Air Pollution: Beyond Human Causes
In environmental issues, industry is often the primary scapegoat. However, nature itself can exacerbate pollution: due to various weather conditions, harmful emissions can either accumulate in one area or spread widely. Details in our post.
Wind and Atmospheric Pressure
Air is constantly moving, spreading pollutants from one place to another and even across borders. For example, acid rains in Sweden are caused by sulfur and nitrogen oxides carried by winds from UK and German industries. Asia faces its own weather phenomenon - yellow dust. Powerful spring winds pick up dust particles from the Gobi Desert located in China and Mongolia and sweep it over the Korean Peninsula and Japan.
Within industrial hubs, even a low wind speed can pose a threat. At speeds of 1–2 m/s, toxic substances from ventilation systems settle on the ground, and at 4–6 m/s, from large power plants. The direction matters too; wind blowing from factories towards city centers will lead to pollution.
The most dangerous situation is a calm associated with a high-pressure area or anticyclone. Pollutants remain near the ground, trapped in one region. Conversely, in low-pressure areas or cyclones, swirling currents rise and precipitation occurs, scattering or washing away pollutants.
Air Temperature and Humidity
Temperature affects air movement: warmer, lighter currents rise and cooler, denser ones sink, a phenomenon called convection. Which pollutants travel depends on seasonal weather.
Cold Weather Impact
In cold seasons, exhaust fumes and smoke are more noticeable. One might wonder whether it’s just more visible or if there's more pollution. The answer is both. Firstly, exhausts are a mix of carbon dioxide, nitrogen, warm steam, and harmful impurities. We see condensed water droplets when steam hits cold temperatures. Moreover, during late autumn and winter, vehicles often idle, burning extra fuel and producing more emissions.
Secondly, even if industrial waste remains constant throughout the year, there's more heating during colder months, releasing carbon monoxide and other toxic hydrocarbons.
Temperature inversions can exacerbate the situation. Typically, warm air rises, carrying pollutants that disperse over large areas. But sometimes, a layer of unusually cold air forms at the ground with warmer air above, preventing the cold air from rising. This traps pollutants below, resulting in smog.
During hot periods, ground-level ozone accumulates in cities and rural areas. In the stratosphere, this gas protects against ultraviolet rays, but at ground level, it's harmful. It's advisable to stay indoors during extreme heat, tracking hourly forecasts on our service. Luckily, summer often brings seasonal thunderstorms. Scientists note that high humidity helps break down ozone, so rain reduces it, and clouds inhibit its production.
May the air in your city be pure and your mood cloudless!