Air Pollution & Winter

Winter smogs worsens our health system.The cycles of extreme air pollution episodes or the severity of smog and its period of occurrence during winter season is triggered by a combination of a number of factors. These factors include specific emission sources – incomplete combustion, heavy traffic, unique geographical location, and the adverse weather conditions such as temperature inversion, humidity and the wind speed at ground level. In addition, atmospheric dispersion is another key factor responsible for winter smog and its persistence. The lower the level of atmospheric dispersion, the higher the level of winter smog.

During the normal conditions, the pollutants in the air are carried away in upward direction by layer of warm rising air to the colder air higher up so that it can reach maximum height and get dispersed vertically. When temperature inversion happens in the winter, the warm air is unable to rise up due to presence of warmer air near the cold air at the ground level. As a result, the pollutants in the colder air at the ground level remain trapped in the area for a longer period of time and cannot be pushed up and dispersed, causing maximum harm to the people and environment.

Also during the winter months, in general, the wind speed is low and because of that the wind pushes and disperses the pollutants horizontally at slower rate. When there is no wind, the air become stagnant at a place and it causes buildup of pollutants in the air. Furthermore, air pollution not only varies by season but also it varies in type, day of the week and by time of the day. So in addition to making plans and enjoying this winter, let’s also give attention to the effects that winter air has on our air quality and public health as a whole.


Winter Smog and Health Hazards

Since smog is made of a combination of air pollutants, it has detrimental effect on human health, ecosystem and even can cause property damage. Health experts believe that winter smogs may result in a rise in premature death as well as a rise in respiratory and heart-related problems. In humans, smog can cause and aggravate respiratory health problems such as asthma, emphysema, chronic bronchitis, eye irritation, reduce the body’s immunity to fight cold and infection of lungs. These conditions often affect those with chronic obstructive pulmonary disease (COPD), because of the combination of poor air quality, cold temperatures and more coughs and colds during the winter season.

Air pollution & winter

Some people can experience more adverse health effect than others, depending upon their age, pre-existing health condition and period of exposure. These groups of people include children, adults who spend most of the time outdoors, people with respiratory diseases and the elderly people with low immunity.

As we often tend to look at outdoor pollution as a greater risk to us,
we should be aware indoor air pollution is equally fatal. How?

Air pollution & winter

Increased insulation

How many of us become conscious of the air leaks from the house during winter? It is common in doors, windows, where pipes and wire enter the house, while we get better insulation to increase comfort.

Unfortunately, there is a downside to improving insulation around the home — a decrease in indoor air quality. When contaminants cannot escape your home, they gather and multiply quickly. These include bacteria, viruses, mold spores, and dust mites that can easily make you sick, especially if you don’t have a strong immune system.

Use of heat recovery ventilator or energy recovery ventilator could be an option.

Dust and Dirt

The cold air outside could make you feel like staying at home all day but also realize even if you have a heat recovery ventilator that is introducing fresh air into the home, it may not make much of a difference if your home is filthy.

If you shine a flashlight beam in a dark room and you see a flurry of particles in the air, that is a sure indication that you need to clean.  All of those airborne particles can make it look like the winter storm is happening inside! The circulation of dust is also what dirties up your house causing clogged air filters and indoor air quality problems leading to a lot of health issues which may range from skin allergies to respiratory infections.

Cleaning and wiping up dirty, dusty surfaces is important for maintain a healthy home. It’s also extremely important that you change your air filter every month. Since you can’t exactly dust or vacuum the particles that are already in the air, your air filter does the job for you. You may also want to clean all of the vents and grilles with a damp cloth. If your air filter is dirty and clogged, not only will this cause airflow problems that could cause a system breakdown, but the dirt and dust will also get recirculated back into the air and eventually into your lungs.

Smoke and Combustion Gases

air pollution & winterDon’t smoke in the home! While smoking in general is bad for you, secondhand smoke is arguably even worse and lingers in the home for a long time after the cigarette is put out. For optimum indoor air quality, do not allow smoking in the home.

While winter calls for delicious eateries also remember, Smoke and other particles can also come from your fireplace and heating system. These particles include radon gas, carbon monoxide, and other residual contaminants degrading the quality of indoor air and of course entering your lungs.


Pets are great for a lot of reasons. What they aren’t great for, however, is indoor air quality. If you have pets at home, here are some suggestions for keeping pet-related contaminants from severely decreasing your indoor air quality.

  • Don’t allow pets in the bedroom
  • Don’t allow pets on furniture
  • Have your pet bathed and cleaned every couple of months.


Solutions to Winter Air Pollution Hazards

In short term, the impact of air pollution due to winter smog can be reduced by limiting outdoor activities and travel time, using appropriate face masks when outdoor, keeping children, elderly and the people who are at high risk to respiratory diseases away from exposure, suppressing dust particles by spraying water from the air, banning of open burning of domestic wastes and agricultural wastes, proper handling and disposal of solid waste.

The following are some tips  for winter wellness.

air pollution & winter



Priyasha Maharjan
Janata Clinic | Samartha Nepal



Prakriti Acharya
Intern – Research
Janata Clinic | Samartha Nepal