What causes air pollution? Vehicle emissions are one culprit, as are industry emissions, fires, and even weather conditions that allow smoke to linger in the air. California, for example, faced its deadliest fire season in October, made worse by winds that pushed air quality levels to “very unhealthy,” or when the air quality potentially starts to impact people’s health. This month, Delhi, the capital of India, surpassed a rating of 999 in air quality, which is deemed hazardous. What could possibly make a city’s pollution levels this high? Delhi’s pollution during the rest of the year is a result of vehicles (more than ten million!), construction, and fumes from factories and industrial waste. But during the winter, a few other factors make pollution even worse. Residents who can’t afford cleaner ways to heat homes often resort to burning fires, which causes dust and ash to mix with the air. Furthermore, Diwali, the Hindu festival of lights, often includes fireworks, and local farmers even add to the pollution by burning land to get it ready for the next cycle of crops. Mixed with the winter fog, all of these other factors can cause the smog to persist, and without enough wind, that smog gets trapped above the city. The Indian government has taken measures to reduce pollution, such as banning fireworks and using bricks for heat, but these efforts don’t always get pollution levels down to acceptable levels. Check out this map of the most polluted cities in ten countries. Do you think the reasons for pollution are the same for each country?
November 16, 2019