Should windows be closed at night?

You must have wondered that the air gets fresh and clean at night as there is less traffic on roads and less industrial emissions. And that’s why it is totally safe to open windows at night. But is that even true? Have you ever wondered where that black smoke and pollution goes at night?  Should windows be closed or we can open them at night?

In this article we will answer all your queries such as;  should windows be closed at night? How it affects our health. Also we’ll suggest some pro tips to cleanse the air quality of your bedroom without the need of opening the windows. 

Should windows be closed at night?

Yes, the windows should be closed at night; especially, if you live in urban areas. You might think that the air quality must be good at night as there is less traffic on roads, and most of the factories are closed.

But the air quality is worse at night. The reason being that at night there is less wind which allows pollutants, such as smoke, dust and particles to settle closer to the ground.

Why is the air quality worse at night? 

The air quality gets worse at night due to two reasons:

  • atmospheric stability.  
  • Urban heat island effect 

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

At night 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.

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.

The other reason is the Urban Heat Island effect. There is a difference in meteorology of urban and rural areas.

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. For clear skies  cities are several degrees warmer than the countryside due to urban heat island effect. And several anthropogenic activities such as vehicular emissions, industrial pollution etc are the main factors responsible for Urban Heat Island effect.

What are the effects of air pollutants on our health? 

There are several health effects of air pollutants on our health: 

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

Let us discuss each of these in brief: 

Affect lungsCausing Affect  brainCausing Affect  heartCausing Sleeping disordersDisrupt REM cyclesAffect mood 

shortness of breath
Oxidative stressinflammation dementiaCardiovascular morbidity Sleep apnea restricts oxygen flow in the body. 
high CO2 concentrations disrupts  their REM cycles. emotional imbalance. 
Wheezing Coughing(PM2.5) can enter brainreduce cognitive functionLow blood oxygen levels, and damages mucous membrane of throat and nose,
mood swings, 
Asthma and chest painreduce semantic memoryreduced quality of sleep.causes nasal congestionMakes you feel groggymemory lapse.
Lung cancerreduce brain volumeCardiovascular mortality The two pollutants namely PM2.5 and NO2 are believed to cause obstructive sleep apnea.higher quantities of CO2 cause drowsinessIrritability 

Ways to improve the air quality without the need to open the windows

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

Use air 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 purifier: GermGuardian True HEPA Filter Air Purifier

  • Features: 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 noise
  • Voice control feature

Air purifier: Instant Air Purifier

  • Features: Instant air purifiers are proven to kill 99.9% of covid-19 virus, bacteria, mold, and other harmful viruses.
  • With its Advanced 3-in-1filtration; HEPA-13, Activated Carbon, Antimicrobial coating and plasma ion technology it removes 99.97% of pollutants like tobacco smoke, pet dander, certain odors and other impurities.
  • Its advanced sensors offer a 24×7 air quality monitoring with auto fan speed adjust feature.
  • It filters the air in an area of 126 sq ft 5x per hour
  • With its whisper quiet night mode it offers lower noise for a sound sleep.
  • The filters last upto 8 month, after that it needs to be replaced.

Air purifiers: TOPPIN HEPA Air Purifiers

  • Features: Efficiency 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 ft
  • Low noise levels
  • Uv lamps are covered to avoid direct eye contact

Air purifiers: Shark Air Purifier

  • Features With its high speed  six micro fan speed it offers an even distribution of airflow. 
  • Its Clean Sense IQ monitors  air quality, auto-adjusts power and constantly maintains clean airflow.
  • The filter has an efficiency of 99.98% against particle size upto 0.3 microns. 
  • Highly efficient against dust, dander, allergens, smoke, and household odors like cooking, smoking, cleaning products etc. 
  •  Ideal for rooms having a dimension of 1,200 square feet. 

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 link: 

Air conditioners: whynter portable air conditioner

  • Features: It has four operational modes; AC, fan, dehumidifier and auto mode.
  • Offers an airflow rate of 300 m3/h
  • Has an eco- friendly CFC free technology
  • Dehumidifying capacity of 81 Pts/day



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: Gocheer Upgraded Dehumidifier

  • Features: High 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 40dB
  • Comes 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. 

Dehumidifiers: COSVI Upgrade Dehumidifier

  • Features: COSVI home dehumidifier keeps moisture below 35%
  • Comes with one-button switch design for easy operation
  • Offers a whisper quiet operation with sound levels below 35 dB
  • Energy efficient; consumes less energy with a power only 48W/ hour after running for 24 hours. 
  • Cost effective 
  • Comes with an auto shut feature
  • Compact and lightweight ideal for bathrooms, basements, kitchen, bedrooms etc.



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  Honeywell Air Cleaner

  • Features: This can be operated with gas, oil and AC systems. 
  • Efficiency for capturing particles is upto 98%.
  • Has a very low pressure drop

HVAC Systems  DAIKIN Air Conditioner Heat Pump System

  • Features: Daikin’s ductless technology offers  greater  energy efficiency; cools and warms up the room fast.
  • Smart inverter technology with integrated inverted variable speed compressor
  • Provides continuous heating and cooling with minimum temperature fluctuations.
  • Quiet operation; with indoor sound levels as low as 37 decibels.

Introduce indoor plants 

Introducing indoor plants at home not only provides 24×7 oxygen supply but also helps you sleep better. 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
  • Warneck Dracaena
  • Bamboo palm
  • Gerber Daisies or Gerbera jamesonii
  • English ivy

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

Should I run an air conditioner while smoking?

Should I open windows at night in summer?

Should I exercise in bad air quality?


In this article we tried to answer all your queries such as;  should windows be closed at night? How it affects our health. Also we suggested some pro tips to cleanse the air quality of your bedroom without the need of opening the windows. 


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