P:Under India’s 2009 NAAQS, the annual time-weighted $PM_{10}$ standard exceeds the $PM_{2.5}$ standard. Q:Under the National AQI released in 2015,the $PM_{10}$ subindex can be less than the $PM_{2.5}$ subindex. Choose the truth values.
The annual limits in the referenced 2009 standards are 60 µg/m³ for PM₁₀ and 40 µg/m³ for PM₂.₅,so P is true. AQI subindices use pollutant-specific concentration breakpoints. Even though PM₂.₅ is part of PM₁₀,its lower breakpoints can produce the higher subindex; Q is also true. Thus **C**.
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