Does Air Quality Get Better at Night?

We all might think that the Air Quality gets better at night as there is less traffic on roads and less industrial emissions. But is that even true? 

In this article we will answer all your queries regarding nighttime pollution, how it affects our health. We will  share with you some simple yet useful tips to get you a good night’s sleep. Also we’ll suggest some pro tips to cleanse the air quality of your bedroom and how you can  keep harmful pollutants at bay. 

Does Air Quality Get Better at Night?

No, the air quality does not get better at night. The air quality actually  gets worse at night. The reason being that at night there is less wind which allows pollutants, such as smoke and dust particles to settle closer to the ground.

Why does air quality get worse at night? 

To understand this in depth we have to get into the topic of meteorology a little deeper. 

Atmospheric stability can occur at any time but it is more prevalent at night. During Daytime the ground is heated by the sun with the phenomenon of convection. This results in the constant overturning and promotes vertical mixing of air. Therefore the pollutants released have a higher probability of dispersing into the atmosphere. 

During the early morning the atmospheric boundary layer is thin (around 50-200m). After the sunrise when the land gets heated up, the atmospheric boundary layer grows upto the values of 1000-2000m due to the atmospheric turbulence. The pollutants get diluted over a deeper layer till the afternoon. Consequently the atmospheric pollutant concentration is diluted to a greater extent.

Whereas at night  the reverse happens. The  land gets cooled due to loss of solar radiation. This results in air-surface temperature difference leading to a relatively stable atmosphere. This promotes higher chances of immediate environmental exposure.

Atmospheric stability is defined as the tendency for vertical mixing of air in the atmosphere. 

This explains that a more stable atmosphere will have less potential for vertical mixing and more potential for horizontal spread.

These weather conditions are responsible for high atmospheric pollutant concentrations, particularly nitrogen oxides, ozone, etc.

Therefore, both the dynamics of the atmospheric boundary layer and atmospheric chemistry is responsible for the diurnal cycle of air quality. 

Hence both the elevated pollutant concentration and urban heat island effect result in adverse health effects.

Also there is a difference in meteorology of urban and rural areas.  For clear skies  cities are several degrees warmer than the countryside due to urban heat island effect.

Difference in the structures and land covers leads to urban heat island effect. The cities have smaller albedo and higher heating capacity due to the presence of fabric, concrete and asphalt. There is a restricted emission of thermal radiation, especially at night. And several anthropogenic activities such as vehicular emissions, industrial pollution etc are the main factors responsible for Urban Heat Island effect.

How does air quality at night affect us?

Studies have shown that over one third of Americans are not getting a good night’s sleep due to bad air quality at night. 

There are several ways how air quality at night affect us:

  • Air pollution affect vital organs such as; lungs, heart and brain
  • Sleeping disorders like sleep apnea
  • Affects mood
  • Disrupts the REM cycle

We will explain each of these in brief so stay tuned with us. 

Air quality affect our vital organs like; lungs brain and heart

Effect on lungs

  • shortness of breath
  • Coughing 
  • Wheezing
  • Asthma and chest pain
  • Lung cancer 

Effect on brain

  • Inflammation and oxidative stress 
  • Can also lead to dementia 
  • Particulate matter having size less than 2.5 (PM2.5) can enter the brain directly and can reduce cognitive function
  • PM2.5 can reduce semantic memory 
  • PM2.5 can also reduce brain volume

Effect on heart

  • Several air pollutants like ozone, NO2, CO, and particulate matter have detrimental effects on vascular system 
  • Sleep-disordered breathing and air pollution are linked together for increased risk of cardiovascular disease and low blood oxygen levels.
  • Increased episodes of cardiovascular morbidity and mortality
  • Low blood oxygen levels, and reduced quality of sleep.

Air pollution can cause sleeping disorders

  • Studies have linked sleep disorders with air pollution. The two pollutants namely PM2.5 and NO2 are believed to cause obstructive sleep apnea. 
  • Sleep apnea is caused by blockage in the upper airway causing restricted oxygen flow in the body. 
  • Air pollution damages the mucous membrane of throat and nose, which causes nasal congestion, multiplying the risk of getting sleep apnea
  • People living near power plants, industries and high traffic areas are at a greater risk of experiencing sleep apnea. 
  • Sleeping disorder can also be linked with increase in temperature and increased pollution during summer months. 
  • Researchers have shown that you are 13% more likely to have shallow breathing if pollution levels are elevated consequently, affecting the sleep patterns.

Air pollution can disrupt REM cycles

  • Too much of Carbon dioxide plays a negative impact on our sleep quality. 
  • It is believed that people who sleep under high CO2 concentrations have their REM cycles (the state of deep sleep ) disrupted. 
  • CO2 is not harmful in small quantities but higher quantities can cause drowsiness and makes you feel groggy. 

