acid precipitation, cause detrimental effects on the living organisms on the Earth. It can damage natural resources as well as animal health. The emission pollutants which initiate this process are as follows:

  • Nitrogen oxides
  • Sulphur dioxide
  • Sulphur trioxide

Let’s first learn about air pollution.

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:

  • Transportation
  • Combustion of fossil fuel
  •  Cooking activities
  • Energy generation and consumption
  • Agriculture
  •  Improper Solid Waste Management
  • Industries and factories
  • Household pollution
  • Celebrations
  • 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
  • Cigarette 
  • Radon 
  • Poor ventilation 
  • Uncleaned furniture 
  • Pets 
  • Asbestos

 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 50Good           
51 to 100Moderate
101 to 150Unhealthy for Sensitive group
151 to 200Unhealthy
201 to 300Very Unhealthy
301 to 500Hazardous

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 is 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 understand the requirement of rains in our life.

Why do you need rain?

Rains are essential for the survival of unicellular to multicellular organisms on the Earth. Everyone needs water to drink and to maintain the proper metabolism of the body. Around 71% of the earth’s 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. 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.

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.

How are acid rains formed?

Acid rains are undeniably one of the worst consequences of air pollution. Such types of showers can happen due to natural and man-made air pollution. They release hazardous pollutants such as sulphur dioxide (SO2) and nitrogen oxides (NOx).

These toxic contaminants can easily dissolve in the water. When mixed with water, oxygen, and other compounds to form the following:

  • Sulfurous oxide
  • Nitric acid
  • Sulfuric acid

These acids can quickly transfer by winds through the atmosphere to other regions. Thus, acid rains can also cause transboundary pollution.

The sources such as factories, combustion of fossil fuels for mobile sources such as cars and other vehicles emit sulphur oxides and nitrogen oxides. Natural sources such as volcanic eruptions and rotting of vegetation can also generate the same nasty stuff. However, the United States Environmental Protection Agency (US EPA) states that the main reason is human-based air pollution.

Acid rain is a type of acid that appears in many forms. Let’s see its types in detail.

What are the main types of Acid rains?

Wet Deposition

Wet deposition is commonly called acid rain itself. It is the deposition of sulphuric and nitric acids mixed with rains, fog, smog or hail. A wet deposition requires moisture for the process.

Dry Deposition

Dry deposition occurs without the presence of moisture. As a result,  acidic particles and gases lingering in the atmosphere can deposit on the water bodies such as lakes and streams and the leaves of the vegetation. These acids do not spare even the buildings. The magnificent Taj Mahal, a symbol of eternal love, is a classic example of the dry deposition of acids. The marbles of the structure have turned yellow due to this process.

Besides, these acids can transform into larger particles that can cause danger to human health. The entry of nitric acid on the Earth can disrupt the healthy nitrogen cycle of the ecosystem. The next rains can wash off the accumulated chemicals on the soil and seep into the aquifers and plants. Such a process can disrupt the food web and can cause bioaccumulation.

How much are acid rains acidic?

You must have done a litmus paper test in your science practical. The PH scale is used to measure the acidity and alkalinity of any solutions. PH at 7.0 indicates that the answer is neutral. Any value lower than 7.0 is called acidic, and greater than 7.0 is alkaline. Distilled water found in the science labs is neutral, whereas seawater is alkaline; it has a PH value of 8.1. Acid rain generally has a PH between4.2 to 4.4.

Many researchers of various fields and policymakers rely on the National Atmospheric Deposition Program (NADP) and National Trends Network (NTN) for wet deposition measurements. The NADP and NTN collect acid rain at more than 250 monitoring sites throughout the US, Canada, Alaska, Hawaii, and the US Virgin Islands. But then what about dry deposition? While a wet deposition is easy to measure, it is pretty difficult and expensive to measure dry deposition.

The dry deposition estimates for the accumulated acids are done by Clean Air Status and Trends Network (CASTNET). They measure air concentrations at more than 90 locations. In addition, the Long-Term Monitoring (LTM) Network measures and monitors surface water chemistry at around 280 sites to keep a tab on the acid deposition on the lakes and streams. Such monitoring networks can provide important information about the aquatic ecosystem.

What happens when we get acid rains?

In an ecosystem, components such as air, water, and soil are intertwined with each other. Therefore, there should be a proper balance to protect the living organisms of the environment.

Aquatic Environment

As per US EPA, the impacts of acid rains are majorly seen in the aquatic ecosystem. Researchers claim that water bodies such as lakes, streams, and marshes are susceptible to acid rains. These water bodies are homes to many fish, birds, and wildlife animals. The more intrusion of acid rains into the water bodies releases more quantities of aluminum into the water.

However, some plants and animals can resist acidic waters and medium levels of aluminum. The ones which are sensitive to such alterations will lose the battle of survival. Animal enthusiasts found out that the young ones of most animal species are more vulnerable to the fluctuations than the adults. For instance, most fish eggs cannot hatch in the water, having Ph levels of 5. There are also cases where some adult fish were killed at low PH levels. Another example is that frogs have a crucial PH around 4.0, and frogs relish on mayflies. But, these mayflies are more vulnerable to the changes of the PH levels and may not survive PH below 5.5.

