Verified Answer :

  • The Air Quality Index (AQI) is categorized into levels that indicate health risks, where the "Good" range is defined as \(0\) to \(50\).
  • Comparing the given options: \(50\) falls within the "Good" range, while the others fall into "Moderate" or "Unhealthy" categories.
  • Conclude that the correct choice representing good air quality is A.
  • Final Answer: \(\boxed{A}\)

Explanation

  1. Understanding the Air Quality Index (AQI) System

The Air Quality Index (AQI) is a standardized tool used by environmental agencies globally to communicate the quality of the air to the public. It converts complex air pollution measurements into a simple, easy-to-understand scale that helps people make informed decisions about their daily activities. The scale is segmented into various color-coded categories, each corresponding to a specific health risk level. These ranges are established based on the concentration of pollutants like ground-level ozone and particulate matter.

  1. AQI Categorical Definitions

The AQI scale is categorized into six levels, ranging from the safest to the most hazardous:

  • Good (0–50): Air quality is considered satisfactory, and air pollution poses little or no risk.
  • Moderate (51–100): Air quality is acceptable; however, there may be a risk for some people who are unusually sensitive to air pollution.
  • Unhealthy for Sensitive Groups (101–150): Members of sensitive groups may experience health effects. The general public is less likely to be affected.
  • Unhealthy (151–200): Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects.
  • Very Unhealthy (201–300): Health alert: The risk of health effects is increased for everyone.
  • Hazardous (301 and higher): Health warning of emergency conditions: everyone is more likely to be affected.
  1. Identifying the Correct Category

We are asked to identify which of the provided options represents "Good" air quality. Based on the defined standard, the "Good" category encompasses values ranging from \(0\) to \(50\).

  • Option A: \(50\) falls within the "Good" range (0–50).
  • Option B: \(100\) falls within the "Moderate" range (51–100).
  • Option C: \(150\) falls within the "Unhealthy for Sensitive Groups" range (101–150).
  • Option D: \(200\) falls within the "Unhealthy" range (151–200).

Thus, \(50\) is the only value provided that represents "Good" air quality.

  1. Final Answer

Based on the standard AQI definitions, the value \(50\) is the upper limit of the "Good" range. Therefore, the correct option is A. \(\boxed{A}\)

Examples

Imagine you are planning a morning jog in your city. Before heading out, you check the local weather and environmental reports, which state that the current Air Quality Index (AQI) is \(35\). Since \(35\) is within the "Good" range (\(0\text{-}50\)), you can safely proceed with your outdoor exercise knowing that the air pollution levels are low and pose minimal risk to your health. Understanding these categories helps you make daily decisions that protect your well-being.

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