Q. In the context of WHO Air Quality Guidelines, consider the following statements:
1. The 24-hour mean of PM2.5 should not exceed 15 ug/m³ and annual mean of PM2.5 should not exceed 5 µg/m³.
2. In a year, the highest levels of ozone pollution occur during the periods of inclement weather.
3. PM10 can penetrate the lung barrier and enter the bloodstream.
4. Excessive ozone in the air can trigger asthma.
Which of the statements given above are correct?
Exp) Option b is the correct answer.
Statement 1 is correct:The World Health Organization(WHO) has released the Global Air Quality Guidelines(AQGs).The new guidelines recommend air quality levels for six pollutants particulate matter (PM) 2.5 and PM 10, ozone (O3), nitrogen dioxide (NO2), sulfur dioxide (SO2) and carbon monoxide (CO).
Statement 2 is incorrect: Ozone at ground level is formed by the reaction with sunlight (photochemical reaction) of pollutants such as nitrogen oxides (NOx) from vehicle and industry emissions and volatile organic compounds (VOCs) emitted by vehicles, solvents and industry. As a result, the highest levels of ozone pollution occur during periods of sunny weather and not during inclement weather.
Statement 3 is incorrect: PM is a common proxy indicator for air pollution. It affects more people than any other pollutant. The major components of PM are sulfate, nitrates, ammonia, sodium chloride, black carbon, mineral dust and water. It consists of a complex mixture of solid and liquid particles of organic and inorganic substances suspended in the air. While particles with a diameter of 10 microns or less, (≤ PM10) can penetrate and lodge deep inside the lungs, the even more health-damaging particles are those with a diameter of 2.5 microns or less, (≤ PM2.5). PM2.5 can penetrate the lung barrier and enter the blood system. Chronic exposure to particles contributes to the risk of developing cardiovascular and respiratory diseases, as well as of lung cancer.
Statement 4 is correct: Excessive ozone in the air can have a marked effect on human health. It causes breathing problems, trigger asthma, reduce lung function and cause lung diseases. Ozone triggers asthma because it is very irritating to the lungs and airways.
Source:
https://forumias.com/blog/who-says-air-pollution-kills-7-million-a-year-toughens-guidelines/