Air pollution affect mood 

  • Air pollution has also been linked with emotional imbalance. People living in high pollution zones are likely to experience mood swings, low concentration and even memory lapse.
  •  Further people living in high pollution zones who are used to smoking are at even greater risk of sleep apnea, cardio-vascular disorders and even lung cancer. 

What Researchers need to say about the issue of deteriorating  Air Quality at Night ?

Recent studies have highlighted the detrimental effect of PM2.5 on the health of people in the United States. It was shown that only a 5ug/m3 of PM2.5 exposure increased the number of hospital admissions for Alzheimer’s, dementia and Parkinson’s by about 33-100%.

Even in New Delhi people are exposed to the worst air pollution at night and early morning. A study conducted by The Centre for Science and Environment (CSE) found that the concentration of PM2.5 was highest, especially during night, and even indoor air quality was extremely poor. 

How to improve the air quality at night?

You can improve the air quality at night by using or doing the below mentioned things:

Installing an HVAC system 

The HVAC system works efficiently towards filtering airborne contaminants. The filter should be upgraded on a timely basis in order to maintain its efficiency. 

Here are a few HVAC systems that you can buy: 

HVAC Systems Why i recommend it 
Honeywell F300E1019 Electronic Air Cleaner

This can be operated with gas, oil and AC systems. Efficiency for capturing particles is upto 98%.Has a very low pressure drop
DAIKIN 9,000 BTU 17 SEER Wall-Mounted Ductless Mini-Split Inverter Air Conditioner Heat Pump System Daikin’s ductless technology offers  greater  energy efficiency; cools and warms up the room fast.Smart inverter technology with integrated inverted variable speed compressorProvides continuous heating and cooling with minimum temperature fluctuations.Quiet operation; with indoor sound levels as low as 37 decibels. 

Install an air conditioning system

Apart from cooling, the air conditioners also help in ventilation by the circulation of air inside the room.The air conditioner works on a principle that it draws the warm air of the room and replaces it with cool air, thus ensuring proper air circulation.

Air conditioners also help in keeping the dampness at bay.

If you are looking for some portable yet efficient air conditioners check out the below mentioned links: 

Air conditioners Why i recommend it 
Whynter ECO-Friendly 11000 11,000 BTU Dual Hose Portable Air ConditionerIt has four operational modes; AC, fan, dehumidifier and auto mode.Offers an airflow rate of 300 m3/hHas an eco- friendly CFC free technologyDehumidifying capacity of 81 Pts/day
Whynter ARC-14S 14,000 BTU Dual Hose Portable Air Conditioner, Dehumidifier, Fan with Activated Carbon FilterIt comes with three operational modes;Air conditioner, dehumidifier or fanMaximum power consumption of about 1300 W / 11.6AOffers a dehumidifying capacity  of 71 pints/ dayEco friendly and CFC free technology 


Use a Dehumidifier 

Dehumidifiers help extract the excessive moisture out of your room. Dehumidifier works on a two step principle:

Firstly it draws moisture out of the air and collects the water on a drip tray Secondly it warms up the collected dry and cold air and finally fan the dry air back in the room. 

Check out these links for some of the best Dehumidifiers: 


Dehumidifiers     Why i recommend it
Gocheer Upgraded DehumidifierHigh efficiency dehumidifier Equipped with a 2000ml water tank capacity It is very compact and portable suitable for highly humid areas; such as the bathroom, basement, kitchen, living room etc. Quiet operation of as low as 40dBComes with automatic shut off mode to prevent overflowing of water tank Saves energy with a consumption of only 1.15 kW of electricity within 24 hours of operation.  
COSVI Upgrade DehumidifierCOSVI home dehumidifier keeps moisture below 35%Comes with one-button switch design for easy operationOffers a whisper quiet operation with sound levels below 35 dBEnergy efficient; consumes less energy with a power only 48W/ hour after running for 24 hours. Cost effective Comes with an auto shut featureCompact and lightweight ideal for bathrooms, basements, kitchen, bedrooms etc. 

Use air cleaners and purifiers

The simplest way to improve nighttime air quality is to install air purifiers. Air purifiers are devices which circulate the air through a set of filters and capture the contaminants like; microscopic particles such as dust, allergens, molds, spores, bacteria, etc, that are floating around.

Nowadays there are many filters available in markets having several features like HEPA filter, Activated carbon filter, and ultraviolet light. 

