3rd April, 2022, Sunday

12 noon to 1pm

• The World Air Quality Report 2021 was released by the WHO on 22^nd March, 2022.
• Air pollution is considered to be the world’s largest threat to health and accounts for 7 million premature deaths every year.
• Air pollution aggravates many diseases ranging from asthma, lung cancer, heart disease.
• According to the report, 40,000 deaths in children under the age of 5 years, are directly linked to PM2.5.
• This report is based only on one parameter, which is PM2.5 and includes data from 6475 cities in 117 countries around the world.
• The annual PM2.5 concentration of 5 µg as defined by the WHO in its latest air quality guidelines, is very difficult to achieve. Countries in South East Asia, South Asia and the Far East suffer from the highest annual PM2.5. Out of the 107 capital cities listed, only 4 meet the WHO guideline of 5 µg for PM2.5.
• PM2.5 is more than 10 times the WHO limit in almost 50% of the cities in India.
• Avoidable sources of air pollution should be completely eliminated e.g., diesel gen sets are used in situation of power breakdown. If there is no power breakdown, gen sets will not be needed. Another example is resuspension of dust. 
• Green belt can be used as a wall against the entry of fine dust, odor and sound. Instead of just increasing the quantity of greenery, green belts should be created at appropriate places keeping in view the meteorological conditions.
• To control roadside dusts, the area should either be paved or should be green.
• The method of measuring air quality needs to be reviewed. Benzene and other VOCs which are now known to be present in urban air are not measured or controlled.
• Research is still needed so that we do not continue with the old parameters.
• According to the new report, New Delhi is the most polluted capital city in the world and Bhiwadi in Rajasthan is the most polluted city. 
• Delhi should instead be called the most “dusty” capital. We are measuring mass in ug, but we don’t know how toxic it is. So, its not correct to label one city as the most polluted. Delhi is in the Indo-Gangetic plain. There is windblown dust and mainly PM10 (60-70%); PM 2.5 increases only in winters because of burning etc.
• Now Gen sets up to 800 kv have to include a system which can collect 70% of PM2.5 emissions, according to a directive of the Commission for Air Quality Management.
• There is 20% reduction in PM2.5 from 2018 vs 2021; PM10 also shows 12%-15% reduction.
• The report does not mention geogenic, climate and geography aspects of pollution.
• Emission data among different cities in the same country or even different places in the same city is not comparable. This is neither realistic or logical.
• We cannot control the geogenic sources of air pollution.
• The validity of low-cost sensors is questionable. Temperature and humidity make a major difference to the low-cost sensors. These sensors have to be calibrated thoroughly for 3-4 seasonal cycles.
• It may give indicative measurement only in case of particulate matter and not any other parameter.
• If it cannot be calibrated, then it should not be used as there is no sanctity of data. It may vary from 50% to 300%.
• Low-cost sensors are just sensors, they are not analysers.
• They can give a qualitative indication of air pollution, but whether the same can be taken for quantitative analysis needs to be questioned.
• Without correction factors, with normalization, without understanding the anthropogenic or geogenic sources, the scientific veracity of this report is questionable.
• The CPCB has come out with directions to not include low-cost sensor data in any national network on AQI or any other national regulatory purpose.
• India has calibration facility in the National Physical Laboratory (NPL), but cost of this may be more than the cost of the sensor.
• Disposal of dust collected during mechanical sweeping of roads is most important. Unless this is done, the dust will resuspend in the ambient air.
• Pollution more than 50% cannot be controlled. The year 2020 was the cleanest year in the last decade. Data showed that PM2.5 was 28-30 and PM10 was more than 40. This data was when all activities had been shut down due to the lockdown.
• Greenery should not be less than 20-30% of the area of the development. There are no guidelines on how much greenery should be developed in new townships. 
• A change in approach to city planning is required.
• We have to be careful about greenery and water sprinkling as ozone levels increase with greenery and bigger particulates are formed with water sprinkling.
• In Delhi, biomass is freely available because of pruning.
• Water sprinkling is not a proven mitigation method. It has to be tested and the quantity also has to be optimized. Its an emergency measure and can be done once in a week/month, but should not be a regular option to control air pollution.
• Natural VOCs contribute to the formation of ozone.
• Its important to distinguish between survival emissions and luxury emissions. 

Participants

Dr Anil Kumar

Mr Vivek Kumar

Mr Paritosh Tyagi

Dr M George

Dr Dipankar Saha

Dr Rajeev Sharma

Mr Neeraj Tyagi

Mr Ankit Sethi

Mr Vikas Singhal

Mr Pradeep Khandelwal

Ms Ira Gupta

Dr S Sharma