Plant and Forest Community

How to figure out if the trees or plants in your areas are affected by the acid deposition? Just carefully observe the trees and plants around you. If they are on the verge of dying or dead, it is a prominent indication that they are affected by acid rain. This is because acid rains percolate aluminum from the soil. This percolation can be dangerous to trees and wildlife depend on it.

When you hike or travel to higher altitudes, you may notice fog and clouds nearby. You may feel good all about it, but this fog and clouds could contain acid. These acidic fogs might shred nutrients from trees’ foliage, turning the leaves into brown or dead leaves and needles. As a result, the trees get less inability to absorb sunlight. This certainly weakens their immunity, and they can little withstand freezing temperatures.

Buffering Capacity

The US EPA stated that many forests and water bodies that come in contact with the acid rain don’t get much affected because the soil in that area can bear or buffer the acid rain by neutralizing the acidity of the rainwater coming in contact with it.

The buffering capacity entirely depends upon the thickness and composition of the soil. Therefore, the type of bedrock also plays a significant role in it. However, in the mountainous regions of the Northeastern part of the United States, the soil thickness is thin. Therefore, its overall composition cannot sufficiently neutralize the acid in the rainwater. Thus, these areas are particularly susceptible to acid and aluminum accumulation.  

Episodic Acidification

Heavy precipitations and the melting of snow can cause a phenomenon known as episodic precipitation. Lakes having a perfect balance of acidity levels can be changed due to melting snow or heavy shower. These additions cause acidic deposition and the inability of the soil to buffer it. These temporary levels of lower PH values can result in short-term stress on the ecosystem, and a variety of plant and animal species can get injured and may face death.

Nitrogen Pollution

Acid rains also disrupt the nitrogen cycle essential of the ecosystem. As acid rains contain nitric acid and it creates nitrogen pollution. Such nitrogen pollution in the coastal waters is partly responsible for the declining fish and shellfish population.

Human Health

Exposure to acid deposition can affect human health. It can lead to various respiratory ailments like bronchitis and asthma and can disrupt gut health. Acids in the rains can also cause harm to the skin and can cause various skin diseases. In addition, sulphuric and nitric acids can exacerbate existing conditions. In the past, acid rains have even caused 50,000 premature deaths in the United States and Canada.

What has been done to reduce acid rains?

EPA’s Acid Rain Program

Congress has already passed a law known as the Clean Air Act Amendments of 1990. This passed law emphasized that EPA should start the Acid Rain Program. The program notes to put a limit on the sulphur dioxide and nitrogen oxide emissions.

Reduction of pollution

Scientists have initiated to urge the use of coal that has less sulphur. Another method that researchers have suggested is to use the washing method on the coals to remove some sulphur. Such washing methods can be done using equipment known as scrubbers. Or else, the use of fossil fuels can be changed into the renewable energy sector.

Reduction of vehicular transport

As cars and other vehicles emit nitrogen and sulphur oxides, car manufacturers should reduce the number of nitrogen oxides and other pollutants produced by vehicles. Equipment known as catalytic convertor helps in reducing such pollutants. Newly built cars can also use natural gas and can also switch to electric fuels. There are also guidelines given by EPA.

In the below section, I have also provided some of the solutions to minimize air pollution.

What can I do to protect myself from air pollution?

I will elaborate on some of the measures to protect yourself from air pollution.

Personal Hygiene

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.

Quit Smoking

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 Exercise 

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.

Breathing Exercise 

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.

Good diet 

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.

Use Mask

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 MASKEAPI 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 maskFour layers mask Flexible nose pad, dual strapsDisposable maskEasy to breathe
BASE CAMP Reusable Cloth Face MaskThree 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.

Plant Trees

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.

Discourage Plastic

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.

Create Awareness

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

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: 

Air purifiers

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:

NameWhy I recommend it
Blueair Pro XL Air Purifier99.7% of airborne pollutants such as mould, allergens, smoke particles and pollens are captured. 
AIRMEGA 400SReduction 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 121Includes 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 HumidifierPortable Mini-humidifier500 ml capacity, still produces longer mistsEasy to operate
LEVOIT HumidifierIt 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 DehumidifierCan extract 50 pints of moisture a dayEnergy-saving auto-off systemBuilt-in Humidity sensor
HOmeLabs DehumidifierEliminates moistness, odour controllerEasy to cleanRemovable water tank
TCL Portable Dehumidifier20 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.

How does air pollution affect the economy?

How Does Air Pollution Affect the Immune System?

How Does Air Pollution affect the Climate?


In this blog post, we discussed “How does air pollution cause acid rain?” Firstly, we talked about air pollution. Then, we also discussed the essentiality of the rains. After that, we highlighted the connection between rains and pollutants. In the end, the article provided practical solutions to improve air quality.

Frequently Asked Questions (FAQs): How does air pollution cause acid rain?

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, there are many cases of delaying rainfall that has 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:

  • Dust
  • Particles
  • Smoke
  • SOx
  • NOx

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


Aerosol pollution may affect rainfall patterns. Down To Earth. Available at:  

Air pollution can prevent rainfall. ScienceDaily. Available at:

Air pollution ’causes more rain – but also less rain’. Available at:—but-also-less-rain/15279/  

What is acid rain, and how is it formed? Sustainability for all. Available at: