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Zoology · Ch 13 — Environmental Issues

Control of Air Pollution

13.2.4

Control of Air Pollution

A range of measures help remove air pollutants, reduce their concentration, or prevent their release altogether. Trees are described as the best remedy for urban particulate and gaseous pollution: forests function as carbon sinks and are often called the 'lungs of the planet'. At the vehicle level, catalytic converters drastically cut polluting gas emissions, while diesel exhaust filters trap particulate matter; at the industrial level, electrostatic precipitators reduce the release of industrial pollutants. Cost-effective indoor solutions such as houseplants and high-performance biofilters can also improve indoor air quality. Broader policy measures include increasing green cover along roads through avenue tree planting, promoting the Swachh Bharat Abhiyan cleanliness campaign, enacting and enforcing stricter environmental laws, maintaining air-quality standards through proper monitoring, reducing carbon emissions, encouraging renewable energy, limiting the sale of firecrackers while developing eco-friendly alternatives, and making Environmental Impact Assessment mandatory for major projects. Public understanding of air quality is aided by the Air Quality Index (AQI), a single number that government agencies use to communicate how polluted the air is at a given time, banded from 'Good' at the cleanest end to 'Hazardous' at the most polluted. The section closes with a striking economic illustration of trees' pollution-control value: a healthy tree produces roughly 1,00,375 …

Table 13.2.4-T1Air Quality Index (AQI) bands
AQIAir Pollution Level
0–50Good
51–100Moderate
101–150Unhealthy for Sensitive Groups
151–200Unhealthy
Table 13.2.4-T2Economic value of oxygen from a tree
QuantityValue
Average human oxygen consumption per day550 L
Cost of a 2.75 L oxygen cylinder₹6,500
Cost of 550 L of oxygen bought as cylinder gas₹13,00,000
Oxygen produced by one healthy tree per year1,00,375 L