Why is Air Pollution Worse during winter?

Yes, it is a myth that the level of air pollutants increase during summer. Air Pollution is actually worse during winter. It is generally misunderstood by the people of urban areas may be due to suffocating environment they face every day. In reality, it is in winter when earth’s level of air is affected by pollutants. Globally it has been found that during winters more fuels and biomass are burnt. However, industrial pollution remains constant throughout the year. Perhaps people also believe that summer air quality is worse because of the long day hours and ultraviolet radiation. It becomes more suffocating in a sun-baked concrete weather. People may also believe this because of the high temperature of summer which feels like something huge and bad occurring above the earth layer. When winter arrives these cities can expect air that is more than twice as polluted as during the spring and summer.

In a lower income country where they burn garbage and coal for heating, the levels of toxic gas like carbon monoxide increases significantly. The increase of toxins in the air combined with the temperature inversion creates the smog that they breathe every winter. And winter is the season people burn woods, some people use plastic and tires to comfort them from cold.

The main reason for winter pollution is that during winter, inversion condition takes place in the atmosphere. A temperature inversion is where the air temperature rises with altitude. Inversion condition in short means that increase in height and the temperature increases, this condition usually breaks with the sunrise when the earth again becomes warm and the temperature starts falling with altitude. Inversion of temperature does not let pollutants escape into the atmosphere. Basically, summer air is better than winter air because summer brings a clearer sky and certainly clearer air. But during the winter, cold air traps pollutants close to the ground. Summer heat prevents inversion, which does improve the air quality. That’s why it is only during the winters the pollution level rises.

For the last few decades, Central heating in china was mainly powered by coal. When there is a discussion for pollution in an Asian country, Beijing air considerably became thicker during winter. Keeping this in priority the Beijing authorities have issued a red alert warning.

While talking about Asian countries, the country India can’t be ignored. In India, Delhi and its surrounding areas are totally affected by air pollution. Crop burning during winter is also an interesting phenomenon and starting of winter means the end of the harvest season so farmers are likely to burn the stubble off their fields. NASA has released satellite images of the great plumes of smoke from burning rice paddies in Punjab, India in October and November. The burning of paddy straw every year in October and November in Haryana and Punjab are the major contributors to air pollution in the national capital region in India. Along with this, the festival Dipawali is also a good contributor for the winter air pollution.

The measures get implemented when the level touches ‘severe’ it also includes, closing of brick kilns, hot-mix plants, stone crushers and maximizing power generation from the existing natural gas-based plants. When the pollution level dips to ‘severe’, a ban is imposed on the entry of trucks, except those carrying essential commodities, into Delhi, and construction activities gets disrupted. Additionally, the ‘odd-even’ scheme for private vehicles based on a license plate numbers was introduced.

In contrast when summer air is hot and still, vehicle emission build in Utah valley, resulting in poor air quality. Ground level ozone, the main ingredient of smog, can reach levels that are dangerous to people’s health. Emission from area sources like buildings and homes, transportation emissions from motor vehicle exhaust or gasoline vapors and things like chemical solvents are some of the major sources of chemical air pollutants.

While the science behind the two air quality issues are different, a major factor in both is transportation emission. So by simply reducing vehicle trips we can protect our health, environment and the quality of our life in summer. The idea of using less vehicle is less effective for winter pollution as winter air which is a blanket of pollutants can’t be ventilated easily.