Below are the best air purifiers for improving the air flow in your bedroom:

Air purifiers

Why I recommend it
HATHA SPACE air purifier HEPA Air filterParticle efficiency of about 99.97% for particle size 0.3-0.1 micron.Effective against pollen, dust, VOCs, tobacco smoke, odors, pet hair, etc.Medical grade filterGood for extra large roomsAuto mode available for fan speed adjustmentComes with a 5 years warranty
LEVOIT Air Purifiers for Home
You can access this device from anywhere, fan speeds can be operated through your smartphone. Better purification with its 360 degree design. Suitable for large rooms. It has an ultra fine nylon pre filter and activated carbon filter. Highly efficient against 99.7% contaminants for particles as small as 0.3 microns such as; dust pollen, pet hair, mold, odor etc. Does not make much noiseVoice control feature 
Germ guardian true HEPA filter air purifier with UVlight sanitizer
Particle efficiency of about 99.7% for particles as small as 0.3 microns.UV C light sanitizer is effective against viruses like; staph, rhinovirus, influenza, and VOCs.Effective against allergens; pet dander and other large particles. It has a carbon filter and is highly effective against odors like; smoking, pets, odor from cooking, etc. Does not make much noise 
TOPPIN HEPA Air Purifiers for HomeEfficiency of about 95% for particle size of 0.3 microns. It has UV light, carbon filter and nano silver filter coating. Highly efficient against airborne contaminants; dust, pet hair, pollen and also efficient against odors, tobacco smoke etc. Fragrance sponge and aroma diffuser are also present. Purifies a large area of upto 160 sq ftLow noise levelsUv lamps are covered to avoid direct eye contact.

How can you get a good night’s sleep ?

Who wants to wake up groggy in the morning? Noone right. We all want a good night’s sleep. Afterall it is essential for our overall health. 

Here we will share some tips with you to get you a sound sleep. And also we will tell you about some low maintenance plants that help combat air pollution leaving your home fresh, clean and beautiful.

Tips to get you a sound sleep

  • Your bedroom temperature should be optimum
  • Avoid overheating of your bedroom
  • Keep your room well ventilated.
  • Keeping plants like Snake plant, Warneck Dracaena, English Ivy, Areca Palm, Aloe Vera in your bedroom

Introducing certain plants at your home not only adds value to your decor but also purifies the air around you. These plants are of low maintenance offering you numerous benefits. Whether it is filtering out the harmful toxins or providing you a 24×7 oxygen supply. 

So introduce the following plants into your house today and feel the difference. 

Snake plant or Sansevieria

Snake plant is number one on our list as this plant is a 24×7 oxygen emitting plant.They pump oxygen day and night constantly purifying air. Apart from that their large leaves are also efficient at removing certain harmful chemicals like xylene, toluene, benzene, formaldehyde and trichloroethylene.

Warneck Dracaena 

You can place this plant anywhere from your office to your home. Dracaena is known for its pollution combating properties; it works wonders against toxins like paints, varnishes, detergents and oils. They are low maintenance plants and do not need direct sunlight.

Bamboo palm

This plant not only has a beautifying effect on your house but also it filters out toxins like benzene, trichloroethylene, formaldehyde, toluene and xylene.This plant does not require much watering. 

Gerber Daisies or Gerbera jamesonii

The Gerbera plant is excellent at absorbing harmful carbon monoxide and benzene. Gerbera has beautiful bright flowers and adds to the aesthetic value of your house along with constant oxygen supply. 


English ivy

Next on our list is the English Ivy. Apart from its attractive looks, this plant helps absorb excessive dampness at your home and catches airborne mold. It also helps combat issues related to poor respiration and prevents you from developing infection.

Aloe vera

Aloe vera is the most common plant and is usually found in almost every household. This plant is normally used against minor cuts, burns, skin related issues. But apart from this aloe vera makes oxygen even at night, keeping your bedroom air clean and fresh.


Lavender is best known for its relaxing properties. It has been proven scientifically that this plant helps with anxiety, reduces blood pressure and lowers heart rate and helps you unwind. Lavender can be kept in your bedroom or you can also use lavender essential oil. Put some drops of oil onto your pillow. The scent of lavender helps you fall asleep faster and calms your nights.

I am sure these plants have caught your attention. So what are you waiting for? Go grab these wonderful plants to reap their benefits to the maximum. 

Other FAQs about Air Quality that you may be interested in.

How to Improve Air Quality in a Basement Apartment

Methane Gas: What do you need to know?

Why is PM10 harmful?


In this article we shared with you some simple yet useful tips to get you a good night’s sleep. We also discussed some pro tips to cleanse the Air Quality of your bedroom and how you can  keep harmful pollutants at bay. 

If you have any questions please write to us. We will try to answer all your queries.

Thank you.


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