- The System of Air Quality and Weather Forecasting And Research (SAFAR) is a national initiative introduced by the Ministry of Earth Sciences (MoES) to measure the air quality of a metropolitan city, by measuring the overall pollution level and the location-specific air quality of the city.
- The SAFAR system was indigenously developed by the Indian Institute of Tropical Meteorology (IITM), Pune, and operationalized by the India Meteorological Department (IMD).
- It has a giant true color LED display that gives out real-time air quality index on a 24×7 basis with color-coding (along with a 72-hour advance forecast).
- The ultimate objective of the project is to increase awareness among the general public regarding the air quality in their city so that appropriate mitigation measures and systematic action can be taken.
- It organizes an awareness drive by educating the public (prompting self-mitigation), and
- It also helps the policy-makers to develop mitigation strategies keeping in mind the nation’s economic development.
- SAFAR is an integral part of India’s first air quality early warning system, which was operational in Delhi.
- It monitors all weather parameters like temperature, rainfall, humidity, wind speed, wind direction, UV radiation, and solar radiation.
- Pollutants monitored: PM2.5, PM10, Ozone, Carbon Monoxide (CO), Nitrogen Oxides (NOx), Sulfur Dioxide (SO2), Benzene, Toluene, Xylene, and Mercury.
- The World Meteorological Organization has recognized SAFAR as a prototype activity on the basis of the high-quality control and standards maintained in its implementation.
- SAFAR system would benefit cost savings to several other sectors like agriculture, aviation, infrastructure, disaster management, tourism, etc. which directly or indirectly get affected by air quality and weather.
Air Quality Index (AQI)
The AQI is an index for reporting daily air quality.
- It focuses on health effects one might experience within a few hours or days after breathing polluted air.
- AQI is calculated for eight major air pollutants:
- Ground-level ozone,
- PM10,
- PM2.5,
- Carbon monoxide,
- Sulfur dioxide,
- Nitrogen dioxide,
- Ammonia,
- Lead,
- Ground-level ozone and airborne particles are the two pollutants that pose the greatest threat to human health in India.
Main Causes of Air Pollution During Winters?
Stubble Burning:
- Farmers in Punjab and Haryana burn crop residues to clear their fields for the next cropping season. This produces a lot of smoke and particulate matter(PM) that gets carried by the wind to Delhi and other parts of north India.
- According to the System of Air Quality and Weather Forecasting And Research (SAFAR), in 2023, stubble burning’s contribution to Delhi pollution was significant.
- Stubble burning emits toxic pollutants in the atmosphere containing harmful gases like Carbon Monoxide (CO), methane (CH4), and volatile organic compounds (VOC).
Vehicle Emissions:
- Vehicular emissions from Delhi’s numerous cars, trucks, buses, and two-wheelers are major sources of air pollution.
- As per a research paper published in the Observer Research Foundation, the transport sector is the main source of PM 2.5 emissions in Delhi (28% of all PM2.5 emissions).
- According to the Delhi Pollution Control Committee (DPCC), traffic hot spots in Delhi have been experiencing dangerous levels of ground-level ozone (O3) pollution, which can have serious health consequences.
Wind Direction:
- Wind direction plays a significant role in Delhi’s air pollution, especially during the winter months. The predominant direction of winds in Delhi is northwesterly post-monsoon. These winds bring dust and smoke to the city when stubble is being burnt in Haryana and Punjab.
- According to a study conducted by the National Physical Laboratory, 72% of Delhi’s wind in winter comes from the northwestern parts of India and Pakistan, while the remaining 28 % comes from the Indo-Gangetic plains.
- A change in wind direction means these pollutants are not carried into the city.
- La Niña can significantly impact wind patterns in Delhi by altering atmospheric circulation dynamics.
Dry and Still Air:
In winter, reduced rainfall and lower wind speeds prevent pollutants from being washed away or dispersed, leading to a decrease in air quality and accumulation of PM in the air.
Temperature Inversion:
- Temperature inversion is a phenomenon that occurs when the air temperature increases with altitude, instead of decreasing as usual. This creates a layer of warm air above a layer of cold air, trapping the pollutants near the ground.
- Temperature inversion affects Delhi’s pollution in winter when the weather is cold and calm. The pollutants accumulate in the lower atmosphere and form a thick layer of smog that prevents pollutants from rising and dispersing, leading to higher pollution levels near the surface.
