Q. Consider the following statements regarding particulate matter:
1. PM2.5 and PM10 are mixture of solid and liquid particles generally having diameters of a single strand of average human hair.
2. The common chemical composition of particulate matter includes nitrates, sulfates, ammonium, and also metals and biological components.
Which of the statements above given is/are correct?
Answer: C
Notes:
PM2.5 and PM10 are mixture of solid and liquid particles generally having diameters of or less than 2.5 and 10 micrometers— smaller than the diameter of a single strand of average human hair, which is about 70 micrometers.
- The 24-hour exposure limit of PM2.5 in India is 60 micrograms per cubic meter air (ug/m3), while that of PM10 is 100 ug/m3.
- At the three highly polluted areas in Delhi between 12PM Thursday and Friday, the levels of PM2.5 and PM10 had reached 500 ug/m3 or close to it.
- These particulates are emitted from various sources and can be inhaled, causing serious health problems.
- Their physical and chemical characteristics vary by location, and common chemical composition includes nitrates, sulfates, ammonium, and also metals and biological components.
