Explained: What Does Air Quality Index Tell Us, Is Bad Air Quality Harmful For COVID Patients?

As the winter approaches, the AQI (Air Quality Index) of Delhi's Anand Vihar has recently surged to 322, reaching the 'hazardous' category for the first time this year along with the pollutants PM 2.5 and PM 10 remaining prominent in the air. Simultaneously, with the retreat of the monsoon season, the air quality of Delhi-NCR has continually been degrading as the AQI rose to 171.

So, what is AQI?

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AQI is a number which is used to communicate to the public how polluted the air currently is or how polluted it is expected to get. As AQI increases, an increasingly large percentage of the population is likely to experience adverse health effects. Most developed countries have their own colour-coded Air Quality Indices corresponding to different national air quality standards.

India's colour-coded index or National Air Quality Index Standard (NAQI) was launched by the Ministry for Environment, Forests & Climate Change in the year 2014. The initiative is a part of the Modi Government＊s mission to introduce the ※culture of cleanliness§, as air pollution has been a huge concern in the country, especially in urban areas. The National Air Monitoring Program (NAMP), which covers 240 cities in the country, has been operated by the Central Pollution Control Board (CPCB) and developed by the Indian Institute of Technology, Kanpur (IIT).

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The index throws up one number which is displayed publicly and people know每based on this number one associated colour code每 what the health of their air is每how good or bad their air quality is.

Earlier, these pollution numbers didn't used to be publicly displayed.

Why do we need it?

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The pollution sources in India 每 and in most asian countries 每 are numerous and incompletely understood.

In Delhi, for example, it comes mostly from light and heavy vehicle traffic emissions, road dust, solid fuel combustion for heating and cooking, biomass, waste burning, thermal power plants, diesel generators, construction and small-scale local industries.

The purpose of the AQI is to help people know how the local air quality impacts their health. And therefore, each country and state has to have their own AQI values.

How is AQI calculated?

Although different countries use different point scales to report air quality, however, the Index everywhere remains chiefly centred around five pollutants 每 Particulate Matter with a diameter less than 10 micrometres (PM10) and 2.5 micrometers (PM2.5), Sulfur dioxide, Ground-level ozone (O3), Nitrogen Dioxide (NO2), and Carbon Monoxide (CO).

A monitoring station is expected to provide the concentration of a particular pollutant for that moment in time, and its average over a period of time 每 for CO and O3, the average is taken over eight hours, while for the other three, it is a 24-hour average. The unit of measurement is microgram (or milligram in the case of CO) per cubic meter.

India has set standards for what it thinks are appropriate warnings for a particular level of pollutant. Here＊s what the code is:

AQI Pollution Chart

The higher the AQI value, the greater the level of air pollution and the greater the health concerns. The concept of AQI has been widely in use for over the last three decades because it quickly disseminates air quality information in real-time.

Every day monitors record concentrations of the major pollutants. These raw measurements are converted into a separate AQI value for each pollutant (ground-level ozone, particle pollution, carbon monoxide, and sulfurdioxide) using standard formulae developed by the Environmental Protection Agency (EPA). The highest of these AQI values are reported as the AQI value for that day.

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In simpler terms, to understand how the AQI works, one just has to know the six range categories (Good, Satisfactory, Moderately Polluted, Poor, Very Poor, and Severe) and check the associated health impacts. Solutions should be taken based on the AQI Category and the pollutant associated with it.

Does poor air quality affect those with Covid-19?

Yes, it does. Experts believe that pollution combined with coronavirus can make it a more hazardous situation. Accordingly, where there is more pollution, the chances of Covid-19 spreading rapidly are higher, reducing the survival rate. Covid-19 and smoke are a dangerous combination, as both affect the respiratory system, making those exposed to the virus more vulnerable.

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Studies have also shown that in areas with poor air quality, people are more likely to die if they contract the virus. And coughing, difficulty breathing and headaches are symptoms that both the virus and wildfire smoke exposure can cause, making it more difficult to know which may be the source.

Can a mask help?

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A little. An N95 respirator mask, worn properly, can filter out some of the particles. But it does little to protect against harmful gases in wildfire smoke, like carbon monoxide. The looser facial coverings some of us wear now to lower our risk of spreading or becoming infected with the coronavirus provides negligible protection against wildfire pollutants.

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